docs: update readme about go version and how to build from source

Reviewed-on: #100

.drone.jsonnet

@@ -0,0 +1,148 @@
+// generate .drone.yaml, run:
+// drone jsonnet --format --stream
+
+
+local CreateRelease() = {
+  name: 'create release',
+  image: 'plugins/gitea-release',
+  settings: {
+    api_key: { from_secret: 'GITEA_API_KEY' },
+    base_url: 'https://git.unlock-music.dev',
+    files: [
+      'um-*.tar.gz',
+      'um-*.zip',
+    ],
+    checksum: 'sha256',
+    draft: true,
+    title: '${DRONE_TAG}',
+  },
+};
+
+
+local StepGoBuild(GOOS, GOARCH) = {
+  local windows = GOOS == 'windows',
+  local archiveExt = if windows then 'zip' else 'tar.gz',
+  local filepath = 'dist/um-%s-%s-%s.%s' % [GOOS, GOARCH, '$(git describe --tags --always)', archiveExt],
+
+  local archive = if windows then [
+    // Ensure zip is installed
+    'command -v zip >/dev/null || (apt update && apt install -y zip)',
+    'zip -9 -j -r "%s" $DIST_DIR' % filepath,
+  ] else [
+    'tar -c -C $DIST_DIR um | gzip -9 > "%s"' % filepath,
+  ],
+
+  name: 'go build %s/%s' % [GOOS, GOARCH],
+  image: 'golang:1.23',
+  environment: {
+    GOOS: GOOS,
+    GOARCH: GOARCH,
+    GOPROXY: 'https://goproxy.io,direct',
+  },
+  commands: [
+    'DIST_DIR=$(mktemp -d)',
+    'go build -v -trimpath -ldflags="-w -s -X main.AppVersion=$(git describe --tags --always)" -o $DIST_DIR ./cmd/um',
+    'mkdir -p dist',
+  ] + archive,
+};
+
+local StepUploadArtifact(GOOS, GOARCH) = {
+  local windows = GOOS == 'windows',
+  local archiveExt = if windows then 'zip' else 'tar.gz',
+  local filename = 'um-%s-%s-%s.%s' % [GOOS, GOARCH, '$(git describe --tags --always)', archiveExt],
+  local filepath = 'dist/%s' % filename,
+  local pkgname = '${DRONE_REPO_NAME}-build',
+
+  name: 'upload artifact',
+  image: 'golang:1.23',  // reuse golang:1.19 for curl
+  environment: {
+    DRONE_GITEA_SERVER: 'https://git.unlock-music.dev',
+    GITEA_API_KEY: { from_secret: 'GITEA_API_KEY' },
+  },
+  commands: [
+    'curl --fail --include --user "um-release-bot:$GITEA_API_KEY" ' +
+    '--upload-file "%s" ' % filepath +
+    '"$DRONE_GITEA_SERVER/api/packages/${DRONE_REPO_NAMESPACE}/generic/%s/${DRONE_BUILD_NUMBER}/%s"' % [pkgname, filename],
+    'sha256sum %s' % filepath,
+    'echo $DRONE_GITEA_SERVER/${DRONE_REPO_NAMESPACE}/-/packages/generic/%s/${DRONE_BUILD_NUMBER}' % pkgname,
+  ],
+};
+
+
+local PipelineBuild(GOOS, GOARCH, RUN_TEST) = {
+  name: 'build %s/%s' % [GOOS, GOARCH],
+  kind: 'pipeline',
+  type: 'docker',
+  steps: [
+           {
+             name: 'fetch tags',
+             image: 'alpine/git',
+             commands: ['git fetch --tags'],
+           },
+         ] +
+         (
+           if RUN_TEST then [{
+             name: 'go test',
+             image: 'golang:1.23',
+             environment: {
+               GOPROXY: 'https://goproxy.io,direct',
+             },
+             commands: ['go test -v ./...'],
+           }] else []
+         )
+         +
+         [
+           StepGoBuild(GOOS, GOARCH),
+           StepUploadArtifact(GOOS, GOARCH),
+         ],
+  trigger: {
+    event: ['push', 'pull_request'],
+  },
+};
+
+local PipelineRelease() = {
+  name: 'release',
+  kind: 'pipeline',
+  type: 'docker',
+  steps: [
+    {
+      name: 'fetch tags',
+      image: 'alpine/git',
+      commands: ['git fetch --tags'],
+    },
+    {
+      name: 'go test',
+      image: 'golang:1.23',
+      environment: {
+        GOPROXY: 'https://goproxy.io,direct',
+      },
+      commands: ['go test -v ./...'],
+    },
+    StepGoBuild('linux', 'amd64'),
+    StepGoBuild('linux', 'arm64'),
+    StepGoBuild('linux', '386'),
+    StepGoBuild('windows', 'amd64'),
+    StepGoBuild('windows', 'arm64'),
+    StepGoBuild('windows', '386'),
+    StepGoBuild('darwin', 'amd64'),
+    StepGoBuild('darwin', 'arm64'),
+    {
+      name: 'prepare root',
+      image: 'golang:1.23',
+      commands: [
+        'mv dist/*.tar.gz dist/*.zip ./',
+      ],
+    },
+    CreateRelease(),
+  ],
+  trigger: {
+    event: ['tag'],
+  },
+};
+
+[
+  PipelineBuild('linux', 'amd64', true),
+  PipelineBuild('windows', 'amd64', false),
+  PipelineBuild('darwin', 'amd64', false),
+  PipelineRelease(),
+]

.drone.yml

@@ -0,0 +1,257 @@
+---
+kind: pipeline
+name: build linux/amd64
+steps:
+- commands:
+  - git fetch --tags
+  image: alpine/git
+  name: fetch tags
+- commands:
+  - go test -v ./...
+  environment:
+    GOPROXY: https://goproxy.io,direct
+  image: golang:1.23
+  name: go test
+- commands:
+  - DIST_DIR=$(mktemp -d)
+  - go build -v -trimpath -ldflags="-w -s -X main.AppVersion=$(git describe --tags
+    --always)" -o $DIST_DIR ./cmd/um
+  - mkdir -p dist
+  - tar -c -C $DIST_DIR um | gzip -9 > "dist/um-linux-amd64-$(git describe --tags
+    --always).tar.gz"
+  environment:
+    GOARCH: amd64
+    GOOS: linux
+    GOPROXY: https://goproxy.io,direct
+  image: golang:1.23
+  name: go build linux/amd64
+- commands:
+  - curl --fail --include --user "um-release-bot:$GITEA_API_KEY" --upload-file "dist/um-linux-amd64-$(git
+    describe --tags --always).tar.gz" "$DRONE_GITEA_SERVER/api/packages/${DRONE_REPO_NAMESPACE}/generic/${DRONE_REPO_NAME}-build/${DRONE_BUILD_NUMBER}/um-linux-amd64-$(git
+    describe --tags --always).tar.gz"
+  - sha256sum dist/um-linux-amd64-$(git describe --tags --always).tar.gz
+  - echo $DRONE_GITEA_SERVER/${DRONE_REPO_NAMESPACE}/-/packages/generic/${DRONE_REPO_NAME}-build/${DRONE_BUILD_NUMBER}
+  environment:
+    DRONE_GITEA_SERVER: https://git.unlock-music.dev
+    GITEA_API_KEY:
+      from_secret: GITEA_API_KEY
+  image: golang:1.23
+  name: upload artifact
+trigger:
+  event:
+  - push
+  - pull_request
+type: docker
+---
+kind: pipeline
+name: build windows/amd64
+steps:
+- commands:
+  - git fetch --tags
+  image: alpine/git
+  name: fetch tags
+- commands:
+  - DIST_DIR=$(mktemp -d)
+  - go build -v -trimpath -ldflags="-w -s -X main.AppVersion=$(git describe --tags
+    --always)" -o $DIST_DIR ./cmd/um
+  - mkdir -p dist
+  - command -v zip >/dev/null || (apt update && apt install -y zip)
+  - zip -9 -j -r "dist/um-windows-amd64-$(git describe --tags --always).zip" $DIST_DIR
+  environment:
+    GOARCH: amd64
+    GOOS: windows
+    GOPROXY: https://goproxy.io,direct
+  image: golang:1.23
+  name: go build windows/amd64
+- commands:
+  - curl --fail --include --user "um-release-bot:$GITEA_API_KEY" --upload-file "dist/um-windows-amd64-$(git
+    describe --tags --always).zip" "$DRONE_GITEA_SERVER/api/packages/${DRONE_REPO_NAMESPACE}/generic/${DRONE_REPO_NAME}-build/${DRONE_BUILD_NUMBER}/um-windows-amd64-$(git
+    describe --tags --always).zip"
+  - sha256sum dist/um-windows-amd64-$(git describe --tags --always).zip
+  - echo $DRONE_GITEA_SERVER/${DRONE_REPO_NAMESPACE}/-/packages/generic/${DRONE_REPO_NAME}-build/${DRONE_BUILD_NUMBER}
+  environment:
+    DRONE_GITEA_SERVER: https://git.unlock-music.dev
+    GITEA_API_KEY:
+      from_secret: GITEA_API_KEY
+  image: golang:1.23
+  name: upload artifact
+trigger:
+  event:
+  - push
+  - pull_request
+type: docker
+---
+kind: pipeline
+name: build darwin/amd64
+steps:
+- commands:
+  - git fetch --tags
+  image: alpine/git
+  name: fetch tags
+- commands:
+  - DIST_DIR=$(mktemp -d)
+  - go build -v -trimpath -ldflags="-w -s -X main.AppVersion=$(git describe --tags
+    --always)" -o $DIST_DIR ./cmd/um
+  - mkdir -p dist
+  - tar -c -C $DIST_DIR um | gzip -9 > "dist/um-darwin-amd64-$(git describe --tags
+    --always).tar.gz"
+  environment:
+    GOARCH: amd64
+    GOOS: darwin
+    GOPROXY: https://goproxy.io,direct
+  image: golang:1.23
+  name: go build darwin/amd64
+- commands:
+  - curl --fail --include --user "um-release-bot:$GITEA_API_KEY" --upload-file "dist/um-darwin-amd64-$(git
+    describe --tags --always).tar.gz" "$DRONE_GITEA_SERVER/api/packages/${DRONE_REPO_NAMESPACE}/generic/${DRONE_REPO_NAME}-build/${DRONE_BUILD_NUMBER}/um-darwin-amd64-$(git
+    describe --tags --always).tar.gz"
+  - sha256sum dist/um-darwin-amd64-$(git describe --tags --always).tar.gz
+  - echo $DRONE_GITEA_SERVER/${DRONE_REPO_NAMESPACE}/-/packages/generic/${DRONE_REPO_NAME}-build/${DRONE_BUILD_NUMBER}
+  environment:
+    DRONE_GITEA_SERVER: https://git.unlock-music.dev
+    GITEA_API_KEY:
+      from_secret: GITEA_API_KEY
+  image: golang:1.23
+  name: upload artifact
+trigger:
+  event:
+  - push
+  - pull_request
+type: docker
+---
+kind: pipeline
+name: release
+steps:
+- commands:
+  - git fetch --tags
+  image: alpine/git
+  name: fetch tags
+- commands:
+  - go test -v ./...
+  environment:
+    GOPROXY: https://goproxy.io,direct
+  image: golang:1.23
+  name: go test
+- commands:
+  - DIST_DIR=$(mktemp -d)
+  - go build -v -trimpath -ldflags="-w -s -X main.AppVersion=$(git describe --tags
+    --always)" -o $DIST_DIR ./cmd/um
+  - mkdir -p dist
+  - tar -c -C $DIST_DIR um | gzip -9 > "dist/um-linux-amd64-$(git describe --tags
+    --always).tar.gz"
+  environment:
+    GOARCH: amd64
+    GOOS: linux
+    GOPROXY: https://goproxy.io,direct
+  image: golang:1.23
+  name: go build linux/amd64
+- commands:
+  - DIST_DIR=$(mktemp -d)
+  - go build -v -trimpath -ldflags="-w -s -X main.AppVersion=$(git describe --tags
+    --always)" -o $DIST_DIR ./cmd/um
+  - mkdir -p dist
+  - tar -c -C $DIST_DIR um | gzip -9 > "dist/um-linux-arm64-$(git describe --tags
+    --always).tar.gz"
+  environment:
+    GOARCH: arm64
+    GOOS: linux
+    GOPROXY: https://goproxy.io,direct
+  image: golang:1.23
+  name: go build linux/arm64
+- commands:
+  - DIST_DIR=$(mktemp -d)
+  - go build -v -trimpath -ldflags="-w -s -X main.AppVersion=$(git describe --tags
+    --always)" -o $DIST_DIR ./cmd/um
+  - mkdir -p dist
+  - tar -c -C $DIST_DIR um | gzip -9 > "dist/um-linux-386-$(git describe --tags --always).tar.gz"
+  environment:
+    GOARCH: "386"
+    GOOS: linux
+    GOPROXY: https://goproxy.io,direct
+  image: golang:1.23
+  name: go build linux/386
+- commands:
+  - DIST_DIR=$(mktemp -d)
+  - go build -v -trimpath -ldflags="-w -s -X main.AppVersion=$(git describe --tags
+    --always)" -o $DIST_DIR ./cmd/um
+  - mkdir -p dist
+  - command -v zip >/dev/null || (apt update && apt install -y zip)
+  - zip -9 -j -r "dist/um-windows-amd64-$(git describe --tags --always).zip" $DIST_DIR
+  environment:
+    GOARCH: amd64
+    GOOS: windows
+    GOPROXY: https://goproxy.io,direct
+  image: golang:1.23
+  name: go build windows/amd64
+- commands:
+  - DIST_DIR=$(mktemp -d)
+  - go build -v -trimpath -ldflags="-w -s -X main.AppVersion=$(git describe --tags
+    --always)" -o $DIST_DIR ./cmd/um
+  - mkdir -p dist
+  - command -v zip >/dev/null || (apt update && apt install -y zip)
+  - zip -9 -j -r "dist/um-windows-arm64-$(git describe --tags --always).zip" $DIST_DIR
+  environment:
+    GOARCH: arm64
+    GOOS: windows
+    GOPROXY: https://goproxy.io,direct
+  image: golang:1.23
+  name: go build windows/arm64
+- commands:
+  - DIST_DIR=$(mktemp -d)
+  - go build -v -trimpath -ldflags="-w -s -X main.AppVersion=$(git describe --tags
+    --always)" -o $DIST_DIR ./cmd/um
+  - mkdir -p dist
+  - command -v zip >/dev/null || (apt update && apt install -y zip)
+  - zip -9 -j -r "dist/um-windows-386-$(git describe --tags --always).zip" $DIST_DIR
+  environment:
+    GOARCH: "386"
+    GOOS: windows
+    GOPROXY: https://goproxy.io,direct
+  image: golang:1.23
+  name: go build windows/386
+- commands:
+  - DIST_DIR=$(mktemp -d)
+  - go build -v -trimpath -ldflags="-w -s -X main.AppVersion=$(git describe --tags
+    --always)" -o $DIST_DIR ./cmd/um
+  - mkdir -p dist
+  - tar -c -C $DIST_DIR um | gzip -9 > "dist/um-darwin-amd64-$(git describe --tags
+    --always).tar.gz"
+  environment:
+    GOARCH: amd64
+    GOOS: darwin
+    GOPROXY: https://goproxy.io,direct
+  image: golang:1.23
+  name: go build darwin/amd64
+- commands:
+  - DIST_DIR=$(mktemp -d)
+  - go build -v -trimpath -ldflags="-w -s -X main.AppVersion=$(git describe --tags
+    --always)" -o $DIST_DIR ./cmd/um
+  - mkdir -p dist
+  - tar -c -C $DIST_DIR um | gzip -9 > "dist/um-darwin-arm64-$(git describe --tags
+    --always).tar.gz"
+  environment:
+    GOARCH: arm64
+    GOOS: darwin
+    GOPROXY: https://goproxy.io,direct
+  image: golang:1.23
+  name: go build darwin/arm64
+- commands:
+  - mv dist/*.tar.gz dist/*.zip ./
+  image: golang:1.23
+  name: prepare root
+- image: plugins/gitea-release
+  name: create release
+  settings:
+    api_key:
+      from_secret: GITEA_API_KEY
+    base_url: https://git.unlock-music.dev
+    checksum: sha256
+    draft: true
+    files:
+    - um-*.tar.gz
+    - um-*.zip
+    title: ${DRONE_TAG}
+trigger:
+  event:
+  - tag
+type: docker

.gitignore

@@ -1 +1,7 @@
 .idea
+
+/dist
+*.exe
+
+/um-*.tar.gz
+/um-*.zip

README.md

@@ -1,25 +1,48 @@
 # Unlock Music Project - CLI Edition
 
-Original: Web Edition https://github.com/ix64/unlock-music
+Original: Web Edition https://git.unlock-music.dev/um/web
 
-- [Release Download](https://github.com/unlock-music/cli/releases/latest)
+- [![Build Status](https://ci.unlock-music.dev/api/badges/um/cli/status.svg)](https://ci.unlock-music.dev/um/cli)
+- [Release Download](https://git.unlock-music.dev/um/cli/releases/latest)
+- [Latest Build](https://git.unlock-music.dev/um/-/packages/generic/cli-build/)
+
+> **WARNING**
+> 在本站 fork 不会起到备份的作用，只会浪费服务器储存空间。如无必要请勿 fork 该仓库。
 
 ## Features
 
-- [x] All Algorithm Supported By `ix64/unlock-music`
-- [ ] Complete Cover Image
-- [ ] Parse Meta Data
-- [ ] Complete Meta Data
+- [x] All Algorithm Supported By `unlock-music/web`
+- [x] Complete Metadata & Cover Image
 
-## Hou to Build
+## Release
 
-- Requirements: **Golang 1.17**
+[Latest release](https://git.unlock-music.dev/um/cli/releases/latest).
 
-1. Clone this repo `git clone https://github.com/unlock-music/cli && cd cli`
-2. Build the executable `go build ./cmd/um`
+## Install from source
+
+- Requirements: **Golang 1.23.3**
+
+1. run `go install unlock-music.dev/cli/cmd/um@master`
+
+### Build from repo source
+
+1. Pull repo source.
+2. Build with `go build ./cmd/um`.
+
+It will produce `um` or `um.exe` (Windows).
 
 ## How to use
 
 - Drag the encrypted file to `um.exe` (Tested on Windows)
 - Run: `./um [-o <output dir>] [-i] <input dir/file>`
 - Use `./um -h` to show help menu
+
+## Update CI pipeline
+
+1. Install [Drone CI binary](https://docs.drone.io/cli/install/)
+2. Edit `.drone.jsonnet`
+3. Update drone CI pipeline:
+
+   ```sh
+   drone jsonnet --format --stream
+   ```

algo/common/common.go

@@ -1,16 +0,0 @@
-package common
-
-type Decoder interface {
-	Validate() error
-	Decode() error
-	GetCoverImage() []byte
-	GetAudioData() []byte
-	GetAudioExt() string
-	GetMeta() Meta
-}
-
-type Meta interface {
-	GetArtists() []string
-	GetTitle() string
-	GetAlbum() string
-}

algo/common/dispatch.go

@@ -1,30 +1,49 @@
 package common
 
 import (
+	"io"
 	"path/filepath"
 	"strings"
+
+	"go.uber.org/zap"
 )
 
-type NewDecoderFunc func([]byte) Decoder
+type DecoderParams struct {
+	Reader    io.ReadSeeker // required
+	Extension string        // required, source extension, eg. ".mp3"
 
-type decoderItem struct {
+	FilePath string // optional, source file path
+
+	Logger *zap.Logger // required
+}
+type NewDecoderFunc func(p *DecoderParams) Decoder
+
+type DecoderFactory struct {
 	noop   bool
-	decoder NewDecoderFunc
+	Suffix string
+	Create NewDecoderFunc
 }
 
-var DecoderRegistry = make(map[string][]decoderItem)
+var DecoderRegistry []DecoderFactory
 
 func RegisterDecoder(ext string, noop bool, dispatchFunc NewDecoderFunc) {
-	DecoderRegistry[ext] = append(DecoderRegistry[ext],
-		decoderItem{noop: noop, decoder: dispatchFunc})
+	DecoderRegistry = append(DecoderRegistry,
+		DecoderFactory{noop: noop, Create: dispatchFunc, Suffix: "." + strings.TrimPrefix(ext, ".")})
+}
+
+func GetDecoder(filename string, skipNoop bool) []DecoderFactory {
+	var result []DecoderFactory
+	// Some extensions contains multiple dots, e.g. ".kgm.flac", hence iterate
+	//   all decoders for each extension.
+	name := strings.ToLower(filepath.Base(filename))
+	for _, dec := range DecoderRegistry {
+		if !strings.HasSuffix(name, dec.Suffix) {
+			continue
 		}
-func GetDecoder(filename string, skipNoop bool) (rs []NewDecoderFunc) {
-	ext := strings.ToLower(strings.TrimLeft(filepath.Ext(filename), "."))
-	for _, dec := range DecoderRegistry[ext] {
 		if skipNoop && dec.noop {
 			continue
 		}
-		rs = append(rs, dec.decoder)
+		result = append(result, dec)
 	}
-	return
+	return result
 }

algo/common/interface.go

@@ -0,0 +1,29 @@
+package common
+
+import (
+	"context"
+	"io"
+)
+
+type StreamDecoder interface {
+	Decrypt(buf []byte, offset int)
+}
+
+type Decoder interface {
+	Validate() error
+	io.Reader
+}
+
+type CoverImageGetter interface {
+	GetCoverImage(ctx context.Context) ([]byte, error)
+}
+
+type AudioMeta interface {
+	GetArtists() []string
+	GetTitle() string
+	GetAlbum() string
+}
+
+type AudioMetaGetter interface {
+	GetAudioMeta(ctx context.Context) (AudioMeta, error)
+}

algo/common/meta.go

@@ -0,0 +1,50 @@
+package common
+
+import (
+	"path"
+	"strings"
+)
+
+type filenameMeta struct {
+	artists []string
+	title   string
+	album   string
+}
+
+func (f *filenameMeta) GetArtists() []string {
+	return f.artists
+}
+
+func (f *filenameMeta) GetTitle() string {
+	return f.title
+}
+
+func (f *filenameMeta) GetAlbum() string {
+	return f.album
+}
+
+func ParseFilenameMeta(filename string) (meta AudioMeta) {
+	partName := strings.TrimSuffix(filename, path.Ext(filename))
+	items := strings.Split(partName, "-")
+	ret := &filenameMeta{}
+
+	switch len(items) {
+	case 0:
+		// no-op
+	case 1:
+		ret.title = strings.TrimSpace(items[0])
+	default:
+		ret.title = strings.TrimSpace(items[len(items)-1])
+
+		for _, v := range items[:len(items)-1] {
+			artists := strings.FieldsFunc(v, func(r rune) bool {
+				return r == ',' || r == '_'
+			})
+			for _, artist := range artists {
+				ret.artists = append(ret.artists, strings.TrimSpace(artist))
+			}
+		}
+	}
+
+	return ret
+}

algo/common/meta_test.go

@@ -0,0 +1,38 @@
+package common
+
+import (
+	"reflect"
+	"testing"
+)
+
+func TestParseFilenameMeta(t *testing.T) {
+
+	tests := []struct {
+		name     string
+		wantMeta AudioMeta
+	}{
+		{
+			name:     "test1",
+			wantMeta: &filenameMeta{title: "test1"},
+		},
+		{
+			name:     "周杰伦 - 晴天.flac",
+			wantMeta: &filenameMeta{artists: []string{"周杰伦"}, title: "晴天"},
+		},
+		{
+			name:     "Alan Walker _ Iselin Solheim - Sing Me to Sleep.flac",
+			wantMeta: &filenameMeta{artists: []string{"Alan Walker", "Iselin Solheim"}, title: "Sing Me to Sleep"},
+		},
+		{
+			name:     "Christopher,Madcon - Limousine.flac",
+			wantMeta: &filenameMeta{artists: []string{"Christopher", "Madcon"}, title: "Limousine"},
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if gotMeta := ParseFilenameMeta(tt.name); !reflect.DeepEqual(gotMeta, tt.wantMeta) {
+				t.Errorf("ParseFilenameMeta() = %v, want %v", gotMeta, tt.wantMeta)
+			}
+		})
+	}
+}

algo/common/raw.go

@@ -2,46 +2,41 @@ package common
 
 import (
 	"errors"
-	"strings"
+	"fmt"
+	"io"
+
+	"unlock-music.dev/cli/internal/sniff"
 )
 
 type RawDecoder struct {
-	file     []byte
+	rd io.ReadSeeker
+
 	audioExt string
 }
 
-func NewRawDecoder(file []byte) Decoder {
-	return &RawDecoder{file: file}
+func NewRawDecoder(p *DecoderParams) Decoder {
+	return &RawDecoder{rd: p.Reader}
 }
 
 func (d *RawDecoder) Validate() error {
-	for ext, sniffer := range snifferRegistry {
-		if sniffer(d.file) {
-			d.audioExt = strings.ToLower(ext)
-			return nil
+	header := make([]byte, 16)
+	if _, err := io.ReadFull(d.rd, header); err != nil {
+		return fmt.Errorf("read file header failed: %v", err)
 	}
-	}
-	return errors.New("audio doesn't recognized")
+	if _, err := d.rd.Seek(0, io.SeekStart); err != nil {
+		return fmt.Errorf("seek file failed: %v", err)
 	}
 
-func (d RawDecoder) Decode() error {
+	var ok bool
+	d.audioExt, ok = sniff.AudioExtension(header)
+	if !ok {
+		return errors.New("raw: sniff audio type failed")
+	}
 	return nil
 }
 
-func (d RawDecoder) GetCoverImage() []byte {
-	return nil
-}
-
-func (d RawDecoder) GetAudioData() []byte {
-	return d.file
-}
-
-func (d RawDecoder) GetAudioExt() string {
-	return d.audioExt
-}
-
-func (d RawDecoder) GetMeta() Meta {
-	return nil
+func (d *RawDecoder) Read(p []byte) (n int, err error) {
+	return d.rd.Read(p)
 }
 
 func init() {

algo/common/sniff.go

@@ -1,55 +0,0 @@
-package common
-
-import "bytes"
-
-type Sniffer func(header []byte) bool
-
-var snifferRegistry = map[string]Sniffer{
-	".mp3":  SnifferMP3,
-	".flac": SnifferFLAC,
-	".ogg":  SnifferOGG,
-	".m4a":  SnifferM4A,
-	".wav":  SnifferWAV,
-	".wma":  SnifferWMA,
-	".aac":  SnifferAAC,
-	".dff":  SnifferDFF,
-}
-
-func SniffAll(header []byte) (string, bool) {
-	for ext, sniffer := range snifferRegistry {
-		if sniffer(header) {
-			return ext, true
-		}
-	}
-	return "", false
-}
-
-func SnifferM4A(header []byte) bool {
-	return len(header) >= 8 && bytes.Equal([]byte("ftyp"), header[4:8])
-}
-
-func SnifferOGG(header []byte) bool {
-	return bytes.HasPrefix(header, []byte("OggS"))
-}
-
-func SnifferFLAC(header []byte) bool {
-	return bytes.HasPrefix(header, []byte("fLaC"))
-}
-func SnifferMP3(header []byte) bool {
-	return bytes.HasPrefix(header, []byte("ID3"))
-}
-func SnifferWAV(header []byte) bool {
-	return bytes.HasPrefix(header, []byte("RIFF"))
-}
-func SnifferWMA(header []byte) bool {
-	return bytes.HasPrefix(header, []byte("\x30\x26\xb2\x75\x8e\x66\xcf\x11\xa6\xd9\x00\xaa\x00\x62\xce\x6c"))
-}
-func SnifferAAC(header []byte) bool {
-	return bytes.HasPrefix(header, []byte{0xFF, 0xF1})
-}
-
-// SnifferDFF sniff a DSDIFF format
-// reference to: https://www.sonicstudio.com/pdf/dsd/DSDIFF_1.5_Spec.pdf
-func SnifferDFF(header []byte) bool {
-	return bytes.HasPrefix(header, []byte("FRM8"))
-}

algo/kgm/kgm.go

@@ -1,94 +1,67 @@
 package kgm
 
 import (
-	"bytes"
-	"encoding/binary"
-	"errors"
-	"github.com/unlock-music/cli/algo/common"
-	"github.com/unlock-music/cli/internal/logging"
-)
+	"fmt"
+	"io"
 
-var (
-	vprHeader = []byte{
-		0x05, 0x28, 0xBC, 0x96, 0xE9, 0xE4, 0x5A, 0x43,
-		0x91, 0xAA, 0xBD, 0xD0, 0x7A, 0xF5, 0x36, 0x31}
-	kgmHeader = []byte{
-		0x7C, 0xD5, 0x32, 0xEB, 0x86, 0x02, 0x7F, 0x4B,
-		0xA8, 0xAF, 0xA6, 0x8E, 0x0F, 0xFF, 0x99, 0x14}
-	ErrKgmMagicHeader = errors.New("kgm/vpr magic header not matched")
+	"unlock-music.dev/cli/algo/common"
 )
 
 type Decoder struct {
-	file  []byte
-	key   []byte
-	isVpr bool
-	audio []byte
+	rd io.ReadSeeker
+
+	cipher common.StreamDecoder
+	offset int
+
+	header header
 }
 
-func NewDecoder(file []byte) common.Decoder {
-	return &Decoder{
-		file: file,
-	}
+func NewDecoder(p *common.DecoderParams) common.Decoder {
+	return &Decoder{rd: p.Reader}
+}
+
+// Validate checks if the file is a valid Kugou (.kgm, .vpr, .kgma) file.
+// rd will be seeked to the beginning of the encrypted audio.
+func (d *Decoder) Validate() (err error) {
+	if err := d.header.FromFile(d.rd); err != nil {
+		return err
+	}
+	// TODO; validate crypto version
+
+	switch d.header.CryptoVersion {
+	case 3:
+		d.cipher, err = newKgmCryptoV3(&d.header)
+		if err != nil {
+			return fmt.Errorf("kgm init crypto v3: %w", err)
+		}
+	default:
+		return fmt.Errorf("kgm: unsupported crypto version %d", d.header.CryptoVersion)
+	}
+
+	// prepare for read
+	if _, err := d.rd.Seek(int64(d.header.AudioOffset), io.SeekStart); err != nil {
+		return fmt.Errorf("kgm seek to audio: %w", err)
 	}
 
-func (d Decoder) GetCoverImage() []byte {
 	return nil
 }
 
-func (d Decoder) GetAudioData() []byte {
-	return d.audio
+func (d *Decoder) Read(buf []byte) (int, error) {
+	n, err := d.rd.Read(buf)
+	if n > 0 {
+		d.cipher.Decrypt(buf[:n], d.offset)
+		d.offset += n
+	}
+	return n, err
 }
 
-func (d Decoder) GetAudioExt() string {
-	return "" // use sniffer
-}
-
-func (d Decoder) GetMeta() common.Meta {
-	return nil
-}
-
-func (d *Decoder) Validate() error {
-	if bytes.Equal(kgmHeader, d.file[:len(kgmHeader)]) {
-		d.isVpr = false
-	} else if bytes.Equal(vprHeader, d.file[:len(vprHeader)]) {
-		d.isVpr = true
-	} else {
-		return ErrKgmMagicHeader
-	}
-
-	d.key = d.file[0x1c:0x2c]
-	d.key = append(d.key, 0x00)
-	_ = d.file[0x2c:0x3c] //todo: key2
-	return nil
-}
-
-func (d *Decoder) Decode() error {
-	headerLen := binary.LittleEndian.Uint32(d.file[0x10:0x14])
-	dataEncrypted := d.file[headerLen:]
-	lenData := len(dataEncrypted)
-	initMask()
-	if fullMaskLen < lenData {
-		logging.Log().Warn("The file is too large and the processed audio is incomplete, " +
-			"please report to us about this file at https://github.com/unlock-music/cli/issues")
-		lenData = fullMaskLen
-	}
-	d.audio = make([]byte, lenData)
-
-	for i := 0; i < lenData; i++ {
-		med8 := dataEncrypted[i] ^ d.key[i%17] ^ maskV2PreDef[i%(16*17)] ^ maskV2[i>>4]
-		d.audio[i] = med8 ^ (med8&0xf)<<4
-	}
-	if d.isVpr {
-		for i := 0; i < lenData; i++ {
-			d.audio[i] ^= maskDiffVpr[i%17]
-		}
-	}
-	return nil
-}
 func init() {
 	// Kugou
 	common.RegisterDecoder("kgm", false, NewDecoder)
 	common.RegisterDecoder("kgma", false, NewDecoder)
 	// Viper
 	common.RegisterDecoder("vpr", false, NewDecoder)
+	// Kugou Android
+	common.RegisterDecoder("kgm.flac", false, NewDecoder)
+	common.RegisterDecoder("vpr.flac", false, NewDecoder)
 }

algo/kgm/kgm_header.go

@@ -0,0 +1,64 @@
+package kgm
+
+import (
+	"bytes"
+	"encoding/binary"
+	"errors"
+	"fmt"
+	"io"
+)
+
+var (
+	vprHeader = []byte{
+		0x05, 0x28, 0xBC, 0x96, 0xE9, 0xE4, 0x5A, 0x43,
+		0x91, 0xAA, 0xBD, 0xD0, 0x7A, 0xF5, 0x36, 0x31,
+	}
+	kgmHeader = []byte{
+		0x7C, 0xD5, 0x32, 0xEB, 0x86, 0x02, 0x7F, 0x4B,
+		0xA8, 0xAF, 0xA6, 0x8E, 0x0F, 0xFF, 0x99, 0x14,
+	}
+
+	ErrKgmMagicHeader = errors.New("kgm magic header not matched")
+)
+
+// header is the header of a KGM file.
+type header struct {
+	MagicHeader    []byte // 0x00-0x0f: magic header
+	AudioOffset    uint32 // 0x10-0x13: offset of audio data
+	CryptoVersion  uint32 // 0x14-0x17: crypto version
+	CryptoSlot     uint32 // 0x18-0x1b: crypto key slot
+	CryptoTestData []byte // 0x1c-0x2b: crypto test data
+	CryptoKey      []byte // 0x2c-0x3b: crypto key
+}
+
+func (h *header) FromFile(rd io.ReadSeeker) error {
+	if _, err := rd.Seek(0, io.SeekStart); err != nil {
+		return fmt.Errorf("kgm seek start: %w", err)
+	}
+
+	buf := make([]byte, 0x3c)
+	if _, err := io.ReadFull(rd, buf); err != nil {
+		return fmt.Errorf("kgm read header: %w", err)
+	}
+
+	return h.FromBytes(buf)
+}
+
+func (h *header) FromBytes(buf []byte) error {
+	if len(buf) < 0x3c {
+		return errors.New("invalid kgm header length")
+	}
+
+	h.MagicHeader = buf[:0x10]
+	if !bytes.Equal(kgmHeader, h.MagicHeader) && !bytes.Equal(vprHeader, h.MagicHeader) {
+		return ErrKgmMagicHeader
+	}
+
+	h.AudioOffset = binary.LittleEndian.Uint32(buf[0x10:0x14])
+	h.CryptoVersion = binary.LittleEndian.Uint32(buf[0x14:0x18])
+	h.CryptoSlot = binary.LittleEndian.Uint32(buf[0x18:0x1c])
+	h.CryptoTestData = buf[0x1c:0x2c]
+	h.CryptoKey = buf[0x2c:0x3c]
+
+	return nil
+}

algo/kgm/kgm_v3.go

@@ -0,0 +1,55 @@
+package kgm
+
+import (
+	"crypto/md5"
+	"fmt"
+
+	"unlock-music.dev/cli/algo/common"
+)
+
+// kgmCryptoV3 is kgm file crypto v3
+type kgmCryptoV3 struct {
+	slotBox []byte
+	fileBox []byte
+}
+
+var kgmV3Slot2Key = map[uint32][]byte{
+	1: {0x6C, 0x2C, 0x2F, 0x27},
+}
+
+func newKgmCryptoV3(header *header) (common.StreamDecoder, error) {
+	c := &kgmCryptoV3{}
+
+	slotKey, ok := kgmV3Slot2Key[header.CryptoSlot]
+	if !ok {
+		return nil, fmt.Errorf("kgm3: unknown crypto slot %d", header.CryptoSlot)
+	}
+	c.slotBox = kugouMD5(slotKey)
+
+	c.fileBox = append(kugouMD5(header.CryptoKey), 0x6b)
+
+	return c, nil
+}
+
+func (d *kgmCryptoV3) Decrypt(b []byte, offset int) {
+	for i := 0; i < len(b); i++ {
+		b[i] ^= d.fileBox[(offset+i)%len(d.fileBox)]
+		b[i] ^= b[i] << 4
+		b[i] ^= d.slotBox[(offset+i)%len(d.slotBox)]
+		b[i] ^= xorCollapseUint32(uint32(offset + i))
+	}
+}
+
+func xorCollapseUint32(i uint32) byte {
+	return byte(i) ^ byte(i>>8) ^ byte(i>>16) ^ byte(i>>24)
+}
+
+func kugouMD5(b []byte) []byte {
+	digest := md5.Sum(b)
+	ret := make([]byte, 16)
+	for i := 0; i < md5.Size; i += 2 {
+		ret[i] = digest[14-i]
+		ret[i+1] = digest[14-i+1]
+	}
+	return ret
+}

algo/kgm/mask.go

@@ -1,59 +0,0 @@
-package kgm
-
-import (
-	"bytes"
-	_ "embed"
-	"github.com/ulikunitz/xz"
-	"github.com/unlock-music/cli/internal/logging"
-	"go.uber.org/zap"
-	"io"
-)
-
-var maskDiffVpr = []byte{
-	0x25, 0xDF, 0xE8, 0xA6, 0x75, 0x1E, 0x75, 0x0E,
-	0x2F, 0x80, 0xF3, 0x2D, 0xB8, 0xB6, 0xE3, 0x11,
-	0x00}
-
-var maskV2PreDef = []byte{
-	0xB8, 0xD5, 0x3D, 0xB2, 0xE9, 0xAF, 0x78, 0x8C, 0x83, 0x33, 0x71, 0x51, 0x76, 0xA0, 0xCD, 0x37,
-	0x2F, 0x3E, 0x35, 0x8D, 0xA9, 0xBE, 0x98, 0xB7, 0xE7, 0x8C, 0x22, 0xCE, 0x5A, 0x61, 0xDF, 0x68,
-	0x69, 0x89, 0xFE, 0xA5, 0xB6, 0xDE, 0xA9, 0x77, 0xFC, 0xC8, 0xBD, 0xBD, 0xE5, 0x6D, 0x3E, 0x5A,
-	0x36, 0xEF, 0x69, 0x4E, 0xBE, 0xE1, 0xE9, 0x66, 0x1C, 0xF3, 0xD9, 0x02, 0xB6, 0xF2, 0x12, 0x9B,
-	0x44, 0xD0, 0x6F, 0xB9, 0x35, 0x89, 0xB6, 0x46, 0x6D, 0x73, 0x82, 0x06, 0x69, 0xC1, 0xED, 0xD7,
-	0x85, 0xC2, 0x30, 0xDF, 0xA2, 0x62, 0xBE, 0x79, 0x2D, 0x62, 0x62, 0x3D, 0x0D, 0x7E, 0xBE, 0x48,
-	0x89, 0x23, 0x02, 0xA0, 0xE4, 0xD5, 0x75, 0x51, 0x32, 0x02, 0x53, 0xFD, 0x16, 0x3A, 0x21, 0x3B,
-	0x16, 0x0F, 0xC3, 0xB2, 0xBB, 0xB3, 0xE2, 0xBA, 0x3A, 0x3D, 0x13, 0xEC, 0xF6, 0x01, 0x45, 0x84,
-	0xA5, 0x70, 0x0F, 0x93, 0x49, 0x0C, 0x64, 0xCD, 0x31, 0xD5, 0xCC, 0x4C, 0x07, 0x01, 0x9E, 0x00,
-	0x1A, 0x23, 0x90, 0xBF, 0x88, 0x1E, 0x3B, 0xAB, 0xA6, 0x3E, 0xC4, 0x73, 0x47, 0x10, 0x7E, 0x3B,
-	0x5E, 0xBC, 0xE3, 0x00, 0x84, 0xFF, 0x09, 0xD4, 0xE0, 0x89, 0x0F, 0x5B, 0x58, 0x70, 0x4F, 0xFB,
-	0x65, 0xD8, 0x5C, 0x53, 0x1B, 0xD3, 0xC8, 0xC6, 0xBF, 0xEF, 0x98, 0xB0, 0x50, 0x4F, 0x0F, 0xEA,
-	0xE5, 0x83, 0x58, 0x8C, 0x28, 0x2C, 0x84, 0x67, 0xCD, 0xD0, 0x9E, 0x47, 0xDB, 0x27, 0x50, 0xCA,
-	0xF4, 0x63, 0x63, 0xE8, 0x97, 0x7F, 0x1B, 0x4B, 0x0C, 0xC2, 0xC1, 0x21, 0x4C, 0xCC, 0x58, 0xF5,
-	0x94, 0x52, 0xA3, 0xF3, 0xD3, 0xE0, 0x68, 0xF4, 0x00, 0x23, 0xF3, 0x5E, 0x0A, 0x7B, 0x93, 0xDD,
-	0xAB, 0x12, 0xB2, 0x13, 0xE8, 0x84, 0xD7, 0xA7, 0x9F, 0x0F, 0x32, 0x4C, 0x55, 0x1D, 0x04, 0x36,
-	0x52, 0xDC, 0x03, 0xF3, 0xF9, 0x4E, 0x42, 0xE9, 0x3D, 0x61, 0xEF, 0x7C, 0xB6, 0xB3, 0x93, 0x50,
-}
-
-//go:embed kgm.v2.mask
-var maskV2Xz []byte
-
-var maskV2 []byte
-var fullMaskLen int
-var initMaskOK = false
-
-//todo: decompress mask on demand
-func initMask() {
-	if initMaskOK {
-		return
-	}
-	maskReader, err := xz.NewReader(bytes.NewReader(maskV2Xz))
-	if err != nil {
-		logging.Log().Fatal("load kgm mask failed", zap.Error(err))
-	}
-	maskV2, err = io.ReadAll(maskReader)
-	if err != nil {
-		logging.Log().Fatal("load kgm mask failed", zap.Error(err))
-	}
-	fullMaskLen = len(maskV2) * 16
-	initMaskOK = true
-}

algo/kwm/kwm.go

@@ -2,109 +2,80 @@ package kwm
 
 import (
 	"bytes"
-	"encoding/binary"
 	"errors"
-	"github.com/unlock-music/cli/algo/common"
+	"fmt"
+	"io"
 	"strconv"
 	"strings"
 	"unicode"
+
+	"unlock-music.dev/cli/algo/common"
 )
 
-var (
-	magicHeader = []byte{
-		0x79, 0x65, 0x65, 0x6C, 0x69, 0x6F, 0x6E, 0x2D,
-		0x6B, 0x75, 0x77, 0x6F, 0x2D, 0x74, 0x6D, 0x65}
-	ErrKwFileSize    = errors.New("kwm invalid file size")
-	ErrKwMagicHeader = errors.New("kwm magic header not matched")
-)
-
+const magicHeader1 = "yeelion-kuwo-tme"
+const magicHeader2 = "yeelion-kuwo\x00\x00\x00\x00"
 const keyPreDefined = "MoOtOiTvINGwd2E6n0E1i7L5t2IoOoNk"
 
 type Decoder struct {
-	file []byte
+	rd io.ReadSeeker
+
+	cipher common.StreamDecoder
+	offset int
 
-	key       []byte
 	outputExt string
 	bitrate   int
-	mask      []byte
-
-	audio []byte
-}
-
-func (d *Decoder) GetCoverImage() []byte {
-	return nil
-}
-
-func (d *Decoder) GetAudioData() []byte {
-	return d.audio
 }
 
 func (d *Decoder) GetAudioExt() string {
 	return "." + d.outputExt
 }
 
-func (d *Decoder) GetMeta() common.Meta {
-	return nil
-}
-
-func NewDecoder(data []byte) common.Decoder {
-	//todo: Notice the input data will be changed for now
-	return &Decoder{file: data}
+func NewDecoder(p *common.DecoderParams) common.Decoder {
+	return &Decoder{rd: p.Reader}
 }
 
+// Validate checks if the file is a valid Kuwo .kw file.
+// rd will be seeked to the beginning of the encrypted audio.
 func (d *Decoder) Validate() error {
-	lenData := len(d.file)
-	if lenData < 1024 {
-		return ErrKwFileSize
-	}
-	if !bytes.Equal(magicHeader, d.file[:16]) {
-		return ErrKwMagicHeader
-	}
-
-	return nil
-}
-
-func generateMask(key []byte) []byte {
-	keyInt := binary.LittleEndian.Uint64(key)
-	keyStr := strconv.FormatUint(keyInt, 10)
-	keyStrTrim := padOrTruncate(keyStr, 32)
-	mask := make([]byte, 32)
-	for i := 0; i < 32; i++ {
-		mask[i] = keyPreDefined[i] ^ keyStrTrim[i]
-	}
-	return mask
-}
-
-func (d *Decoder) parseBitrateAndType() {
-	bitType := string(bytes.TrimRight(d.file[0x30:0x38], string(byte(0))))
-	charPos := 0
-	for charPos = range bitType {
-		if !unicode.IsNumber(rune(bitType[charPos])) {
-			break
-		}
-	}
-	var err error
-	d.bitrate, err = strconv.Atoi(bitType[:charPos])
+	header := make([]byte, 0x400) // kwm header is fixed to 1024 bytes
+	_, err := io.ReadFull(d.rd, header)
 	if err != nil {
-		d.bitrate = 0
-	}
-	d.outputExt = strings.ToLower(bitType[charPos:])
-
+		return fmt.Errorf("kwm read header: %w", err)
 	}
 
-func (d *Decoder) Decode() error {
-	d.parseBitrateAndType()
-
-	d.mask = generateMask(d.file[0x18:0x20])
-
-	d.audio = d.file[1024:]
-	dataLen := len(d.audio)
-	for i := 0; i < dataLen; i++ {
-		d.audio[i] ^= d.mask[i&0x1F] //equals: [i % 32]
+	// check magic header, 0x00 - 0x0F
+	magicHeader := header[:0x10]
+	if !bytes.Equal([]byte(magicHeader1), magicHeader) &&
+		!bytes.Equal([]byte(magicHeader2), magicHeader) {
+		return errors.New("kwm magic header not matched")
 	}
+
+	d.cipher = newKwmCipher(header[0x18:0x20])                      // Crypto Key, 0x18 - 0x1F
+	d.bitrate, d.outputExt = parseBitrateAndType(header[0x30:0x38]) // Bitrate & File Extension, 0x30 - 0x38
+
 	return nil
 }
 
+func parseBitrateAndType(header []byte) (int, string) {
+	tmp := strings.TrimRight(string(header), "\x00")
+	sep := strings.IndexFunc(tmp, func(r rune) bool {
+		return !unicode.IsDigit(r)
+	})
+
+	bitrate, _ := strconv.Atoi(tmp[:sep]) // just ignore the error
+	outputExt := strings.ToLower(tmp[sep:])
+	return bitrate, outputExt
+}
+
+func (d *Decoder) Read(b []byte) (int, error) {
+	n, err := d.rd.Read(b)
+	if n > 0 {
+		d.cipher.Decrypt(b[:n], d.offset)
+		d.offset += n
+	}
+	return n, err
+}
+
 func padOrTruncate(raw string, length int) string {
 	lenRaw := len(raw)
 	out := raw

algo/kwm/kwm_cipher.go

@@ -0,0 +1,31 @@
+package kwm
+
+import (
+	"encoding/binary"
+	"strconv"
+)
+
+type kwmCipher struct {
+	mask []byte
+}
+
+func newKwmCipher(key []byte) *kwmCipher {
+	return &kwmCipher{mask: generateMask(key)}
+}
+
+func generateMask(key []byte) []byte {
+	keyInt := binary.LittleEndian.Uint64(key)
+	keyStr := strconv.FormatUint(keyInt, 10)
+	keyStrTrim := padOrTruncate(keyStr, 32)
+	mask := make([]byte, 32)
+	for i := 0; i < 32; i++ {
+		mask[i] = keyPreDefined[i] ^ keyStrTrim[i]
+	}
+	return mask
+}
+
+func (c kwmCipher) Decrypt(buf []byte, offset int) {
+	for i := range buf {
+		buf[i] ^= c.mask[(offset+i)&0x1F] // equivalent: [i % 32]
+	}
+}

algo/ncm/meta.go

@@ -1,25 +1,31 @@
 package ncm
 
 import (
-	"github.com/unlock-music/cli/algo/common"
+	"go.uber.org/zap"
 	"strings"
+
+	"unlock-music.dev/cli/algo/common"
 )
 
-type RawMeta interface {
-	common.Meta
+type ncmMeta interface {
+	common.AudioMeta
+
+	// GetFormat return the audio format, e.g. mp3, flac
 	GetFormat() string
+
+	// GetAlbumImageURL return the album image url
 	GetAlbumImageURL() string
 }
-type RawMetaMusic struct {
+
+type ncmMetaMusic struct {
+	logger *zap.Logger
+
 	Format        string        `json:"format"`
-	MusicID       int             `json:"musicId"`
 	MusicName     string        `json:"musicName"`
-	Artist        [][]interface{} `json:"artist"`
+	Artist        interface{}   `json:"artist"`
 	Album         string        `json:"album"`
-	AlbumID       int             `json:"albumId"`
 	AlbumPicDocID interface{}   `json:"albumPicDocId"`
 	AlbumPic      string        `json:"albumPic"`
-	MvID          int             `json:"mvId"`
 	Flag          int           `json:"flag"`
 	Bitrate       int           `json:"bitrate"`
 	Duration      int           `json:"duration"`
@@ -27,37 +33,53 @@ type RawMetaMusic struct {
 	TransNames    []interface{} `json:"transNames"`
 }
 
-func (m RawMetaMusic) GetAlbumImageURL() string {
+func newNcmMetaMusic(logger *zap.Logger) *ncmMetaMusic {
+	ncm := new(ncmMetaMusic)
+	ncm.logger = logger.With(zap.String("module", "ncmMetaMusic"))
+	return ncm
+}
+
+func (m *ncmMetaMusic) GetAlbumImageURL() string {
 	return m.AlbumPic
 }
-func (m RawMetaMusic) GetArtists() (artists []string) {
-	for _, artist := range m.Artist {
-		for _, item := range artist {
-			name, ok := item.(string)
-			if ok {
+
+func (m *ncmMetaMusic) GetArtists() []string {
+	m.logger.Debug("ncm artists", zap.Any("artists", m.Artist))
+
+	var artists []string = nil
+	if jsonArtists, ok := m.Artist.([][]string); ok {
+		for _, artist := range jsonArtists {
+			for _, name := range artist {
 				artists = append(artists, name)
 			}
 		}
+	} else if artist, ok := m.Artist.(string); ok {
+		// #78: artist is a string type.
+		// https://git.unlock-music.dev/um/cli/issues/78
+		artists = []string{artist}
+	} else {
+		m.logger.Warn("unexpected artist type", zap.Any("artists", m.Artist))
 	}
-	return
+	return artists
 }
 
-func (m RawMetaMusic) GetTitle() string {
+func (m *ncmMetaMusic) GetTitle() string {
 	return m.MusicName
 }
 
-func (m RawMetaMusic) GetAlbum() string {
+func (m *ncmMetaMusic) GetAlbum() string {
 	return m.Album
 }
-func (m RawMetaMusic) GetFormat() string {
+
+func (m *ncmMetaMusic) GetFormat() string {
 	return m.Format
 }
 
 //goland:noinspection SpellCheckingInspection
-type RawMetaDJ struct {
+type ncmMetaDJ struct {
 	ProgramID          int          `json:"programId"`
 	ProgramName        string       `json:"programName"`
-	MainMusic          RawMetaMusic `json:"mainMusic"`
+	MainMusic          ncmMetaMusic `json:"mainMusic"`
 	DjID               int          `json:"djId"`
 	DjName             string       `json:"djName"`
 	DjAvatarURL        string       `json:"djAvatarUrl"`
@@ -79,32 +101,32 @@ type RawMetaDJ struct {
 	RadioPurchaseCount int          `json:"radioPurchaseCount"`
 }
 
-func (m RawMetaDJ) GetArtists() []string {
+func (m *ncmMetaDJ) GetArtists() []string {
 	if m.DjName != "" {
 		return []string{m.DjName}
 	}
 	return m.MainMusic.GetArtists()
 }
 
-func (m RawMetaDJ) GetTitle() string {
+func (m *ncmMetaDJ) GetTitle() string {
 	if m.ProgramName != "" {
 		return m.ProgramName
 	}
 	return m.MainMusic.GetTitle()
 }
 
-func (m RawMetaDJ) GetAlbum() string {
+func (m *ncmMetaDJ) GetAlbum() string {
 	if m.Brand != "" {
 		return m.Brand
 	}
 	return m.MainMusic.GetAlbum()
 }
 
-func (m RawMetaDJ) GetFormat() string {
+func (m *ncmMetaDJ) GetFormat() string {
 	return m.MainMusic.GetFormat()
 }
 
-func (m RawMetaDJ) GetAlbumImageURL() string {
+func (m *ncmMetaDJ) GetAlbumImageURL() string {
 	if strings.HasPrefix(m.MainMusic.GetAlbumImageURL(), "http") {
 		return m.MainMusic.GetAlbumImageURL()
 	}

algo/ncm/ncm.go

@@ -2,203 +2,207 @@ package ncm
 
 import (
 	"bytes"
+	"context"
 	"encoding/base64"
 	"encoding/binary"
 	"encoding/json"
 	"errors"
-	"github.com/unlock-music/cli/algo/common"
-	"github.com/unlock-music/cli/internal/logging"
-	"github.com/unlock-music/cli/internal/utils"
+	"fmt"
 	"go.uber.org/zap"
-	"io/ioutil"
+	"io"
 	"net/http"
 	"strings"
+
+	"unlock-music.dev/cli/algo/common"
+	"unlock-music.dev/cli/internal/utils"
 )
 
+const magicHeader = "CTENFDAM"
+
 var (
-	magicHeader = []byte{
-		0x43, 0x54, 0x45, 0x4E, 0x46, 0x44, 0x41, 0x4D}
 	keyCore = []byte{
 		0x68, 0x7a, 0x48, 0x52, 0x41, 0x6d, 0x73, 0x6f,
-		0x35, 0x6b, 0x49, 0x6e, 0x62, 0x61, 0x78, 0x57}
+		0x35, 0x6b, 0x49, 0x6e, 0x62, 0x61, 0x78, 0x57,
+	}
 	keyMeta = []byte{
 		0x23, 0x31, 0x34, 0x6C, 0x6A, 0x6B, 0x5F, 0x21,
-		0x5C, 0x5D, 0x26, 0x30, 0x55, 0x3C, 0x27, 0x28}
+		0x5C, 0x5D, 0x26, 0x30, 0x55, 0x3C, 0x27, 0x28,
+	}
 )
 
-func NewDecoder(data []byte) common.Decoder {
-	return &Decoder{
-		file:    data,
-		fileLen: uint32(len(data)),
-	}
+func NewDecoder(p *common.DecoderParams) common.Decoder {
+	return &Decoder{rd: p.Reader, logger: p.Logger.With(zap.String("module", "ncm"))}
 }
 
 type Decoder struct {
-	file    []byte
-	fileLen uint32
+	logger *zap.Logger
+	rd     io.ReadSeeker // rd is the original file reader
 
-	key []byte
-	box []byte
+	offset int
+	cipher common.StreamDecoder
 
 	metaRaw  []byte
 	metaType string
-	meta     RawMeta
-
+	meta     ncmMeta
 	cover    []byte
-	audio []byte
-
-	offsetKey   uint32
-	offsetMeta  uint32
-	offsetCover uint32
-	offsetAudio uint32
 }
 
+// Validate checks if the file is a valid Netease .ncm file.
+// rd will be seeked to the beginning of the encrypted audio.
 func (d *Decoder) Validate() error {
-	if !bytes.Equal(magicHeader, d.file[:len(magicHeader)]) {
+	if err := d.validateMagicHeader(); err != nil {
+		return err
+	}
+
+	if _, err := d.rd.Seek(2, io.SeekCurrent); err != nil { // 2 bytes gap
+		return fmt.Errorf("ncm seek file: %w", err)
+	}
+
+	keyData, err := d.readKeyData()
+	if err != nil {
+		return err
+	}
+
+	if err := d.readMetaData(); err != nil {
+		return fmt.Errorf("read meta date failed: %w", err)
+	}
+
+	if _, err := d.rd.Seek(5, io.SeekCurrent); err != nil { // 5 bytes gap
+		return fmt.Errorf("ncm seek gap: %w", err)
+	}
+
+	if err := d.readCoverData(); err != nil {
+		return fmt.Errorf("parse ncm cover file failed: %w", err)
+	}
+
+	if err := d.parseMeta(); err != nil {
+		return fmt.Errorf("parse meta failed: %w (raw json=%s)", err, string(d.metaRaw))
+	}
+
+	d.cipher = newNcmCipher(keyData)
+	return nil
+}
+
+func (d *Decoder) validateMagicHeader() error {
+	header := make([]byte, len(magicHeader)) // 0x00 - 0x07
+	if _, err := d.rd.Read(header); err != nil {
+		return fmt.Errorf("ncm read magic header: %w", err)
+	}
+
+	if !bytes.Equal([]byte(magicHeader), header) {
 		return errors.New("ncm magic header not match")
 	}
-	d.offsetKey = 8 + 2
+
 	return nil
 }
 
-func (d *Decoder) readKeyData() error {
-	if d.offsetKey == 0 || d.offsetKey+4 > d.fileLen {
-		return errors.New("invalid cover file offset")
+func (d *Decoder) readKeyData() ([]byte, error) {
+	bKeyLen := make([]byte, 4) //
+	if _, err := io.ReadFull(d.rd, bKeyLen); err != nil {
+		return nil, fmt.Errorf("ncm read key length: %w", err)
 	}
-	bKeyLen := d.file[d.offsetKey : d.offsetKey+4]
 	iKeyLen := binary.LittleEndian.Uint32(bKeyLen)
-	d.offsetMeta = d.offsetKey + 4 + iKeyLen
 
 	bKeyRaw := make([]byte, iKeyLen)
+	if _, err := io.ReadFull(d.rd, bKeyRaw); err != nil {
+		return nil, fmt.Errorf("ncm read key data: %w", err)
+	}
 	for i := uint32(0); i < iKeyLen; i++ {
-		bKeyRaw[i] = d.file[i+4+d.offsetKey] ^ 0x64
+		bKeyRaw[i] ^= 0x64
 	}
 
-	d.key = utils.PKCS7UnPadding(utils.DecryptAes128Ecb(bKeyRaw, keyCore))[17:]
-	return nil
+	return utils.PKCS7UnPadding(utils.DecryptAES128ECB(bKeyRaw, keyCore))[17:], nil
 }
 
 func (d *Decoder) readMetaData() error {
-	if d.offsetMeta == 0 || d.offsetMeta+4 > d.fileLen {
-		return errors.New("invalid meta file offset")
+	bMetaLen := make([]byte, 4) //
+	if _, err := io.ReadFull(d.rd, bMetaLen); err != nil {
+		return fmt.Errorf("ncm read key length: %w", err)
 	}
-	bMetaLen := d.file[d.offsetMeta : d.offsetMeta+4]
 	iMetaLen := binary.LittleEndian.Uint32(bMetaLen)
-	d.offsetCover = d.offsetMeta + 4 + iMetaLen
+
 	if iMetaLen == 0 {
-		return errors.New("no any meta file found")
+		return nil // no meta data
 	}
 
-	// Why sub 22: Remove "163 key(Don't modify):"
-	bKeyRaw := make([]byte, iMetaLen-22)
-	for i := uint32(0); i < iMetaLen-22; i++ {
-		bKeyRaw[i] = d.file[d.offsetMeta+4+22+i] ^ 0x63
+	bMetaRaw := make([]byte, iMetaLen)
+	if _, err := io.ReadFull(d.rd, bMetaRaw); err != nil {
+		return fmt.Errorf("ncm read meta data: %w", err)
+	}
+	bMetaRaw = bMetaRaw[22:] // skip "163 key(Don't modify):"
+	for i := 0; i < len(bMetaRaw); i++ {
+		bMetaRaw[i] ^= 0x63
 	}
 
-	cipherText, err := base64.StdEncoding.DecodeString(string(bKeyRaw))
+	cipherText, err := base64.StdEncoding.DecodeString(string(bMetaRaw))
 	if err != nil {
 		return errors.New("decode ncm meta failed: " + err.Error())
 	}
-	metaRaw := utils.PKCS7UnPadding(utils.DecryptAes128Ecb(cipherText, keyMeta))
-	sepIdx := bytes.IndexRune(metaRaw, ':')
-	if sepIdx == -1 {
+	metaRaw := utils.PKCS7UnPadding(utils.DecryptAES128ECB(cipherText, keyMeta))
+	sep := bytes.IndexByte(metaRaw, ':')
+	if sep == -1 {
 		return errors.New("invalid ncm meta file")
 	}
 
-	d.metaType = string(metaRaw[:sepIdx])
-	d.metaRaw = metaRaw[sepIdx+1:]
+	d.metaType = string(metaRaw[:sep])
+	d.metaRaw = metaRaw[sep+1:]
+
 	return nil
 }
 
-func (d *Decoder) buildKeyBox() {
-	box := make([]byte, 256)
-	for i := 0; i < 256; i++ {
-		box[i] = byte(i)
+func (d *Decoder) readCoverData() error {
+	bCoverFrameLen := make([]byte, 4)
+	if _, err := io.ReadFull(d.rd, bCoverFrameLen); err != nil {
+		return fmt.Errorf("ncm read cover length: %w", err)
 	}
 
-	keyLen := len(d.key)
-	var j byte
-	for i := 0; i < 256; i++ {
-		j = box[i] + j + d.key[i%keyLen]
-		box[i], box[j] = box[j], box[i]
+	coverFrameStartOffset, err := d.rd.Seek(0, io.SeekCurrent)
+	if err != nil {
+		return fmt.Errorf("ncm fetch cover frame start offset: %w", err)
 	}
+	coverFrameLen := binary.LittleEndian.Uint32(bCoverFrameLen)
 
-	d.box = make([]byte, 256)
-	var _i byte
-	for i := 0; i < 256; i++ {
-		_i = byte(i + 1)
-		si := box[_i]
-		sj := box[_i+si]
-		d.box[i] = box[si+sj]
+	bCoverLen := make([]byte, 4)
+	if _, err := io.ReadFull(d.rd, bCoverLen); err != nil {
+		return fmt.Errorf("ncm read cover length: %w", err)
 	}
+	iCoverLen := binary.LittleEndian.Uint32(bCoverLen)
+
+	coverBuf := make([]byte, iCoverLen)
+	if _, err := io.ReadFull(d.rd, coverBuf); err != nil {
+		return fmt.Errorf("ncm read cover data: %w", err)
+	}
+	d.cover = coverBuf
+
+	offsetAudioData := coverFrameStartOffset + int64(coverFrameLen) + 4
+	_, err = d.rd.Seek(offsetAudioData, io.SeekStart)
+
+	return err
 }
 
 func (d *Decoder) parseMeta() error {
 	switch d.metaType {
 	case "music":
-		d.meta = new(RawMetaMusic)
+		d.meta = newNcmMetaMusic(d.logger)
 		return json.Unmarshal(d.metaRaw, d.meta)
 	case "dj":
-		d.meta = new(RawMetaDJ)
+		d.meta = new(ncmMetaDJ)
 		return json.Unmarshal(d.metaRaw, d.meta)
 	default:
 		return errors.New("unknown ncm meta type: " + d.metaType)
 	}
 }
 
-func (d *Decoder) readCoverData() error {
-	if d.offsetCover == 0 || d.offsetCover+13 > d.fileLen {
-		return errors.New("invalid cover file offset")
+func (d *Decoder) Read(buf []byte) (int, error) {
+	n, err := d.rd.Read(buf)
+	if n > 0 {
+		d.cipher.Decrypt(buf[:n], d.offset)
+		d.offset += n
+	}
+	return n, err
 }
 
-	coverLenStart := d.offsetCover + 5 + 4
-	bCoverLen := d.file[coverLenStart : coverLenStart+4]
-
-	iCoverLen := binary.LittleEndian.Uint32(bCoverLen)
-	d.offsetAudio = coverLenStart + 4 + iCoverLen
-	if iCoverLen == 0 {
-		return errors.New("no any cover file found")
-	}
-	d.cover = d.file[coverLenStart+4 : 4+coverLenStart+iCoverLen]
-	return nil
-}
-
-func (d *Decoder) readAudioData() error {
-	if d.offsetAudio == 0 || d.offsetAudio > d.fileLen {
-		return errors.New("invalid audio offset")
-	}
-	audioRaw := d.file[d.offsetAudio:]
-	audioLen := len(audioRaw)
-	d.audio = make([]byte, audioLen)
-	for i := uint32(0); i < uint32(audioLen); i++ {
-		d.audio[i] = d.box[i&0xff] ^ audioRaw[i]
-	}
-	return nil
-}
-
-func (d *Decoder) Decode() error {
-	if err := d.readKeyData(); err != nil {
-		return err
-	}
-	d.buildKeyBox()
-
-	err := d.readMetaData()
-	if err == nil {
-		err = d.parseMeta()
-	}
-	if err != nil {
-		logging.Log().Warn("parse ncm meta file failed", zap.Error(err))
-	}
-
-	err = d.readCoverData()
-	if err != nil {
-		logging.Log().Warn("parse ncm cover file failed", zap.Error(err))
-	}
-
-	return d.readAudioData()
-}
-
-func (d Decoder) GetAudioExt() string {
+func (d *Decoder) GetAudioExt() string {
 	if d.meta != nil {
 		if format := d.meta.GetFormat(); format != "" {
 			return "." + d.meta.GetFormat()
@@ -207,41 +211,40 @@ func (d Decoder) GetAudioExt() string {
 	return ""
 }
 
-func (d Decoder) GetAudioData() []byte {
-	return d.audio
+func (d *Decoder) GetCoverImage(ctx context.Context) ([]byte, error) {
+	if d.cover != nil {
+		return d.cover, nil
 	}
 
-func (d Decoder) GetCoverImage() []byte {
-	if d.cover != nil {
-		return d.cover
+	if d.meta == nil {
+		return nil, errors.New("ncm meta not found")
 	}
-	{
 	imgURL := d.meta.GetAlbumImageURL()
-		if d.meta != nil && !strings.HasPrefix(imgURL, "http") {
-			return nil
+	if !strings.HasPrefix(imgURL, "http") {
+		return nil, nil // no cover image
 	}
-		resp, err := http.Get(imgURL)
+
+	// fetch cover image
+	req, err := http.NewRequestWithContext(ctx, http.MethodGet, imgURL, nil)
+	resp, err := http.DefaultClient.Do(req)
 	if err != nil {
-			logging.Log().Warn("download image failed", zap.Error(err), zap.String("url", imgURL))
-			return nil
+		return nil, fmt.Errorf("ncm download image failed: %w", err)
 	}
 	defer resp.Body.Close()
+
 	if resp.StatusCode != http.StatusOK {
-			logging.Log().Warn("download image failed", zap.String("http", resp.Status),
-				zap.String("url", imgURL))
-			return nil
+		return nil, fmt.Errorf("ncm download image failed: unexpected http status %s", resp.Status)
 	}
-		data, err := ioutil.ReadAll(resp.Body)
+	d.cover, err = io.ReadAll(resp.Body)
 	if err != nil {
-			logging.Log().Warn("download image failed", zap.Error(err), zap.String("url", imgURL))
-			return nil
-		}
-		return data
-	}
+		return nil, fmt.Errorf("ncm download image failed: %w", err)
 	}
 
-func (d Decoder) GetMeta() common.Meta {
-	return d.meta
+	return d.cover, nil
+}
+
+func (d *Decoder) GetAudioMeta(_ context.Context) (common.AudioMeta, error) {
+	return d.meta, nil
 }
 
 func init() {

algo/ncm/ncm_cipher.go

@@ -0,0 +1,42 @@
+package ncm
+
+type ncmCipher struct {
+	key []byte
+	box []byte
+}
+
+func newNcmCipher(key []byte) *ncmCipher {
+	return &ncmCipher{
+		key: key,
+		box: buildKeyBox(key),
+	}
+}
+
+func (c *ncmCipher) Decrypt(buf []byte, offset int) {
+	for i := 0; i < len(buf); i++ {
+		buf[i] ^= c.box[(i+offset)&0xff]
+	}
+}
+
+func buildKeyBox(key []byte) []byte {
+	box := make([]byte, 256)
+	for i := 0; i < 256; i++ {
+		box[i] = byte(i)
+	}
+
+	var j byte
+	for i := 0; i < 256; i++ {
+		j = box[i] + j + key[i%len(key)]
+		box[i], box[j] = box[j], box[i]
+	}
+
+	ret := make([]byte, 256)
+	var _i byte
+	for i := 0; i < 256; i++ {
+		_i = byte(i + 1)
+		si := box[_i]
+		sj := box[_i+si]
+		ret[i] = box[si+sj]
+	}
+	return ret
+}

algo/qmc/cipher.go

@@ -1,5 +0,0 @@
-package qmc
-
-type streamCipher interface {
-	Decrypt(buf []byte, offset int)
-}

algo/qmc/cipher_map.go

@@ -8,7 +8,7 @@ type mapCipher struct {
 	size int
 }
 
-func NewMapCipher(key []byte) (*mapCipher, error) {
+func newMapCipher(key []byte) (*mapCipher, error) {
 	if len(key) == 0 {
 		return nil, errors.New("qmc/cipher_map: invalid key size")
 	}

algo/qmc/cipher_map_test.go

@@ -39,7 +39,7 @@ func Test_mapCipher_Decrypt(t *testing.T) {
 			if err != nil {
 				t.Fatalf("load testing data failed: %s", err)
 			}
-			c, err := NewMapCipher(key)
+			c, err := newMapCipher(key)
 			if err != nil {
 				t.Errorf("init mapCipher failed: %s", err)
 				return

algo/qmc/cipher_rc4.go

@@ -9,20 +9,19 @@ type rc4Cipher struct {
 	box  []byte
 	key  []byte
 	hash uint32
-	boxTmp []byte
+	n    int
 }
 
-// NewRC4Cipher creates and returns a new rc4Cipher. The key argument should be the
+// newRC4Cipher creates and returns a new rc4Cipher. The key argument should be the
 // RC4 key, at least 1 byte and at most 256 bytes.
-func NewRC4Cipher(key []byte) (*rc4Cipher, error) {
+func newRC4Cipher(key []byte) (*rc4Cipher, error) {
 	n := len(key)
 	if n == 0 {
 		return nil, errors.New("qmc/cipher_rc4: invalid key size")
 	}
 
-	var c = rc4Cipher{key: key}
+	var c = rc4Cipher{key: key, n: n}
 	c.box = make([]byte, n)
-	c.boxTmp = make([]byte, n)
 
 	for i := 0; i < n; i++ {
 		c.box[i] = byte(i)
@@ -39,7 +38,7 @@ func NewRC4Cipher(key []byte) (*rc4Cipher, error) {
 
 func (c *rc4Cipher) getHashBase() {
 	c.hash = 1
-	for i := 0; i < len(c.key); i++ {
+	for i := 0; i < c.n; i++ {
 		v := uint32(c.key[i])
 		if v == 0 {
 			continue
@@ -52,7 +51,10 @@ func (c *rc4Cipher) getHashBase() {
 	}
 }
 
-const rc4SegmentSize = 5120
+const (
+	rc4SegmentSize      = 5120
+	rc4FirstSegmentSize = 128
+)
 
 func (c *rc4Cipher) Decrypt(src []byte, offset int) {
 	toProcess := len(src)
@@ -64,10 +66,10 @@ func (c *rc4Cipher) Decrypt(src []byte, offset int) {
 		return toProcess == 0
 	}
 
-	if offset < 128 {
+	if offset < rc4FirstSegmentSize {
 		blockSize := toProcess
-		if blockSize > 128-offset {
-			blockSize = 128 - offset
+		if blockSize > rc4FirstSegmentSize-offset {
+			blockSize = rc4FirstSegmentSize - offset
 		}
 		c.encFirstSegment(src[:blockSize], offset)
 		if markProcess(blockSize) {
@@ -80,8 +82,7 @@ func (c *rc4Cipher) Decrypt(src []byte, offset int) {
 		if blockSize > rc4SegmentSize-offset%rc4SegmentSize {
 			blockSize = rc4SegmentSize - offset%rc4SegmentSize
 		}
-		k := src[processed : processed+blockSize]
-		c.encASegment(k, offset)
+		c.encASegment(src[processed:processed+blockSize], offset)
 		if markProcess(blockSize) {
 			return
 		}
@@ -96,38 +97,28 @@ func (c *rc4Cipher) Decrypt(src []byte, offset int) {
 	}
 }
 func (c *rc4Cipher) encFirstSegment(buf []byte, offset int) {
-	n := len(c.box)
 	for i := 0; i < len(buf); i++ {
-		idx1 := offset + i
-		segmentID := int(c.key[idx1%n])
-		idx2 := int(float64(c.hash) / float64((idx1+1)*segmentID) * 100.0)
-		buf[i] ^= c.key[idx2%n]
+		buf[i] ^= c.key[c.getSegmentSkip(offset+i)]
 	}
 }
 
 func (c *rc4Cipher) encASegment(buf []byte, offset int) {
-	n := len(c.box)
-	copy(c.boxTmp, c.box)
-
-	segmentID := (offset / rc4SegmentSize) & 0x1FF
-
-	if n <= segmentID {
-		return
-	}
-
-	idx2 := int64(float64(c.hash) /
-		float64((offset/rc4SegmentSize+1)*int(c.key[segmentID])) *
-		100.0)
-	skipLen := int((idx2 & 0x1FF) + int64(offset%rc4SegmentSize))
-
+	box := make([]byte, c.n)
+	copy(box, c.box)
 	j, k := 0, 0
 
+	skipLen := (offset % rc4SegmentSize) + c.getSegmentSkip(offset/rc4SegmentSize)
 	for i := -skipLen; i < len(buf); i++ {
-		j = (j + 1) % n
-		k = (int(c.boxTmp[j]) + k) % n
-		c.boxTmp[j], c.boxTmp[k] = c.boxTmp[k], c.boxTmp[j]
+		j = (j + 1) % c.n
+		k = (int(box[j]) + k) % c.n
+		box[j], box[k] = box[k], box[j]
 		if i >= 0 {
-			buf[i] ^= c.boxTmp[int(c.boxTmp[j])+int(c.boxTmp[k])%n]
+			buf[i] ^= box[(int(box[j])+int(box[k]))%c.n]
 		}
 	}
 }
+func (c *rc4Cipher) getSegmentSkip(id int) int {
+	seed := int(c.key[id%c.n])
+	idx := int64(float64(c.hash) / float64((id+1)*seed) * 100.0)
+	return int(idx % int64(c.n))
+}

algo/qmc/cipher_rc4_test.go

@@ -6,16 +6,17 @@ import (
 	"testing"
 )
 
-func loadTestRC4CipherData() ([]byte, []byte, []byte, error) {
-	key, err := os.ReadFile("./testdata/mflac0_rc4_key.bin")
+func loadTestRC4CipherData(name string) ([]byte, []byte, []byte, error) {
+	prefix := "./testdata/" + name
+	key, err := os.ReadFile(prefix + "_key.bin")
 	if err != nil {
 		return nil, nil, nil, err
 	}
-	raw, err := os.ReadFile("./testdata/mflac0_rc4_raw.bin")
+	raw, err := os.ReadFile(prefix + "_raw.bin")
 	if err != nil {
 		return nil, nil, nil, err
 	}
-	target, err := os.ReadFile("./testdata/mflac0_rc4_target.bin")
+	target, err := os.ReadFile(prefix + "_target.bin")
 	if err != nil {
 		return nil, nil, nil, err
 	}
@@ -23,12 +24,20 @@ func loadTestRC4CipherData() ([]byte, []byte, []byte, error) {
 	return key, raw, target, nil
 }
 func Test_rc4Cipher_Decrypt(t *testing.T) {
-	key, raw, target, err := loadTestRC4CipherData()
+	tests := []struct {
+		name    string
+		wantErr bool
+	}{
+		{"mflac0_rc4", false},
+		{"mflac_rc4", false},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			key, raw, target, err := loadTestRC4CipherData(tt.name)
 			if err != nil {
 				t.Fatalf("load testing data failed: %s", err)
 			}
-	t.Run("overall", func(t *testing.T) {
-		c, err := NewRC4Cipher(key)
+			c, err := newRC4Cipher(key)
 			if err != nil {
 				t.Errorf("init rc4Cipher failed: %s", err)
 				return
@@ -38,16 +47,32 @@ func Test_rc4Cipher_Decrypt(t *testing.T) {
 				t.Error("overall")
 			}
 		})
+	}
 
 }
+func BenchmarkRc4Cipher_Decrypt(b *testing.B) {
+	key, raw, _, err := loadTestRC4CipherData("mflac0_rc4")
+	if err != nil {
+		b.Fatalf("load testing data failed: %s", err)
+	}
+	c, err := newRC4Cipher(key)
+	if err != nil {
+		b.Errorf("init rc4Cipher failed: %s", err)
+		return
+	}
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		c.Decrypt(raw, 0)
+	}
+}
 
 func Test_rc4Cipher_encFirstSegment(t *testing.T) {
-	key, raw, target, err := loadTestRC4CipherData()
+	key, raw, target, err := loadTestRC4CipherData("mflac0_rc4")
 	if err != nil {
 		t.Fatalf("load testing data failed: %s", err)
 	}
 	t.Run("first-block(0~128)", func(t *testing.T) {
-		c, err := NewRC4Cipher(key)
+		c, err := newRC4Cipher(key)
 		if err != nil {
 			t.Errorf("init rc4Cipher failed: %s", err)
 			return
@@ -60,13 +85,13 @@ func Test_rc4Cipher_encFirstSegment(t *testing.T) {
 }
 
 func Test_rc4Cipher_encASegment(t *testing.T) {
-	key, raw, target, err := loadTestRC4CipherData()
+	key, raw, target, err := loadTestRC4CipherData("mflac0_rc4")
 	if err != nil {
 		t.Fatalf("load testing data failed: %s", err)
 	}
 
 	t.Run("align-block(128~5120)", func(t *testing.T) {
-		c, err := NewRC4Cipher(key)
+		c, err := newRC4Cipher(key)
 		if err != nil {
 			t.Errorf("init rc4Cipher failed: %s", err)
 			return
@@ -77,7 +102,7 @@ func Test_rc4Cipher_encASegment(t *testing.T) {
 		}
 	})
 	t.Run("simple-block(5120~10240)", func(t *testing.T) {
-		c, err := NewRC4Cipher(key)
+		c, err := newRC4Cipher(key)
 		if err != nil {
 			t.Errorf("init rc4Cipher failed: %s", err)
 			return

algo/qmc/cipher_static.go

@@ -1,6 +1,6 @@
 package qmc
 
-func NewStaticCipher() *staticCipher {
+func newStaticCipher() *staticCipher {
 	return &defaultStaticCipher
 }
 

algo/qmc/client/base.go

@@ -0,0 +1,146 @@
+package client
+
+import (
+	"bytes"
+	"context"
+	"encoding/json"
+	"fmt"
+	"io"
+	"net/http"
+	"time"
+)
+
+type QQMusic struct {
+	http *http.Client
+}
+
+func (c *QQMusic) rpcDoRequest(ctx context.Context, reqBody any) ([]byte, error) {
+	reqBodyBuf, err := json.Marshal(reqBody)
+	if err != nil {
+		return nil, fmt.Errorf("qqMusicClient[rpcDoRequest] marshal request: %w", err)
+	}
+
+	const endpointURL = "https://u.y.qq.com/cgi-bin/musicu.fcg"
+	req, err := http.NewRequestWithContext(ctx, http.MethodPost,
+		endpointURL+fmt.Sprintf("?pcachetime=%d", time.Now().Unix()),
+		bytes.NewReader(reqBodyBuf),
+	)
+	if err != nil {
+		return nil, fmt.Errorf("qqMusicClient[rpcDoRequest] create request: %w", err)
+	}
+
+	req.Header.Set("Accept", "*/*")
+	req.Header.Set("Accept-Language", "zh-CN")
+	req.Header.Set("User-Agent", "Mozilla/5.0 (compatible; MSIE 9.0; Windows NT 6.1; WOW64; Trident/5.0)")
+	req.Header.Set("Content-Type", "application/x-www-form-urlencoded")
+	// req.Header.Set("Accept-Encoding", "gzip, deflate")
+
+	reqp, err := c.http.Do(req)
+	if err != nil {
+		return nil, fmt.Errorf("qqMusicClient[rpcDoRequest] send request: %w", err)
+	}
+	defer reqp.Body.Close()
+
+	respBodyBuf, err := io.ReadAll(reqp.Body)
+	if err != nil {
+		return nil, fmt.Errorf("qqMusicClient[rpcDoRequest] read response: %w", err)
+	}
+
+	return respBodyBuf, nil
+}
+
+type rpcRequest struct {
+	Method string `json:"method"`
+	Module string `json:"module"`
+	Param  any    `json:"param"`
+}
+
+type rpcResponse struct {
+	Code    int    `json:"code"`
+	Ts      int64  `json:"ts"`
+	StartTs int64  `json:"start_ts"`
+	TraceID string `json:"traceid"`
+}
+
+type rpcSubResponse struct {
+	Code int             `json:"code"`
+	Data json.RawMessage `json:"data"`
+}
+
+func (c *QQMusic) rpcCall(ctx context.Context,
+	protocol string, method string, module string,
+	param any,
+) (json.RawMessage, error) {
+	reqBody := map[string]any{protocol: rpcRequest{
+		Method: method,
+		Module: module,
+		Param:  param,
+	}}
+
+	respBodyBuf, err := c.rpcDoRequest(ctx, reqBody)
+	if err != nil {
+		return nil, fmt.Errorf("qqMusicClient[rpcCall] do request: %w", err)
+	}
+
+	// check rpc response status
+	respStatus := rpcResponse{}
+	if err := json.Unmarshal(respBodyBuf, &respStatus); err != nil {
+		return nil, fmt.Errorf("qqMusicClient[rpcCall] unmarshal response: %w", err)
+	}
+	if respStatus.Code != 0 {
+		return nil, fmt.Errorf("qqMusicClient[rpcCall] rpc error: %d", respStatus.Code)
+	}
+
+	// parse response data
+	var respBody map[string]json.RawMessage
+	if err := json.Unmarshal(respBodyBuf, &respBody); err != nil {
+		return nil, fmt.Errorf("qqMusicClient[rpcCall] unmarshal response: %w", err)
+	}
+
+	subRespBuf, ok := respBody[protocol]
+	if !ok {
+		return nil, fmt.Errorf("qqMusicClient[rpcCall] sub-response not found")
+	}
+
+	subResp := rpcSubResponse{}
+	if err := json.Unmarshal(subRespBuf, &subResp); err != nil {
+		return nil, fmt.Errorf("qqMusicClient[rpcCall] unmarshal sub-response: %w", err)
+	}
+
+	if subResp.Code != 0 {
+		return nil, fmt.Errorf("qqMusicClient[rpcCall] sub-response error: %d", subResp.Code)
+	}
+
+	return subResp.Data, nil
+}
+
+func (c *QQMusic) downloadFile(ctx context.Context, url string) ([]byte, error) {
+	req, err := http.NewRequestWithContext(ctx, http.MethodGet, url, nil)
+	if err != nil {
+		return nil, fmt.Errorf("qmc[downloadFile] init request: %w", err)
+	}
+
+	//req.Header.Set("Accept", "image/webp,image/*,*/*;q=0.8") // jpeg is preferred to embed in audio
+	req.Header.Set("Accept-Language", "zh-CN,zh;q=0.8,en-US;q=0.6,en;q=0.5;q=0.4")
+	req.Header.Set("User-Agent", "Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/53.0.47.134 Safari/537.36 QBCore/3.53.47.400 QQBrowser/9.0.2524.400")
+
+	resp, err := c.http.Do(req)
+	if err != nil {
+		return nil, fmt.Errorf("qmc[downloadFile] send request: %w", err)
+	}
+	defer resp.Body.Close()
+
+	if resp.StatusCode != http.StatusOK {
+		return nil, fmt.Errorf("qmc[downloadFile] unexpected http status %s", resp.Status)
+	}
+
+	return io.ReadAll(resp.Body)
+}
+
+func NewQQMusicClient() *QQMusic {
+	return &QQMusic{
+		http: &http.Client{
+			Timeout: 10 * time.Second,
+		},
+	}
+}

algo/qmc/client/cover.go

@@ -0,0 +1,21 @@
+package client
+
+import (
+	"context"
+	"fmt"
+	"strconv"
+)
+
+func (c *QQMusic) AlbumCoverByID(ctx context.Context, albumID int) ([]byte, error) {
+	u := fmt.Sprintf("https://imgcache.qq.com/music/photo/album/%s/albumpic_%s_0.jpg",
+		strconv.Itoa(albumID%100),
+		strconv.Itoa(albumID),
+	)
+	return c.downloadFile(ctx, u)
+}
+
+func (c *QQMusic) AlbumCoverByMediaID(ctx context.Context, mediaID string) ([]byte, error) {
+	// original: https://y.gtimg.cn/music/photo_new/T002M000%s.jpg
+	u := fmt.Sprintf("https://y.gtimg.cn/music/photo_new/T002R500x500M000%s.jpg", mediaID)
+	return c.downloadFile(ctx, u)
+}

algo/qmc/client/search.go

@@ -0,0 +1,52 @@
+package client
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+)
+
+type searchParams struct {
+	Grp         int    `json:"grp"`
+	NumPerPage  int    `json:"num_per_page"`
+	PageNum     int    `json:"page_num"`
+	Query       string `json:"query"`
+	RemotePlace string `json:"remoteplace"`
+	SearchType  int    `json:"search_type"`
+	//SearchID    string `json:"searchid"` // todo: it seems generated randomly
+}
+
+type searchResponse struct {
+	Body struct {
+		Song struct {
+			List []*TrackInfo `json:"list"`
+		} `json:"song"`
+	} `json:"body"`
+	Code int `json:"code"`
+}
+
+func (c *QQMusic) Search(ctx context.Context, keyword string) ([]*TrackInfo, error) {
+
+	resp, err := c.rpcCall(ctx,
+		"music.search.SearchCgiService",
+		"DoSearchForQQMusicDesktop",
+		"music.search.SearchCgiService",
+		&searchParams{
+			SearchType: 0, Query: keyword,
+			PageNum: 1, NumPerPage: 40,
+
+			// static values
+			Grp: 1, RemotePlace: "sizer.newclient.song",
+		})
+	if err != nil {
+		return nil, fmt.Errorf("qqMusicClient[Search] rpc call: %w", err)
+	}
+
+	respData := searchResponse{}
+	if err := json.Unmarshal(resp, &respData); err != nil {
+		return nil, fmt.Errorf("qqMusicClient[Search] unmarshal response: %w", err)
+	}
+
+	return respData.Body.Song.List, nil
+
+}

algo/qmc/client/track.go

@@ -0,0 +1,178 @@
+package client
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+
+	"github.com/samber/lo"
+)
+
+type getTrackInfoParams struct {
+	Ctx   int   `json:"ctx"`
+	Ids   []int `json:"ids"`
+	Types []int `json:"types"`
+}
+
+type getTrackInfoResponse struct {
+	Tracks []*TrackInfo `json:"tracks"`
+}
+
+func (c *QQMusic) GetTracksInfo(ctx context.Context, songIDs []int) ([]*TrackInfo, error) {
+	resp, err := c.rpcCall(ctx,
+		"Protocol_UpdateSongInfo",
+		"CgiGetTrackInfo",
+		"music.trackInfo.UniformRuleCtrl",
+		&getTrackInfoParams{Ctx: 0, Ids: songIDs, Types: []int{0}},
+	)
+	if err != nil {
+		return nil, fmt.Errorf("qqMusicClient[GetTrackInfo] rpc call: %w", err)
+	}
+	respData := getTrackInfoResponse{}
+	if err := json.Unmarshal(resp, &respData); err != nil {
+		return nil, fmt.Errorf("qqMusicClient[GetTrackInfo] unmarshal response: %w", err)
+	}
+
+	return respData.Tracks, nil
+}
+
+func (c *QQMusic) GetTrackInfo(ctx context.Context, songID int) (*TrackInfo, error) {
+	tracks, err := c.GetTracksInfo(ctx, []int{songID})
+	if err != nil {
+		return nil, fmt.Errorf("qqMusicClient[GetTrackInfo] get tracks info: %w", err)
+	}
+
+	if len(tracks) == 0 {
+		return nil, fmt.Errorf("qqMusicClient[GetTrackInfo] track not found")
+	}
+
+	return tracks[0], nil
+}
+
+type TrackSinger struct {
+	Id    int    `json:"id"`
+	Mid   string `json:"mid"`
+	Name  string `json:"name"`
+	Title string `json:"title"`
+	Type  int    `json:"type"`
+	Uin   int    `json:"uin"`
+	Pmid  string `json:"pmid"`
+}
+type TrackAlbum struct {
+	Id       int    `json:"id"`
+	Mid      string `json:"mid"`
+	Name     string `json:"name"`
+	Title    string `json:"title"`
+	Subtitle string `json:"subtitle"`
+	Pmid     string `json:"pmid"`
+}
+type TrackInfo struct {
+	Id       int           `json:"id"`
+	Type     int           `json:"type"`
+	Mid      string        `json:"mid"`
+	Name     string        `json:"name"`
+	Title    string        `json:"title"`
+	Subtitle string        `json:"subtitle"`
+	Singer   []TrackSinger `json:"singer"`
+	Album    TrackAlbum    `json:"album"`
+	Mv       struct {
+		Id    int    `json:"id"`
+		Vid   string `json:"vid"`
+		Name  string `json:"name"`
+		Title string `json:"title"`
+		Vt    int    `json:"vt"`
+	} `json:"mv"`
+	Interval   int    `json:"interval"`
+	Isonly     int    `json:"isonly"`
+	Language   int    `json:"language"`
+	Genre      int    `json:"genre"`
+	IndexCd    int    `json:"index_cd"`
+	IndexAlbum int    `json:"index_album"`
+	TimePublic string `json:"time_public"`
+	Status     int    `json:"status"`
+	Fnote      int    `json:"fnote"`
+	File       struct {
+		MediaMid      string        `json:"media_mid"`
+		Size24Aac     int           `json:"size_24aac"`
+		Size48Aac     int           `json:"size_48aac"`
+		Size96Aac     int           `json:"size_96aac"`
+		Size192Ogg    int           `json:"size_192ogg"`
+		Size192Aac    int           `json:"size_192aac"`
+		Size128Mp3    int           `json:"size_128mp3"`
+		Size320Mp3    int           `json:"size_320mp3"`
+		SizeApe       int           `json:"size_ape"`
+		SizeFlac      int           `json:"size_flac"`
+		SizeDts       int           `json:"size_dts"`
+		SizeTry       int           `json:"size_try"`
+		TryBegin      int           `json:"try_begin"`
+		TryEnd        int           `json:"try_end"`
+		Url           string        `json:"url"`
+		SizeHires     int           `json:"size_hires"`
+		HiresSample   int           `json:"hires_sample"`
+		HiresBitdepth int           `json:"hires_bitdepth"`
+		B30S          int           `json:"b_30s"`
+		E30S          int           `json:"e_30s"`
+		Size96Ogg     int           `json:"size_96ogg"`
+		Size360Ra     []interface{} `json:"size_360ra"`
+		SizeDolby     int           `json:"size_dolby"`
+		SizeNew       []interface{} `json:"size_new"`
+	} `json:"file"`
+	Pay struct {
+		PayMonth   int `json:"pay_month"`
+		PriceTrack int `json:"price_track"`
+		PriceAlbum int `json:"price_album"`
+		PayPlay    int `json:"pay_play"`
+		PayDown    int `json:"pay_down"`
+		PayStatus  int `json:"pay_status"`
+		TimeFree   int `json:"time_free"`
+	} `json:"pay"`
+	Action struct {
+		Switch   int `json:"switch"`
+		Msgid    int `json:"msgid"`
+		Alert    int `json:"alert"`
+		Icons    int `json:"icons"`
+		Msgshare int `json:"msgshare"`
+		Msgfav   int `json:"msgfav"`
+		Msgdown  int `json:"msgdown"`
+		Msgpay   int `json:"msgpay"`
+		Switch2  int `json:"switch2"`
+		Icon2    int `json:"icon2"`
+	} `json:"action"`
+	Ksong struct {
+		Id  int    `json:"id"`
+		Mid string `json:"mid"`
+	} `json:"ksong"`
+	Volume struct {
+		Gain float64 `json:"gain"`
+		Peak float64 `json:"peak"`
+		Lra  float64 `json:"lra"`
+	} `json:"volume"`
+	Label       string   `json:"label"`
+	Url         string   `json:"url"`
+	Ppurl       string   `json:"ppurl"`
+	Bpm         int      `json:"bpm"`
+	Version     int      `json:"version"`
+	Trace       string   `json:"trace"`
+	DataType    int      `json:"data_type"`
+	ModifyStamp int      `json:"modify_stamp"`
+	Aid         int      `json:"aid"`
+	Tid         int      `json:"tid"`
+	Ov          int      `json:"ov"`
+	Sa          int      `json:"sa"`
+	Es          string   `json:"es"`
+	Vs          []string `json:"vs"`
+}
+
+func (t *TrackInfo) GetArtists() []string {
+	return lo.Map(t.Singer, func(v TrackSinger, i int) string {
+		return v.Name
+	})
+}
+
+func (t *TrackInfo) GetTitle() string {
+	return t.Title
+}
+
+func (t *TrackInfo) GetAlbum() string {
+	return t.Album.Name
+}

algo/qmc/key_derive.go

@@ -1,8 +1,10 @@
 package qmc
 
 import (
+	"bytes"
 	"encoding/base64"
 	"errors"
+	"fmt"
 	"math"
 
 	"golang.org/x/crypto/tea"
@@ -16,16 +18,30 @@ func simpleMakeKey(salt byte, length int) []byte {
 	}
 	return keyBuf
 }
-func DecryptKey(rawKey []byte) ([]byte, error) {
+
+const rawKeyPrefixV2 = "QQMusic EncV2,Key:"
+
+func deriveKey(rawKey []byte) ([]byte, error) {
 	rawKeyDec := make([]byte, base64.StdEncoding.DecodedLen(len(rawKey)))
 	n, err := base64.StdEncoding.Decode(rawKeyDec, rawKey)
 	if err != nil {
 		return nil, err
 	}
-	if n < 16 {
+	rawKeyDec = rawKeyDec[:n]
+
+	if bytes.HasPrefix(rawKeyDec, []byte(rawKeyPrefixV2)) {
+		rawKeyDec, err = deriveKeyV2(bytes.TrimPrefix(rawKeyDec, []byte(rawKeyPrefixV2)))
+		if err != nil {
+			return nil, fmt.Errorf("deriveKeyV2 failed: %w", err)
+		}
+	}
+	return deriveKeyV1(rawKeyDec)
+}
+
+func deriveKeyV1(rawKeyDec []byte) ([]byte, error) {
+	if len(rawKeyDec) < 16 {
 		return nil, errors.New("key length is too short")
 	}
-	rawKeyDec = rawKeyDec[:n]
 
 	simpleKey := simpleMakeKey(106, 8)
 	teaKey := make([]byte, 16)
@@ -40,6 +56,37 @@ func DecryptKey(rawKey []byte) ([]byte, error) {
 	}
 	return append(rawKeyDec[:8], rs...), nil
 }
+
+var (
+	deriveV2Key1 = []byte{
+		0x33, 0x38, 0x36, 0x5A, 0x4A, 0x59, 0x21, 0x40,
+		0x23, 0x2A, 0x24, 0x25, 0x5E, 0x26, 0x29, 0x28,
+	}
+
+	deriveV2Key2 = []byte{
+		0x2A, 0x2A, 0x23, 0x21, 0x28, 0x23, 0x24, 0x25,
+		0x26, 0x5E, 0x61, 0x31, 0x63, 0x5A, 0x2C, 0x54,
+	}
+)
+
+func deriveKeyV2(raw []byte) ([]byte, error) {
+	buf, err := decryptTencentTea(raw, deriveV2Key1)
+	if err != nil {
+		return nil, err
+	}
+
+	buf, err = decryptTencentTea(buf, deriveV2Key2)
+	if err != nil {
+		return nil, err
+	}
+
+	n, err := base64.StdEncoding.Decode(buf, buf)
+	if err != nil {
+		return nil, err
+	}
+	return buf[:n], nil
+}
+
 func decryptTencentTea(inBuf []byte, key []byte) ([]byte, error) {
 	const saltLen = 2
 	const zeroLen = 7
@@ -59,9 +106,7 @@ func decryptTencentTea(inBuf []byte, key []byte) ([]byte, error) {
 	blk.Decrypt(destBuf, inBuf)
 	padLen := int(destBuf[0] & 0x7)
 	outLen := len(inBuf) - 1 - padLen - saltLen - zeroLen
-	if padLen+saltLen != 8 {
-		return nil, errors.New("invalid pad len")
-	}
+
 	out := make([]byte, outLen)
 
 	ivPrev := make([]byte, 8)
@@ -108,6 +153,7 @@ func decryptTencentTea(inBuf []byte, key []byte) ([]byte, error) {
 
 	return out, nil
 }
+
 func xor8Bytes(dst, a, b []byte) {
 	for i := 0; i < 8; i++ {
 		dst[i] = a[i] ^ b[i]

algo/qmc/key_derive_test.go

@@ -27,7 +27,6 @@ func loadDecryptKeyData(name string) ([]byte, []byte, error) {
 	return keyRaw, keyDec, nil
 }
 func TestDecryptKey(t *testing.T) {
-
 	tests := []struct {
 		name     string
 		filename string
@@ -35,20 +34,22 @@ func TestDecryptKey(t *testing.T) {
 	}{
 		{"mflac0_rc4(512)", "mflac0_rc4", false},
 		{"mflac_map(256)", "mflac_map", false},
+		{"mflac_rc4(256)", "mflac_rc4", false},
+		{"mgg_map(256)", "mgg_map", false},
 	}
 	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
 			raw, want, err := loadDecryptKeyData(tt.filename)
 			if err != nil {
 				t.Fatalf("load test data failed: %s", err)
 			}
-		t.Run(tt.name, func(t *testing.T) {
-			got, err := DecryptKey(raw)
+			got, err := deriveKey(raw)
 			if (err != nil) != tt.wantErr {
-				t.Errorf("DecryptKey() error = %v, wantErr %v", err, tt.wantErr)
+				t.Errorf("deriveKey() error = %v, wantErr %v", err, tt.wantErr)
 				return
 			}
 			if !reflect.DeepEqual(got, want) {
-				t.Errorf("DecryptKey() got = %v..., want %v...",
+				t.Errorf("deriveKey() got = %v..., want %v...",
 					string(got[:32]), string(want[:32]))
 			}
 		})

algo/qmc/key_mmkv.go

@@ -0,0 +1,158 @@
+package qmc
+
+import (
+	"errors"
+	"fmt"
+	"os"
+	"path/filepath"
+	"runtime"
+
+	"github.com/samber/lo"
+	"go.uber.org/zap"
+	"golang.org/x/exp/slices"
+	"golang.org/x/text/unicode/norm"
+	"unlock-music.dev/mmkv"
+)
+
+var streamKeyVault mmkv.Vault
+
+// TODO: move to factory
+func readKeyFromMMKV(file string, logger *zap.Logger) ([]byte, error) {
+	if file == "" {
+		return nil, errors.New("file path is required while reading key from mmkv")
+	}
+
+	//goland:noinspection GoBoolExpressions
+	if runtime.GOOS != "darwin" {
+		return nil, errors.New("mmkv vault not supported on this platform")
+	}
+
+	if streamKeyVault == nil {
+		mmkvDir, err := getRelativeMMKVDir(file)
+		if err != nil {
+			mmkvDir, err = getDefaultMMKVDir()
+			if err != nil {
+				return nil, fmt.Errorf("mmkv key valut not found: %w", err)
+			}
+		}
+
+		mgr, err := mmkv.NewManager(mmkvDir)
+		if err != nil {
+			return nil, fmt.Errorf("init mmkv manager: %w", err)
+		}
+
+		streamKeyVault, err = mgr.OpenVault("MMKVStreamEncryptId")
+		if err != nil {
+			return nil, fmt.Errorf("open mmkv vault: %w", err)
+		}
+
+		logger.Debug("mmkv vault opened", zap.Strings("keys", streamKeyVault.Keys()))
+	}
+
+	_, partName := filepath.Split(file)
+	partName = normalizeUnicode(partName)
+
+	buf, err := streamKeyVault.GetBytes(file)
+	if buf == nil {
+		filePaths := streamKeyVault.Keys()
+		fileNames := lo.Map(filePaths, func(filePath string, _ int) string {
+			_, name := filepath.Split(filePath)
+			return normalizeUnicode(name)
+		})
+
+		for _, key := range fileNames { // fallback: match filename only
+			if key != partName {
+				continue
+			}
+			idx := slices.Index(fileNames, key)
+			buf, err = streamKeyVault.GetBytes(filePaths[idx])
+			if err != nil {
+				logger.Warn("read key from mmkv", zap.String("key", filePaths[idx]), zap.Error(err))
+			}
+		}
+
+	}
+
+	if len(buf) == 0 {
+		return nil, errors.New("key not found in mmkv vault")
+	}
+
+	return deriveKey(buf)
+}
+
+func OpenMMKV(mmkvPath string, key string, logger *zap.Logger) error {
+	filePath, fileName := filepath.Split(mmkvPath)
+	mgr, err := mmkv.NewManager(filepath.Dir(filePath))
+	if err != nil {
+		return fmt.Errorf("init mmkv manager: %w", err)
+	}
+
+	// If `vaultKey` is empty, the key is ignored.
+	streamKeyVault, err = mgr.OpenVaultCrypto(fileName, key)
+
+	if err != nil {
+		return fmt.Errorf("open mmkv vault: %w", err)
+	}
+
+	logger.Debug("mmkv vault opened", zap.Strings("keys", streamKeyVault.Keys()))
+	return nil
+}
+
+// /
+func readKeyFromMMKVCustom(mid string) ([]byte, error) {
+	if streamKeyVault == nil {
+		return nil, fmt.Errorf("mmkv vault not loaded")
+	}
+
+	// get ekey from mmkv vault
+	eKey, err := streamKeyVault.GetBytes(mid)
+	if err != nil {
+		return nil, fmt.Errorf("get eKey error: %w", err)
+	}
+	return deriveKey(eKey)
+}
+
+// / getRelativeMMKVDir get mmkv dir relative to file (legacy QQMusic for macOS behaviour)
+func getRelativeMMKVDir(file string) (string, error) {
+	mmkvDir := filepath.Join(filepath.Dir(file), "../mmkv")
+	if _, err := os.Stat(mmkvDir); err != nil {
+		return "", fmt.Errorf("stat default mmkv dir: %w", err)
+	}
+
+	keyFile := filepath.Join(mmkvDir, "MMKVStreamEncryptId")
+	if _, err := os.Stat(keyFile); err != nil {
+		return "", fmt.Errorf("stat default mmkv file: %w", err)
+	}
+
+	return mmkvDir, nil
+}
+
+func getDefaultMMKVDir() (string, error) {
+	homeDir, err := os.UserHomeDir()
+	if err != nil {
+		return "", fmt.Errorf("get user home dir: %w", err)
+	}
+
+	mmkvDir := filepath.Join(
+		homeDir,
+		"Library/Containers/com.tencent.QQMusicMac/Data",
+		"Library/Application Support/QQMusicMac/mmkv",
+	)
+	if _, err := os.Stat(mmkvDir); err != nil {
+		return "", fmt.Errorf("stat default mmkv dir: %w", err)
+	}
+
+	keyFile := filepath.Join(mmkvDir, "MMKVStreamEncryptId")
+	if _, err := os.Stat(keyFile); err != nil {
+		return "", fmt.Errorf("stat default mmkv file: %w", err)
+	}
+
+	return mmkvDir, nil
+}
+
+// normalizeUnicode normalizes unicode string to NFC.
+// since macOS may change some characters in the file name.
+// e.g. "ぜ"(e3 81 9c) -> "ぜ"(e3 81 9b e3 82 99)
+func normalizeUnicode(str string) string {
+	return norm.NFC.String(str)
+}

algo/qmc/qmc.go

@@ -4,136 +4,187 @@ import (
 	"bytes"
 	"encoding/binary"
 	"errors"
+	"fmt"
+	"go.uber.org/zap"
 	"io"
+	"runtime"
 	"strconv"
 	"strings"
 
-	"github.com/unlock-music/cli/algo/common"
+	"unlock-music.dev/cli/algo/common"
+	"unlock-music.dev/cli/internal/sniff"
 )
 
 type Decoder struct {
-	r       io.ReadSeeker
-	fileExt string
+	raw    io.ReadSeeker // raw is the original file reader
+	params *common.DecoderParams
 
-	audioLen   int
-	decodedKey []byte
-	cipher     streamCipher
-	offset     int
+	audio    io.Reader // audio is the encrypted audio data
+	audioLen int       // audioLen is the audio data length
+	offset   int       // offset is the current audio read position
 
-	rawMetaExtra1 int
+	decodedKey []byte // decodedKey is the decoded key for cipher
+	cipher     common.StreamDecoder
+
+	songID        int
 	rawMetaExtra2 int
+
+	albumID      int
+	albumMediaID string
+
+	// cache
+	meta          common.AudioMeta
+	cover         []byte
+	embeddedCover bool          // embeddedCover is true if the cover is embedded in the file
+	probeBuf      *bytes.Buffer // probeBuf is the buffer for sniffing metadata, TODO: consider pipe?
+
+	// provider
+	logger *zap.Logger
 }
 
 // Read implements io.Reader, offer the decrypted audio data.
 // Validate should call before Read to check if the file is valid.
 func (d *Decoder) Read(p []byte) (int, error) {
-	n := len(p)
-	if d.audioLen-d.offset <= 0 {
-		return 0, io.EOF
-	} else if d.audioLen-d.offset < n {
-		n = d.audioLen - d.offset
+	n, err := d.audio.Read(p)
+	if n > 0 {
+		d.cipher.Decrypt(p[:n], d.offset)
+		d.offset += n
+
+		_, _ = d.probeBuf.Write(p[:n]) // bytes.Buffer.Write never return error
 	}
-	m, err := d.r.Read(p[:n])
-	if m == 0 {
-		return 0, err
+	return n, err
 }
 
-	d.cipher.Decrypt(p[:m], d.offset)
-	d.offset += m
-	return m, err
-}
-
-func NewDecoder(r io.ReadSeeker) (*Decoder, error) {
-	d := &Decoder{r: r}
-	err := d.searchKey()
-	if err != nil {
-		return nil, err
-	}
-
-	if len(d.decodedKey) > 300 {
-		d.cipher, err = NewRC4Cipher(d.decodedKey)
-		if err != nil {
-			return nil, err
-		}
-	} else if len(d.decodedKey) != 0 {
-		d.cipher, err = NewMapCipher(d.decodedKey)
-		if err != nil {
-			return nil, err
-		}
-	} else {
-		d.cipher = NewStaticCipher()
-	}
-
-	_, err = d.r.Seek(0, io.SeekStart)
-	if err != nil {
-		return nil, err
-	}
-
-	return d, nil
+func NewDecoder(p *common.DecoderParams) common.Decoder {
+	return &Decoder{raw: p.Reader, params: p, logger: p.Logger}
 }
 
 func (d *Decoder) Validate() error {
-	buf := make([]byte, 16)
-	if _, err := io.ReadFull(d.r, buf); err != nil {
-		return err
-	}
-	_, err := d.r.Seek(0, io.SeekStart)
+	// search & derive key
+	err := d.searchKey()
 	if err != nil {
 		return err
 	}
 
+	// check cipher type and init decode cipher
+	if len(d.decodedKey) > 300 {
+		d.cipher, err = newRC4Cipher(d.decodedKey)
+		if err != nil {
+			return err
+		}
+	} else if len(d.decodedKey) != 0 {
+		d.cipher, err = newMapCipher(d.decodedKey)
+		if err != nil {
+			return err
+		}
+	} else {
+		d.cipher = newStaticCipher()
+	}
+
+	// test with first 16 bytes
+	if err := d.validateDecode(); err != nil {
+		return err
+	}
+
+	// reset position, limit to audio, prepare for Read
+	if _, err := d.raw.Seek(0, io.SeekStart); err != nil {
+		return err
+	}
+	d.audio = io.LimitReader(d.raw, int64(d.audioLen))
+
+	// prepare for sniffing metadata
+	d.probeBuf = bytes.NewBuffer(make([]byte, 0, d.audioLen))
+
+	return nil
+}
+
+func (d *Decoder) validateDecode() error {
+	_, err := d.raw.Seek(0, io.SeekStart)
+	if err != nil {
+		return fmt.Errorf("qmc seek to start: %w", err)
+	}
+
+	buf := make([]byte, 64)
+	if _, err := io.ReadFull(d.raw, buf); err != nil {
+		return fmt.Errorf("qmc read header: %w", err)
+	}
+
 	d.cipher.Decrypt(buf, 0)
-	fileExt, ok := common.SniffAll(buf)
+	_, ok := sniff.AudioExtension(buf)
 	if !ok {
-		return errors.New("detect file type failed")
+		return errors.New("qmc: detect file type failed")
 	}
-	d.fileExt = fileExt
 	return nil
 }
 
-func (d Decoder) GetFileExt() string {
-	return d.fileExt
+func (d *Decoder) searchKey() (err error) {
+	fileSizeM4, err := d.raw.Seek(-4, io.SeekEnd)
+	if err != nil {
+		return err
+	}
+	fileSize := int(fileSizeM4) + 4
+
+	//goland:noinspection GoBoolExpressions
+	if runtime.GOOS == "darwin" && !strings.HasPrefix(d.params.Extension, ".qmc") {
+		d.decodedKey, err = readKeyFromMMKV(d.params.FilePath, d.logger)
+		if err == nil {
+			d.audioLen = fileSize
+			return
+		}
+		d.logger.Warn("read key from mmkv failed", zap.Error(err))
 	}
 
-func (d *Decoder) searchKey() error {
-	fileSizeM4, err := d.r.Seek(-4, io.SeekEnd)
+	suffixBuf := make([]byte, 4)
+	if _, err := io.ReadFull(d.raw, suffixBuf); err != nil {
+		return err
+	}
+
+	switch string(suffixBuf) {
+	case "QTag":
+		return d.readRawMetaQTag()
+	case "STag":
+		return errors.New("qmc: file with 'STag' suffix doesn't contains media key")
+	case "cex\x00":
+		footer, err := NewMusicExTag(d.raw)
 		if err != nil {
 			return err
 		}
-	buf, err := io.ReadAll(io.LimitReader(d.r, 4))
+		d.audioLen = fileSize - int(footer.TagSize)
+		d.decodedKey, err = readKeyFromMMKVCustom(footer.MediaFileName)
 		if err != nil {
 			return err
 		}
-	if string(buf) == "QTag" {
-		if err := d.readRawMetaQTag(); err != nil {
-			return err
-		}
-	} else {
-		size := binary.LittleEndian.Uint32(buf)
-		if size < 0x300 && size != 0 {
+		return nil
+	default:
+		size := binary.LittleEndian.Uint32(suffixBuf)
+
+		if size <= 0xFFFF && size != 0 { // assume size is key len
 			return d.readRawKey(int64(size))
-		} else {
+		}
+
 		// try to use default static cipher
-			d.audioLen = int(fileSizeM4 + 4)
+		d.audioLen = fileSize
 		return nil
 	}
-	}
-	return nil
+
 }
 
 func (d *Decoder) readRawKey(rawKeyLen int64) error {
-	audioLen, err := d.r.Seek(-(4 + rawKeyLen), io.SeekEnd)
+	audioLen, err := d.raw.Seek(-(4 + rawKeyLen), io.SeekEnd)
 	if err != nil {
 		return err
 	}
 	d.audioLen = int(audioLen)
 
-	rawKeyData, err := io.ReadAll(io.LimitReader(d.r, rawKeyLen))
+	rawKeyData, err := io.ReadAll(io.LimitReader(d.raw, rawKeyLen))
 	if err != nil {
 		return err
 	}
 
-	d.decodedKey, err = DecryptKey(rawKeyData)
+	// clean suffix NULs
+	rawKeyData = bytes.TrimRight(rawKeyData, "\x00")
+
+	d.decodedKey, err = deriveKey(rawKeyData)
 	if err != nil {
 		return err
 	}
@@ -143,22 +194,22 @@ func (d *Decoder) readRawKey(rawKeyLen int64) error {
 
 func (d *Decoder) readRawMetaQTag() error {
 	// get raw meta data len
-	if _, err := d.r.Seek(-8, io.SeekEnd); err != nil {
+	if _, err := d.raw.Seek(-8, io.SeekEnd); err != nil {
 		return err
 	}
-	buf, err := io.ReadAll(io.LimitReader(d.r, 4))
+	buf, err := io.ReadAll(io.LimitReader(d.raw, 4))
 	if err != nil {
 		return err
 	}
 	rawMetaLen := int64(binary.BigEndian.Uint32(buf))
 
 	// read raw meta data
-	audioLen, err := d.r.Seek(-(8 + rawMetaLen), io.SeekEnd)
+	audioLen, err := d.raw.Seek(-(8 + rawMetaLen), io.SeekEnd)
 	if err != nil {
 		return err
 	}
 	d.audioLen = int(audioLen)
-	rawMetaData, err := io.ReadAll(io.LimitReader(d.r, rawMetaLen))
+	rawMetaData, err := io.ReadAll(io.LimitReader(d.raw, rawMetaLen))
 	if err != nil {
 		return err
 	}
@@ -168,12 +219,12 @@ func (d *Decoder) readRawMetaQTag() error {
 		return errors.New("invalid raw meta data")
 	}
 
-	d.decodedKey, err = DecryptKey([]byte(items[0]))
+	d.decodedKey, err = deriveKey([]byte(items[0]))
 	if err != nil {
 		return err
 	}
 
-	d.rawMetaExtra1, err = strconv.Atoi(items[1])
+	d.songID, err = strconv.Atoi(items[1])
 	if err != nil {
 		return err
 	}
@@ -194,8 +245,8 @@ func init() {
 		"qmcogg",  //QQ Music OGG
 
 		"tkm", //QQ Music Accompaniment M4A
-		"bkcmp3",  //Moo Music Mp3
-		"bkcflac", //Moo Music Flac
+
+		"bkcmp3", "bkcm4a", "bkcflac", "bkcwav", "bkcape", "bkcogg", "bkcwma", //Moo Music
 
 		"666c6163", //QQ Music Weiyun Flac
 		"6d7033",   //QQ Music Weiyun Mp3
@@ -203,61 +254,20 @@ func init() {
 		"6d3461",   //QQ Music Weiyun M4a
 		"776176",   //QQ Music Weiyun Wav
 
-		"mgg", "mgg1", //QQ Music New Ogg
-		"mflac", "mflac0", //QQ Music New Flac
+		"mmp4", // QQ Music MP4 Container, tipically used for Dolby EAC3 stream
 	}
 	for _, ext := range supportedExts {
-		common.RegisterDecoder(ext, false, newCompactDecoder)
-	}
+		common.RegisterDecoder(ext, false, NewDecoder)
 	}
 
-type compactDecoder struct {
-	decoder   *Decoder
-	createErr error
-	buf       *bytes.Buffer
+	// New ogg/flac:
+	extraExtsCanHaveSuffix := []string{"mgg", "mflac"}
+	// Mac also adds some extra suffix to ext:
+	extraExtSuffix := []string{"0", "1", "a", "h", "l"}
+	for _, ext := range extraExtsCanHaveSuffix {
+		common.RegisterDecoder(ext, false, NewDecoder)
+		for _, suffix := range extraExtSuffix {
+			common.RegisterDecoder(ext+suffix, false, NewDecoder)
 		}
-
-func newCompactDecoder(p []byte) common.Decoder {
-	r := bytes.NewReader(p)
-	d, err := NewDecoder(r)
-	c := compactDecoder{
-		decoder:   d,
-		createErr: err,
 	}
-	return &c
-}
-
-func (c *compactDecoder) Validate() error {
-	if c.createErr != nil {
-		return c.createErr
-	}
-	return c.decoder.Validate()
-}
-
-func (c *compactDecoder) Decode() error {
-	if c.createErr != nil {
-		return c.createErr
-	}
-	c.buf = bytes.NewBuffer(nil)
-	_, err := io.Copy(c.buf, c.decoder)
-	return err
-}
-
-func (c *compactDecoder) GetCoverImage() []byte {
-	return nil
-}
-
-func (c *compactDecoder) GetAudioData() []byte {
-	return c.buf.Bytes()
-}
-
-func (c *compactDecoder) GetAudioExt() string {
-	if c.createErr != nil {
-		return ""
-	}
-	return c.decoder.GetFileExt()
-}
-
-func (c *compactDecoder) GetMeta() common.Meta {
-	return nil
 }

algo/qmc/qmc_footer_musicex.go

@@ -0,0 +1,93 @@
+package qmc
+
+import (
+	bytes "bytes"
+	"encoding/binary"
+	"errors"
+	"fmt"
+	"io"
+	"strings"
+)
+
+type MusicExTagV1 struct {
+	SongID        uint32 // Song ID
+	Unknown1      uint32 // unused & unknown
+	Unknown2      uint32 // unused & unknown
+	MediaID       string // Media ID
+	MediaFileName string // real file name
+	Unknown3      uint32 // unused; uninitialized memory?
+
+	// 16 byte at the end of tag.
+	// TagSize should be respected when parsing.
+	TagSize    uint32 // 19.57: fixed value: 0xC0
+	TagVersion uint32 // 19.57: fixed value: 0x01
+	TagMagic   []byte // fixed value "musicex\0" (8 bytes)
+}
+
+func NewMusicExTag(f io.ReadSeeker) (*MusicExTagV1, error) {
+	_, err := f.Seek(-16, io.SeekEnd)
+	if err != nil {
+		return nil, fmt.Errorf("musicex seek error: %w", err)
+	}
+
+	buffer := make([]byte, 16)
+	bytesRead, err := f.Read(buffer)
+	if err != nil {
+		return nil, fmt.Errorf("get musicex error: %w", err)
+	}
+	if bytesRead != 16 {
+		return nil, fmt.Errorf("MusicExV1: read %d bytes (expected %d)", bytesRead, 16)
+	}
+
+	tag := &MusicExTagV1{
+		TagSize:    binary.LittleEndian.Uint32(buffer[0x00:0x04]),
+		TagVersion: binary.LittleEndian.Uint32(buffer[0x04:0x08]),
+		TagMagic:   buffer[0x04:0x0C],
+	}
+
+	if !bytes.Equal(tag.TagMagic, []byte("musicex\x00")) {
+		return nil, errors.New("MusicEx magic mismatch")
+	}
+	if tag.TagVersion != 1 {
+		return nil, errors.New(fmt.Sprintf("unsupported musicex tag version. expecting 1, got %d", tag.TagVersion))
+	}
+
+	if tag.TagSize < 0xC0 {
+		return nil, errors.New(fmt.Sprintf("unsupported musicex tag size. expecting at least 0xC0, got 0x%02x", tag.TagSize))
+	}
+
+	buffer = make([]byte, tag.TagSize)
+	bytesRead, err = f.Read(buffer)
+	if err != nil {
+		return nil, err
+	}
+	if uint32(bytesRead) != tag.TagSize {
+		return nil, fmt.Errorf("MusicExV1: read %d bytes (expected %d)", bytesRead, tag.TagSize)
+	}
+
+	tag.SongID = binary.LittleEndian.Uint32(buffer[0x00:0x04])
+	tag.Unknown1 = binary.LittleEndian.Uint32(buffer[0x04:0x08])
+	tag.Unknown2 = binary.LittleEndian.Uint32(buffer[0x08:0x0C])
+	tag.MediaID = readUnicodeTagName(buffer[0x0C:], 30*2)
+	tag.MediaFileName = readUnicodeTagName(buffer[0x48:], 50*2)
+	tag.Unknown3 = binary.LittleEndian.Uint32(buffer[0xAC:0xB0])
+	return tag, nil
+}
+
+// readUnicodeTagName reads a buffer to maxLen.
+// reconstruct text by skipping alternate char (ascii chars encoded in UTF-16-LE),
+// until finding a zero or reaching maxLen.
+func readUnicodeTagName(buffer []byte, maxLen int) string {
+	builder := strings.Builder{}
+
+	for i := 0; i < maxLen; i += 2 {
+		chr := buffer[i]
+		if chr != 0 {
+			builder.WriteByte(chr)
+		} else {
+			break
+		}
+	}
+
+	return builder.String()
+}

algo/qmc/qmc_meta.go

@@ -0,0 +1,128 @@
+package qmc
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"strings"
+
+	"github.com/samber/lo"
+
+	"unlock-music.dev/cli/algo/common"
+	"unlock-music.dev/cli/algo/qmc/client"
+	"unlock-music.dev/cli/internal/ffmpeg"
+)
+
+func (d *Decoder) GetAudioMeta(ctx context.Context) (common.AudioMeta, error) {
+	if d.meta != nil {
+		return d.meta, nil
+	}
+
+	if d.songID != 0 {
+		if err := d.getMetaBySongID(ctx); err != nil {
+			return nil, err
+		}
+		return d.meta, nil
+	}
+
+	embedMeta, err := ffmpeg.ProbeReader(ctx, d.probeBuf)
+	if err != nil {
+		return nil, fmt.Errorf("qmc[GetAudioMeta] probe reader: %w", err)
+	}
+	d.meta = embedMeta
+	d.embeddedCover = embedMeta.HasAttachedPic()
+
+	if !d.embeddedCover && embedMeta.HasMetadata() {
+		if err := d.searchMetaOnline(ctx, embedMeta); err != nil {
+			return nil, err
+		}
+		return d.meta, nil
+	}
+
+	return d.meta, nil
+}
+
+func (d *Decoder) getMetaBySongID(ctx context.Context) error {
+	c := client.NewQQMusicClient() // todo: use global client
+	trackInfo, err := c.GetTrackInfo(ctx, d.songID)
+	if err != nil {
+		return fmt.Errorf("qmc[GetAudioMeta] get track info: %w", err)
+	}
+
+	d.meta = trackInfo
+	d.albumID = trackInfo.Album.Id
+	if trackInfo.Album.Pmid == "" {
+		d.albumMediaID = trackInfo.Album.Pmid
+	} else {
+		d.albumMediaID = trackInfo.Album.Mid
+	}
+	return nil
+}
+
+func (d *Decoder) searchMetaOnline(ctx context.Context, original common.AudioMeta) error {
+	c := client.NewQQMusicClient() // todo: use global client
+	keyword := lo.WithoutEmpty(append(
+		[]string{original.GetTitle(), original.GetAlbum()},
+		original.GetArtists()...),
+	)
+	if len(keyword) == 0 {
+		return errors.New("qmc[searchMetaOnline] no keyword")
+	}
+
+	trackList, err := c.Search(ctx, strings.Join(keyword, " "))
+	if err != nil {
+		return fmt.Errorf("qmc[searchMetaOnline] search: %w", err)
+	}
+
+	if len(trackList) == 0 {
+		return errors.New("qmc[searchMetaOnline] no result")
+	}
+
+	meta := trackList[0]
+	d.meta = meta
+	d.albumID = meta.Album.Id
+	if meta.Album.Pmid == "" {
+		d.albumMediaID = meta.Album.Pmid
+	} else {
+		d.albumMediaID = meta.Album.Mid
+	}
+
+	return nil
+}
+
+func (d *Decoder) GetCoverImage(ctx context.Context) ([]byte, error) {
+	if d.cover != nil {
+		return d.cover, nil
+	}
+
+	if d.embeddedCover {
+		img, err := ffmpeg.ExtractAlbumArt(ctx, d.probeBuf)
+		if err != nil {
+			return nil, fmt.Errorf("qmc[GetCoverImage] extract album art: %w", err)
+		}
+
+		d.cover = img.Bytes()
+
+		return d.cover, nil
+	}
+
+	c := client.NewQQMusicClient() // todo: use global client
+	var err error
+
+	if d.albumMediaID != "" {
+		d.cover, err = c.AlbumCoverByMediaID(ctx, d.albumMediaID)
+		if err != nil {
+			return nil, fmt.Errorf("qmc[GetCoverImage] get cover by media id: %w", err)
+		}
+	} else if d.albumID != 0 {
+		d.cover, err = c.AlbumCoverByID(ctx, d.albumID)
+		if err != nil {
+			return nil, fmt.Errorf("qmc[GetCoverImage] get cover by id: %w", err)
+		}
+	} else {
+		return nil, errors.New("qmc[GetAudioMeta] album (or media) id is empty")
+	}
+
+	return d.cover, nil
+
+}

algo/qmc/qmc_test.go

@@ -7,6 +7,8 @@ import (
 	"os"
 	"reflect"
 	"testing"
+
+	"unlock-music.dev/cli/algo/common"
 )
 
 func loadTestDataQmcDecoder(filename string) ([]byte, []byte, error) {
@@ -29,12 +31,14 @@ func loadTestDataQmcDecoder(filename string) ([]byte, []byte, error) {
 func TestMflac0Decoder_Read(t *testing.T) {
 	tests := []struct {
 		name    string
+		fileExt string
 		wantErr bool
 	}{
-		{"mflac0_rc4", false},
-		{"mflac_map", false},
-		{"mgg_map", false},
-		{"qmc0_static", false},
+		{"mflac0_rc4", ".mflac0", false},
+		{"mflac_rc4", ".mflac", false},
+		{"mflac_map", ".mflac", false},
+		{"mgg_map", ".mgg", false},
+		{"qmc0_static", ".qmc0", false},
 	}
 
 	for _, tt := range tests {
@@ -44,11 +48,14 @@ func TestMflac0Decoder_Read(t *testing.T) {
 				t.Fatal(err)
 			}
 
-			d, err := NewDecoder(bytes.NewReader(raw))
-			if err != nil {
-				t.Error(err)
-				return
+			d := NewDecoder(&common.DecoderParams{
+				Reader:    bytes.NewReader(raw),
+				Extension: tt.fileExt,
+			})
+			if err := d.Validate(); err != nil {
+				t.Errorf("validate file error = %v", err)
 			}
+
 			buf := make([]byte, len(target))
 			if _, err := io.ReadFull(d, buf); err != nil {
 				t.Errorf("read bytes from decoder error = %v", err)
@@ -80,19 +87,15 @@ func TestMflac0Decoder_Validate(t *testing.T) {
 			if err != nil {
 				t.Fatal(err)
 			}
-			d, err := NewDecoder(bytes.NewReader(raw))
-			if err != nil {
-				t.Error(err)
-				return
-			}
+			d := NewDecoder(&common.DecoderParams{
+				Reader:    bytes.NewReader(raw),
+				Extension: tt.fileExt,
+			})
 
 			if err := d.Validate(); err != nil {
 				t.Errorf("read bytes from decoder error = %v", err)
 				return
 			}
-			if tt.fileExt != d.GetFileExt() {
-				t.Errorf("Decrypt() got = %v, want %v", d.GetFileExt(), tt.fileExt)
-			}
 		})
 	}
 }

algo/qmc/testdata/mflac_rc4_key.bin

@@ -0,0 +1 @@
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

algo/qmc/testdata/mflac_rc4_key_raw.bin

@@ -0,0 +1 @@
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

algo/tm/tm.go

@@ -3,77 +3,56 @@ package tm
 import (
 	"bytes"
 	"errors"
-	"github.com/unlock-music/cli/algo/common"
+	"fmt"
+	"io"
+
+	"unlock-music.dev/cli/algo/common"
+	"unlock-music.dev/cli/internal/sniff"
 )
 
 var replaceHeader = []byte{0x00, 0x00, 0x00, 0x20, 0x66, 0x74, 0x79, 0x70}
 var magicHeader = []byte{0x51, 0x51, 0x4D, 0x55} //0x15, 0x1D, 0x1A, 0x21
 
 type Decoder struct {
-	file        []byte
-	audio       []byte
-	headerMatch bool
-	audioExt    string
-}
+	raw io.ReadSeeker // raw is the original file reader
 
-func (d *Decoder) GetCoverImage() []byte {
-	return nil
-}
-
-func (d *Decoder) GetAudioData() []byte {
-	return d.audio
-}
-
-func (d *Decoder) GetAudioExt() string {
-	if d.audioExt != "" {
-		return "." + d.audioExt
-	}
-	return ""
-}
-
-func (d *Decoder) GetMeta() common.Meta {
-	return nil
+	offset int
+	audio  io.Reader // audio is the decrypted audio data
 }
 
 func (d *Decoder) Validate() error {
-	if len(d.file) < 8 {
-		return errors.New("invalid file size")
+	header := make([]byte, 8)
+	if _, err := io.ReadFull(d.raw, header); err != nil {
+		return fmt.Errorf("tm read header: %w", err)
 	}
-	if !bytes.Equal(magicHeader, d.file[:4]) {
-		return errors.New("not a valid tm file")
-	}
-	d.headerMatch = true
+
+	if bytes.Equal(magicHeader, header[:len(magicHeader)]) { // replace m4a header
+		d.audio = io.MultiReader(bytes.NewReader(replaceHeader), d.raw)
 		return nil
 	}
 
-func (d *Decoder) Decode() error {
-	d.audio = d.file
-	if d.headerMatch {
-		for i := 0; i < 8; i++ {
-			d.audio[i] = replaceHeader[i]
-		}
-		d.audioExt = "m4a"
-	}
+	if _, ok := sniff.AudioExtension(header); ok { // not encrypted
+		d.audio = io.MultiReader(bytes.NewReader(header), d.raw)
 		return nil
 	}
 
-//goland:noinspection GoUnusedExportedFunction
-func NewDecoder(data []byte) common.Decoder {
-	return &Decoder{file: data}
+	return errors.New("tm: valid magic header")
 }
 
-func DecoderFuncWithExt(ext string) common.NewDecoderFunc {
-	return func(file []byte) common.Decoder {
-		return &Decoder{file: file, audioExt: ext}
+func (d *Decoder) Read(buf []byte) (int, error) {
+	return d.audio.Read(buf)
 }
+
+func NewTmDecoder(p *common.DecoderParams) common.Decoder {
+	return &Decoder{raw: p.Reader}
 }
 
 func init() {
-	// QQ Music IOS M4a
-	common.RegisterDecoder("tm2", false, DecoderFuncWithExt("m4a"))
-	common.RegisterDecoder("tm6", false, DecoderFuncWithExt("m4a"))
-	// QQ Music IOS Mp3
-	common.RegisterDecoder("tm0", false, common.NewRawDecoder)
-	common.RegisterDecoder("tm3", false, common.NewRawDecoder)
+	// QQ Music IOS M4a (replace header)
+	common.RegisterDecoder("tm2", false, NewTmDecoder)
+	common.RegisterDecoder("tm6", false, NewTmDecoder)
 
+	// QQ Music IOS Mp3 (not encrypted)
+	common.RegisterDecoder("tm0", false, NewTmDecoder)
+	common.RegisterDecoder("tm3", false, NewTmDecoder)
 }

algo/xiami/xm.go

@@ -0,0 +1,91 @@
+package xiami
+
+import (
+	"bytes"
+	"errors"
+	"fmt"
+	"io"
+
+	"unlock-music.dev/cli/algo/common"
+)
+
+var (
+	magicHeader  = []byte{'i', 'f', 'm', 't'}
+	magicHeader2 = []byte{0xfe, 0xfe, 0xfe, 0xfe}
+	typeMapping  = map[string]string{
+		" WAV": "wav",
+		"FLAC": "flac",
+		" MP3": "mp3",
+		" A4M": "m4a",
+	}
+	ErrMagicHeader = errors.New("xm magic header not matched")
+)
+
+type Decoder struct {
+	rd     io.ReadSeeker // rd is the original file reader
+	offset int
+
+	cipher    common.StreamDecoder
+	outputExt string
+}
+
+func (d *Decoder) GetAudioExt() string {
+	if d.outputExt != "" {
+		return "." + d.outputExt
+
+	}
+	return ""
+}
+
+func NewDecoder(p *common.DecoderParams) common.Decoder {
+	return &Decoder{rd: p.Reader}
+}
+
+// Validate checks if the file is a valid xiami .xm file.
+// rd will set to the beginning of the encrypted audio data.
+func (d *Decoder) Validate() error {
+	header := make([]byte, 16) // xm header is fixed to 16 bytes
+
+	if _, err := io.ReadFull(d.rd, header); err != nil {
+		return fmt.Errorf("xm read header: %w", err)
+	}
+
+	// 0x00 - 0x03 and 0x08 - 0x0B: magic header
+	if !bytes.Equal(magicHeader, header[:4]) || !bytes.Equal(magicHeader2, header[8:12]) {
+		return ErrMagicHeader
+	}
+
+	// 0x04 - 0x07: Audio File Type
+	var ok bool
+	d.outputExt, ok = typeMapping[string(header[4:8])]
+	if !ok {
+		return fmt.Errorf("xm detect unknown audio type: %s", string(header[4:8]))
+	}
+
+	// 0x0C - 0x0E, Encrypt Start At, LittleEndian Unit24
+	encStartAt := uint32(header[12]) | uint32(header[13])<<8 | uint32(header[14])<<16
+
+	// 0x0F, XOR Mask
+	d.cipher = newXmCipher(header[15], int(encStartAt))
+
+	return nil
+}
+
+func (d *Decoder) Read(p []byte) (int, error) {
+	n, err := d.rd.Read(p)
+	if n > 0 {
+		d.cipher.Decrypt(p[:n], d.offset)
+		d.offset += n
+	}
+	return n, err
+}
+
+func init() {
+	// Xiami Wav/M4a/Mp3/Flac
+	common.RegisterDecoder("xm", false, NewDecoder)
+	// Xiami Typed Format
+	common.RegisterDecoder("wav", false, NewDecoder)
+	common.RegisterDecoder("mp3", false, NewDecoder)
+	common.RegisterDecoder("flac", false, NewDecoder)
+	common.RegisterDecoder("m4a", false, NewDecoder)
+}

algo/xiami/xm_cipher.go

@@ -0,0 +1,21 @@
+package xiami
+
+type xmCipher struct {
+	mask           byte
+	encryptStartAt int
+}
+
+func newXmCipher(mask byte, encryptStartAt int) *xmCipher {
+	return &xmCipher{
+		mask:           mask,
+		encryptStartAt: encryptStartAt,
+	}
+}
+
+func (c *xmCipher) Decrypt(buf []byte, offset int) {
+	for i := 0; i < len(buf); i++ {
+		if offset+i >= c.encryptStartAt {
+			buf[i] ^= c.mask
+		}
+	}
+}

algo/ximalaya/x2m_crypto.go

@@ -0,0 +1,34 @@
+package ximalaya
+
+import (
+	_ "embed"
+	"encoding/binary"
+)
+
+const x2mHeaderSize = 1024
+
+var x2mKey = [...]byte{'x', 'm', 'l', 'y'}
+var x2mScrambleTable = [x2mHeaderSize]uint16{}
+
+//go:embed x2m_scramble_table.bin
+var x2mScrambleTableBytes []byte
+
+func init() {
+	if len(x2mScrambleTableBytes) != 2*x2mHeaderSize {
+		panic("invalid x2m scramble table")
+	}
+	for i := range x2mScrambleTable {
+		x2mScrambleTable[i] = binary.LittleEndian.Uint16(x2mScrambleTableBytes[i*2:])
+	}
+}
+
+// decryptX2MHeader decrypts the header of ximalaya .x2m file.
+// make sure input src is 1024(x2mHeaderSize) bytes long.
+func decryptX2MHeader(src []byte) []byte {
+	dst := make([]byte, len(src))
+	for dstIdx := range src {
+		srcIdx := x2mScrambleTable[dstIdx]
+		dst[dstIdx] = src[srcIdx] ^ x2mKey[dstIdx%len(x2mKey)]
+	}
+	return dst
+}

algo/ximalaya/x3m_crypto.go

@@ -0,0 +1,40 @@
+package ximalaya
+
+import (
+	_ "embed"
+	"encoding/binary"
+)
+
+var x3mKey = [...]byte{
+	'3', '9', '8', '9', 'd', '1', '1', '1',
+	'a', 'a', 'd', '5', '6', '1', '3', '9',
+	'4', '0', 'f', '4', 'f', 'c', '4', '4',
+	'b', '6', '3', '9', 'b', '2', '9', '2',
+}
+
+const x3mHeaderSize = 1024
+
+var x3mScrambleTable = [x3mHeaderSize]uint16{}
+
+//go:embed x3m_scramble_table.bin
+var x3mScrambleTableBytes []byte
+
+func init() {
+	if len(x3mScrambleTableBytes) != 2*x3mHeaderSize {
+		panic("invalid x3m scramble table")
+	}
+	for i := range x3mScrambleTable {
+		x3mScrambleTable[i] = binary.LittleEndian.Uint16(x3mScrambleTableBytes[i*2:])
+	}
+}
+
+// decryptX3MHeader decrypts the header of ximalaya .x3m file.
+// make sure input src is 1024 (x3mHeaderSize) bytes long.
+func decryptX3MHeader(src []byte) []byte {
+	dst := make([]byte, len(src))
+	for dstIdx := range src {
+		srcIdx := x3mScrambleTable[dstIdx]
+		dst[dstIdx] = src[srcIdx] ^ x3mKey[dstIdx%len(x3mKey)]
+	}
+	return dst
+}

algo/ximalaya/ximalaya.go

@@ -0,0 +1,57 @@
+package ximalaya
+
+import (
+	"bytes"
+	"fmt"
+	"io"
+
+	"unlock-music.dev/cli/algo/common"
+	"unlock-music.dev/cli/internal/sniff"
+)
+
+type Decoder struct {
+	rd     io.ReadSeeker
+	offset int
+
+	audio io.Reader
+}
+
+func NewDecoder(p *common.DecoderParams) common.Decoder {
+	return &Decoder{rd: p.Reader}
+}
+
+func (d *Decoder) Validate() error {
+	encryptedHeader := make([]byte, x2mHeaderSize)
+	if _, err := io.ReadFull(d.rd, encryptedHeader); err != nil {
+		return fmt.Errorf("ximalaya read header: %w", err)
+	}
+
+	{ // try to decode with x2m
+		header := decryptX2MHeader(encryptedHeader)
+		if _, ok := sniff.AudioExtension(header); ok {
+			d.audio = io.MultiReader(bytes.NewReader(header), d.rd)
+			return nil
+		}
+	}
+
+	{ // try to decode with x3m
+		// not read file again, since x2m and x3m have the same header size
+		header := decryptX3MHeader(encryptedHeader)
+		if _, ok := sniff.AudioExtension(header); ok {
+			d.audio = io.MultiReader(bytes.NewReader(header), d.rd)
+			return nil
+		}
+	}
+
+	return fmt.Errorf("ximalaya: unknown format")
+}
+
+func (d *Decoder) Read(p []byte) (n int, err error) {
+	return d.audio.Read(p)
+}
+
+func init() {
+	common.RegisterDecoder("x2m", false, NewDecoder)
+	common.RegisterDecoder("x3m", false, NewDecoder)
+	common.RegisterDecoder("xm", false, NewDecoder)
+}

algo/xm/xm.go

@@ -1,106 +0,0 @@
-package xm
-
-import (
-	"bytes"
-	"errors"
-	"github.com/unlock-music/cli/algo/common"
-	"github.com/unlock-music/cli/internal/logging"
-	"go.uber.org/zap"
-)
-
-var (
-	magicHeader  = []byte{'i', 'f', 'm', 't'}
-	magicHeader2 = []byte{0xfe, 0xfe, 0xfe, 0xfe}
-	typeMapping  = map[string]string{
-		" WAV": "wav",
-		"FLAC": "flac",
-		" MP3": "mp3",
-		" A4M": "m4a",
-	}
-	ErrFileSize    = errors.New("xm invalid file size")
-	ErrMagicHeader = errors.New("xm magic header not matched")
-)
-
-type Decoder struct {
-	file      []byte
-	headerLen uint32
-	outputExt string
-	mask      byte
-	audio     []byte
-}
-
-func (d *Decoder) GetCoverImage() []byte {
-	return nil
-}
-
-func (d *Decoder) GetAudioData() []byte {
-	return d.audio
-}
-
-func (d *Decoder) GetAudioExt() string {
-	if d.outputExt != "" {
-		return "." + d.outputExt
-
-	}
-	return ""
-}
-
-func (d *Decoder) GetMeta() common.Meta {
-	return nil
-}
-
-func NewDecoder(data []byte) common.Decoder {
-	return &Decoder{file: data}
-}
-
-func (d *Decoder) Validate() error {
-	lenData := len(d.file)
-	if lenData < 16 {
-		return ErrFileSize
-	}
-	if !bytes.Equal(magicHeader, d.file[:4]) ||
-		!bytes.Equal(magicHeader2, d.file[8:12]) {
-		return ErrMagicHeader
-	}
-
-	var ok bool
-	d.outputExt, ok = typeMapping[string(d.file[4:8])]
-	if !ok {
-		return errors.New("detect unknown xm file type: " + string(d.file[4:8]))
-	}
-
-	if d.file[14] != 0 {
-		logging.Log().Warn("not a simple xm file", zap.Uint8("b[14]", d.file[14]))
-	}
-	d.headerLen = uint32(d.file[12]) | uint32(d.file[13])<<8 | uint32(d.file[14])<<16 // LittleEndian Unit24
-	if d.headerLen+16 > uint32(lenData) {
-		return ErrFileSize
-	}
-	return nil
-}
-
-func (d *Decoder) Decode() error {
-	d.mask = d.file[15]
-	d.audio = d.file[16:]
-	dataLen := uint32(len(d.audio))
-	for i := d.headerLen; i < dataLen; i++ {
-		d.audio[i] = ^(d.audio[i] - d.mask)
-	}
-	return nil
-}
-
-func DecoderFuncWithExt(ext string) common.NewDecoderFunc {
-	return func(file []byte) common.Decoder {
-		return &Decoder{file: file, outputExt: ext}
-	}
-}
-
-func init() {
-	// Xiami Wav/M4a/Mp3/Flac
-	common.RegisterDecoder("xm", false, NewDecoder)
-	// Xiami Typed Format
-	common.RegisterDecoder("wav", false, DecoderFuncWithExt("wav"))
-	common.RegisterDecoder("mp3", false, DecoderFuncWithExt("mp3"))
-	common.RegisterDecoder("flac", false, DecoderFuncWithExt("flac"))
-	common.RegisterDecoder("m4a", false, DecoderFuncWithExt("m4a"))
-}

cmd/um/main.go

@@ -1,63 +1,123 @@
 package main
 
 import (
+	"bytes"
+	"context"
 	"errors"
 	"fmt"
-	"os"
-	"path/filepath"
-	"runtime"
-	"sort"
-	"strings"
-
+	"github.com/fsnotify/fsnotify"
 	"github.com/urfave/cli/v2"
 	"go.uber.org/zap"
-
-	"github.com/unlock-music/cli/algo/common"
-	_ "github.com/unlock-music/cli/algo/kgm"
-	_ "github.com/unlock-music/cli/algo/kwm"
-	_ "github.com/unlock-music/cli/algo/ncm"
-	_ "github.com/unlock-music/cli/algo/qmc"
-	_ "github.com/unlock-music/cli/algo/tm"
-	_ "github.com/unlock-music/cli/algo/xm"
-	"github.com/unlock-music/cli/internal/logging"
+	"go.uber.org/zap/zapcore"
+	"io"
+	"os"
+	"os/signal"
+	"path/filepath"
+	"runtime"
+	"runtime/debug"
+	"sort"
+	"strings"
+	"time"
+	"unlock-music.dev/cli/algo/common"
+	_ "unlock-music.dev/cli/algo/kgm"
+	_ "unlock-music.dev/cli/algo/kwm"
+	_ "unlock-music.dev/cli/algo/ncm"
+	"unlock-music.dev/cli/algo/qmc"
+	_ "unlock-music.dev/cli/algo/tm"
+	_ "unlock-music.dev/cli/algo/xiami"
+	_ "unlock-music.dev/cli/algo/ximalaya"
+	"unlock-music.dev/cli/internal/ffmpeg"
+	"unlock-music.dev/cli/internal/sniff"
+	"unlock-music.dev/cli/internal/utils"
 )
 
-var AppVersion = "v0.0.6"
+var AppVersion = "v0.2.11"
+
+var logger = setupLogger(false) // TODO: inject logger to application, instead of using global logger
 
 func main() {
+	module, ok := debug.ReadBuildInfo()
+	if ok && module.Main.Version != "(devel)" {
+		AppVersion = module.Main.Version
+	}
 	app := cli.App{
 		Name:     "Unlock Music CLI",
 		HelpName: "um",
-		Usage:    "Unlock your encrypted music file https://github.com/unlock-music/cli",
+		Usage:    "Unlock your encrypted music file https://git.unlock-music.dev/um/cli",
 		Version:  fmt.Sprintf("%s (%s,%s/%s)", AppVersion, runtime.Version(), runtime.GOOS, runtime.GOARCH),
 		Flags: []cli.Flag{
 			&cli.StringFlag{Name: "input", Aliases: []string{"i"}, Usage: "path to input file or dir", Required: false},
 			&cli.StringFlag{Name: "output", Aliases: []string{"o"}, Usage: "path to output dir", Required: false},
+			&cli.StringFlag{Name: "qmc-mmkv", Aliases: []string{"db"}, Usage: "path to qmc mmkv (.crc file also required)", Required: false},
+			&cli.StringFlag{Name: "qmc-mmkv-key", Aliases: []string{"key"}, Usage: "mmkv password (16 ascii chars)", Required: false},
+			&cli.BoolFlag{Name: "remove-source", Aliases: []string{"rs"}, Usage: "remove source file", Required: false, Value: false},
 			&cli.BoolFlag{Name: "skip-noop", Aliases: []string{"n"}, Usage: "skip noop decoder", Required: false, Value: true},
-			&cli.BoolFlag{Name: "supported-ext", Usage: "Show supported file extensions and exit", Required: false, Value: false},
+			&cli.BoolFlag{Name: "verbose", Aliases: []string{"V"}, Usage: "verbose logging", Required: false, Value: false},
+			&cli.BoolFlag{Name: "update-metadata", Usage: "update metadata & album art from network", Required: false, Value: false},
+			&cli.BoolFlag{Name: "overwrite", Usage: "overwrite output file without asking", Required: false, Value: false},
+			&cli.BoolFlag{Name: "watch", Usage: "watch the input dir and process new files", Required: false, Value: false},
+
+			&cli.BoolFlag{Name: "supported-ext", Usage: "show supported file extensions and exit", Required: false, Value: false},
 		},
 
 		Action:          appMain,
-		Copyright:       "Copyright (c) 2020 - 2021 Unlock Music https://github.com/unlock-music/cli/blob/master/LICENSE",
+		Copyright:       fmt.Sprintf("Copyright (c) 2020 - %d Unlock Music https://git.unlock-music.dev/um/cli/src/branch/master/LICENSE", time.Now().Year()),
 		HideHelpCommand: true,
 		UsageText:       "um [-o /path/to/output/dir] [--extra-flags] [-i] /path/to/input",
 	}
+
 	err := app.Run(os.Args)
 	if err != nil {
-		logging.Log().Fatal("run app failed", zap.Error(err))
+		logger.Fatal("run app failed", zap.Error(err))
 	}
 }
+
 func printSupportedExtensions() {
-	exts := []string{}
-	for ext := range common.DecoderRegistry {
+	var exts []string
+	extSet := make(map[string]int)
+	for _, factory := range common.DecoderRegistry {
+		ext := strings.TrimPrefix(factory.Suffix, ".")
+		if n, ok := extSet[ext]; ok {
+			extSet[ext] = n + 1
+		} else {
+			extSet[ext] = 1
+		}
+	}
+	for ext := range extSet {
 		exts = append(exts, ext)
 	}
 	sort.Strings(exts)
 	for _, ext := range exts {
-		fmt.Printf("%s: %d\n", ext, len(common.DecoderRegistry[ext]))
+		fmt.Printf("%s: %d\n", ext, extSet[ext])
 	}
 }
+
+func setupLogger(verbose bool) *zap.Logger {
+	logConfig := zap.NewProductionEncoderConfig()
+	logConfig.EncodeLevel = zapcore.CapitalColorLevelEncoder
+	logConfig.EncodeTime = zapcore.RFC3339TimeEncoder
+	enabler := zap.LevelEnablerFunc(func(level zapcore.Level) bool {
+		if verbose {
+			return true
+		}
+		return level >= zapcore.InfoLevel
+	})
+
+	return zap.New(zapcore.NewCore(
+		zapcore.NewConsoleEncoder(logConfig),
+		os.Stdout,
+		enabler,
+	))
+}
+
 func appMain(c *cli.Context) (err error) {
+	logger = setupLogger(c.Bool("verbose"))
+
+	cwd, err := os.Getwd()
+	if err != nil {
+		return err
+	}
+
 	if c.Bool("supported-ext") {
 		printSupportedExtensions()
 		return nil
@@ -66,10 +126,7 @@ func appMain(c *cli.Context) (err error) {
 	if input == "" {
 		switch c.Args().Len() {
 		case 0:
-			input, err = os.Getwd()
-			if err != nil {
-				return err
-			}
+			input = cwd
 		case 1:
 			input = c.Args().Get(0)
 		default:
@@ -77,25 +134,34 @@ func appMain(c *cli.Context) (err error) {
 		}
 	}
 
+	input, absErr := filepath.Abs(input)
+	if absErr != nil {
+		return fmt.Errorf("get abs path failed: %w", absErr)
+	}
+
 	output := c.String("output")
-	if output == "" {
-		var err error
-		output, err = os.Getwd()
-		if err != nil {
-			return err
-		}
-		if input == output {
-			return errors.New("input and output path are same")
-		}
-	}
-
-	skipNoop := c.Bool("skip-noop")
-
 	inputStat, err := os.Stat(input)
 	if err != nil {
 		return err
 	}
 
+	var inputDir string
+	if inputStat.IsDir() {
+		inputDir = input
+	} else {
+		inputDir = filepath.Dir(input)
+	}
+	inputDir, absErr = filepath.Abs(inputDir)
+	if absErr != nil {
+		return fmt.Errorf("get abs path (inputDir) failed: %w", absErr)
+	}
+
+	if output == "" {
+		// Default to where the input dir is
+		output = inputDir
+	}
+	logger.Debug("resolve input/output path", zap.String("inputDir", inputDir), zap.String("input", input), zap.String("output", output))
+
 	outputStat, err := os.Stat(output)
 	if err != nil {
 		if errors.Is(err, os.ErrNotExist) {
@@ -108,79 +174,276 @@ func appMain(c *cli.Context) (err error) {
 		return errors.New("output should be a writable directory")
 	}
 
-	if inputStat.IsDir() {
-		return dealDirectory(input, output, skipNoop)
-	} else {
-		allDec := common.GetDecoder(inputStat.Name(), skipNoop)
-		if len(allDec) == 0 {
-			logging.Log().Fatal("skipping while no suitable decoder")
+	if mmkv := c.String("qmc-mmkv"); mmkv != "" {
+		// If key is not set, the mmkv vault will be treated as unencrypted.
+		key := c.String("qmc-mmkv-key")
+		err := qmc.OpenMMKV(mmkv, key, logger)
+		if err != nil {
+			return err
 		}
-		return tryDecFile(input, output, allDec)
+	}
+
+	proc := &processor{
+		logger:          logger,
+		inputDir:        inputDir,
+		outputDir:       output,
+		skipNoopDecoder: c.Bool("skip-noop"),
+		removeSource:    c.Bool("remove-source"),
+		updateMetadata:  c.Bool("update-metadata"),
+		overwriteOutput: c.Bool("overwrite"),
+	}
+
+	if inputStat.IsDir() {
+		watchDir := c.Bool("watch")
+		if !watchDir {
+			return proc.processDir(input)
+		} else {
+			return proc.watchDir(input)
+		}
+	} else {
+		return proc.processFile(input)
 	}
 
 }
-func dealDirectory(inputDir string, outputDir string, skipNoop bool) error {
+
+type processor struct {
+	logger    *zap.Logger
+	inputDir  string
+	outputDir string
+
+	skipNoopDecoder bool
+	removeSource    bool
+	updateMetadata  bool
+	overwriteOutput bool
+}
+
+func (p *processor) watchDir(inputDir string) error {
+	if err := p.processDir(inputDir); err != nil {
+		return err
+	}
+
+	watcher, err := fsnotify.NewWatcher()
+	if err != nil {
+		return fmt.Errorf("failed to create watcher: %w", err)
+	}
+	defer watcher.Close()
+
+	go func() {
+		for {
+			select {
+			case event, ok := <-watcher.Events:
+				if !ok {
+					return
+				}
+
+				if event.Has(fsnotify.Create) || event.Has(fsnotify.Write) {
+					// try open with exclusive mode, to avoid file is still writing
+					f, err := os.OpenFile(event.Name, os.O_RDONLY, os.ModeExclusive)
+					if err != nil {
+						logger.Debug("failed to open file exclusively", zap.String("path", event.Name), zap.Error(err))
+						time.Sleep(1 * time.Second) // wait for file writing complete
+						continue
+					}
+					_ = f.Close()
+
+					if err := p.processFile(event.Name); err != nil {
+						logger.Warn("failed to process file", zap.String("path", event.Name), zap.Error(err))
+					}
+				}
+			case err, ok := <-watcher.Errors:
+				if !ok {
+					return
+				}
+				logger.Error("file watcher got error", zap.Error(err))
+			}
+		}
+	}()
+
+	err = watcher.Add(inputDir)
+	if err != nil {
+		return fmt.Errorf("failed to watch dir %s: %w", inputDir, err)
+	}
+
+	signalCtx, stop := signal.NotifyContext(context.Background(), os.Interrupt)
+	defer stop()
+
+	<-signalCtx.Done()
+	return nil
+}
+
+func (p *processor) processDir(inputDir string) error {
 	items, err := os.ReadDir(inputDir)
 	if err != nil {
 		return err
 	}
+
+	var lastError error = nil
 	for _, item := range items {
+		filePath := filepath.Join(inputDir, item.Name())
 		if item.IsDir() {
+			if err = p.processDir(filePath); err != nil {
+				lastError = err
+			}
 			continue
 		}
-		allDec := common.GetDecoder(item.Name(), skipNoop)
+
+		if err := p.processFile(filePath); err != nil {
+			lastError = err
+			logger.Error("conversion failed", zap.String("source", item.Name()), zap.Error(err))
+		}
+	}
+	if lastError != nil {
+		return fmt.Errorf("last error: %w", lastError)
+	}
+	return nil
+}
+
+func (p *processor) processFile(filePath string) error {
+	p.logger.Debug("processFile", zap.String("file", filePath), zap.String("inputDir", p.inputDir))
+
+	allDec := common.GetDecoder(filePath, p.skipNoopDecoder)
 	if len(allDec) == 0 {
-			logging.Log().Info("skipping while no suitable decoder", zap.String("file", item.Name()))
-			continue
+		return errors.New("skipping while no suitable decoder")
 	}
 
-		err := tryDecFile(filepath.Join(inputDir, item.Name()), outputDir, allDec)
-		if err != nil {
-			logging.Log().Error("conversion failed", zap.String("source", item.Name()))
+	if err := p.process(filePath, allDec); err != nil {
+		return err
 	}
+
+	// if source file need to be removed
+	if p.removeSource {
+		err := os.RemoveAll(filePath)
+		if err != nil {
+			return err
+		}
+		logger.Info("source file removed after success conversion", zap.String("source", filePath))
 	}
 	return nil
 }
 
-func tryDecFile(inputFile string, outputDir string, allDec []common.NewDecoderFunc) error {
-	file, err := os.ReadFile(inputFile)
+func (p *processor) findDecoder(decoders []common.DecoderFactory, params *common.DecoderParams) (*common.Decoder, *common.DecoderFactory, error) {
+	for _, factory := range decoders {
+		dec := factory.Create(params)
+		err := dec.Validate()
+		if err == nil {
+			return &dec, &factory, nil
+		}
+		logger.Warn("try decode failed", zap.Error(err))
+	}
+	return nil, nil, errors.New("no any decoder can resolve the file")
+}
+
+func (p *processor) process(inputFile string, allDec []common.DecoderFactory) error {
+	file, err := os.Open(inputFile)
 	if err != nil {
 		return err
 	}
+	defer file.Close()
+	logger := logger.With(zap.String("source", inputFile))
 
-	var dec common.Decoder
-	for _, decFunc := range allDec {
-		dec = decFunc(file)
-		if err := dec.Validate(); err == nil {
-			break
+	pDec, decoderFactory, err := p.findDecoder(allDec, &common.DecoderParams{
+		Reader:    file,
+		Extension: filepath.Ext(inputFile),
+		FilePath:  inputFile,
+		Logger:    logger,
+	})
+	if err != nil {
+		return err
 	}
-		logging.Log().Warn("try decode failed", zap.Error(err))
-		dec = nil
+	dec := *pDec
+
+	params := &ffmpeg.UpdateMetadataParams{}
+
+	header := bytes.NewBuffer(nil)
+	_, err = io.CopyN(header, dec, 64)
+	if err != nil {
+		return fmt.Errorf("read header failed: %w", err)
 	}
-	if dec == nil {
-		return errors.New("no any decoder can resolve the file")
+	audio := io.MultiReader(header, dec)
+	params.AudioExt = sniff.AudioExtensionWithFallback(header.Bytes(), ".mp3")
+
+	if p.updateMetadata {
+		if audioMetaGetter, ok := dec.(common.AudioMetaGetter); ok {
+			ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
+			defer cancel()
+
+			// since ffmpeg doesn't support multiple input streams,
+			// we need to write the audio to a temp file.
+			// since qmc decoder doesn't support seeking & relying on ffmpeg probe, we need to read the whole file.
+			// TODO: support seeking or using pipe for qmc decoder.
+			params.Audio, err = utils.WriteTempFile(audio, params.AudioExt)
+			if err != nil {
+				return fmt.Errorf("updateAudioMeta write temp file: %w", err)
 			}
-	if err := dec.Decode(); err != nil {
-		return errors.New("failed while decoding: " + err.Error())
+			defer os.Remove(params.Audio)
+
+			params.Meta, err = audioMetaGetter.GetAudioMeta(ctx)
+			if err != nil {
+				logger.Warn("get audio meta failed", zap.Error(err))
 			}
 
-	outData := dec.GetAudioData()
-	outExt := dec.GetAudioExt()
-	if outExt == "" {
-		if ext, ok := common.SniffAll(outData); ok {
-			outExt = ext
+			if params.Meta == nil { // reset audio meta if failed
+				audio, err = os.Open(params.Audio)
+				if err != nil {
+					return fmt.Errorf("updateAudioMeta open temp file: %w", err)
+				}
+			}
+		}
+	}
+
+	if p.updateMetadata && params.Meta != nil {
+		if coverGetter, ok := dec.(common.CoverImageGetter); ok {
+			ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
+			defer cancel()
+
+			if cover, err := coverGetter.GetCoverImage(ctx); err != nil {
+				logger.Warn("get cover image failed", zap.Error(err))
+			} else if imgExt, ok := sniff.ImageExtension(cover); !ok {
+				logger.Warn("sniff cover image type failed", zap.Error(err))
 			} else {
-			outExt = ".mp3"
+				params.AlbumArtExt = imgExt
+				params.AlbumArt = cover
+			}
 		}
 	}
-	filenameOnly := strings.TrimSuffix(filepath.Base(inputFile), filepath.Ext(inputFile))
 
-	outPath := filepath.Join(outputDir, filenameOnly+outExt)
-	err = os.WriteFile(outPath, outData, 0644)
+	inputRelDir, err := filepath.Rel(p.inputDir, filepath.Dir(inputFile))
+	if err != nil {
+		return fmt.Errorf("get relative dir failed: %w", err)
+	}
+
+	inFilename := strings.TrimSuffix(filepath.Base(inputFile), decoderFactory.Suffix)
+	outPath := filepath.Join(p.outputDir, inputRelDir, inFilename+params.AudioExt)
+
+	if !p.overwriteOutput {
+		_, err := os.Stat(outPath)
+		if err == nil {
+			logger.Warn("output file already exist, skip", zap.String("destination", outPath))
+			return nil
+		} else if !errors.Is(err, os.ErrNotExist) {
+			return fmt.Errorf("stat output file failed: %w", err)
+		}
+	}
+
+	if params.Meta == nil {
+		outFile, err := os.OpenFile(outPath, os.O_CREATE|os.O_WRONLY|os.O_TRUNC, 0644)
 		if err != nil {
 			return err
 		}
-	logging.Log().Info("successfully converted",
-		zap.String("source", inputFile), zap.String("destination", outPath))
+		defer outFile.Close()
+
+		if _, err := io.Copy(outFile, audio); err != nil {
+			return err
+		}
+	} else {
+		ctx, cancel := context.WithTimeout(context.Background(), time.Minute)
+		defer cancel()
+
+		if err := ffmpeg.UpdateMeta(ctx, outPath, params, logger); err != nil {
+			return err
+		}
+	}
+
+	logger.Info("successfully converted", zap.String("source", inputFile), zap.String("destination", outPath))
 	return nil
 }

go.mod

@@ -1,17 +1,26 @@
-module github.com/unlock-music/cli
+module unlock-music.dev/cli
 
-go 1.17
+go 1.23.3
 
 require (
-	github.com/ulikunitz/xz v0.5.10
-	github.com/urfave/cli/v2 v2.3.0
-	go.uber.org/zap v1.19.1
-	golang.org/x/crypto v0.0.0-20191011191535-87dc89f01550
+	github.com/fsnotify/fsnotify v1.8.0
+	github.com/go-flac/flacpicture v0.3.0
+	github.com/go-flac/flacvorbis v0.2.0
+	github.com/go-flac/go-flac v1.0.0
+	github.com/samber/lo v1.47.0
+	github.com/urfave/cli/v2 v2.27.5
+	go.uber.org/zap v1.27.0
+	golang.org/x/crypto v0.29.0
+	golang.org/x/exp v0.0.0-20241108190413-2d47ceb2692f
+	golang.org/x/text v0.20.0
+	unlock-music.dev/mmkv v0.1.0
 )
 
 require (
-	github.com/cpuguy83/go-md2man/v2 v2.0.1 // indirect
+	github.com/cpuguy83/go-md2man/v2 v2.0.5 // indirect
 	github.com/russross/blackfriday/v2 v2.1.0 // indirect
-	go.uber.org/atomic v1.9.0 // indirect
-	go.uber.org/multierr v1.7.0 // indirect
+	github.com/xrash/smetrics v0.0.0-20240521201337-686a1a2994c1 // indirect
+	go.uber.org/multierr v1.11.0 // indirect
+	golang.org/x/sys v0.27.0 // indirect
+	google.golang.org/protobuf v1.35.2 // indirect
 )

go.sum

@@ -1,73 +1,60 @@
-github.com/BurntSushi/toml v0.3.1/go.mod h1:xHWCNGjB5oqiDr8zfno3MHue2Ht5sIBksp03qcyfWMU=
-github.com/benbjohnson/clock v1.1.0 h1:Q92kusRqC1XV2MjkWETPvjJVqKetz1OzxZB7mHJLju8=
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internal/ffmpeg/ffmpeg.go

@@ -0,0 +1,126 @@
+package ffmpeg
+
+import (
+	"bytes"
+	"context"
+	"fmt"
+	"go.uber.org/zap"
+	"io"
+	"os"
+	"os/exec"
+	"strings"
+
+	"unlock-music.dev/cli/algo/common"
+	"unlock-music.dev/cli/internal/utils"
+)
+
+func ExtractAlbumArt(ctx context.Context, rd io.Reader) (*bytes.Buffer, error) {
+	cmd := exec.CommandContext(ctx, "ffmpeg",
+		"-i", "pipe:0", // input from stdin
+		"-an",              // disable audio
+		"-codec:v", "copy", // copy video(image) codec
+		"-f", "image2", // use image2 muxer
+		"pipe:1", // output to stdout
+	)
+
+	cmd.Stdin = rd
+	stdout, stderr := &bytes.Buffer{}, &bytes.Buffer{}
+	cmd.Stdout, cmd.Stderr = stdout, stderr
+
+	if err := cmd.Run(); err != nil {
+		return nil, fmt.Errorf("ffmpeg run: %w", err)
+	}
+
+	return stdout, nil
+}
+
+type UpdateMetadataParams struct {
+	Audio    string // required
+	AudioExt string // required
+
+	Meta common.AudioMeta // required
+
+	AlbumArt    []byte // optional
+	AlbumArtExt string // required if AlbumArt is not nil
+}
+
+func UpdateMeta(ctx context.Context, outPath string, params *UpdateMetadataParams, logger *zap.Logger) error {
+	if params.AudioExt == ".flac" {
+		return updateMetaFlac(ctx, outPath, params, logger.With(zap.String("module", "updateMetaFlac")))
+	} else {
+		return updateMetaFFmpeg(ctx, outPath, params)
+	}
+}
+func updateMetaFFmpeg(ctx context.Context, outPath string, params *UpdateMetadataParams) error {
+	builder := newFFmpegBuilder()
+
+	out := newOutputBuilder(outPath) // output to file
+	builder.SetFlag("y")             // overwrite output file
+	builder.AddOutput(out)
+
+	// input audio -> output audio
+	builder.AddInput(newInputBuilder(params.Audio)) // input 0: audio
+	out.AddOption("map", "0:a")
+	out.AddOption("codec:a", "copy")
+
+	// input cover -> output cover
+	if params.AlbumArt != nil &&
+		params.AudioExt != ".wav" /* wav doesn't support attached image */ {
+
+		// write cover to temp file
+		artPath, err := utils.WriteTempFile(bytes.NewReader(params.AlbumArt), params.AlbumArtExt)
+		if err != nil {
+			return fmt.Errorf("updateAudioMeta write temp file: %w", err)
+		}
+		defer os.Remove(artPath)
+
+		builder.AddInput(newInputBuilder(artPath)) // input 1: cover
+		out.AddOption("map", "1:v")
+
+		switch params.AudioExt {
+		case ".ogg": // ogg only supports theora codec
+			out.AddOption("codec:v", "libtheora")
+		case ".m4a": // .m4a(mp4) requires set codec, disposition, stream metadata
+			out.AddOption("codec:v", "mjpeg")
+			out.AddOption("disposition:v", "attached_pic")
+			out.AddMetadata("s:v", "title", "Album cover")
+			out.AddMetadata("s:v", "comment", "Cover (front)")
+		case ".mp3":
+			out.AddOption("codec:v", "mjpeg")
+			out.AddMetadata("s:v", "title", "Album cover")
+			out.AddMetadata("s:v", "comment", "Cover (front)")
+		default: // other formats use default behavior
+		}
+	}
+
+	// set file metadata
+	album := params.Meta.GetAlbum()
+	if album != "" {
+		out.AddMetadata("", "album", album)
+	}
+
+	title := params.Meta.GetTitle()
+	if album != "" {
+		out.AddMetadata("", "title", title)
+	}
+
+	artists := params.Meta.GetArtists()
+	if len(artists) != 0 {
+		// TODO: it seems that ffmpeg doesn't support multiple artists
+		out.AddMetadata("", "artist", strings.Join(artists, " / "))
+	}
+
+	if params.AudioExt == ".mp3" {
+		out.AddOption("write_id3v1", "true")
+		out.AddOption("id3v2_version", "3")
+	}
+
+	// execute ffmpeg
+	cmd := builder.Command(ctx)
+
+	if stdout, err := cmd.CombinedOutput(); err != nil {
+		return fmt.Errorf("ffmpeg run: %w, %s", err, string(stdout))
+	}
+
+	return nil
+}

internal/ffmpeg/ffprobe.go

@@ -0,0 +1,141 @@
+package ffmpeg
+
+import (
+	"bytes"
+	"context"
+	"encoding/json"
+	"io"
+	"os/exec"
+	"strings"
+
+	"github.com/samber/lo"
+)
+
+type Result struct {
+	Format  *Format   `json:"format"`
+	Streams []*Stream `json:"streams"`
+}
+
+func (r *Result) HasAttachedPic() bool {
+	return lo.ContainsBy(r.Streams, func(s *Stream) bool {
+		return s.CodecType == "video"
+	})
+}
+
+func (r *Result) getTagByKey(key string) string {
+	for k, v := range r.Format.Tags {
+		if key == strings.ToLower(k) {
+			return v
+		}
+	}
+
+	for _, stream := range r.Streams { // try to find in streams
+		if stream.CodecType != "audio" {
+			continue
+		}
+		for k, v := range stream.Tags {
+			if key == strings.ToLower(k) {
+				return v
+			}
+		}
+	}
+	return ""
+}
+func (r *Result) GetTitle() string {
+	return r.getTagByKey("title")
+}
+
+func (r *Result) GetAlbum() string {
+	return r.getTagByKey("album")
+}
+
+func (r *Result) GetArtists() []string {
+	artists := strings.Split(r.getTagByKey("artist"), "/")
+	for i := range artists {
+		artists[i] = strings.TrimSpace(artists[i])
+	}
+	return artists
+}
+
+func (r *Result) HasMetadata() bool {
+	return r.GetTitle() != "" || r.GetAlbum() != "" || len(r.GetArtists()) > 0
+}
+
+type Format struct {
+	Filename       string            `json:"filename"`
+	NbStreams      int               `json:"nb_streams"`
+	NbPrograms     int               `json:"nb_programs"`
+	FormatName     string            `json:"format_name"`
+	FormatLongName string            `json:"format_long_name"`
+	StartTime      string            `json:"start_time"`
+	Duration       string            `json:"duration"`
+	BitRate        string            `json:"bit_rate"`
+	ProbeScore     int               `json:"probe_score"`
+	Tags           map[string]string `json:"tags"`
+}
+
+type Stream struct {
+	Index          int               `json:"index"`
+	CodecName      string            `json:"codec_name"`
+	CodecLongName  string            `json:"codec_long_name"`
+	CodecType      string            `json:"codec_type"`
+	CodecTagString string            `json:"codec_tag_string"`
+	CodecTag       string            `json:"codec_tag"`
+	SampleFmt      string            `json:"sample_fmt"`
+	SampleRate     string            `json:"sample_rate"`
+	Channels       int               `json:"channels"`
+	ChannelLayout  string            `json:"channel_layout"`
+	BitsPerSample  int               `json:"bits_per_sample"`
+	RFrameRate     string            `json:"r_frame_rate"`
+	AvgFrameRate   string            `json:"avg_frame_rate"`
+	TimeBase       string            `json:"time_base"`
+	StartPts       int               `json:"start_pts"`
+	StartTime      string            `json:"start_time"`
+	BitRate        string            `json:"bit_rate"`
+	Disposition    *ProbeDisposition `json:"disposition"`
+	Tags           map[string]string `json:"tags"`
+}
+
+type ProbeDisposition struct {
+	Default         int `json:"default"`
+	Dub             int `json:"dub"`
+	Original        int `json:"original"`
+	Comment         int `json:"comment"`
+	Lyrics          int `json:"lyrics"`
+	Karaoke         int `json:"karaoke"`
+	Forced          int `json:"forced"`
+	HearingImpaired int `json:"hearing_impaired"`
+	VisualImpaired  int `json:"visual_impaired"`
+	CleanEffects    int `json:"clean_effects"`
+	AttachedPic     int `json:"attached_pic"`
+	TimedThumbnails int `json:"timed_thumbnails"`
+	Captions        int `json:"captions"`
+	Descriptions    int `json:"descriptions"`
+	Metadata        int `json:"metadata"`
+	Dependent       int `json:"dependent"`
+	StillImage      int `json:"still_image"`
+}
+
+func ProbeReader(ctx context.Context, rd io.Reader) (*Result, error) {
+	cmd := exec.CommandContext(ctx, "ffprobe",
+		"-v", "quiet", // disable logging
+		"-print_format", "json", // use json format
+		"-show_format", "-show_streams", "-show_error", // retrieve format and streams
+		"pipe:0", // input from stdin
+	)
+
+	cmd.Stdin = rd
+	stdout, stderr := &bytes.Buffer{}, &bytes.Buffer{}
+	cmd.Stdout, cmd.Stderr = stdout, stderr
+
+	if err := cmd.Run(); err != nil {
+		return nil, err
+	}
+
+	ret := new(Result)
+	if err := json.Unmarshal(stdout.Bytes(), ret); err != nil {
+		return nil, err
+	}
+
+	return ret, nil
+}

internal/ffmpeg/meta_flac.go

@@ -0,0 +1,94 @@
+package ffmpeg
+
+import (
+	"context"
+	"go.uber.org/zap"
+	"mime"
+	"strings"
+
+	"github.com/go-flac/flacpicture"
+	"github.com/go-flac/flacvorbis"
+	"github.com/go-flac/go-flac"
+	"golang.org/x/exp/slices"
+)
+
+func updateMetaFlac(_ context.Context, outPath string, m *UpdateMetadataParams, logger *zap.Logger) error {
+	f, err := flac.ParseFile(m.Audio)
+	if err != nil {
+		return err
+	}
+
+	// generate comment block
+	comment := flacvorbis.MetaDataBlockVorbisComment{Vendor: "unlock-music.dev"}
+
+	// add metadata
+	title := m.Meta.GetTitle()
+	if title != "" {
+		_ = comment.Add(flacvorbis.FIELD_TITLE, title)
+	}
+
+	album := m.Meta.GetAlbum()
+	if album != "" {
+		_ = comment.Add(flacvorbis.FIELD_ALBUM, album)
+	}
+
+	artists := m.Meta.GetArtists()
+	for _, artist := range artists {
+		_ = comment.Add(flacvorbis.FIELD_ARTIST, artist)
+	}
+
+	existCommentIdx := slices.IndexFunc(f.Meta, func(b *flac.MetaDataBlock) bool {
+		return b.Type == flac.VorbisComment
+	})
+	if existCommentIdx >= 0 { // copy existing comment fields
+		exist, err := flacvorbis.ParseFromMetaDataBlock(*f.Meta[existCommentIdx])
+		if err != nil {
+			for _, s := range exist.Comments {
+				if strings.HasPrefix(s, flacvorbis.FIELD_TITLE+"=") && title != "" ||
+					strings.HasPrefix(s, flacvorbis.FIELD_ALBUM+"=") && album != "" ||
+					strings.HasPrefix(s, flacvorbis.FIELD_ARTIST+"=") && len(artists) != 0 {
+					continue
+				}
+				comment.Comments = append(comment.Comments, s)
+			}
+		}
+	}
+
+	// add / replace flac comment
+	cmtBlock := comment.Marshal()
+	if existCommentIdx < 0 {
+		f.Meta = append(f.Meta, &cmtBlock)
+	} else {
+		f.Meta[existCommentIdx] = &cmtBlock
+	}
+
+	if m.AlbumArt != nil {
+		coverMime := mime.TypeByExtension(m.AlbumArtExt)
+		logger.Debug("cover image mime detect", zap.String("mime", coverMime))
+		cover, err := flacpicture.NewFromImageData(
+			flacpicture.PictureTypeFrontCover,
+			"Front cover",
+			m.AlbumArt,
+			coverMime,
+		)
+
+		if err != nil {
+			logger.Warn("failed to create flac cover", zap.Error(err))
+		} else {
+			coverBlock := cover.Marshal()
+			f.Meta = append(f.Meta, &coverBlock)
+
+			// add / replace flac cover
+			coverIdx := slices.IndexFunc(f.Meta, func(b *flac.MetaDataBlock) bool {
+				return b.Type == flac.Picture
+			})
+			if coverIdx < 0 {
+				f.Meta = append(f.Meta, &coverBlock)
+			} else {
+				f.Meta[coverIdx] = &coverBlock
+			}
+		}
+	}
+
+	return f.Save(outPath)
+}

internal/ffmpeg/options.go

@@ -0,0 +1,131 @@
+package ffmpeg
+
+import (
+	"context"
+	"os/exec"
+	"strings"
+)
+
+type ffmpegBuilder struct {
+	binary  string            // ffmpeg binary path
+	options map[string]string // global options
+	inputs  []*inputBuilder   // input options
+	outputs []*outputBuilder  // output options
+}
+
+func newFFmpegBuilder() *ffmpegBuilder {
+	return &ffmpegBuilder{
+		binary:  "ffmpeg",
+		options: make(map[string]string),
+	}
+}
+
+func (b *ffmpegBuilder) AddInput(src *inputBuilder) {
+	b.inputs = append(b.inputs, src)
+}
+
+func (b *ffmpegBuilder) AddOutput(dst *outputBuilder) {
+	b.outputs = append(b.outputs, dst)
+}
+
+func (b *ffmpegBuilder) SetBinary(bin string) {
+	b.binary = bin
+}
+
+func (b *ffmpegBuilder) SetFlag(flag string) {
+	b.options[flag] = ""
+}
+
+func (b *ffmpegBuilder) SetOption(name, value string) {
+	b.options[name] = value
+}
+
+func (b *ffmpegBuilder) Args() (args []string) {
+	for name, val := range b.options {
+		args = append(args, "-"+name)
+		if val != "" {
+			args = append(args, val)
+		}
+	}
+
+	for _, input := range b.inputs {
+		args = append(args, input.Args()...)
+	}
+	for _, output := range b.outputs {
+		args = append(args, output.Args()...)
+	}
+
+	return
+}
+
+func (b *ffmpegBuilder) Command(ctx context.Context) *exec.Cmd {
+	bin := "ffmpeg"
+	if b.binary != "" {
+		bin = b.binary
+	}
+
+	return exec.CommandContext(ctx, bin, b.Args()...)
+}
+
+// inputBuilder is the builder for ffmpeg input options
+type inputBuilder struct {
+	path    string
+	options map[string][]string
+}
+
+func newInputBuilder(path string) *inputBuilder {
+	return &inputBuilder{
+		path:    path,
+		options: make(map[string][]string),
+	}
+}
+
+func (b *inputBuilder) AddOption(name, value string) {
+	b.options[name] = append(b.options[name], value)
+}
+
+func (b *inputBuilder) Args() (args []string) {
+	for name, values := range b.options {
+		for _, val := range values {
+			args = append(args, "-"+name, val)
+		}
+	}
+	return append(args, "-i", b.path)
+}
+
+// outputBuilder is the builder for ffmpeg output options
+type outputBuilder struct {
+	path    string
+	options map[string][]string
+}
+
+func newOutputBuilder(path string) *outputBuilder {
+	return &outputBuilder{
+		path:    path,
+		options: make(map[string][]string),
+	}
+}
+
+func (b *outputBuilder) AddOption(name, value string) {
+	b.options[name] = append(b.options[name], value)
+}
+
+func (b *outputBuilder) Args() (args []string) {
+	for name, values := range b.options {
+		for _, val := range values {
+			args = append(args, "-"+name, val)
+		}
+	}
+	return append(args, b.path)
+}
+
+// AddMetadata is the shortcut for adding "metadata" option
+func (b *outputBuilder) AddMetadata(stream, key, value string) {
+	optVal := strings.TrimSpace(key) + "=" + strings.TrimSpace(value)
+
+	if stream != "" {
+		b.AddOption("metadata:"+stream, optVal)
+	} else {
+		b.AddOption("metadata", optVal)
+	}
+}

internal/logging/logging.go

@@ -1,41 +0,0 @@
-package logging
-
-import (
-	"os"
-	"sync"
-	"time"
-)
-
-import (
-	"go.uber.org/zap"
-	"go.uber.org/zap/zapcore"
-)
-
-// newDefaultProductionLog configures a custom log that is
-// intended for use by default if no other log is specified
-// in a config. It writes to stderr, uses the console encoder,
-// and enables INFO-level logs and higher.
-func newDefaultProductionLog() *zap.Logger {
-	encCfg := zap.NewProductionEncoderConfig()
-	// if interactive terminal, make output more human-readable by default
-	encCfg.EncodeTime = func(ts time.Time, encoder zapcore.PrimitiveArrayEncoder) {
-		encoder.AppendString(ts.Format("2006/01/02 15:04:05.000"))
-	}
-	encCfg.EncodeLevel = zapcore.CapitalColorLevelEncoder
-	enc := zapcore.NewConsoleEncoder(encCfg)
-	core := zapcore.NewCore(enc, zapcore.Lock(os.Stdout), zap.NewAtomicLevelAt(zap.DebugLevel))
-	return zap.New(core)
-
-}
-
-// Log returns the current default logger.
-func Log() *zap.Logger {
-	defaultLoggerMu.RLock()
-	defer defaultLoggerMu.RUnlock()
-	return defaultLogger
-}
-
-var (
-	defaultLogger   = newDefaultProductionLog()
-	defaultLoggerMu sync.RWMutex
-)

internal/logging/zap.go

@@ -0,0 +1,14 @@
+package logging
+
+import (
+	"go.uber.org/zap"
+	"go.uber.org/zap/zapcore"
+)
+
+func NewZapLogger() (*zap.Logger, error) {
+	zapCfg := zap.NewDevelopmentConfig()
+	zapCfg.DisableStacktrace = true
+	zapCfg.EncoderConfig.EncodeLevel = zapcore.CapitalColorLevelEncoder
+	zapCfg.EncoderConfig.EncodeTime = zapcore.TimeEncoderOfLayout("2006/01/02 15:04:05.000")
+	return zapCfg.Build()
+}

internal/sniff/audio.go

@@ -0,0 +1,106 @@
+package sniff
+
+import (
+	"bytes"
+	"encoding/binary"
+
+	"golang.org/x/exp/slices"
+)
+
+type Sniffer interface {
+	Sniff(header []byte) bool
+}
+
+var audioExtensions = map[string]Sniffer{
+	// ref: https://mimesniff.spec.whatwg.org
+	".mp3": prefixSniffer("ID3"), // todo: check mp3 without ID3v2 tag
+	".ogg": prefixSniffer("OggS"),
+	".wav": prefixSniffer("RIFF"),
+
+	// ref: https://www.loc.gov/preservation/digital/formats/fdd/fdd000027.shtml
+	".wma": prefixSniffer{
+		0x30, 0x26, 0xb2, 0x75, 0x8e, 0x66, 0xcf, 0x11,
+		0xa6, 0xd9, 0x00, 0xaa, 0x00, 0x62, 0xce, 0x6c,
+	},
+
+	// ref: https://www.garykessler.net/library/file_sigs.html
+	".m4a": m4aSniffer{},    // MPEG-4 container, Apple Lossless Audio Codec
+	".mp4": &mpeg4Sniffer{}, // MPEG-4 container, other fallback
+
+	".flac": prefixSniffer("fLaC"), // ref: https://xiph.org/flac/format.html
+	".dff":  prefixSniffer("FRM8"), // DSDIFF, ref: https://www.sonicstudio.com/pdf/dsd/DSDIFF_1.5_Spec.pdf
+
+}
+
+// AudioExtension sniffs the known audio types, and returns the file extension.
+// header is recommended to at least 16 bytes.
+func AudioExtension(header []byte) (string, bool) {
+	for ext, sniffer := range audioExtensions {
+		if sniffer.Sniff(header) {
+			return ext, true
+		}
+	}
+	return "", false
+}
+
+// AudioExtensionWithFallback is equivalent to AudioExtension, but returns fallback
+// most likely to use .mp3 as fallback, because mp3 files may not have ID3v2 tag.
+func AudioExtensionWithFallback(header []byte, fallback string) string {
+	ext, ok := AudioExtension(header)
+	if !ok {
+		return fallback
+	}
+	return ext
+}
+
+type prefixSniffer []byte
+
+func (s prefixSniffer) Sniff(header []byte) bool {
+	return bytes.HasPrefix(header, s)
+}
+
+type m4aSniffer struct{}
+
+func (m4aSniffer) Sniff(header []byte) bool {
+	box := readMpeg4FtypBox(header)
+	if box == nil {
+		return false
+	}
+
+	return box.majorBrand == "M4A " || slices.Contains(box.compatibleBrands, "M4A ")
+}
+
+type mpeg4Sniffer struct{}
+
+func (s *mpeg4Sniffer) Sniff(header []byte) bool {
+	return readMpeg4FtypBox(header) != nil
+}
+
+type mpeg4FtpyBox struct {
+	majorBrand       string
+	minorVersion     uint32
+	compatibleBrands []string
+}
+
+func readMpeg4FtypBox(header []byte) *mpeg4FtpyBox {
+	if (len(header) < 8) || !bytes.Equal([]byte("ftyp"), header[4:8]) {
+		return nil // not a valid ftyp box
+	}
+
+	size := binary.BigEndian.Uint32(header[0:4]) // size
+	if size < 16 || size%4 != 0 {
+		return nil // invalid ftyp box
+	}
+
+	box := mpeg4FtpyBox{
+		majorBrand:   string(header[8:12]),
+		minorVersion: binary.BigEndian.Uint32(header[12:16]),
+	}
+
+	// compatible brands
+	for i := 16; i < int(size) && i+4 < len(header); i += 4 {
+		box.compatibleBrands = append(box.compatibleBrands, string(header[i:i+4]))
+	}
+
+	return &box
+}

internal/sniff/image.go

@@ -0,0 +1,30 @@
+package sniff
+
+// ref: https://mimesniff.spec.whatwg.org
+var imageMIMEs = map[string]Sniffer{
+	"image/jpeg": prefixSniffer{0xFF, 0xD8, 0xFF},
+	"image/png":  prefixSniffer{0x89, 'P', 'N', 'G', '\r', '\n', 0x1A, '\n'},
+	"image/bmp":  prefixSniffer("BM"),
+	"image/webp": prefixSniffer("RIFF"),
+	"image/gif":  prefixSniffer("GIF8"),
+}
+
+// ImageMIME sniffs the well-known image types, and returns its MIME.
+func ImageMIME(header []byte) (string, bool) {
+	for ext, sniffer := range imageMIMEs {
+		if sniffer.Sniff(header) {
+			return ext, true
+		}
+	}
+	return "", false
+}
+
+// ImageExtension is equivalent to ImageMIME, but returns file extension
+func ImageExtension(header []byte) (string, bool) {
+	ext, ok := ImageMIME(header)
+	if !ok {
+		return "", false
+	}
+	// todo: use mime.ExtensionsByType
+	return "." + ext[6:], true // "image/" is 6 bytes
+}

internal/utils/crypto.go

@@ -8,7 +8,7 @@ func PKCS7UnPadding(encrypt []byte) []byte {
 	return encrypt[:(length - unPadding)]
 }
 
-func DecryptAes128Ecb(data, key []byte) []byte {
+func DecryptAES128ECB(data, key []byte) []byte {
 	cipher, _ := aes.NewCipher(key)
 	decrypted := make([]byte, len(data))
 	size := 16

internal/utils/temp.go

@@ -0,0 +1,24 @@
+package utils
+
+import (
+	"fmt"
+	"io"
+	"os"
+)
+
+func WriteTempFile(rd io.Reader, ext string) (string, error) {
+	audioFile, err := os.CreateTemp("", "*"+ext)
+	if err != nil {
+		return "", fmt.Errorf("ffmpeg create temp file: %w", err)
+	}
+
+	if _, err := io.Copy(audioFile, rd); err != nil {
+		return "", fmt.Errorf("ffmpeg write temp file: %w", err)
+	}
+
+	if err := audioFile.Close(); err != nil {
+		return "", fmt.Errorf("ffmpeg close temp file: %w", err)
+	}
+
+	return audioFile.Name(), nil
+}

misc/release.sh

@@ -0,0 +1,32 @@
+#!/bin/bash
+set -e
+
+PLATFORMS=(
+  "linux/amd64"
+  "linux/arm64"
+  "darwin/amd64"
+  "darwin/arm64"
+  "windows/amd64"
+  "windows/386"
+)
+
+DEST_DIR=${DEST_DIR:-"dist"}
+
+for PLATFORM in "${PLATFORMS[@]}"; do
+  GOOS=${PLATFORM%/*}
+  GOARCH=${PLATFORM#*/}
+  echo "Building for $GOOS/$GOARCH"
+
+  FILENAME="um-$GOOS-$GOARCH"
+  if [ "$GOOS" = "windows" ]; then
+    FILENAME="$FILENAME.exe"
+  fi
+
+  GOOS=$GOOS GOARCH=$GOARCH go build -v \
+    -o "${DEST_DIR}/${FILENAME}" \
+    -ldflags "-s -w -X main.AppVersion=$(git describe --tags --always --dirty)" \
+    ./cmd/um
+done
+
+cd "$DEST_DIR"
+sha256sum um-* > sha256sums.txt