From 9856f52070ec8a837f20016690ade738f34c88ce Mon Sep 17 00:00:00 2001
From: Unlock Music Dev <dev@unlock-music.dev>
Date: Mon, 28 Nov 2022 18:52:19 +0800
Subject: [PATCH] feat: add meta parser from filename

---
 algo/common/meta.go      | 50 ++++++++++++++++++++++++++++++++++++++++
 algo/common/meta_test.go | 38 ++++++++++++++++++++++++++++++
 2 files changed, 88 insertions(+)
 create mode 100644 algo/common/meta.go
 create mode 100644 algo/common/meta_test.go

diff --git a/algo/common/meta.go b/algo/common/meta.go
new file mode 100644
index 0000000..8c174dc
--- /dev/null
+++ b/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
+}
diff --git a/algo/common/meta_test.go b/algo/common/meta_test.go
new file mode 100644
index 0000000..f91a27f
--- /dev/null
+++ b/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)
+			}
+		})
+	}
+}