From e8b220b3df8f122df8b6fd0e6b09abd32225c0a2 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E9=B2=81=E6=A0=91=E4=BA=BA?= <lu.shuren@um-react.app>
Date: Wed, 18 Sep 2024 23:02:05 +0100
Subject: [PATCH] feat: add xmly support

---
 src/decrypt-worker/Deciphers.ts         |  8 ++-
 src/decrypt-worker/decipher/Ximalaya.ts | 70 +++++++++++++++++++++++++
 2 files changed, 76 insertions(+), 2 deletions(-)
 create mode 100644 src/decrypt-worker/decipher/Ximalaya.ts

diff --git a/src/decrypt-worker/Deciphers.ts b/src/decrypt-worker/Deciphers.ts
index ace5f1c..a98b6ac 100644
--- a/src/decrypt-worker/Deciphers.ts
+++ b/src/decrypt-worker/Deciphers.ts
@@ -4,6 +4,7 @@ import type { DecryptCommandOptions } from '~/decrypt-worker/types.ts';
 import { QQMusicV1Decipher, QQMusicV2Decipher } from '~/decrypt-worker/decipher/QQMusic.ts';
 import { KuwoMusicDecipher } from '~/decrypt-worker/decipher/KuwoMusic.ts';
 import { KugouMusicDecipher } from '~/decrypt-worker/decipher/KugouMusic.ts';
+import { XimalayaAndroidDecipher, XimalayaPCDecipher } from '~/decrypt-worker/decipher/Ximalaya.ts';
 
 export enum Status {
   OK = 0,
@@ -46,6 +47,9 @@ export const allCryptoFactories: DecipherFactory[] = [
   // KWMv1 (*.kwm)
   KuwoMusicDecipher.make,
 
+  // Ximalaya PC (*.xm)
+  XimalayaPCDecipher.make,
+
   // Xiami (*.xm)
   // XiamiCrypto.make,
 
@@ -67,8 +71,8 @@ export const allCryptoFactories: DecipherFactory[] = [
   QQMusicV1Decipher.create,
 
   // Ximalaya (Android)
-  // XimalayaAndroidCrypto.makeX2M,
-  // XimalayaAndroidCrypto.makeX3M,
+  XimalayaAndroidDecipher.makeX2M,
+  XimalayaAndroidDecipher.makeX3M,
 
   // QingTingFM (Android)
   // QingTingFM$Device.make,
diff --git a/src/decrypt-worker/decipher/Ximalaya.ts b/src/decrypt-worker/decipher/Ximalaya.ts
new file mode 100644
index 0000000..fae3734
--- /dev/null
+++ b/src/decrypt-worker/decipher/Ximalaya.ts
@@ -0,0 +1,70 @@
+import { DecipherInstance, DecipherOK, DecipherResult, Status } from '~/decrypt-worker/Deciphers';
+import type { DecryptCommandOptions } from '~/decrypt-worker/types.ts';
+import { decryptX2MHeader, decryptX3MHeader, XmlyPC } from '@unlock-music/crypto';
+import { isDataLooksLikeAudio } from '~/decrypt-worker/util/audioType.ts';
+import { UnsupportedSourceFile } from '~/decrypt-worker/util/DecryptError.ts';
+
+export class XimalayaAndroidDecipher implements DecipherInstance {
+  cipherName: string;
+
+  constructor(
+    private decipher: (buffer: Uint8Array) => void,
+    private cipherType: string,
+  ) {
+    this.cipherName = `Ximalaya (Android, ${cipherType})`;
+  }
+
+  async decrypt(buffer: Uint8Array, _options: DecryptCommandOptions): Promise<DecipherResult | DecipherOK> {
+    // Detect with first 0x400 bytes
+    const slice = buffer.slice(0, 0x400);
+    this.decipher(slice);
+    if (!isDataLooksLikeAudio(slice)) {
+      throw new UnsupportedSourceFile(`Not a Xmly android file (${this.cipherType})`);
+    }
+    const result = new Uint8Array(buffer);
+    result.set(slice, 0);
+    return {
+      cipherName: this.cipherName,
+      status: Status.OK,
+      data: result,
+    };
+  }
+
+  public static makeX2M() {
+    return new XimalayaAndroidDecipher(decryptX2MHeader, 'X2M');
+  }
+
+  public static makeX3M() {
+    return new XimalayaAndroidDecipher(decryptX3MHeader, 'X3M');
+  }
+}
+
+export class XimalayaPCDecipher implements DecipherInstance {
+  cipherName = 'Ximalaya (PC)';
+
+  async decrypt(buffer: Uint8Array, _options: DecryptCommandOptions): Promise<DecipherResult | DecipherOK> {
+    // Detect with first 0x400 bytes
+    const headerSize = XmlyPC.getHeaderSize(buffer.subarray(0, 1024));
+    const xm = new XmlyPC(buffer.subarray(0, headerSize));
+    const { audioHeader, encryptedHeaderOffset, encryptedHeaderSize } = xm;
+    const plainAudioDataOffset = encryptedHeaderOffset + encryptedHeaderSize;
+    const plainAudioDataLength = buffer.byteLength - plainAudioDataOffset;
+    const encryptedAudioPart = buffer.slice(encryptedHeaderOffset, plainAudioDataOffset);
+    const encryptedAudioPartLen = xm.decrypt(encryptedAudioPart);
+    const audioSize = audioHeader.byteLength + encryptedAudioPartLen + plainAudioDataLength;
+
+    const result = new Uint8Array(audioSize);
+    result.set(audioHeader);
+    result.set(encryptedAudioPart, audioHeader.byteLength);
+    result.set(buffer.subarray(plainAudioDataOffset), audioHeader.byteLength + encryptedAudioPartLen);
+    return {
+      status: Status.OK,
+      data: result,
+      cipherName: this.cipherName,
+    };
+  }
+
+  public static make() {
+    return new XimalayaPCDecipher();
+  }
+}