From f0875ad1753b5d96d1e17303cdddcbaa1ba42bf6 Mon Sep 17 00:00:00 2001
From: Emmm Monster <58943012+emmmx@users.noreply.github.com>
Date: Thu, 3 Jun 2021 12:47:06 +0800
Subject: [PATCH] fix: decrypt/qmc-cache adapt: decrypt/qmc for qmc-cache

---
 src/decrypt/qmc.ts      |  6 ++---
 src/decrypt/qmccache.ts | 57 +++++++++++++++++++++++------------------
 src/decrypt/utils.ts    |  8 ++++++
 3 files changed, 43 insertions(+), 28 deletions(-)

diff --git a/src/decrypt/qmc.ts b/src/decrypt/qmc.ts
index 2aeb71d..8c70b76 100644
--- a/src/decrypt/qmc.ts
+++ b/src/decrypt/qmc.ts
@@ -22,7 +22,7 @@ interface Handler {
     handler(data?: Uint8Array): QmcMask | undefined
 }
 
-const HandlerMap: { [key: string]: Handler } = {
+export const HandlerMap: { [key: string]: Handler } = {
     "mgg": {handler: QmcMaskDetectMgg, ext: "ogg", detect: true},
     "mflac": {handler: QmcMaskDetectMflac, ext: "flac", detect: true},
     "mgg.cache": {handler: QmcMaskDetectMgg, ext: "ogg", detect: false},
@@ -42,8 +42,8 @@ const HandlerMap: { [key: string]: Handler } = {
     "776176": {handler: QmcMaskGetDefault, ext: "wav", detect: false}
 };
 
-export async function Decrypt(file: File, raw_filename: string, raw_ext: string): Promise<DecryptResult> {
-    if (!(raw_ext in HandlerMap)) throw "File type is incorrect!";
+export async function Decrypt(file: Blob, raw_filename: string, raw_ext: string): Promise<DecryptResult> {
+    if (!(raw_ext in HandlerMap)) throw `Qmc cannot handle type: ${raw_ext}`;
     const handler = HandlerMap[raw_ext];
 
     const fileData = new Uint8Array(await GetArrayBuffer(file));
diff --git a/src/decrypt/qmccache.ts b/src/decrypt/qmccache.ts
index 34e7165..adb3fda 100644
--- a/src/decrypt/qmccache.ts
+++ b/src/decrypt/qmccache.ts
@@ -1,34 +1,41 @@
-import {AudioMimeType, GetArrayBuffer, GetCoverFromFile, GetMetaFromFile, SniffAudioExt} from "@/decrypt/utils.ts";
+import {
+    AudioMimeType,
+    GetArrayBuffer,
+    GetCoverFromFile,
+    GetMetaFromFile,
+    SniffAudioExt,
+    SplitFilename
+} from "@/decrypt/utils.ts";
 
-import {Decrypt as QmcDecrypt} from "@/decrypt/qmc";
+import {Decrypt as QmcDecrypt, HandlerMap} from "@/decrypt/qmc";
 
 import {DecryptResult} from "@/decrypt/entity";
 
 import {parseBlob as metaParseBlob} from "music-metadata-browser";
 
-export async function Decrypt(file: Blob, raw_filename: string, raw_ext: string, detect: boolean = true)
+export async function Decrypt(file: Blob, raw_filename: string, _: string)
     : Promise<DecryptResult> {
-    let ext = raw_ext;
-    if (detect) {
-        const buffer = new Uint8Array(await GetArrayBuffer(file));
-        let length = buffer.length
-        for (let i = 0; i < length; i++) {
-             buffer[i] ^= 0xf4
-             if(buffer[i] <= 0x3f)buffer[i] = buffer[i] * 4;
-             else if(buffer[i] <= 0x7f)buffer[i] = (buffer[i] - 0x40) * 4 + 1;
-             else if(buffer[i] <= 0xbf)buffer[i] = (buffer[i] - 0x80) * 4 + 2;
-             else buffer[i] = (buffer[i] - 0xc0) * 4 + 3;
-        }
-        ext = SniffAudioExt(buffer, raw_ext);
-        if (ext !== raw_ext) file = new Blob([buffer], {type: AudioMimeType[ext]})
-        else {
-            file = new Blob([buffer], {type: "application/octet-stream"})
-            let ext = raw_filename.substring(file.name.lastIndexOf(".") + 1, file.name.length).toLowerCase();
-            if (ext !== "mgg" && ext !== "mflac") throw "不支持的QQ音乐缓存格式：" + raw_filename + ".cache";
-            return QmcDecrypt(file, raw_filename, ext+".cache");
-        }
+    const buffer = new Uint8Array(await GetArrayBuffer(file));
+    let length = buffer.length
+    for (let i = 0; i < length; i++) {
+        buffer[i] ^= 0xf4
+        if (buffer[i] <= 0x3f) buffer[i] = buffer[i] * 4;
+        else if (buffer[i] <= 0x7f) buffer[i] = (buffer[i] - 0x40) * 4 + 1;
+        else if (buffer[i] <= 0xbf) buffer[i] = (buffer[i] - 0x80) * 4 + 2;
+        else buffer[i] = (buffer[i] - 0xc0) * 4 + 3;
     }
-    const tag = await metaParseBlob(file);
+    let ext = SniffAudioExt(buffer, "");
+    const newName = SplitFilename(raw_filename)
+    let audioBlob: Blob
+    if (ext !== "" || newName.ext === "mp3") {
+        audioBlob = new Blob([buffer], {type: AudioMimeType[ext]})
+    } else if (newName.ext in HandlerMap) {
+        audioBlob = new Blob([buffer], {type: "application/octet-stream"})
+        return QmcDecrypt(audioBlob, newName.name, newName.ext);
+    } else {
+        throw "不支持的QQ音乐缓存格式"
+    }
+    const tag = await metaParseBlob(audioBlob);
     const {title, artist} = GetMetaFromFile(raw_filename, tag.common.title, tag.common.artist)
 
     return {
@@ -37,8 +44,8 @@ export async function Decrypt(file: Blob, raw_filename: string, raw_ext: string,
         ext,
         album: tag.common.album,
         picture: GetCoverFromFile(tag),
-        file: URL.createObjectURL(file),
-        blob: file,
+        file: URL.createObjectURL(audioBlob),
+        blob: audioBlob,
         mime: AudioMimeType[ext]
     }
 }
diff --git a/src/decrypt/utils.ts b/src/decrypt/utils.ts
index f10753a..cef54f6 100644
--- a/src/decrypt/utils.ts
+++ b/src/decrypt/utils.ts
@@ -160,3 +160,11 @@ export function WriteMetaToFlac(audioData: Buffer, info: IMusicMeta, original: I
     }
     return writer.save()
 }
+
+export function SplitFilename(n: string): { name: string; ext: string } {
+    const pos = n.lastIndexOf(".")
+    return {
+        ext: n.substring(pos + 1).toLowerCase(),
+        name: n.substring(0, pos)
+    }
+}