Upload packed version helper.

.gitignore

@@ -1,2 +1,10 @@
 /save/
 /temp/
+/main.build/
+/main.dist/
+/build/
+/dist/
+/*.egg-info/
+/.idea/
+__pycache__/
+*.py[cod]

PlaylistSaver.spec

@@ -0,0 +1,87 @@
+from pathlib import Path
+import platform
+
+
+project_dir = Path(SPEC).resolve().parent
+
+
+def data_tree(source: Path, destination: str):
+    """Return PyInstaller data tuples while retaining the directory tree."""
+    return [
+        (str(path), str(Path(destination) / path.relative_to(source).parent))
+        for path in source.rglob("*")
+        if path.is_file()
+    ]
+
+
+def bundled_mpv_dir() -> Path:
+    system = platform.system().lower()
+    machine = platform.machine().lower()
+
+    if system == "windows":
+        os_dir = "nt"
+    elif system in {"darwin", "linux"}:
+        os_dir = system
+    else:
+        raise SystemExit(f"Unsupported build platform: {platform.system()}")
+
+    if machine in {"amd64", "x86_64"}:
+        arch_dir = "x64"
+    elif machine in {"arm64", "aarch64"}:
+        arch_dir = "arm"
+    elif machine in {"x86", "i386", "i686"}:
+        arch_dir = "x86"
+    else:
+        raise SystemExit(f"Unsupported build architecture: {platform.machine()}")
+
+    return project_dir / "bin" / "mpv" / os_dir / arch_dir
+
+
+mpv_dir = bundled_mpv_dir()
+if not mpv_dir.is_dir():
+    raise SystemExit(f"Bundled mpv directory does not exist: {mpv_dir}")
+
+datas = data_tree(project_dir / "assets", "assets")
+datas += data_tree(
+    mpv_dir,
+    str(Path("bin") / "mpv" / mpv_dir.parent.name / mpv_dir.name),
+)
+
+a = Analysis(
+    [str(project_dir / "main.py")],
+    pathex=[str(project_dir)],
+    binaries=[],
+    datas=datas,
+    hiddenimports=[],
+    hookspath=[],
+    hooksconfig={},
+    runtime_hooks=[],
+    excludes=["customtkinter", "PIL"],
+    noarchive=False,
+    optimize=1,
+)
+pyz = PYZ(a.pure)
+
+exe = EXE(
+    pyz,
+    a.scripts,
+    [],
+    exclude_binaries=True,
+    name="PlaylistSaver",
+    debug=False,
+    bootloader_ignore_signals=False,
+    strip=False,
+    upx=False,
+    console=False,
+    icon=str(project_dir / "assets" / "icon.ico"),
+)
+
+coll = COLLECT(
+    exe,
+    a.binaries,
+    a.datas,
+    strip=False,
+    upx=False,
+    name="PlaylistSaver",
+)
+

PlaylistSaverHelper/background.js

@@ -1,34 +1,127 @@
+function bytesToBase64Url(bytes) {
+    let binary = "";
+    for (let offset = 0; offset < bytes.length; offset += 8192) {
+        binary += String.fromCharCode(...bytes.subarray(offset, offset + 8192));
+    }
+    return btoa(binary).replaceAll("+", "-").replaceAll("/", "_").replace(/=+$/, "");
+}
+
+function base64UrlToBytes(value) {
+    const padded = value.replaceAll("-", "+").replaceAll("_", "/")
+        + "=".repeat((4 - value.length % 4) % 4);
+    return Uint8Array.from(atob(padded), character => character.charCodeAt(0));
+}
+
+async function hmacSha256(keyBytes, data) {
+    const key = await crypto.subtle.importKey(
+        "raw", keyBytes, { name: "HMAC", hash: "SHA-256" }, false, ["sign"]
+    );
+    return new Uint8Array(await crypto.subtle.sign("HMAC", key, data));
+}
+
+function joinBytes(...arrays) {
+    const result = new Uint8Array(arrays.reduce((size, array) => size + array.length, 0));
+    let offset = 0;
+    for (const array of arrays) {
+        result.set(array, offset);
+        offset += array.length;
+    }
+    return result;
+}
+
+async function encryptCookies(plaintext, secretKey) {
+    const masterKey = base64UrlToBytes(secretKey);
+    if (masterKey.length !== 32) {
+        throw new Error("The Helper secret key is invalid.");
+    }
+
+    const encoder = new TextEncoder();
+    const encryptionKey = await hmacSha256(masterKey, encoder.encode("PlaylistSaver cookie encryption"));
+    const authenticationKey = await hmacSha256(masterKey, encoder.encode("PlaylistSaver cookie authentication"));
+    const nonce = crypto.getRandomValues(new Uint8Array(16));
+    const plaintextBytes = encoder.encode(plaintext);
+    const ciphertext = new Uint8Array(plaintextBytes.length);
+
+    for (let offset = 0; offset < plaintextBytes.length; offset += 32) {
+        const counter = new Uint8Array(4);
+        new DataView(counter.buffer).setUint32(0, offset / 32, false);
+        const stream = await hmacSha256(encryptionKey, joinBytes(nonce, counter));
+        const blockLength = Math.min(32, plaintextBytes.length - offset);
+        for (let index = 0; index < blockLength; index++) {
+            ciphertext[offset + index] = plaintextBytes[offset + index] ^ stream[index];
+        }
+    }
+
+    const signedData = joinBytes(Uint8Array.of(1), nonce, ciphertext);
+    const tag = await hmacSha256(authenticationKey, signedData);
+    return bytesToBase64Url(joinBytes(signedData, tag));
+}
+
+async function launchPlaylistSaver() {
+    const { secretKey } = await chrome.storage.local.get("secretKey");
+    if (!secretKey) {
+        await chrome.storage.local.set({ showMissingKeyAlert: true });
+        await chrome.runtime.openOptionsPage();
+        return;
+    }
+
+    const cookies = await chrome.cookies.getAll({ domain: ".youtube.com" });
+    let output = "# Netscape HTTP Cookie File\n";
+    for (const cookie of cookies) {
+        const rawDomain = cookie.domain;
+        const domain = cookie.httpOnly ? `#HttpOnly_${rawDomain}` : rawDomain;
+        output += [
+            domain,
+            rawDomain.startsWith(".") ? "TRUE" : "FALSE",
+            cookie.path,
+            cookie.secure ? "TRUE" : "FALSE",
+            cookie.expirationDate ? Math.floor(cookie.expirationDate) : 0,
+            cookie.name,
+            cookie.value
+        ].join("\t") + "\n";
+    }
+
+    const encrypted = await encryptCookies(output, secretKey.trim());
+    const tabs = await chrome.tabs.query({ active: true, currentWindow: true });
+    if (!tabs[0]?.id) {
+        throw new Error("No active tab is available to launch PlaylistSaver.");
+    }
+    await chrome.tabs.update(tabs[0].id, {
+        url: `playlistsaver://open?encryptedcookies=${encrypted}`
+    });
+}
+
+async function openHelperSettings() {
+    await chrome.runtime.openOptionsPage();
+}
+
 chrome.commands.onCommand.addListener((command) => {
     if (command === "openPLKey") {
+        launchPlaylistSaver().catch(error => console.error("Unable to launch PlaylistSaver:", error));
+    } else if (command === "openPLSettingPageKey") {
+        openHelperSettings().catch(error => console.error("Unable to open Helper settings:", error));
+    }
+});
 
-        chrome.cookies.getAll({ domain: ".youtube.com" }, (cookies) => {
+chrome.runtime.onInstalled.addListener(() => {
-            let output = "# Netscape HTTP Cookie File\n";
+    chrome.contextMenus.removeAll(() => {
-
+        chrome.contextMenus.create({
-            cookies.forEach(c => {
+            id: "openPlaylistSaver",
-                const domain = c.domain;
+            title: "Open PlaylistSaver",
-                const flag = domain.startsWith('.') ? "TRUE" : "FALSE";
+            contexts: ["page"]
-                const path = c.path;
+        });
-                const secure = c.secure ? "TRUE" : "FALSE";
+        chrome.contextMenus.create({
-                const expiration = c.expirationDate ? Math.floor(c.expirationDate) : 0;
+            id: "openHelperSettings",
+            title: "PlaylistSaver Helper Settings",
+            contexts: ["page"]
+        });
+    });
+});
 
-                output += [
+chrome.contextMenus.onClicked.addListener((info) => {
-                    domain,
+    if (info.menuItemId === "openPlaylistSaver") {
-                    flag,
+        launchPlaylistSaver().catch(error => console.error("Unable to launch PlaylistSaver:", error));
-                    path,
+    } else if (info.menuItemId === "openHelperSettings") {
-                    secure,
+        openHelperSettings().catch(error => console.error("Unable to open Helper settings:", error));
-                    expiration,
-                    c.name,
-                    c.value
-                ].join("\t") + "\n";
-            });
-
-            const encoded = btoa(output);
-
-            chrome.tabs.query({ active: true, currentWindow: true }, (tabs) => {
-                chrome.tabs.update(tabs[0].id, {
-                    url: `PlaylistSaver://open?base64cookies=${encoded}`
-                });
-            });
-        });
     }
 });

PlaylistSaverHelper/manifest.json

@@ -1,12 +1,13 @@
 {
   "manifest_version": 3,
   "name": "Playlist Helper",
-  "version": "1.0",
+  "version": "1.0.003",
 
   "permissions": [
-  "scripting",
   "activeTab",
-  "cookies"
+  "contextMenus",
+  "cookies",
+  "storage"
 ],
 "host_permissions": [
   "*://*.youtube.com/*"
@@ -16,11 +17,21 @@
     "service_worker": "background.js"
   },
 
+  "options_page": "options.html",
+  "icons": {
+    "128": "icon.png"
+  },
   "commands": {
-    "openPLKey": {
+    "openPLSettingPageKey": {
       "suggested_key": {
         "default": "Alt+Z"
       },
+      "description": "Open settings page"
+    },
+    "openPLKey": {
+      "suggested_key": {
+        "default": "Alt+Y"
+      },
       "description": "Launch PlaylistSaver"
     }
   }

PlaylistSaverHelper/options.css

@@ -0,0 +1,10 @@
+:root { color-scheme: light dark; font-family: system-ui, sans-serif; }
+body { margin: 0; background: #181818; color: #f2f2f2; }
+main { width: min(620px, calc(100% - 48px)); margin: 64px auto; padding: 28px; background: #242424; border: 1px solid #404040; border-radius: 12px; }
+h1 { margin-top: 0; }
+label { display: block; margin: 24px 0 8px; font-weight: 600; }
+.key-row, .actions { display: flex; gap: 10px; align-items: center; }
+input { flex: 1; min-width: 0; padding: 10px 12px; border: 1px solid #555; border-radius: 7px; font: 14px ui-monospace, monospace; }
+button { padding: 10px 14px; border: 1px solid #666; border-radius: 7px; cursor: pointer; }
+.actions { margin-top: 16px; }
+#status { color: #8bd39a; }

PlaylistSaverHelper/options.html

@@ -0,0 +1,25 @@
+<!doctype html>
+<html lang="en">
+<head>
+    <meta charset="utf-8">
+    <meta name="viewport" content="width=device-width, initial-scale=1">
+    <title>PlaylistSaver Helper Settings</title>
+    <link rel="stylesheet" href="options.css">
+</head>
+<body>
+<main>
+    <h1>PlaylistSaver Helper</h1>
+    <p>Copy the secret key from PlaylistSaver and paste it below.</p>
+    <label for="secretKey">Secret key</label>
+    <div class="key-row">
+        <input id="secretKey" type="password" autocomplete="off" spellcheck="false">
+        <button id="toggleKey" type="button">Show</button>
+    </div>
+    <div class="actions">
+        <button id="saveKey" type="button">Save key</button>
+        <span id="status" role="status"></span>
+    </div>
+</main>
+<script src="options.js"></script>
+</body>
+</html>

PlaylistSaverHelper/options.js

@@ -0,0 +1,31 @@
+const keyInput = document.querySelector("#secretKey");
+const status = document.querySelector("#status");
+
+chrome.storage.local.get(["secretKey", "showMissingKeyAlert"]).then(async ({ secretKey, showMissingKeyAlert }) => {
+    keyInput.value = secretKey || "";
+
+    if (showMissingKeyAlert) {
+        await chrome.storage.local.remove("showMissingKeyAlert");
+        alert("Set the PlaylistSaver secret key before exporting cookies.");
+        keyInput.focus();
+    }
+});
+
+document.querySelector("#toggleKey").addEventListener("click", event => {
+    const showing = keyInput.type === "text";
+    keyInput.type = showing ? "password" : "text";
+    event.currentTarget.textContent = showing ? "Show" : "Hide";
+});
+
+document.querySelector("#saveKey").addEventListener("click", async () => {
+    const secretKey = keyInput.value.trim();
+    if (!/^[A-Za-z0-9_-]{43}$/.test(secretKey)) {
+        status.textContent = "Invalid key. Copy it again from PlaylistSaver.";
+        status.style.color = "#ff8989";
+        return;
+    }
+
+    await chrome.storage.local.set({ secretKey });
+    status.textContent = "Secret key saved.";
+    status.style.color = "#8bd39a";
+});

README.md

@@ -1,3 +1,39 @@
 # PlaylistSaver
 
-A tool to save your youtube playlist. **VERY UNSTABLE**
+A tool to save your YouTube playlist.
+
+## Run from source
+
+Sync project and install dependencies.
+```bash
+uv sync
+```
+
+Run from source:
+
+```bash
+python main.py
+```
+
+## Build
+
+> [!IMPORTANT]
+> This project does not support Nuitka for building. Some packages used in this project, such as mpv and yt-dlp, 
+> may not be able to function or may cause crashes in the building process.
+
+Install build tools:
+```bash
+uv pip install -e ".[build]"
+```
+
+Build this project with PyInstaller:
+
+```powershell
+.\build.ps1 -Clean
+```
+
+The build is written to `dist\PlaylistSaver`. This includes only the
+bundled mpv files matching the operating system and CPU architecture on which the
+build is performed. Build each target platform on that platform.
+
+## How to use

app.py

@@ -0,0 +1,390 @@
+# Qt
+import logging
+import os
+import secrets
+import threading
+import webbrowser
+from concurrent.futures import ThreadPoolExecutor
+from pathlib import Path
+
+from PySide6.QtWidgets import QApplication, QMessageBox
+from PySide6.QtCore import QSize
+
+from yt_dlp import YoutubeDL
+
+from constant import PROGRAM_DIR
+from window import PlaylistMainWindow
+from yt_lib import sanitize_filename, fetch_playlists_data, PlaylistFetchException, resolve_video_page_url
+from utils import save_json, read_json
+from pl_lib import messagebox
+
+logger = logging.getLogger(__name__)
+logger.setLevel(logging.INFO)
+
+class PlaylistSaver(QApplication):
+    DEFAULT_PROFILE_NAME = "default"
+    THUMBNAIL_SIZE = QSize(144, 81)
+    mpv_processes = {}
+
+    def __init__(self, work_dir: Path, url_schema=None, cookie_file: str | Path | None = None):
+        super().__init__()
+        self.setApplicationName("PlaylistSaver")
+
+        self.url_schema = url_schema
+        self.cookie_file = Path(cookie_file) if cookie_file else None
+
+        # Path
+        self.work_dir = work_dir
+        self.save_path = Path( self.work_dir, "save")
+        self.temp_path = Path( self.work_dir, "temp")
+        self.profiles_meta_path = Path(self.save_path, "profiles.json")
+        self.profiles_path = Path(self.save_path, "profiles")
+        self.cookie_path = Path(self.profiles_path, self.DEFAULT_PROFILE_NAME, "cookies.txt")
+        self.secret_key_path = Path(self.save_path, "helper-secret.key")
+        self.secret_key = self.load_or_create_secret_key()
+
+        # Profile
+        self.active_profile_name = self.DEFAULT_PROFILE_NAME
+
+        # Data
+        self.playlists: dict[str, list] = {
+            "entries": []
+        }
+
+        self.main_window = PlaylistMainWindow(
+            self
+        )
+
+        # Lock
+        self.fetch_playlist_lock = threading.Lock()
+        self.download_pool = ThreadPoolExecutor(max_workers=4, thread_name_prefix="video-download")
+        self.download_tasks = set()
+        self.download_tasks_lock = threading.Lock()
+        self.download_cancel_event = threading.Event()
+        self.aboutToQuit.connect(lambda: self.download_pool.shutdown(wait=False, cancel_futures=False))
+
+        # flags
+        self.use_custom_cookie_file_path = self.cookie_file is not None
+
+        if self.use_custom_cookie_file_path:
+            cookie_path = self.cookie_file
+
+            if not cookie_path.exists() or not cookie_path.is_file():
+                self.main_window.signals.error.emit(
+                    "Cookie file does not exist or is not a file."
+                )
+            else:
+                self.cookie_path = cookie_path
+
+        self.init()
+        self.main_window.show()
+
+    def init(self):
+        self.initialize_profiles()
+        # Start background thread after root is ready for UI callbacks.
+        self.reload_playlists()
+
+    def reload_playlists(self):
+        self.main_window.loading_label.setText("Loading playlists...")
+
+        threading.Thread(
+            target=fetch_playlists_data,
+            args=(self.url_schema,
+                  self.get_profile_cookie_path(self.active_profile_name),
+                  self.get_ydl_opts(),
+                  self.on_data_ready,
+                  self.work_dir,
+                  self.fetch_playlist_lock,
+                  PROGRAM_DIR / "main.py",
+                  self.secret_key,
+                  ),
+            daemon=True,
+        ).start()
+
+    #
+    # Profile
+    #
+    def load_or_create_secret_key(self):
+        try:
+            if self.secret_key_path.exists():
+                key = self.secret_key_path.read_text(encoding="utf-8").strip()
+                if key:
+                    return key
+
+            self.secret_key_path.parent.mkdir(parents=True, exist_ok=True)
+            key = secrets.token_urlsafe(32)
+            self.secret_key_path.write_text(key, encoding="utf-8")
+            return key
+        except OSError as e:
+            logger.error("Unable to load or create Helper secret key: %s", e)
+            return None
+
+    def initialize_profiles(self):
+        try:
+            self.profiles_path.parent.mkdir(parents=True, exist_ok=True)
+        except Exception as e:
+            logger.error("Unable to create profiles folder:", e)
+            QMessageBox.critical(self.main_window, "Error",
+                                 "Unable to create profiles folder.\n"
+                                 f"At path: {self.profiles_path.as_posix()}\n"
+                                 f"Reason: {e}\n"
+                                 f"Solution: Try to remove profiles folder manually and try again.")
+
+        active_name = self.get_active_profile_name()
+        self.ensure_profile_exists(active_name)
+        self.set_active_profile(active_name)
+
+    def ensure_profile_exists(self, profile_name: str):
+        meta = self.load_profiles_meta()
+        profiles = meta["profiles"]
+
+        if profile_name not in profiles:
+            profiles.append(profile_name)
+            meta["profiles"] = profiles
+            self.save_profiles_meta(meta)
+
+        self.get_profile_dir(profile_name).parent.mkdir(parents=True, exist_ok=True)
+
+    def get_active_profile_name(self):
+        meta = self.load_profiles_meta()
+        self.active_profile_name = meta.get("active_profile", None)
+        return self.active_profile_name
+
+    def load_profiles_meta(self):
+        meta = read_json(self.profiles_meta_path)
+        if not meta:
+            return {
+                "active_profile": self.DEFAULT_PROFILE_NAME,
+                "profiles": [self.DEFAULT_PROFILE_NAME],
+            }
+
+        profiles = meta.get("profiles") or [self.DEFAULT_PROFILE_NAME]
+        active_profile = meta.get("active_profile") or profiles[0]
+
+        if active_profile not in profiles:
+            profiles.insert(0, active_profile)
+
+        return {
+            "active_profile": active_profile,
+            "profiles": profiles,
+        }
+
+    def set_active_profile(self, profile_name: str):
+        meta = self.load_profiles_meta()
+        profiles = meta["profiles"]
+
+        if profile_name not in profiles:
+            profiles.append(profile_name)
+
+        meta["profiles"] = profiles
+        meta["active_profile"] = profile_name
+        self.save_profiles_meta(meta)
+
+        self.active_profile_name = profile_name
+        self.cookie_path = self.get_profile_cookie_path(profile_name)
+        self.cookie_path.parent.mkdir(parents=True, exist_ok=True)
+
+    def save_profiles_meta(self, meta: dict):
+        save_json(meta, self.profiles_meta_path)
+
+    def delete_profile(self, profile_name: str):
+        meta = self.load_profiles_meta()
+
+        if not profile_name in meta["profiles"]:
+            return
+
+        meta["profiles"].remove(profile_name)
+
+        self.save_profiles_meta(meta)
+
+    #
+    # Path
+    #
+    def get_profile_cookie_path(self, profile_name: str):
+        if self.use_custom_cookie_file_path:
+            return self.cookie_file
+
+        return Path(self.get_profile_dir(profile_name), "cookies.txt")
+
+    def get_profile_dir(self, profile_name: str):
+        return Path(self.profiles_path, sanitize_filename(profile_name))
+
+    def get_profile_temp_dir(self, profile_name: str | None = None):
+        profile_name = profile_name or self.active_profile_name
+        return self.temp_path / "profiles" / sanitize_filename(profile_name)
+
+    def get_playlist_cache_path(self, playlist_id: str):
+        safe_id = sanitize_filename(playlist_id or "unknown")
+        return self.get_profile_temp_dir() / "playlists" / f"{safe_id}.json"
+
+    #
+    # PlaylistData
+    #
+    def on_data_ready(self, data, error):
+        if isinstance(error, PlaylistFetchException):
+            self.main_window.signals.playlist_fetch_error.emit(error)
+        if data is None:
+            data = {"entries": []}
+
+        self.playlists["entries"] = data.get("entries", [])
+        self.main_window.signals.playlists_ready.emit(self.playlists)
+
+    def load_playlist_videos(self, playlist_id: str):
+        cache_path = self.get_playlist_cache_path(playlist_id)
+        if os.path.exists(cache_path):
+            return read_json(cache_path)
+        return None
+
+    def fetch_playlist_videos(self, playlist: dict):
+        playlist_id = playlist.get("id")
+        playlist_url = playlist.get("url") or playlist.get("webpage_url")
+
+        if not playlist_url and playlist_id and not str(playlist_id).startswith("VL"):
+            playlist_url = f"https://www.youtube.com/playlist?list={playlist_id}"
+
+        if not playlist_url:
+            raise ValueError("Playlist URL not found.")
+
+        cached_data = self.load_playlist_videos(playlist_id)
+        if cached_data:
+            return cached_data
+
+        opts = self.get_ydl_opts()
+
+        opts.update({"extract_flat": True,
+                     "skip_download": True,
+                     "quiet": True, })
+
+        with self.fetch_playlist_lock:
+            with YoutubeDL(opts) as ydl:
+                data = ydl.extract_info(playlist_url, download=False)
+
+        self.save_playlist_videos(playlist_id, data)
+        return data
+
+    def save_playlist_videos(self, playlist_id: str, data: dict):
+        save_json(data, self.get_playlist_cache_path(playlist_id))
+
+    def get_ydl_opts(self):
+        return {
+            'cookiefile': self.get_profile_cookie_path(self.active_profile_name),
+            'verbose': True,
+            'download': False,
+            'js_runtimes': {"node": {}},
+            'extract_flat': False,
+            'lazy_playlist': False,
+            "ignoreerrors": False
+        }
+
+    def get_download_dir(self, playlist_name: str | None = None):
+        directory = self.temp_path / "downloads"
+        if playlist_name:
+            safe_playlist_name = sanitize_filename(playlist_name).strip(" .") or "Unnamed Playlist"
+            directory = directory / "playlists" / safe_playlist_name
+        directory.mkdir(parents=True, exist_ok=True)
+        return directory
+
+    def _download_video_worker(self, video: dict, playlist_name: str | None = None):
+        video_id = str(video.get("id") or "unknown")
+        video_url = resolve_video_page_url(video, video_id)
+        video_name = sanitize_filename(str(video.get("title") or "Unnamed Video")).strip(" .") or "Unnamed Video"
+        output_base = self.get_download_dir(playlist_name) / f"{video_name}-{sanitize_filename(video_id)}"
+
+        opts = self.get_ydl_opts()
+        opts.update({
+            "download": True,
+            "skip_download": False,
+            "quiet": True,
+            "noplaylist": True,
+            "format": "bv*[ext=mp4]+ba[ext=m4a]/b[ext=mp4]/bv*+ba/b",
+            "merge_output_format": "mp4",
+            "outtmpl": f"{output_base}.%(ext)s",
+            "postprocessors": [{"key": "FFmpegVideoRemuxer", "preferedformat": "mp4"}],
+            "progress_hooks": [self._check_download_cancelled],
+        })
+        with YoutubeDL(opts) as ydl:
+            ydl.download([video_url])
+        return Path(f"{output_base}.mp4")
+
+    def _check_download_cancelled(self, _status):
+        if self.download_cancel_event.is_set():
+            raise RuntimeError("Download cancelled because the application is closing.")
+
+    def _submit_download_task(self, function, *args):
+        future = self.download_pool.submit(function, *args)
+        with self.download_tasks_lock:
+            self.download_tasks.add(future)
+        future.add_done_callback(self._forget_download_task)
+        return future
+
+    def _forget_download_task(self, future):
+        with self.download_tasks_lock:
+            self.download_tasks.discard(future)
+
+    def has_active_download_tasks(self):
+        with self.download_tasks_lock:
+            return any(not future.done() for future in self.download_tasks)
+
+    def cancel_download_tasks(self):
+        self.download_cancel_event.set()
+        with self.download_tasks_lock:
+            for future in self.download_tasks:
+                future.cancel()
+
+    def download_video(self, video: dict, playlist_name: str | None = None,
+                       callback=None, reset_cancel=True):
+        if reset_cancel:
+            self.download_cancel_event.clear()
+        future = self._submit_download_task(self._download_video_worker, video, playlist_name)
+        if callback:
+            future.add_done_callback(
+                lambda result: callback(result, video, playlist_name)
+            )
+        return future
+
+    def download_playlist(self, playlist: dict, playlist_data: dict | None = None,
+                          callback=None, queued_callback=None, producer_callback=None,
+                          reset_cancel=True):
+        def queue_videos():
+            try:
+                data = playlist_data or self.fetch_playlist_videos(playlist)
+                entries = [entry for entry in data.get("entries", []) if entry]
+                if self.download_cancel_event.is_set():
+                    return
+                if queued_callback:
+                    queued_callback(len(entries))
+                title = str(playlist.get("title") or playlist.get("id") or "Unnamed Playlist")
+                for video in entries:
+                    if self.download_cancel_event.is_set():
+                        break
+                    self.download_video(video, title, callback, reset_cancel=False)
+            except Exception as error:
+                if queued_callback:
+                    queued_callback(1)
+                if callback:
+                    callback(error, None, playlist.get("title"))
+            finally:
+                if producer_callback:
+                    producer_callback()
+
+        if reset_cancel:
+            self.download_cancel_event.clear()
+        return self._submit_download_task(queue_videos)
+
+    def download_all_playlists(self, callback=None, queued_callback=None,
+                               producer_callback=None):
+        self.download_cancel_event.clear()
+        for playlist in (item for item in self.playlists.get("entries", []) if item):
+            self.download_playlist(
+                playlist, callback=callback, queued_callback=queued_callback,
+                producer_callback=producer_callback, reset_cancel=False
+            )
+
+    def open_download_folder(self):
+        download_dir = self.temp_path / "downloads"
+
+        if not download_dir.is_dir():
+            messagebox.error(self.main_window, title="Error", message="The download folder does not exist.")
+            return
+
+        webbrowser.open(download_dir.as_posix())