import os
import sys
import shutil
import threading

VERSION = "1.1"  # 每次修改 +0.1；大改版 +1 需經小威同意
import tkinter as tk
from tkinter import ttk, messagebox, filedialog

try:
    import yt_dlp
except ImportError:
    messagebox.showerror("缺少依賴", "請先安裝 yt-dlp 套件！")
    sys.exit(1)


class VideoDownloaderApp:
    def __init__(self, root: tk.Tk):
        self.root = root
        self.root.title(f"網頁影片通用下載器 v{VERSION}")
        # 視窗大小依內容決定（見 _center_window），不寫死，避免高解析度螢幕縮放時底部按鈕被切掉。
        self.root.configure(bg="#0f172a")

        # 預設儲存目錄（使用者下載資料夾）
        self.download_dir = os.path.join(os.path.expanduser("~"), "Downloads")
        if not os.path.exists(self.download_dir):
            self.download_dir = os.getcwd()

        self.is_downloading = False
        self.download_thread = None

        self._setup_styles()
        self._build_ui()
        self._center_window()
        self._check_ffmpeg()

    def _setup_styles(self):
        style = ttk.Style()
        try:
            style.theme_use("clam")
        except Exception:
            pass

    def _center_window(self):
        self.root.update_idletasks()
        w = max(self.root.winfo_reqwidth(), 540)
        h = self.root.winfo_reqheight()
        self.root.minsize(w, h)
        ws = self.root.winfo_screenwidth()
        hs = self.root.winfo_screenheight()
        x = max(0, (ws // 2) - (w // 2))
        y = max(0, (hs // 2) - (h // 2))
        self.root.geometry(f"{w}x{h}+{x}+{y}")

    def _check_ffmpeg(self):
        # 檢測系統是否已有 ffmpeg
        ffmpeg_path = shutil.which("ffmpeg")
        if not ffmpeg_path:
            # 嘗試檢查常見 WinGet 或本機路徑
            local_appdata = os.environ.get("LOCALAPPDATA", "")
            winget_path = os.path.join(local_appdata, r"Microsoft\WinGet\Links\ffmpeg.exe")
            if os.path.exists(winget_path):
                os.environ["PATH"] = os.path.dirname(winget_path) + os.pathsep + os.environ.get("PATH", "")

    def _build_ui(self):
        # 主容器
        container = tk.Frame(self.root, bg="#0f172a", padx=24, pady=20)
        container.pack(fill=tk.BOTH, expand=True)

        # 1. 標題與簡介
        header_frame = tk.Frame(container, bg="#0f172a")
        header_frame.pack(fill=tk.X, pady=(0, 16))

        title_label = tk.Label(
            header_frame,
            text="🎬 Universal Video Downloader",
            font=("Segoe UI", 16, "bold"),
            bg="#0f172a",
            fg="#f8fafc"
        )
        title_label.pack(anchor="w")

        subtitle_label = tk.Label(
            header_frame,
            text="支援 YouTube、Bilibili、FB、IG、X/Twitter 等主流串流影片下載",
            font=("Microsoft JhengHei", 9),
            bg="#0f172a",
            fg="#94a3b8"
        )
        subtitle_label.pack(anchor="w", pady=(2, 0))

        # 2. 網址輸入區
        url_label = tk.Label(
            container,
            text="影片網址 (Video URL)：",
            font=("Microsoft JhengHei", 10, "bold"),
            bg="#0f172a",
            fg="#cbd5e1"
        )
        url_label.pack(anchor="w", pady=(0, 6))

        url_input_frame = tk.Frame(container, bg="#0f172a")
        url_input_frame.pack(fill=tk.X, pady=(0, 14))

        self.url_var = tk.StringVar()
        self.url_entry = tk.Entry(
            url_input_frame,
            textvariable=self.url_var,
            font=("Segoe UI", 10),
            bg="#1e293b",
            fg="#ffffff",
            insertbackground="#ffffff",
            relief="flat",
            bd=6
        )
        self.url_entry.pack(side=tk.LEFT, fill=tk.X, expand=True, padx=(0, 8))

        paste_btn = tk.Button(
            url_input_frame,
            text="📋 貼上",
            font=("Microsoft JhengHei", 9, "bold"),
            bg="#334155",
            fg="#f8fafc",
            activebackground="#475569",
            activeforeground="#ffffff",
            relief="flat",
            padx=12,
            pady=4,
            cursor="hand2",
            command=self._paste_clipboard
        )
        paste_btn.pack(side=tk.RIGHT)

        # 3. 下載規格與畫質選擇
        format_frame = tk.LabelFrame(
            container,
            text=" 畫質與格式設定 ",
            font=("Microsoft JhengHei", 9, "bold"),
            bg="#1e293b",
            fg="#94a3b8",
            padx=14,
            pady=10,
            relief="solid",
            bd=1
        )
        format_frame.pack(fill=tk.X, pady=(0, 14))

        self.format_var = tk.StringVar(value="best")
        formats = [
            ("🌟 最佳畫質 (自動合併最高 4K / 1080p MP4)", "best"),
            ("🎬 1080p 高畫質 (MP4)", "1080p"),
            ("📱 720p 標清 (MP4)", "720p"),
            ("🎵 僅擷取音訊 (MP3 音樂檔)", "audio_only")
        ]

        for text, val in formats:
            rb = tk.Radiobutton(
                format_frame,
                text=text,
                value=val,
                variable=self.format_var,
                font=("Microsoft JhengHei", 9),
                bg="#1e293b",
                fg="#f1f5f9",
                selectcolor="#0f172a",
                activebackground="#1e293b",
                activeforeground="#60a5fa",
                cursor="hand2",
                anchor="w"
            )
            rb.pack(fill=tk.X, pady=2)

        # 4. 儲存路徑區
        path_frame = tk.Frame(container, bg="#0f172a")
        path_frame.pack(fill=tk.X, pady=(0, 16))

        path_label = tk.Label(
            path_frame,
            text="儲存資料夾：",
            font=("Microsoft JhengHei", 9, "bold"),
            bg="#0f172a",
            fg="#94a3b8"
        )
        path_label.pack(side=tk.LEFT)

        self.path_display_var = tk.StringVar(value=self.download_dir)
        self.path_entry = tk.Entry(
            path_frame,
            textvariable=self.path_display_var,
            font=("Segoe UI", 9),
            bg="#1e293b",
            fg="#94a3b8",
            relief="flat",
            state="readonly",
            bd=4
        )
        self.path_entry.pack(side=tk.LEFT, fill=tk.X, expand=True, padx=6)

        browse_btn = tk.Button(
            path_frame,
            text="瀏覽...",
            font=("Microsoft JhengHei", 9),
            bg="#334155",
            fg="#f8fafc",
            activebackground="#475569",
            activeforeground="#ffffff",
            relief="flat",
            padx=10,
            pady=2,
            cursor="hand2",
            command=self._browse_dir
        )
        browse_btn.pack(side=tk.RIGHT)

        # 5. 進度顯示區（Canvas 自繪平滑進度條）
        progress_box = tk.Frame(container, bg="#1e293b", padx=12, pady=10, bd=1, relief="solid")
        progress_box.pack(fill=tk.X, pady=(0, 16))

        self.status_title_var = tk.StringVar(value="影片：尚未開始")
        self.status_title_label = tk.Label(
            progress_box,
            textvariable=self.status_title_var,
            font=("Microsoft JhengHei", 9, "bold"),
            bg="#1e293b",
            fg="#e2e8f0",
            anchor="w"
        )
        self.status_title_label.pack(fill=tk.X)

        # 進度條畫布
        self.progress_canvas = tk.Canvas(progress_box, height=14, bg="#0f172a", highlightthickness=0)
        self.progress_canvas.pack(fill=tk.X, pady=6)
        self.progress_bar_rect = self.progress_canvas.create_rectangle(0, 0, 0, 14, fill="#3b82f6", width=0)

        # 詳細狀態 (百分比, 速度, 剩餘時間)
        self.detail_var = tk.StringVar(value="狀態：待命中，請貼上網址後點擊下載")
        self.detail_label = tk.Label(
            progress_box,
            textvariable=self.detail_var,
            font=("Segoe UI", 9),
            bg="#1e293b",
            fg="#94a3b8",
            anchor="w"
        )
        self.detail_label.pack(fill=tk.X)

        # 6. 下載按鈕與開啟目錄
        btn_box = tk.Frame(container, bg="#0f172a")
        btn_box.pack(fill=tk.X)

        self.download_btn = tk.Button(
            btn_box,
            text="⬇️ 開始下載影片",
            font=("Microsoft JhengHei", 11, "bold"),
            bg="#2563eb",
            fg="#ffffff",
            activebackground="#1d4ed8",
            activeforeground="#ffffff",
            relief="flat",
            pady=8,
            cursor="hand2",
            command=self.start_download
        )
        self.download_btn.pack(side=tk.LEFT, fill=tk.X, expand=True, padx=(0, 8))

        self.open_folder_btn = tk.Button(
            btn_box,
            text="📂 開啟下載資料夾",
            font=("Microsoft JhengHei", 10, "bold"),
            bg="#059669",
            fg="#ffffff",
            activebackground="#047857",
            activeforeground="#ffffff",
            relief="flat",
            padx=14,
            pady=8,
            cursor="hand2",
            command=self._open_folder
        )
        self.open_folder_btn.pack(side=tk.RIGHT)

        # 7. 免責聲明
        disclaimer = tk.Label(
            container,
            text="免責聲明：請只下載你擁有權利或已獲授權的影片。下載、轉存他人作品須遵守著作權法與各平台使用條款，使用者須自行承擔責任。",
            font=("Microsoft JhengHei", 8),
            bg="#0f172a",
            fg="#94a3b8",
            justify="left",
            wraplength=480,
        )
        disclaimer.pack(fill=tk.X, pady=(14, 0))

    def _paste_clipboard(self):
        try:
            text = self.root.clipboard_get().strip()
            if text:
                self.url_var.set(text)
        except Exception:
            pass

    def _browse_dir(self):
        selected = filedialog.askdirectory(initialdir=self.download_dir)
        if selected:
            self.download_dir = selected
            self.path_display_var.set(selected)

    def _open_folder(self):
        if os.path.exists(self.download_dir):
            os.startfile(self.download_dir)
        else:
            messagebox.showinfo("提示", "下載資料夾尚未建立或不存在！")

    def _update_progress(self, percent: float, status_text: str, title_text: str = None):
        def _apply():
            if title_text:
                self.status_title_var.set(f"影片：{title_text}")
            self.detail_var.set(status_text)
            
            # 更新 Canvas 進度條寬度
            canvas_width = self.progress_canvas.winfo_width()
            bar_w = int(canvas_width * (percent / 100.0))
            self.progress_canvas.coords(self.progress_bar_rect, 0, 0, bar_w, 14)
        self.root.after(0, _apply)

    def start_download(self):
        if self.is_downloading:
            return

        url = self.url_var.get().strip()
        if not url:
            messagebox.showwarning("請輸入網址", "請先貼上或輸入您要下載的影片網址！")
            return

        self.is_downloading = True
        self.download_btn.config(
            text="⏳ 正在下載與轉碼中...",
            bg="#475569",
            state="disabled",
            cursor="watch"
        )
        self.url_entry.config(state="disabled")
        self._update_progress(0, "正在解析影片串流資訊與提取格式，請稍候...")

        # 背景執行下載
        self.download_thread = threading.Thread(target=self._download_worker, args=(url,), daemon=True)
        self.download_thread.start()

    def _download_worker(self, url: str):
        choice = self.format_var.get()
        outtmpl = os.path.join(self.download_dir, "%(title)s.%(ext)s")

        ydl_opts = {
            "outtmpl": outtmpl,
            "quiet": True,
            "no_warnings": True,
            "nocheckcertificate": True,
            "progress_hooks": [self._ytdl_hook],
            "postprocessor_hooks": [self._postprocessor_hook],
        }

        # 設定畫質參數
        if choice == "audio_only":
            ydl_opts["format"] = "bestaudio/best"
            ydl_opts["postprocessors"] = [{
                "key": "FFmpegExtractAudio",
                "preferredcodec": "mp3",
                "preferredquality": "192",
            }]
        elif choice == "1080p":
            ydl_opts["format"] = "bestvideo[height<=1080]+bestaudio/best[height<=1080]/best"
            ydl_opts["merge_output_format"] = "mp4"
        elif choice == "720p":
            ydl_opts["format"] = "bestvideo[height<=720]+bestaudio/best[height<=720]/best"
            ydl_opts["merge_output_format"] = "mp4"
        else:
            # 最佳畫質
            ydl_opts["format"] = "bestvideo+bestaudio/best"
            ydl_opts["merge_output_format"] = "mp4"

        try:
            with yt_dlp.YoutubeDL(ydl_opts) as ydl:
                info = ydl.extract_info(url, download=False)
                video_title = info.get("title", "未知影片標題")
                self._update_progress(0, "解析成功，開始串流下載...", title_text=video_title)
                ydl.download([url])

            self._update_progress(100, "🎉 下載完成！檔案已妥善儲存。")
            self.root.after(0, lambda: messagebox.showinfo("下載成功", f"影片已成功下載至：\n{self.download_dir}"))
        except Exception as e:
            err_msg = str(e)
            if "HTTP Error 403" in err_msg:
                err_text = "下載失敗：該平台限制存取或需要登入驗證 (403 Forbidden)。"
            elif "Unsupported URL" in err_msg:
                err_text = "下載失敗：不支援的網址格式或不是有效的影片連結。"
            else:
                err_text = f"下載發生錯誤：{err_msg[:120]}"
            self._update_progress(0, f"❌ {err_text}")
            self.root.after(0, lambda: messagebox.showerror("下載失敗", err_text))
        finally:
            self.is_downloading = False
            self.root.after(0, self._reset_ui)

    def _ytdl_hook(self, d):
        status = d.get("status")
        if status == "downloading":
            total = d.get("total_bytes") or d.get("total_bytes_estimate") or 0
            downloaded = d.get("downloaded_bytes", 0)
            speed = d.get("speed") or 0
            eta = d.get("eta") or 0

            percent = 0.0
            if total > 0:
                percent = min(100.0, (downloaded / total) * 100.0)

            # 速度格式化
            if speed > 1024 * 1024:
                speed_str = f"{speed / (1024 * 1024):.1f} MB/s"
            elif speed > 1024:
                speed_str = f"{speed / 1024:.0f} KB/s"
            else:
                speed_str = "-- KB/s"

            # 剩餘時間格式化
            if eta:
                eta_str = f"{int(eta // 60):02d}:{int(eta % 60):02d}"
            else:
                eta_str = "--:--"

            info_text = f"正在下載中: {percent:.1f}% | 速度: {speed_str} | 剩餘時間: {eta_str}"
            self._update_progress(percent, info_text)
        elif status == "finished":
            self._update_progress(100, "下載完成，正在處理影音轉碼合成 (FFmpeg)...")

    def _postprocessor_hook(self, d):
        status = d.get("status")
        if status == "started":
            self._update_progress(100, "正在進行音訊視訊無損合成與封裝...")
        elif status == "finished":
            self._update_progress(100, "轉碼合成完成！")

    def _reset_ui(self):
        self.download_btn.config(
            text="⬇️ 開始下載影片",
            bg="#2563eb",
            state="normal",
            cursor="hand2"
        )
        self.url_entry.config(state="normal")


def main():
    # 讓 Windows 知道程式會自己處理高解析度縮放，文字才不會模糊。
    if sys.platform == "win32":
        try:
            import ctypes
            ctypes.windll.shcore.SetProcessDpiAwareness(1)
        except Exception:
            pass
    root = tk.Tk()
    app = VideoDownloaderApp(root)
    root.mainloop()


if __name__ == "__main__":
    main()