#!/usr/bin/env python3
"""
YouTube 视频下载器
使用 Savenow API 下载 YouTube 视频/音频

使用方法:
    python youtube_dl.py <YouTube_URL> [format]

示例:
    python youtube_dl.py "https://www.youtube.com/watch?v=xxx" mp3
    python youtube_dl.py "https://www.youtube.com/watch?v=xxx" 1080
"""

import requests
import time
import sys
import os
import re
import json

API_KEY = "dfcb6d76f2f6a9894gjkege8a4ab232222"
API_BASES = ["https://p.savenow.to", "https://p.lbserver.xyz"]

VIDEO_FORMATS = {
    "144": "144p Mp4",
    "240": "240p Mp4",
    "360": "360p Mp4",
    "480": "480p Mp4",
    "720": "720p HD Mp4",
    "1080": "1080p FULL HD Mp4",
    "4k": "2160p 4K WEBM",
    "8k": "4320p 8K WEBM",
}

AUDIO_FORMATS = {
    "mp3": "Audio MP3",
    "m4a": "Audio M4A",
    "flac": "Audio FLAC",
    "wav": "Audio WAV",
    "aac": "Audio AAC",
    "opus": "Audio OPUS",
    "ogg": "Audio OGG",
}


def get_title_from_response(response_text):
    """从 API 响应中提取视频标题"""
    try:
        match = re.search(rb'"title":"([^"]+)"', response_text.encode("utf-8"))
        if match:
            escaped = match.group(1).decode("ascii")
            title = bytes(escaped, "ascii").decode("unicode_escape")
            return title
    except:
        pass
    return None


def request_download(url, format="mp3"):
    """请求下载，返回 progress_id"""
    params = {
        "copyright": "0",
        "allow_extended_duration": "1",
        "format": format,
        "url": url,
        "api": API_KEY,
    }

    for base in API_BASES:
        try:
            resp = requests.get(f"{base}/ajax/download.php", params=params, timeout=30)
            data = resp.json()
            if data.get("success"):
                return (
                    data.get("id"),
                    data.get("progress_url"),
                    data.get("info", {}).get("title", ""),
                )
        except Exception as e:
            print(f"尝试 {base} 失败: {e}")
            continue

    raise Exception("所有 API 都失败了")


def poll_progress(progress_url, title):
    """轮询直到下载完成，返回下载链接"""
    print("等待处理中...", end="", flush=True)

    while True:
        time.sleep(3)
        resp = requests.get(progress_url, timeout=30)
        data = resp.json()

        progress = data.get("progress", 0) / 10
        status = data.get("success", 0)

        if status == 1 and progress == 100:
            return data.get("download_url"), data.get("alternative_download_urls", [])

        print(".", end="", flush=True)

    return None, []


def download_file(download_url, output_path):
    """下载文件"""
    print(f"\n正在下载: {output_path}")

    resp = requests.get(download_url, stream=True)
    total = int(resp.headers.get("content-length", 0))

    downloaded = 0
    with open(output_path, "wb") as f:
        for chunk in resp.iter_content(chunk_size=8192):
            if chunk:
                f.write(chunk)
                downloaded += len(chunk)
                if total:
                    percent = downloaded * 100 / total
                    print(f"\r进度: {percent:.1f}%", end="", flush=True)

    print("\n下载完成!")
    return output_path


def main():
    if len(sys.argv) < 2:
        print(__doc__)
        print("\n可用格式:")
        print("视频:", ", ".join(VIDEO_FORMATS.keys()))
        print("音频:", ", ".join(AUDIO_FORMATS.keys()))
        sys.exit(1)

    url = sys.argv[1]
    format = sys.argv[2] if len(sys.argv) > 2 else "mp3"

    # 获取标题
    print(f"请求下载: {url}")
    print(f"格式: {format}")

    progress_id, progress_url, title = request_download(url, format)
    print(f"视频标题: {title}")

    # 轮询下载链接
    download_url, alternatives = poll_progress(progress_url, title)

    if not download_url and alternatives:
        download_url = alternatives[0].get("url")

    if not download_url:
        print("获取下载链接失败!")
        sys.exit(1)

    # 确定文件扩展名
    ext = (
        format
        if format in ["mp3", "m4a", "flac", "wav", "aac", "opus", "ogg"]
        else "mp4"
    )

    # 生成文件名
    safe_title = re.sub(r'[\\/:*?"<>|]', "_", title or "video")
    output_path = f"{safe_title}({format}p).{ext}"

    # 下载
    download_file(download_url, output_path)
    print(f"已保存: {output_path}")


if __name__ == "__main__":
    main()