import logging
import os
import time
from typing import Optional
from urllib.parse import unquote
import yt_dlp

logger = logging.getLogger(__name__)

CACHE_TTL = int(os.getenv("CACHE_TTL", 31536000))
SOCKET_TIMEOUT = int(os.getenv("SOCKET_TIMEOUT", 30))

_session_cache = {}
_cache_timestamps = {}

_ydl_instance = None


def _get_ydl():
    """Get or create a singleton yt-dlp instance."""
    global _ydl_instance
    if _ydl_instance is None:
        _ydl_instance = yt_dlp.YoutubeDL({
            "quiet": True,
            "no_warnings": True,
            "socket_timeout": SOCKET_TIMEOUT,
        })
    return _ydl_instance


def _get_cache_key(video_url: str) -> str:
    return video_url


def _is_cache_expired(video_url: str) -> bool:
    key = _get_cache_key(video_url)
    if key not in _cache_timestamps:
        return True
    return time.time() - _cache_timestamps[key] > CACHE_TTL


def _get_cached_info(video_url: str) -> Optional[dict]:
    key = _get_cache_key(video_url)
    if key in _session_cache and not _is_cache_expired(video_url):
        return _session_cache[key]
    return None


def _set_cached_info(video_url: str, info: dict) -> None:
    key = _get_cache_key(video_url)
    _session_cache[key] = info
    _cache_timestamps[key] = time.time()


def _extract_hls_url(info: dict) -> Optional[str]:
    """Extract HLS URL from yt-dlp info dict."""
    # First check top-level fields (these are set when there's only one format)
    url = info.get("manifest_url") or info.get("url")
    if url and ".m3u8" in url:
        return url
    
    # Check requested_formats (post-processed by yt-dlp)
    if info.get("requested_formats"):
        for f in info["requested_formats"]:
            url = f.get("url") or f.get("manifest_url")
            if url and ".m3u8" in url:
                return url
    
    # Check formats for m3u8_native protocol
    if info.get("formats"):
        for f in reversed(info["formats"]):
            if f.get("protocol") == "m3u8_native":
                url = f.get("manifest_url") or f.get("url")
                if url and ".m3u8" in url:
                    return url
    
    # Try to find any m3u8 URL in formats
    if info.get("formats"):
        for f in info["formats"]:
            url = f.get("url", "")
            if ".m3u8" in url:
                return url
    
    return None


def _extract_direct_url(info: dict) -> Optional[str]:
    """Extract direct video URL when HLS is not available."""
    # Check url field first
    url = info.get("url")
    if url:
        return url
    
    # Check requested_formats
    if info.get("requested_formats"):
        for f in info["requested_formats"]:
            url = f.get("url")
            if url:
                return url
    
    # Check formats for best quality https format
    if info.get("formats"):
        for f in reversed(info["formats"]):
            if f.get("protocol") in ("https", "http"):
                url = f.get("url")
                if url:
                    return url
    
    return None


def _get_video_info(video_url: str) -> dict:
    """Get video info using yt-dlp."""
    cached = _get_cached_info(video_url)
    if cached:
        return cached

    import shutil
    if not shutil.which("node"):
        deno_path = os.path.expanduser("~/.deno/bin/deno")
        if not os.path.exists(deno_path):
            logger.warning("No JavaScript runtime (node/deno) found - YouTube may not work properly")

    ydl = _get_ydl()
    info = ydl.extract_info(video_url, download=False)

    hls_url = _extract_hls_url(info)
    direct_url = _extract_direct_url(info)
    result = {
        "title": info.get("title"),
        "thumbnail": info.get("thumbnail"),
        "hls_url": hls_url,
        "direct_url": direct_url,
        "raw_info": info,
    }
    _set_cached_info(video_url, result)
    return result


def get_stream_info(video_url: str) -> dict:
    """Get video info with all available metadata."""
    info = _get_video_info(video_url)
    
    # Extract useful metadata from raw_info
    raw = info.get("raw_info", {})
    metadata = {
        "title": info["title"],
        "thumbnail": info["thumbnail"],
        "hls_url": info.get("hls_url"),
        "direct_url": info.get("direct_url"),
        # Additional metadata
        "description": raw.get("description"),
        "uploader": raw.get("uploader"),
        "uploader_url": raw.get("uploader_url"),
        "duration": raw.get("duration"),
        "upload_date": raw.get("upload_date"),
        "view_count": raw.get("view_count"),
        "like_count": raw.get("like_count"),
        "dislike_count": raw.get("dislike_count"),
        "comment_count": raw.get("comment_count"),
        "age_limit": raw.get("age_limit"),
        "categories": raw.get("categories"),
        "tags": raw.get("tags"),
        "language": raw.get("language"),
        "license": raw.get("license"),
        "channel": raw.get("channel"),
        "channel_url": raw.get("channel_url"),
        "channel_id": raw.get("channel_id"),
        "extractor": raw.get("extractor"),
        "extractor_key": raw.get("extractor_key"),
        "display_id": raw.get("display_id"),
        "url": raw.get("url"),
        "fulltitle": raw.get("fulltitle"),
        "duration_string": raw.get("duration_string"),
        "resolution": raw.get("resolution"),
        "format": raw.get("format"),
        "format_note": raw.get("format_note"),
        "filesize": raw.get("filesize"),
        "filesize_approx": raw.get("filesize_approx"),
    }
    return metadata


def get_hls_playlist(video_url: str) -> str:
    """Get HLS playlist content with rewritten URLs."""
    import urllib.request
    import urllib.error
    
    # First call _get_video_info to ensure cache is populated (yt-dlp quirk)
    info = _get_video_info(video_url)
    hls_url = info.get("hls_url")
    if not hls_url:
        raise ValueError("No HLS stream available for this video")
    
    # Try to get playlist, retry once if URL expired
    for attempt in range(2):
        try:
            with urllib.request.urlopen(hls_url, timeout=SOCKET_TIMEOUT) as response:
                playlist_content = response.read().decode("utf-8")
            return _rewrite_urls(playlist_content, video_url, hls_url)
        except urllib.error.HTTPError as e:
            if e.code == 410 and attempt == 0:
                # Clear cache and fetch fresh HLS URL
                _session_cache.pop(video_url, None)
                _cache_timestamps.pop(video_url, None)
                logger.info("HLS URL expired, fetching fresh HLS URL")
                info = _get_video_info(video_url)
                hls_url = info.get("hls_url")
                if not hls_url:
                    raise ValueError("No HLS stream available for this video")
                continue
            raise


def get_direct_video_url(video_url: str) -> str:
    """Get direct video URL when HLS is not available."""
    info = _get_video_info(video_url)
    if not info.get("direct_url"):
        raise ValueError("No video URL available for this video")
    return info["direct_url"]


def _rewrite_urls(content: str, video_url: str, base_url: str) -> str:
    """Rewrite relative URLs in HLS playlist to point through proxy."""
    from urllib.parse import urljoin, quote, urlparse, parse_qs, urlencode

    # URL encode the video URL for safe path usage
    encoded_video_url = quote(video_url, safe="")

    # Parse base URL to get directory path and query
    base_parsed = urlparse(base_url)
    base_path = base_parsed.path
    base_query = parse_qs(base_parsed.query)
    
    # Get directory path (remove the .m3u8 filename)
    dir_path = base_path.rsplit("/", 1)[0]

    lines = content.split("\n")
    new_lines = []
    for line in lines:
        if line and not line.startswith("#"):
            parsed = urlparse(line)
            
            if parsed.scheme:
                # Absolute URL - extract just the path component
                # e.g., https://example.com/video/segment.ts -> segment.ts
                filename = quote(parsed.path.split("/")[-1], safe="")
                if parsed.query:
                    filename += "?" + quote(parsed.query, safe="")
            else:
                # Relative URL - use as-is (with query params if any)
                filename = quote(line, safe="")
            
            # New format: /hls/<encoded_video_url>--<filename> (-- is delimiter)
            proxy_url = f"/hls/{encoded_video_url}--{filename}"
            new_lines.append(proxy_url)
            continue
        new_lines.append(line)
    return "\n".join(new_lines)


def get_hls_segment(video_url: str, segment_url: str) -> bytes:
    """Get HLS segment or sub-playlist content."""
    import urllib.request
    import urllib.error
    from urllib.parse import unquote, urlparse, parse_qs, urlencode
    
    # Get the base URL from yt-dlp cache
    info = _get_video_info(video_url)
    hls_url = info.get("hls_url")
    
    if not hls_url:
        raise ValueError("No HLS URL available")
    
    # Parse the HLS URL to get base path
    base_parsed = urlparse(hls_url)
    base_path = base_parsed.path.rsplit("/", 1)[0]
    base_query = parse_qs(base_parsed.query)
    
    # Check if it's a playlist (regardless of query params)
    is_playlist = unquote(segment_url).split("?")[0].endswith(".m3u8")
    
    # Reconstruct full URL from filename
    filename = unquote(segment_url)
    if "?" in filename:
        rel_path, rel_query = filename.split("?", 1)
        rel_qs = parse_qs(rel_query)
        full_url = f"{base_parsed.scheme}://{base_parsed.netloc}{base_path}/{rel_path}"
        merged_qs = {**base_query, **rel_qs}
        if merged_qs:
            full_url += "?" + urlencode(merged_qs, doseq=True)
    else:
        full_url = f"{base_parsed.scheme}://{base_parsed.netloc}{base_path}/{filename}"
    
    try:
        response = urllib.request.urlopen(full_url, timeout=SOCKET_TIMEOUT)
        data = response.read()
    except urllib.error.HTTPError as e:
        if e.code == 410:
            raise ValueError("HLS URL expired (410 Gone)")
        raise

    if is_playlist:
        return _rewrite_urls(data.decode("utf-8"), video_url, full_url).encode("utf-8")
    return data


def get_hls_segment_with_retry(video_url: str, segment_url: str) -> bytes:
    """Get HLS segment with retry on 410 error (refetches sub-playlist if needed)."""
    from urllib.parse import unquote
    
    # Check if this is a segment (not a playlist)
    is_segment = not unquote(segment_url).split("?")[0].endswith(".m3u8")
    
    for attempt in range(2):
        try:
            return get_hls_segment(video_url, segment_url)
        except ValueError as e:
            if "410 Gone" in str(e) and attempt == 0:
                if is_segment:
                    # For segments: re-fetch the sub-playlist (which has fresh segment URLs)
                    logger.info("Segment URL expired, re-fetching sub-playlist")
                    
                    # Get fresh HLS URL
                    info = _get_video_info(video_url)
                    hls_url = info.get("hls_url")
                    if not hls_url:
                        raise ValueError("No HLS stream available")
                    
                    # Fetch the sub-playlist from the fresh HLS URL
                    import urllib.request
                    from urllib.parse import urlparse, parse_qs, urlencode
                    
                    # Get base path from HLS URL
                    parsed = urlparse(hls_url)
                    base_path = parsed.path.rsplit("/", 1)[0]
                    base_query = parse_qs(parsed.query)
                    
                    # Find sub-playlist in main playlist
                    with urllib.request.urlopen(hls_url, timeout=SOCKET_TIMEOUT) as response:
                        playlist_content = response.read().decode("utf-8")
                    
                    # Extract sub-playlist filename from first #EXT-X-STREAM-INF
                    sub_playlist_path = None
                    for line in playlist_content.split("\n"):
                        if line.startswith("#EXT-X-STREAM-INF:"):
                            continue
                        elif line and not line.startswith("#"):
                            sub_playlist_path = line
                            break
                    
                    if not sub_playlist_path:
                        raise ValueError("Could not find sub-playlist URL")
                    
                    # Build full sub-playlist URL with fresh tokens
                    if "?" in sub_playlist_path:
                        rel_path, rel_query = sub_playlist_path.split("?", 1)
                        rel_qs = parse_qs(rel_query)
                        full_url = f"{parsed.scheme}://{parsed.netloc}{base_path}/{rel_path}"
                        merged_qs = {**base_query, **rel_qs}
                        full_url += "?" + urlencode(merged_qs, doseq=True)
                    else:
                        full_url = f"{parsed.scheme}://{parsed.netloc}{base_path}/{sub_playlist_path}"
                    
                    logger.info(f"Fetching fresh sub-playlist: {full_url[:100]}...")
                    
                    # Fetch sub-playlist content
                    with urllib.request.urlopen(full_url, timeout=SOCKET_TIMEOUT) as response:
                        sub_content = response.read().decode("utf-8")
                    
                    # Rewrite URLs in sub-playlist
                    rewritten = _rewrite_urls(sub_content, video_url, full_url)
                    logger.info(f"Rewritten sub-playlist (first 200 chars): {rewritten[:200]}...")
                    return rewritten.encode("utf-8")
                else:
                    # For sub-playlist: clear cache and retry
                    _session_cache.pop(video_url, None)
                    _cache_timestamps.pop(video_url, None)
                    logger.info("Sub-playlist expired, refetching")
                    continue
            raise