import logging
import re
from typing import List, Dict, Any, Optional
from urllib.parse import urljoin

logger = logging.getLogger(__name__)


def find_stream_by_resolution(streams: List[Dict[str, Any]], target_resolution: str) -> Optional[Dict[str, Any]]:
    """
    Find stream matching target resolution (e.g., '1080p', '720p').
    Falls back to closest lower resolution if exact match not found.

    Args:
        streams: List of stream dictionaries with 'resolution' key as (width, height) tuple.
        target_resolution: Target resolution string (e.g., '1080p', '720p').

    Returns:
        The matching stream dictionary, or None if no streams available.
    """
    # Parse target height from "1080p" -> 1080
    target_height = int(target_resolution.rstrip("p"))

    # Filter streams with valid resolution (height > 0), sort by height descending
    valid_streams = [s for s in streams if s.get("resolution", (0, 0))[1] > 0]
    if not valid_streams:
        logger.warning("No streams with valid resolution found")
        return streams[0] if streams else None

    sorted_streams = sorted(valid_streams, key=lambda s: s["resolution"][1], reverse=True)

    # Find exact match or closest lower
    for stream in sorted_streams:
        stream_height = stream["resolution"][1]
        if stream_height <= target_height:
            logger.info(f"Selected stream with resolution {stream['resolution']} for target {target_resolution}")
            return stream

    # If all streams are higher than target, return lowest available
    lowest_stream = sorted_streams[-1]
    logger.info(f"All streams higher than target {target_resolution}, using lowest: {lowest_stream['resolution']}")
    return lowest_stream


def parse_hls_playlist(playlist_content: str, base_url: Optional[str] = None) -> List[Dict[str, Any]]:
    """
    Parses an HLS master playlist to extract stream information.

    Args:
        playlist_content (str): The content of the M3U8 master playlist.
        base_url (str, optional): The base URL of the playlist for resolving relative stream URLs. Defaults to None.

    Returns:
        List[Dict[str, Any]]: A list of dictionaries, each representing a stream variant.
    """
    streams = []
    lines = playlist_content.strip().split("\n")

    # Regex to capture attributes from #EXT-X-STREAM-INF
    stream_inf_pattern = re.compile(r"#EXT-X-STREAM-INF:(.*)")

    for i, line in enumerate(lines):
        if line.startswith("#EXT-X-STREAM-INF"):
            stream_info = {"raw_stream_inf": line}
            match = stream_inf_pattern.match(line)
            if not match:
                logger.warning(f"Could not parse #EXT-X-STREAM-INF line: {line}")
                continue
            attributes_str = match.group(1)

            # Parse attributes like BANDWIDTH, RESOLUTION, etc.
            attributes = re.findall(r'([A-Z-]+)=("([^"]+)"|([^,]+))', attributes_str)
            for key, _, quoted_val, unquoted_val in attributes:
                value = quoted_val if quoted_val else unquoted_val
                if key == "RESOLUTION":
                    try:
                        width, height = map(int, value.split("x"))
                        stream_info["resolution"] = (width, height)
                    except ValueError:
                        stream_info["resolution"] = (0, 0)
                else:
                    stream_info[key.lower().replace("-", "_")] = value

            # The next line should be the stream URL
            if i + 1 < len(lines) and not lines[i + 1].startswith("#"):
                stream_url = lines[i + 1].strip()
                stream_info["url"] = urljoin(base_url, stream_url) if base_url else stream_url
                streams.append(stream_info)

    return streams