import os
import re
import asyncio
from typing import List, Optional
import httpx
from yandex_music import Client
from app.config import settings
from app.providers.base import BaseProvider, TrackMetadata

class YandexMusicProvider(BaseProvider):
    def __init__(self, token: Optional[str] = None):
        self.token = token or settings.YANDEX_MUSIC_TOKEN
        self._client: Optional[Client] = None

    def get_client(self) -> Client:
        if not self._client:
            if not self.token:
                raise ValueError("Yandex Music Token is not configured.")
            self._client = Client(self.token).init()
        return self._client

    def can_handle(self, url: str) -> bool:
        return "music.yandex." in url or url == "yandex:likes"

    async def resolve(self, url: str) -> List[TrackMetadata]:
        loop = asyncio.get_event_loop()
        return await loop.run_in_executor(None, self._resolve_sync, url)

    def _resolve_sync(self, url: str) -> List[TrackMetadata]:
        client = self.get_client()
        tracks: List[TrackMetadata] = []

        if url == "yandex:likes":
            likes = client.users_likes_tracks()
            if not likes or not likes.tracks:
                return []
            track_ids = [t.id for t in likes.tracks]
            # Fetch in batches of 100
            for i in range(0, len(track_ids), 100):
                batch = track_ids[i:i + 100]
                full_tracks = client.tracks(batch)
                for t in full_tracks:
                    meta = self._convert_track(t)
                    if meta:
                        tracks.append(meta)
            return tracks

        # Parse URL
        # e.g., https://music.yandex.ru/album/123/track/456
        track_match = re.search(r'/album/(\d+)/track/(\d+)', url)
        if track_match:
            track_id = track_match.group(2)
            t = client.tracks([track_id])[0]
            meta = self._convert_track(t)
            return [meta] if meta else []

        # Direct track match: /track/123
        direct_track = re.search(r'/track/(\d+)', url)
        if direct_track:
            track_id = direct_track.group(1)
            t = client.tracks([track_id])[0]
            meta = self._convert_track(t)
            return [meta] if meta else []

        # Album match: /album/123
        album_match = re.search(r'/album/(\d+)', url)
        if album_match:
            album_id = album_match.group(1)
            album = client.albums_with_tracks(album_id)
            if album and album.volumes:
                for vol in album.volumes:
                    for t in vol:
                        meta = self._convert_track(t)
                        if meta:
                            tracks.append(meta)
            return tracks

        # Playlist match: /users/username/playlists/123
        playlist_match = re.search(r'/users/([^/]+)/playlists/(\d+)', url)
        if playlist_match:
            owner = playlist_match.group(1)
            kind = playlist_match.group(2)
            pl = client.users_playlists(kind, owner)
            if pl and pl.tracks:
                for item in pl.tracks:
                    meta = self._convert_track(item.track)
                    if meta:
                        tracks.append(meta)
            return tracks

        return []

    def _convert_track(self, t) -> Optional[TrackMetadata]:
        if not t:
            return None
        artists = ", ".join(a.name for a in t.artists) if t.artists else "Unknown"
        album_name = t.albums[0].title if t.albums else "Singles"
        year = t.albums[0].year if t.albums and t.albums[0].year else None
        genre = t.albums[0].genre if t.albums and t.albums[0].genre else None
        track_num = t.albums[0].track_position.index if t.albums and t.albums[0].track_position else None
        
        cover_url = None
        if t.cover_uri:
            cover_url = "https://" + t.cover_uri.replace("%%", "1000x1000")

        return TrackMetadata(
            service="yandex",
            service_id=str(t.id),
            title=t.title,
            artist=artists,
            album=album_name,
            track_number=track_num,
            year=year,
            genre=genre,
            duration_ms=t.duration_ms,
            is_explicit=bool(t.content_warning == "explicit"),
            cover_url=cover_url,
            source_url=f"https://music.yandex.ru/track/{t.id}"
        )

    async def download_track(self, track: TrackMetadata, dest_path: str) -> bool:
        loop = asyncio.get_event_loop()
        return await loop.run_in_executor(None, self._download_sync, track, dest_path)

    def _download_sync(self, track: TrackMetadata, dest_path: str) -> bool:
        client = self.get_client()
        try:
            full_track = client.tracks([track.service_id])[0]
            if not full_track.available:
                print(f"Track {track.title} is not available in Yandex catalog.")
                return False

            tmp_download_path = dest_path + ".tmp"
            full_track.download(tmp_download_path, bitrate_in_kbps=320)
            
            # Fetch cover image
            cover_bytes = None
            if track.cover_url:
                try:
                    with httpx.Client(timeout=10.0) as http_client:
                        resp = http_client.get(track.cover_url)
                        if resp.status_code == 200:
                            cover_bytes = resp.content
                except Exception as e:
                    print(f"Warning: Failed to fetch cover for {track.title}: {e}")

            # Apply ID3 tags
            from app.core.tagger import apply_id3_tags
            apply_id3_tags(
                tmp_download_path,
                title=track.title,
                artist=track.artist,
                album=track.album,
                track_number=track.track_number,
                year=track.year,
                genre=track.genre,
                cover_bytes=cover_bytes
            )

            os.replace(tmp_download_path, dest_path)
            return True
        except Exception as e:
            print(f"Error downloading Yandex track {track.title}: {e}")
            return False