"""Background task que consulta recently_played cada 30s y persiste el historial."""
import asyncio
import logging
from datetime import datetime, timezone

from app.database import SessionLocal
from app.models import PlayHistory
from app import spotify

logger = logging.getLogger(__name__)

POLL_INTERVAL = 30  # segundos


async def start_poller():
    while True:
        try:
            await asyncio.to_thread(_fetch_and_save)
        except Exception as exc:
            logger.warning("history_poller error: %s", exc)
        await asyncio.sleep(POLL_INTERVAL)


def _fetch_and_save():
    if not spotify.is_authenticated():
        return

    sp = spotify.get_client()
    result = sp.current_user_recently_played(limit=50)
    items = result.get("items", [])
    if not items:
        return

    # Recolectar IDs de artistas únicos para lookup de géneros en batch
    artist_ids: set[str] = set()
    for item in items:
        for artist in item["track"]["artists"]:
            artist_ids.add(artist["id"])

    genre_map: dict[str, list[str]] = {}
    artist_id_list = list(artist_ids)
    for i in range(0, len(artist_id_list), 50):
        batch = artist_id_list[i : i + 50]
        try:
            data = sp.artists(batch)
            for a in data.get("artists") or []:
                if a:
                    genre_map[a["id"]] = a.get("genres", [])
        except Exception:
            pass

    db = SessionLocal()
    try:
        saved = 0
        for item in items:
            track = item["track"]
            played_at = datetime.fromisoformat(
                item["played_at"].replace("Z", "+00:00")
            )

            exists = (
                db.query(PlayHistory)
                .filter(
                    PlayHistory.track_id == track["id"],
                    PlayHistory.played_at == played_at,
                )
                .first()
            )
            if exists:
                continue

            track_artists = track.get("artists", [])
            artist_names = [a["name"] for a in track_artists]
            genres: set[str] = set()
            for a in track_artists:
                genres.update(genre_map.get(a["id"], []))

            db.add(
                PlayHistory(
                    track_id=track["id"],
                    track_name=track["name"],
                    artists=", ".join(artist_names),
                    genres=", ".join(sorted(genres)),
                    played_at=played_at,
                )
            )
            saved += 1

        if saved:
            db.commit()
            logger.info("history_poller: guardadas %d reproducciones", saved)
    except Exception:
        db.rollback()
        raise
    finally:
        db.close()