"""Enrichissement de métadonnées via l'API Kitsu (https://kitsu.io/api/edge).

Fusion intelligente : seuls les champs manquants d'un TitleDetails sont complétés.
Les échecs (réseau, cache indisponible) sont loggés en warning et jamais remontés
au caller — la fiche d'origine est retournée inchangée (dégradation gracieuse).
"""

import json
import logging
import re
import sqlite3

import httpx

from app.config import get_settings
from app.db import db
from app.scrapers.base import TitleDetails

logger = logging.getLogger(__name__)

_NOISE_WORDS_RE = re.compile(
    r"\b(?:VOSTFR\d*|VOST|VF[IV]?|TRUEFRENCH|FRENCH|MULTI|SUBFR?)\b", re.IGNORECASE
)
_TRAILING_SEASON_RE = re.compile(r"[\s\-–—:.]*\s*(?:saison|season)\s*\d+\s*$", re.IGNORECASE)
_TRAILING_CODE_RE = re.compile(r"[\s\-–—:.]*\s*S\d+(?:E\d+)?\s*$", re.IGNORECASE)


def normalize_title(title: str) -> str:
    """Nettoie un titre de scraping avant recherche Kitsu (bruit, saison, tirets)."""
    cleaned = _NOISE_WORDS_RE.sub(" ", title)
    cleaned = _TRAILING_SEASON_RE.sub("", cleaned)
    cleaned = _TRAILING_CODE_RE.sub("", cleaned)
    cleaned = re.sub(r"\s*[-–—_]+\s*", " ", cleaned)
    cleaned = re.sub(r"\s+", " ", cleaned)
    return cleaned.strip(" -–—:.")


class KitsuService:
    """Recherche et cache des métadonnées anime depuis l'API Kitsu."""

    async def search_anime(self, title: str) -> dict | None:
        """Recherche le meilleur match Kitsu pour un titre (None si échec/rien trouvé)."""
        settings = get_settings()
        query = normalize_title(title)
        if not query:
            return None
        try:
            async with httpx.AsyncClient(
                timeout=settings.http_timeout,
                headers={
                    "User-Agent": settings.user_agent,
                    "Accept": "application/vnd.api+json",
                },
            ) as client:
                response = await client.get(
                    f"{settings.kitsu_base_url}/anime",
                    params={"filter[text]": query, "page[limit]": 5, "include": "genres"},
                )
                response.raise_for_status()
                payload = response.json()
        except (httpx.HTTPError, ValueError) as exc:
            logger.warning("Recherche Kitsu échouée pour %r : %s", title, exc)
            return None
        return self._pick_best_match(payload, query)

    async def enrich(self, details: TitleDetails) -> TitleDetails:
        """Complète les champs manquants de details via Kitsu (jamais episodes/url/source)."""
        query = normalize_title(details.title)
        cache_key = f"kitsu:anime:{query.casefold()}"

        result = await self.get_cached(cache_key)
        from_cache = result is not None
        if result is None:
            result = await self.search_anime(details.title)
            if result is not None:
                await self.set_cached(cache_key, result)

        if result is None:
            logger.info("Aucune métadonnée Kitsu pour %r — fiche inchangée", details.title)
            return details

        attrs = result.get("attributes", {})
        if not details.synopsis:
            details.synopsis = attrs.get("synopsis")
        if not details.image_url:
            poster = attrs.get("posterImage") or {}
            details.image_url = poster.get("large") or poster.get("medium")
        if not details.banner_url:
            cover = attrs.get("coverImage") or {}
            details.banner_url = cover.get("large") or cover.get("original")
        if not details.genres:
            details.genres = list(result.get("genres", []))
        if details.rating is None:
            details.rating = self._to_rating_10(attrs.get("averageRating"))
        if details.year is None:
            details.year = self._extract_year(attrs.get("startDate"))
        if details.episode_count is None:
            details.episode_count = attrs.get("episodeCount")

        logger.debug(
            "Fiche %r enrichie via Kitsu (cache=%s, id=%s)",
            details.title,
            from_cache,
            result.get("id"),
        )
        return details

    async def get_cached(self, cache_key: str) -> dict | None:
        """Retourne le payload en cache s'il existe et est frais (TTL), sinon None."""
        ttl_hours = get_settings().metadata_cache_ttl_hours
        try:
            row = await db.fetchone(
                "SELECT payload FROM metadata_cache "
                f"WHERE cache_key = ? AND fetched_at > datetime('now', '-{ttl_hours} hours')",
                (cache_key,),
            )
        except (RuntimeError, sqlite3.Error) as exc:
            logger.warning(
                "Cache métadonnées illisible (%s), continuation sans cache : %s", cache_key, exc
            )
            return None
        if row is None:
            return None
        try:
            return json.loads(row["payload"])
        except (TypeError, ValueError) as exc:
            logger.warning("Cache métadonnées corrompu pour %s, re-fetch : %s", cache_key, exc)
            return None

    async def set_cached(self, cache_key: str, payload: dict) -> None:
        """Écrit/upsert une entrée de cache (échec non bloquant, warning seulement)."""
        try:
            await db.execute(
                "INSERT INTO metadata_cache (cache_key, payload, fetched_at) "
                "VALUES (?, ?, datetime('now')) "
                "ON CONFLICT(cache_key) DO UPDATE SET "
                "payload = excluded.payload, fetched_at = excluded.fetched_at",
                (cache_key, json.dumps(payload, ensure_ascii=False)),
            )
        except (RuntimeError, sqlite3.Error) as exc:
            logger.warning(
                "Cache métadonnées non écrit (%s), continuation sans cache : %s", cache_key, exc
            )

    @staticmethod
    def _pick_best_match(payload: dict, query: str) -> dict | None:
        items = [item for item in payload.get("data", []) if item.get("type") == "anime"]
        if not items:
            return None

        genre_names = {
            obj.get("id"): obj.get("attributes", {}).get("name")
            for obj in payload.get("included", [])
            if obj.get("type") == "genres"
        }

        def titles_of(item: dict) -> set[str]:
            attrs = item.get("attributes", {})
            titles = attrs.get("titles") or {}
            return {
                t.strip().casefold()
                for t in (attrs.get("canonicalTitle"), titles.get("en"), titles.get("en_jp"))
                if t
            }

        def popularity(item: dict) -> tuple[int, float]:
            attrs = item.get("attributes", {})
            return (
                attrs.get("userCount") or 0,
                float(attrs.get("averageRating") or 0),
            )

        best = next((item for item in items if query.casefold() in titles_of(item)), None)
        if best is None:
            best = max(items, key=popularity)

        genre_ids = best.get("relationships", {}).get("genres", {}).get("data") or []
        genres = [genre_names[g["id"]] for g in genre_ids if g.get("id") in genre_names]
        return {"id": best.get("id"), "attributes": best.get("attributes", {}), "genres": genres}

    @staticmethod
    def _to_rating_10(average_rating: str | None) -> float | None:
        """Kitsu note sur 100 (chaîne) → note sur 10 arrondie à 1 décimale."""
        if average_rating is None:
            return None
        try:
            return round(float(average_rating) / 10, 1)
        except (TypeError, ValueError):
            return None

    @staticmethod
    def _extract_year(start_date: str | None) -> int | None:
        if not start_date:
            return None
        try:
            return int(str(start_date)[:4])
        except ValueError:
            return None