from __future__ import annotations

from abc import ABC, abstractmethod
from typing import Any, Dict, List, Optional, Type
import requests
import sys

from helper.logger import log, debug

try:  # Optional dependency
    import musicbrainzngs  # type: ignore
except ImportError:  # pragma: no cover - optional
    musicbrainzngs = None


class MetadataProvider(ABC):
    """Base class for metadata providers (music, movies, books, etc.)."""

    def __init__(self, config: Optional[Dict[str, Any]] = None) -> None:
        self.config = config or {}

    @property
    def name(self) -> str:
        return self.__class__.__name__.replace("Provider", "").lower()

    @abstractmethod
    def search(self, query: str, limit: int = 10) -> List[Dict[str, Any]]:
        """Return a list of candidate metadata records."""

    def to_tags(self, item: Dict[str, Any]) -> List[str]:
        """Convert a result item into a list of tags."""
        tags: List[str] = []
        title = item.get("title")
        artist = item.get("artist")
        album = item.get("album")
        year = item.get("year")

        if title:
            tags.append(f"title:{title}")
        if artist:
            tags.append(f"artist:{artist}")
        if album:
            tags.append(f"album:{album}")
        if year:
            tags.append(f"year:{year}")

        tags.append(f"source:{self.name}")
        return tags


class ITunesProvider(MetadataProvider):
    """Metadata provider using the iTunes Search API."""

    def search(self, query: str, limit: int = 10) -> List[Dict[str, Any]]:
        params = {"term": query, "media": "music", "entity": "song", "limit": limit}
        try:
            resp = requests.get("https://itunes.apple.com/search", params=params, timeout=10)
            resp.raise_for_status()
            results = resp.json().get("results", [])
        except Exception as exc:
            log(f"iTunes search failed: {exc}", file=sys.stderr)
            return []

        items: List[Dict[str, Any]] = []
        for r in results:
            item = {
                "title": r.get("trackName"),
                "artist": r.get("artistName"),
                "album": r.get("collectionName"),
                "year": str(r.get("releaseDate", ""))[:4],
                "provider": self.name,
                "raw": r,
            }
            items.append(item)
        debug(f"iTunes returned {len(items)} items for '{query}'")
        return items


class OpenLibraryMetadataProvider(MetadataProvider):
    """Metadata provider for OpenLibrary book metadata."""

    @property
    def name(self) -> str:  # type: ignore[override]
        return "openlibrary"

    def search(self, query: str, limit: int = 10) -> List[Dict[str, Any]]:
        query_clean = (query or "").strip()
        if not query_clean:
            return []

        try:
            # Prefer ISBN-specific search when the query looks like one
            if query_clean.replace("-", "").isdigit() and len(query_clean.replace("-", "")) in (10, 13):
                q = f"isbn:{query_clean.replace('-', '')}"
            else:
                q = query_clean

            resp = requests.get(
                "https://openlibrary.org/search.json",
                params={"q": q, "limit": limit},
                timeout=10,
            )
            resp.raise_for_status()
            data = resp.json()
        except Exception as exc:
            log(f"OpenLibrary search failed: {exc}", file=sys.stderr)
            return []

        items: List[Dict[str, Any]] = []
        for doc in data.get("docs", [])[:limit]:
            authors = doc.get("author_name") or []
            publisher = ""
            publishers = doc.get("publisher") or []
            if isinstance(publishers, list) and publishers:
                publisher = publishers[0]

            # Prefer 13-digit ISBN when available, otherwise 10-digit
            isbn_list = doc.get("isbn") or []
            isbn_13 = next((i for i in isbn_list if len(str(i)) == 13), None)
            isbn_10 = next((i for i in isbn_list if len(str(i)) == 10), None)

            # Derive OLID from key
            olid = ""
            key = doc.get("key", "")
            if isinstance(key, str) and key:
                olid = key.split("/")[-1]

            items.append({
                "title": doc.get("title") or "",
                "artist": ", ".join(authors) if authors else "",
                "album": publisher,
                "year": str(doc.get("first_publish_year") or ""),
                "provider": self.name,
                "authors": authors,
                "publisher": publisher,
                "identifiers": {
                    "isbn_13": isbn_13,
                    "isbn_10": isbn_10,
                    "openlibrary": olid,
                    "oclc": (doc.get("oclc_numbers") or [None])[0],
                    "lccn": (doc.get("lccn") or [None])[0],
                },
                "description": None,
            })

        return items

    def to_tags(self, item: Dict[str, Any]) -> List[str]:
        tags: List[str] = []
        title = item.get("title")
        authors = item.get("authors") or []
        publisher = item.get("publisher")
        year = item.get("year")
        description = item.get("description") or ""

        if title:
            tags.append(f"title:{title}")
        for author in authors:
            if author:
                tags.append(f"author:{author}")
        if publisher:
            tags.append(f"publisher:{publisher}")
        if year:
            tags.append(f"year:{year}")
        if description:
            tags.append(f"description:{description[:200]}")

        identifiers = item.get("identifiers") or {}
        for key, value in identifiers.items():
            if value:
                tags.append(f"{key}:{value}")

        tags.append(f"source:{self.name}")
        return tags


class GoogleBooksMetadataProvider(MetadataProvider):
    """Metadata provider for Google Books volumes API."""

    @property
    def name(self) -> str:  # type: ignore[override]
        return "googlebooks"

    def search(self, query: str, limit: int = 10) -> List[Dict[str, Any]]:
        query_clean = (query or "").strip()
        if not query_clean:
            return []

        # Prefer ISBN queries when possible
        if query_clean.replace("-", "").isdigit() and len(query_clean.replace("-", "")) in (10, 13):
            q = f"isbn:{query_clean.replace('-', '')}"
        else:
            q = query_clean

        try:
            resp = requests.get(
                "https://www.googleapis.com/books/v1/volumes",
                params={"q": q, "maxResults": limit},
                timeout=10,
            )
            resp.raise_for_status()
            payload = resp.json()
        except Exception as exc:
            log(f"Google Books search failed: {exc}", file=sys.stderr)
            return []

        items: List[Dict[str, Any]] = []
        for volume in payload.get("items", [])[:limit]:
            info = volume.get("volumeInfo") or {}
            authors = info.get("authors") or []
            publisher = info.get("publisher", "")
            published_date = info.get("publishedDate", "")
            year = str(published_date)[:4] if published_date else ""

            identifiers_raw = info.get("industryIdentifiers") or []
            identifiers: Dict[str, Optional[str]] = {"googlebooks": volume.get("id")}
            for ident in identifiers_raw:
                if not isinstance(ident, dict):
                    continue
                ident_type = ident.get("type", "").lower()
                ident_value = ident.get("identifier")
                if not ident_value:
                    continue
                if ident_type == "isbn_13":
                    identifiers.setdefault("isbn_13", ident_value)
                elif ident_type == "isbn_10":
                    identifiers.setdefault("isbn_10", ident_value)
                else:
                    identifiers.setdefault(ident_type, ident_value)

            items.append({
                "title": info.get("title") or "",
                "artist": ", ".join(authors) if authors else "",
                "album": publisher,
                "year": year,
                "provider": self.name,
                "authors": authors,
                "publisher": publisher,
                "identifiers": identifiers,
                "description": info.get("description", ""),
            })

        return items

    def to_tags(self, item: Dict[str, Any]) -> List[str]:
        tags: List[str] = []
        title = item.get("title")
        authors = item.get("authors") or []
        publisher = item.get("publisher")
        year = item.get("year")
        description = item.get("description") or ""

        if title:
            tags.append(f"title:{title}")
        for author in authors:
            if author:
                tags.append(f"author:{author}")
        if publisher:
            tags.append(f"publisher:{publisher}")
        if year:
            tags.append(f"year:{year}")
        if description:
            tags.append(f"description:{description[:200]}")

        identifiers = item.get("identifiers") or {}
        for key, value in identifiers.items():
            if value:
                tags.append(f"{key}:{value}")

        tags.append(f"source:{self.name}")
        return tags


class MusicBrainzMetadataProvider(MetadataProvider):
    """Metadata provider for MusicBrainz recordings."""

    @property
    def name(self) -> str:  # type: ignore[override]
        return "musicbrainz"

    def search(self, query: str, limit: int = 10) -> List[Dict[str, Any]]:
        if not musicbrainzngs:
            log("musicbrainzngs is not installed; skipping MusicBrainz scrape", file=sys.stderr)
            return []

        q = (query or "").strip()
        if not q:
            return []

        try:
            # Ensure user agent is set (required by MusicBrainz)
            musicbrainzngs.set_useragent("Medeia-Macina", "0.1")
        except Exception:
            pass

        try:
            resp = musicbrainzngs.search_recordings(query=q, limit=limit)
            recordings = resp.get("recording-list") or resp.get("recordings") or []
        except Exception as exc:
            log(f"MusicBrainz search failed: {exc}", file=sys.stderr)
            return []

        items: List[Dict[str, Any]] = []
        for rec in recordings[:limit]:
            if not isinstance(rec, dict):
                continue
            title = rec.get("title") or ""

            artist = ""
            artist_credit = rec.get("artist-credit") or rec.get("artist_credit")
            if isinstance(artist_credit, list) and artist_credit:
                first = artist_credit[0]
                if isinstance(first, dict):
                    artist = first.get("name") or first.get("artist", {}).get("name", "")
                elif isinstance(first, str):
                    artist = first

            album = ""
            release_list = rec.get("release-list") or rec.get("releases") or rec.get("release")
            if isinstance(release_list, list) and release_list:
                first_rel = release_list[0]
                if isinstance(first_rel, dict):
                    album = first_rel.get("title", "") or ""
                    release_date = first_rel.get("date") or ""
                else:
                    album = str(first_rel)
                    release_date = ""
            else:
                release_date = rec.get("first-release-date") or ""

            year = str(release_date)[:4] if release_date else ""
            mbid = rec.get("id") or ""

            items.append({
                "title": title,
                "artist": artist,
                "album": album,
                "year": year,
                "provider": self.name,
                "mbid": mbid,
                "raw": rec,
            })

        return items

    def to_tags(self, item: Dict[str, Any]) -> List[str]:
        tags = super().to_tags(item)
        mbid = item.get("mbid")
        if mbid:
            tags.append(f"musicbrainz:{mbid}")
        return tags


# Registry ---------------------------------------------------------------

_METADATA_PROVIDERS: Dict[str, Type[MetadataProvider]] = {
    "itunes": ITunesProvider,
    "openlibrary": OpenLibraryMetadataProvider,
    "googlebooks": GoogleBooksMetadataProvider,
    "google": GoogleBooksMetadataProvider,
    "musicbrainz": MusicBrainzMetadataProvider,
}


def register_provider(name: str, provider_cls: Type[MetadataProvider]) -> None:
    _METADATA_PROVIDERS[name.lower()] = provider_cls


def list_metadata_providers(config: Optional[Dict[str, Any]] = None) -> Dict[str, bool]:
    availability: Dict[str, bool] = {}
    for name, cls in _METADATA_PROVIDERS.items():
        try:
            provider = cls(config)
            # Basic availability check: perform lightweight validation if defined
            availability[name] = True
        except Exception:
            availability[name] = False
    return availability


def get_metadata_provider(name: str, config: Optional[Dict[str, Any]] = None) -> Optional[MetadataProvider]:
    cls = _METADATA_PROVIDERS.get(name.lower())
    if not cls:
        return None
    try:
        return cls(config)
    except Exception as exc:
        log(f"Provider init failed for '{name}': {exc}", file=sys.stderr)
        return None