import urllib.request

import imdb
import jsonfile
from jsonfile import PROJECT_ROOT

DETAILS_FILE = "mediaDetails.json"
POSTERS_DIR = PROJECT_ROOT / "static" / "covers" / "media"
POSTERS_PUBLIC_PATH = "/covers/media"
MISSING_VALUE = "N/A"
REQUEST_HEADERS = {"User-Agent": "Mozilla/5.0 (X11; Linux x86_64; rv:140.0) Gecko/20100101 Firefox/140.0"}


def load_details() -> dict[str, dict]:
    return jsonfile.load_data(DETAILS_FILE, {})


def save_details(details: dict[str, dict]) -> None:
    jsonfile.save_data(DETAILS_FILE, dict(sorted(details.items())))


def present(value: str | None) -> str | None:
    return value if value and value != MISSING_VALUE else None


def poster_path(identifier: str):
    return POSTERS_DIR / f"{identifier}.jpg"


def download_poster(identifier: str, source_url: str | None) -> str | None:
    if not source_url:
        return None
    request = urllib.request.Request(source_url, headers=REQUEST_HEADERS)
    with urllib.request.urlopen(request, timeout=15) as response:
        image = response.read()
    POSTERS_DIR.mkdir(parents=True, exist_ok=True)
    poster_path(identifier).write_bytes(image)
    return f"{POSTERS_PUBLIC_PATH}/{identifier}.jpg"


def has_local_poster(identifier: str, stored: dict) -> bool:
    poster = stored.get("poster")
    return poster is None or (poster.startswith(POSTERS_PUBLIC_PATH) and poster_path(identifier).exists())


def has_details(identifier: str) -> bool:
    stored = load_details().get(identifier)
    return bool(stored) and has_local_poster(identifier, stored)


def fetch_details(identifier: str) -> dict:
    result = imdb.lookup(identifier)
    if not result:
        raise ValueError(f"Could not look up {identifier} on OMDb. Check OMDB_API_KEY in .env")

    poster_source = present(result.get("Poster"))
    try:
        poster = download_poster(identifier, poster_source)
    except OSError:
        poster = poster_source

    stored = {
        "title": present(result.get("Title")),
        "poster": poster,
        "posterSource": poster_source,
        "year": present(result.get("Year")),
        "genre": present(result.get("Genre")),
        "runtime": present(result.get("Runtime")),
        "plot": present(result.get("Plot")),
    }
    details = load_details()
    details[identifier] = stored
    save_details(details)
    return stored


def cached_details(identifier: str, fresh: bool = False) -> dict:
    if not fresh and has_details(identifier):
        return load_details()[identifier]
    return fetch_details(identifier)


def remove_details(identifier: str) -> None:
    details = load_details()
    if details.pop(identifier, None) is not None:
        save_details(details)
    if poster_path(identifier).exists():
        poster_path(identifier).unlink()


def missing_identifiers(identifiers: list[str]) -> list[str]:
    return [identifier for identifier in identifiers if not has_details(identifier)]