"""Assembles Person API responses from repository data."""

from __future__ import annotations

import uuid
from collections import defaultdict

from sqlalchemy.ext.asyncio import AsyncSession

from app.core.ids import aurora_id, parse_aurora_id
from app.models.credit import Credit
from app.models.enums import ArtworkType
from app.models.tv import Series
from app.repositories import movie_repository, person_repository, polymorphic, tv_repository
from app.schemas.person import (
    FilmographyCreditOut,
    GuestEpisodeOut,
    PersonCreditsOut,
    PersonDetailOut,
    PersonSummaryOut,
)
from app.services.common import primary_artwork_path, to_artwork_out


class PersonNotFoundError(Exception):
    pass


def _resolve_person_id(aid: str) -> uuid.UUID:
    try:
        return uuid.UUID(parse_aurora_id(aid, expected_type="person"))
    except ValueError as exc:
        raise PersonNotFoundError(str(exc)) from exc


async def get_person_detail(session: AsyncSession, person_aurora_id: str) -> PersonDetailOut:
    person_id = _resolve_person_id(person_aurora_id)
    person = await person_repository.get_person_by_id(session, person_id)
    if person is None:
        raise PersonNotFoundError(person_aurora_id)

    profiles = await polymorphic.get_artwork(session, "person", person_id, ArtworkType.PROFILE)
    external_ids = await polymorphic.get_external_ids(session, "person", person_id)

    return PersonDetailOut(
        id=aurora_id("person", str(person.id)),
        name=person.name,
        aliases=list(person.aliases or []),
        biography=person.biography,
        birthday=person.birthday,
        deathday=person.deathday,
        birthplace=person.birthplace,
        gender=person.gender,
        known_for_department=person.known_for_department,
        popularity=person.popularity,
        profile_images=[to_artwork_out(a) for a in profiles],
        external_ids=external_ids,
        created_at=person.created_at,
        updated_at=person.updated_at,
    )


async def _series_poster_path(session: AsyncSession, series_id: uuid.UUID) -> str | None:
    posters = await polymorphic.get_artwork(session, "series", series_id, ArtworkType.POSTER)
    return primary_artwork_path(posters, ArtworkType.POSTER)


async def get_person_credits(session: AsyncSession, person_aurora_id: str) -> PersonCreditsOut:
    person_id = _resolve_person_id(person_aurora_id)
    person = await person_repository.get_person_by_id(session, person_id)
    if person is None:
        raise PersonNotFoundError(person_aurora_id)

    credits_ = await person_repository.get_person_credits(session, person_id)

    movie_credits = [c for c in credits_ if c.entity_type == "movie"]
    series_credits = [c for c in credits_ if c.entity_type == "series"]
    episode_credits = [c for c in credits_ if c.entity_type == "episode"]

    movies = {
        m.id: m
        for m in await movie_repository.get_movies_by_ids(
            session, [c.entity_id for c in movie_credits]
        )
    }
    episodes = {
        e.id: e
        for e in await tv_repository.get_episodes_by_ids(
            session, [c.entity_id for c in episode_credits]
        )
    }

    # Guest-star episode credits are aggregated to one filmography row per
    # (series, department/job/character) rather than one row per episode —
    # a prolific guest actor would otherwise flood the list with dozens of
    # near-identical entries, one per episode they appeared in.
    episode_groups: dict[tuple, list[Credit]] = defaultdict(list)
    for credit in episode_credits:
        episode = episodes.get(credit.entity_id)
        if episode is None:
            continue
        key = (episode.series_id, credit.department, credit.job, credit.character)
        episode_groups[key].append(credit)

    series_ids = {c.entity_id for c in series_credits} | {
        episode.series_id for episode in episodes.values()
    }
    series_by_id: dict[uuid.UUID, Series] = {
        s.id: s for s in await tv_repository.get_series_by_ids(session, list(series_ids))
    }

    cast: list[FilmographyCreditOut] = []
    crew: list[FilmographyCreditOut] = []

    def _bucket(department: str) -> list[FilmographyCreditOut]:
        return cast if department == "Acting" else crew

    for credit in movie_credits:
        movie = movies.get(credit.entity_id)
        if movie is None:
            continue
        posters = await polymorphic.get_artwork(session, "movie", movie.id, ArtworkType.POSTER)
        _bucket(credit.department).append(
            FilmographyCreditOut(
                id=aurora_id("credit", str(credit.id)),
                media_id=aurora_id("movie", str(movie.id)),
                media_type="movie",
                title=movie.title,
                department=credit.department,
                job=credit.job,
                character=credit.character,
                release_date=movie.primary_release_date,
                poster_path=primary_artwork_path(posters, ArtworkType.POSTER),
            )
        )

    for credit in series_credits:
        series = series_by_id.get(credit.entity_id)
        if series is None:
            continue
        _bucket(credit.department).append(
            FilmographyCreditOut(
                id=aurora_id("credit", str(credit.id)),
                media_id=aurora_id("series", str(series.id)),
                media_type="series",
                title=series.title,
                department=credit.department,
                job=credit.job,
                character=credit.character,
                release_date=series.first_air_date,
                poster_path=await _series_poster_path(session, series.id),
            )
        )

    for (series_id, department, job, character), group in episode_groups.items():
        series = series_by_id.get(series_id)
        if series is None:
            continue
        representative = group[0]
        guest_episodes = sorted(
            (episodes[c.entity_id] for c in group if c.entity_id in episodes),
            key=lambda ep: (ep.season_number, ep.episode_number),
        )
        _bucket(department).append(
            FilmographyCreditOut(
                id=aurora_id("credit", str(representative.id)),
                media_id=aurora_id("series", str(series.id)),
                media_type="series",
                title=series.title,
                department=department,
                job=job,
                character=character,
                release_date=series.first_air_date,
                poster_path=await _series_poster_path(session, series.id),
                episode_count=len(group),
                episodes=[
                    GuestEpisodeOut(
                        id=aurora_id("episode", str(ep.id)),
                        season_number=ep.season_number,
                        episode_number=ep.episode_number,
                        title=ep.title,
                        air_date=ep.air_date,
                    )
                    for ep in guest_episodes
                ],
            )
        )

    return PersonCreditsOut(id=aurora_id("person", str(person.id)), cast=cast, crew=crew)


async def build_person_summary(
    session: AsyncSession, person_id: uuid.UUID
) -> PersonSummaryOut | None:
    person = await person_repository.get_person_by_id(session, person_id)
    if person is None:
        return None
    profiles = await polymorphic.get_artwork(session, "person", person_id, ArtworkType.PROFILE)
    return PersonSummaryOut(
        id=aurora_id("person", str(person.id)),
        name=person.name,
        known_for_department=person.known_for_department,
        profile_path=primary_artwork_path(profiles, ArtworkType.PROFILE),
        popularity=person.popularity,
    )


async def build_person_summaries(
    session: AsyncSession, person_ids: list[uuid.UUID]
) -> list[PersonSummaryOut]:
    out: list[PersonSummaryOut] = []
    for person_id in person_ids:
        summary = await build_person_summary(session, person_id)
        if summary is not None:
            out.append(summary)
    return out