mcma-backend/app/api/v1/artists.py

"""Artist endpoints."""

import uuid

from fastapi import APIRouter, Query

from app.api.deps import (
    AlbumRepoDep,
    ArtistRepoDep,
    CurrentUser,
    RecommendationServiceDep,
    TrackRepoDep,
)
from app.api.schemas.album import AlbumOut
from app.api.schemas.artist import ArtistOut
from app.api.schemas.pagination import PagedResponse
from app.api.schemas.radio import SimilarArtistsOut
from app.api.schemas.track import TrackOut
from app.api.v1.albums import _build_album_out
from app.api.v1.tracks import _build_track_out
from app.domain.errors import NotFoundError

router = APIRouter(prefix="/artists", tags=["artists"])


@router.get("")
async def list_artists(
    artist_repo: ArtistRepoDep,
    _: CurrentUser,
    q: str | None = None,
    limit: int = Query(50, ge=1, le=200),
    offset: int = Query(0, ge=0),
) -> PagedResponse[ArtistOut]:
    artists = await artist_repo.list(q=q, limit=limit, offset=offset)
    total = await artist_repo.count(q=q)

    items = []
    for a in artists:
        album_cnt = await artist_repo.album_count(a.id)
        track_cnt = await artist_repo.track_count(a.id)
        items.append(
            ArtistOut(
                id=a.id,
                name=a.name,
                album_count=album_cnt,
                track_count=track_cnt,
                created_at=a.created_at,
            )
        )

    return PagedResponse(items=items, total=total, limit=limit, offset=offset)


@router.get("/{artist_id}")
async def get_artist(
    artist_id: uuid.UUID,
    artist_repo: ArtistRepoDep,
    _: CurrentUser,
) -> ArtistOut:
    artist = await artist_repo.get_by_id(artist_id)
    if artist is None:
        raise NotFoundError(f"Artist {artist_id} not found.")

    album_cnt = await artist_repo.album_count(artist_id)
    track_cnt = await artist_repo.track_count(artist_id)

    return ArtistOut(
        id=artist.id,
        name=artist.name,
        album_count=album_cnt,
        track_count=track_cnt,
        created_at=artist.created_at,
    )


@router.get("/{artist_id}/albums")
async def get_artist_albums(
    artist_id: uuid.UUID,
    artist_repo: ArtistRepoDep,
    album_repo: AlbumRepoDep,
    _: CurrentUser,
    limit: int = Query(50, ge=1, le=200),
    offset: int = Query(0, ge=0),
) -> PagedResponse[AlbumOut]:
    artist = await artist_repo.get_by_id(artist_id)
    if artist is None:
        raise NotFoundError(f"Artist {artist_id} not found.")

    albums = await album_repo.list(artist_id=artist_id, q=None, limit=limit, offset=offset)
    total = await album_repo.count(artist_id=artist_id, q=None)

    artists_map = {artist.id: artist}
    track_counts = await album_repo.track_count_many([a.id for a in albums])

    items = await _build_album_out(albums, artists_map, track_counts)
    return PagedResponse(items=items, total=total, limit=limit, offset=offset)


@router.get("/{artist_id}/tracks")
async def get_artist_tracks(
    artist_id: uuid.UUID,
    artist_repo: ArtistRepoDep,
    track_repo: TrackRepoDep,
    album_repo: AlbumRepoDep,
    _: CurrentUser,
    limit: int = Query(50, ge=1, le=200),
    offset: int = Query(0, ge=0),
) -> PagedResponse[TrackOut]:
    artist = await artist_repo.get_by_id(artist_id)
    if artist is None:
        raise NotFoundError(f"Artist {artist_id} not found.")

    tracks = await track_repo.list(
        artist_id=artist_id,
        album_id=None,
        q=None,
        sort_by="title",
        order="asc",
        limit=limit,
        offset=offset,
    )
    total = await track_repo.count(artist_id=artist_id, album_id=None, q=None)

    album_ids = list({t.album_id for t in tracks if t.album_id is not None})
    artists_map = {artist.id: artist}
    albums_map = {a.id: a for a in await album_repo.get_many(album_ids)}

    items = await _build_track_out(tracks, artists_map, albums_map)
    return PagedResponse(items=items, total=total, limit=limit, offset=offset)


@router.get("/{artist_id}/similar")
async def get_similar_artists(
    artist_id: uuid.UUID,
    service: RecommendationServiceDep,
    artist_repo: ArtistRepoDep,
    _: CurrentUser,
    limit: int = Query(20, ge=1, le=100),
) -> SimilarArtistsOut:
    """Artists similar to this one (§6.5). ML when configured, else a shared-
    genre metadata heuristic."""
    source, artists = await service.similar_artists(artist_id, limit=limit)
    items = [
        ArtistOut(
            id=a.id,
            name=a.name,
            album_count=await artist_repo.album_count(a.id),
            track_count=await artist_repo.track_count(a.id),
            created_at=a.created_at,
        )
        for a in artists
    ]
    return SimilarArtistsOut(source=source, artists=items)