import { api } from '../index';
import { toTrack, type RawTrack } from '../mappers';
import type { RadioResult } from '../types';

// Radio + similarity (§6.5). Stateless: the client passes the seed + already-
// queued ids and pulls more as the queue drains.

interface RawRadioTrack {
  track: RawTrack;
  reason: string;
}
interface RawRadio {
  source: string;
  tracks: RawRadioTrack[];
}
interface RawSimilar {
  source: string;
  tracks: RawTrack[];
}

export interface RadioArgs {
  seedTrackId?: string;
  fromLikes?: boolean;
  exploration?: number;
  count?: number;
  excludeIds?: string[];
}

const toBody = (a: RadioArgs) => ({
  seed_track_id: a.seedTrackId ?? null,
  from_likes: a.fromLikes ?? false,
  exploration: a.exploration ?? 0.25,
  count: a.count ?? 20,
  exclude_ids: a.excludeIds ?? [],
});

const toRadio = (r: RawRadio): RadioResult => ({
  source: r.source,
  picks: r.tracks.map((x) => ({ track: toTrack(x.track), reason: x.reason })),
});

export const radioApi = api.injectEndpoints({
  endpoints: (build) => ({
    startRadio: build.mutation<RadioResult, RadioArgs>({
      query: (a) => ({ url: '/radio', method: 'POST', body: toBody(a) }),
      transformResponse: (r: RawRadio) => toRadio(r),
    }),
    radioNext: build.mutation<RadioResult, RadioArgs>({
      query: (a) => ({ url: '/radio/next', method: 'POST', body: toBody(a) }),
      transformResponse: (r: RawRadio) => toRadio(r),
    }),
    getSimilarTracks: build.query<RadioResult, string>({
      query: (trackId) => `/tracks/${trackId}/similar`,
      transformResponse: (r: RawSimilar) => ({
        source: r.source,
        picks: r.tracks.map((t) => ({ track: toTrack(t), reason: 'similar' })),
      }),
    }),
  }),
  overrideExisting: false,
});

export const {
  useStartRadioMutation,
  useRadioNextMutation,
  useGetSimilarTracksQuery,
} = radioApi;