import { create } from 'zustand';
import AsyncStorage from '@react-native-async-storage/async-storage';
import { Track, User } from '../services/api';

// ── Offline / Downloads ───────────────────────────────────────────────────────

interface OfflineState {
  downloadedTracks:    Set<number>;
  downloading:         Map<number, number>;
  isOnline:            boolean;
  addDownloadedTrack:  (id: number) => void;
  removeDownloadedTrack: (id: number) => void;
  setDownloading:      (id: number, progress: number) => void;
  clearDownloading:    (id: number) => void;
  loadDownloadedTracks: () => Promise<void>;
  setOnline:           (online: boolean) => void;
}

export const useOffline = create<OfflineState>((set, get) => ({
  downloadedTracks: new Set(),
  downloading:      new Map(),
  isOnline:         true,

  addDownloadedTrack: (id) => {
    const next = new Set(get().downloadedTracks);
    next.add(id);
    set({ downloadedTracks: next });
  },
  removeDownloadedTrack: (id) => {
    const next = new Set(get().downloadedTracks);
    next.delete(id);
    set({ downloadedTracks: next });
  },
  setDownloading: (id, progress) => {
    const next = new Map(get().downloading);
    if (progress >= 1) next.delete(id);
    else next.set(id, progress);
    set({ downloading: next });
  },
  clearDownloading: (id) => {
    const next = new Map(get().downloading);
    next.delete(id);
    set({ downloading: next });
  },
  loadDownloadedTracks: async () => {
    try {
      const { getDownloadedTracks } = await import('../services/offline');
      const ids = await getDownloadedTracks();
      set({ downloadedTracks: new Set(ids) });
    } catch (err) {
      console.warn('Failed to load downloaded tracks:', err);
    }
  },
  setOnline: (online) => set({ isOnline: online }),
}));

// ── Player ────────────────────────────────────────────────────────────────────

interface PlayerState {
  queue:      Track[];
  index:      number;
  playing:    boolean;
  progress:   number;
  duration:   number;
  repeat:     0 | 1 | 2;
  shuffle:    boolean;
  expanded:   boolean;

  setQueue:      (tracks: Track[], index?: number) => void;
  setIndex:      (i: number) => void;
  setPlaying:    (v: boolean) => void;
  setProgress:   (v: number) => void;
  setDuration:   (v: number) => void;
  cycleRepeat:   () => void;
  toggleShuffle: () => void;
  setExpanded:   (v: boolean) => void;
  nextTrack:     () => number;
  prevTrack:     () => number;
}

export const usePlayer = create<PlayerState>((set, get) => ({
  queue:    [],
  index:    -1,
  playing:  false,
  progress: 0,
  duration: 0,
  repeat:   0,
  shuffle:  false,
  expanded: false,

  setQueue:      (tracks, index = 0) => set({ queue: tracks, index }),
  setIndex:      (index) => set({ index }),
  setPlaying:    (playing) => set({ playing }),
  setProgress:   (progress) => set({ progress }),
  setDuration:   (duration) => set({ duration }),
  cycleRepeat:   () => set((s) => ({ repeat: ((s.repeat + 1) % 3) as 0 | 1 | 2 })),
  toggleShuffle: () => set((s) => ({ shuffle: !s.shuffle })),
  setExpanded:   (expanded) => set({ expanded }),

  nextTrack: () => {
    const { queue, index, shuffle, repeat } = get();
    if (repeat === 2) return index;
    if (shuffle) return Math.floor(Math.random() * queue.length);
    const next = index + 1;
    if (next >= queue.length) return repeat === 1 ? 0 : index;
    return next;
  },
  prevTrack: () => {
    const { queue, index, shuffle } = get();
    if (shuffle) return Math.floor(Math.random() * queue.length);
    return index - 1 < 0 ? queue.length - 1 : index - 1;
  },
}));

// ── Auth ──────────────────────────────────────────────────────────────────────

interface AuthState {
  user:     User | null;
  ready:    boolean;
  setUser:  (u: User | null) => void;
  setReady: (v: boolean) => void;
}

export const useAuth = create<AuthState>((set) => ({
  user:     null,
  ready:    false,
  setUser:  (user) => set({ user }),
  setReady: (ready) => set({ ready }),
}));

// ── Likes ─────────────────────────────────────────────────────────────────────

const LIKES_KEY = 'ns-music-likes';

interface LikesState {
  likes:      Set<number>;
  loadLikes:  () => Promise<void>;
  toggleLike: (id: number) => void;
  isLiked:    (id: number) => boolean;
}

export const useLikes = create<LikesState>((set, get) => ({
  likes: new Set(),

  loadLikes: async () => {
    try {
      const raw = await AsyncStorage.getItem(LIKES_KEY);
      const arr: number[] = raw ? JSON.parse(raw) : [];
      set({ likes: new Set(arr) });
    } catch {}
  },
  toggleLike: (id) => {
    const next = new Set(get().likes);
    if (next.has(id)) next.delete(id); else next.add(id);
    set({ likes: next });
    AsyncStorage.setItem(LIKES_KEY, JSON.stringify([...next])).catch(() => {});
  },
  isLiked: (id) => get().likes.has(id),
}));

// ── Hidden Tracks ─────────────────────────────────────────────────────────────

const HIDDEN_KEY = 'ns-music-hidden';

interface HiddenState {
  hidden:      Set<number>;
  loadHidden:  () => Promise<void>;
  toggleHide:  (id: number) => void;
  isHidden:    (id: number) => boolean;
}

export const useHidden = create<HiddenState>((set, get) => ({
  hidden: new Set(),

  loadHidden: async () => {
    try {
      const raw = await AsyncStorage.getItem(HIDDEN_KEY);
      const arr: number[] = raw ? JSON.parse(raw) : [];
      set({ hidden: new Set(arr) });
    } catch {}
  },
  toggleHide: (id) => {
    const next = new Set(get().hidden);
    if (next.has(id)) next.delete(id); else next.add(id);
    set({ hidden: next });
    AsyncStorage.setItem(HIDDEN_KEY, JSON.stringify([...next])).catch(() => {});
  },
  isHidden: (id) => get().hidden.has(id),
}));

// ── Playlists ─────────────────────────────────────────────────────────────────

const PLAYLISTS_KEY = 'ns-music-playlists';

export interface Playlist {
  id:         string;
  name:       string;
  trackIds:   number[];
  createdAt:  number;
}

interface PlaylistState {
  playlists:      Playlist[];
  loadPlaylists:  () => Promise<void>;
  createPlaylist: (name: string) => Playlist;
  deletePlaylist: (id: string) => void;
  renamePlaylist: (id: string, name: string) => void;
  addToPlaylist:  (playlistId: string, trackId: number) => void;
  removeFromPlaylist: (playlistId: string, trackId: number) => void;
}

export const usePlaylists = create<PlaylistState>((set, get) => ({
  playlists: [],

  loadPlaylists: async () => {
    try {
      const raw = await AsyncStorage.getItem(PLAYLISTS_KEY);
      const arr: Playlist[] = raw ? JSON.parse(raw) : [];
      set({ playlists: arr });
    } catch {}
  },

  createPlaylist: (name) => {
    const pl: Playlist = { id: `pl_${Date.now()}`, name, trackIds: [], createdAt: Date.now() };
    const next = [...get().playlists, pl];
    set({ playlists: next });
    AsyncStorage.setItem(PLAYLISTS_KEY, JSON.stringify(next)).catch(() => {});
    return pl;
  },

  deletePlaylist: (id) => {
    const next = get().playlists.filter((p) => p.id !== id);
    set({ playlists: next });
    AsyncStorage.setItem(PLAYLISTS_KEY, JSON.stringify(next)).catch(() => {});
  },

  renamePlaylist: (id, name) => {
    const next = get().playlists.map((p) => p.id === id ? { ...p, name } : p);
    set({ playlists: next });
    AsyncStorage.setItem(PLAYLISTS_KEY, JSON.stringify(next)).catch(() => {});
  },

  addToPlaylist: (playlistId, trackId) => {
    const next = get().playlists.map((p) => {
      if (p.id !== playlistId || p.trackIds.includes(trackId)) return p;
      return { ...p, trackIds: [...p.trackIds, trackId] };
    });
    set({ playlists: next });
    AsyncStorage.setItem(PLAYLISTS_KEY, JSON.stringify(next)).catch(() => {});
  },

  removeFromPlaylist: (playlistId, trackId) => {
    const next = get().playlists.map((p) =>
      p.id !== playlistId ? p : { ...p, trackIds: p.trackIds.filter((id) => id !== trackId) }
    );
    set({ playlists: next });
    AsyncStorage.setItem(PLAYLISTS_KEY, JSON.stringify(next)).catch(() => {});
  },
}));