import AsyncStorage from '@react-native-async-storage/async-storage';
import { Song } from '@/types/song';

export const addToFavoritesStorage = async (song: Song): Promise<boolean> => {
  try {
    const stored = await AsyncStorage.getItem('favorites');
    const parsed: Song[] = stored ? JSON.parse(stored) : [];
    const updatedFavorites = [...parsed, song];
    await AsyncStorage.setItem('favorites', JSON.stringify(updatedFavorites));
    return true;
  } catch (error) {
    console.error('Error adding to favorites:', error);
    return false;
  }
};

export interface FavoriteFolder {
  id: string;
  name: string;
  songs: Song[];
  expanded: boolean;
}

const STORAGE_KEY = 'favoritesFolders';

// 폴더 저장
export const saveFavoriteFolders = async (folders: FavoriteFolder[]): Promise<void> => {
  try {
    await AsyncStorage.setItem(STORAGE_KEY, JSON.stringify(folders));
  } catch (error) {
    console.error('Error saving favorite folders:', error);
  }
};

// 폴더 불러오기
export const loadFavoriteFolders = async (): Promise<FavoriteFolder[]> => {
  try {
    const stored = await AsyncStorage.getItem(STORAGE_KEY);
    return stored ? JSON.parse(stored) : [];
  } catch (error) {
    console.error('Error loading favorite folders:', error);
    return [];
  }
};

// 폴더 초기화
export const clearFavoriteFolders = async (): Promise<void> => {
  try {
    await AsyncStorage.removeItem(STORAGE_KEY);
  } catch (error) {
    console.error('Error clearing favorite folders:', error);
  }
};

// 🔹 폴더에 노래 추가
export const addSongToFolder = async (
  folderId: string,
  song: Song
): Promise<FavoriteFolder[] | null> => {
  try {
    const folders = await loadFavoriteFolders();
    const updated = folders.map((folder) => {
      if (folder.id === folderId) {
        const isDuplicate = folder.songs.some((s) => s.no === song.no);
        if (!isDuplicate) {
          return { ...folder, songs: [...folder.songs, song] };
        }
      }
      return folder;
    });
    await saveFavoriteFolders(updated);
    return updated;
  } catch (error) {
    console.error('Error adding song to folder:', error);
    return null;
  }
};

// 🔸 폴더에서 노래 삭제
export const removeSongFromFolder = async (
  folderId: string,
  songNo: string
): Promise<FavoriteFolder[] | null> => {
  try {
    const folders = await loadFavoriteFolders();
    const updated = folders.map((folder) => {
      if (folder.id === folderId) {
        return {
          ...folder,
          songs: folder.songs.filter((s) => s.no !== songNo),
        };
      }
      return folder;
    });
    await saveFavoriteFolders(updated);
    return updated;
  } catch (error) {
    console.error('Error removing song from folder:', error);
    return null;
  }
};