import { create } from 'zustand';
import type { Word, StudyProgress, StudyStats, DifficultyRating } from '../types/vocabulary';
import { calculateNextReview } from '../utils/srs';
import { db, initDatabase, exportData, importData } from '../db/database';

interface AppState {
  words: Word[];
  progress: Map<string, StudyProgress>;
  stats: StudyStats;
  currentWordIndex: number;
  isFlipped: boolean;
  isLoading: boolean;
  
  // Actions
  init: () => Promise<void>;
  setWords: (words: Word[]) => void;
  addWords: (words: Word[]) => Promise<void>;
  flipCard: () => void;
  rateWord: (rating: DifficultyRating) => Promise<void>;
  nextWord: () => void;
  getCurrentWord: () => Word | null;
  getDueWords: () => Word[];
  exportData: () => Promise<any>;
  importData: (data: any) => Promise<void>;
  speak: (text: string) => void;
}

export const useAppStore = create<AppState>((set, get) => ({
  words: [],
  progress: new Map(),
  stats: {
    totalWords: 0,
    masteredWords: 0,
    studyingWords: 0,
    streakDays: 0,
    todayStudied: 0,
    todayNewWords: 0,
  },
  currentWordIndex: 0,
  isFlipped: false,
  isLoading: true,

  init: async () => {
    await initDatabase();
    
    // Load words from DB
    const wordsFromDB = await db.words.toArray();
    
    // Load progress from DB
    const progressFromDB = await db.progress.toArray();
    const progressMap = new Map<string, StudyProgress>();
    progressFromDB.forEach(p => progressMap.set(p.wordId, p));
    
    // Load stats from DB
    const statsFromDB = await db.stats.get('main');
    
    set({
      words: wordsFromDB,
      progress: progressMap,
      stats: statsFromDB || {
        totalWords: wordsFromDB.length,
        masteredWords: 0,
        studyingWords: 0,
        streakDays: 0,
        todayStudied: 0,
        todayNewWords: 0,
      },
      isLoading: false,
    });
  },

  setWords: (words) => set({ 
    words,
    stats: { ...get().stats, totalWords: words.length }
  }),

  addWords: async (newWords) => {
    const wordsWithDate = newWords.map(w => ({ ...w, addedAt: new Date() }));
    await db.words.bulkAdd(wordsWithDate);
    
    const allWords = await db.words.toArray();
    set({
      words: allWords,
      stats: { ...get().stats, totalWords: allWords.length }
    });
  },

  flipCard: () => set((state) => ({ isFlipped: !state.isFlipped })),

  rateWord: async (rating) => {
    const state = get();
    const currentWord = state.getCurrentWord();
    if (!currentWord) return;

    const existingProgress = state.progress.get(currentWord.id);
    const newProgress = calculateNextReview(
      existingProgress || {
        wordId: currentWord.id,
        interval: 0,
        repetitions: 0,
        easeFactor: 2.5,
        nextReviewDate: new Date(),
        lastStudiedDate: new Date(),
      },
      rating
    );

    // Save to IndexedDB
    await db.progress.put(newProgress);

    const newProgressMap = new Map(state.progress);
    newProgressMap.set(currentWord.id, newProgress);

    const newStats = {
      ...state.stats,
      todayStudied: state.stats.todayStudied + 1,
    };
    
    await db.stats.put({ ...newStats, id: 'main' });

    set({
      progress: newProgressMap,
      isFlipped: false,
      stats: newStats,
    });

    setTimeout(() => get().nextWord(), 300);
  },

  nextWord: () => {
    const state = get();
    const dueWords = state.getDueWords();
    
    if (dueWords.length === 0) {
      set({ currentWordIndex: -1 });
      return;
    }

    const nextIndex = state.words.findIndex(w => w.id === dueWords[0].id);
    set({ 
      currentWordIndex: nextIndex,
      isFlipped: false 
    });
  },

  getCurrentWord: () => {
    const state = get();
    if (state.currentWordIndex < 0 || state.currentWordIndex >= state.words.length) {
      return null;
    }
    return state.words[state.currentWordIndex];
  },

  getDueWords: () => {
    const state = get();
    const now = new Date();
    
    return state.words.filter((word) => {
      const progress = state.progress.get(word.id);
      if (!progress) return true;
      return new Date(progress.nextReviewDate) <= now;
    });
  },

  exportData: async () => {
    return await exportData();
  },

  importData: async (data) => {
    await importData(data);
    await get().init();
  },

  speak: (text: string) => {
    if ('speechSynthesis' in window) {
      const utterance = new SpeechSynthesisUtterance(text);
      utterance.lang = 'fr-FR';
      utterance.rate = 0.8;
      window.speechSynthesis.speak(utterance);
    }
  },
}));