import { useState, useEffect } from 'react'
import { flashcardsService, type Flashcard } from '@/lib/services/flashcards'
import { getReviewTypesByCEFR } from '@/lib/utils/cefrUtils'

// 擴展的Flashcard接口
interface ExtendedFlashcard extends Omit<Flashcard, 'nextReviewDate'> {
  nextReviewDate?: string
  currentInterval?: number
  isOverdue?: boolean
  overdueDays?: number
  baseMasteryLevel?: number
  lastReviewDate?: string
  synonyms?: string[]
  exampleImage?: string
}

// 複習模式類型
type ReviewMode = 'flip-memory' | 'vocab-choice' | 'vocab-listening' | 'sentence-listening' | 'sentence-fill' | 'sentence-reorder' | 'sentence-speaking'

// Hook狀態接口
interface ReviewSessionState {
  currentCard: ExtendedFlashcard | null
  dueCards: ExtendedFlashcard[]
  currentCardIndex: number
  isLoadingCard: boolean
  mode: ReviewMode
  isAutoSelecting: boolean
  showNoDueCards: boolean
  showComplete: boolean
}

// Hook返回接口
interface UseReviewSessionReturn extends ReviewSessionState {
  loadDueCards: () => Promise<void>
  setCurrentCard: (card: ExtendedFlashcard | null) => void
  setCurrentCardIndex: (index: number) => void
  setMode: (mode: ReviewMode) => void
  setIsAutoSelecting: (selecting: boolean) => void
  setShowNoDueCards: (show: boolean) => void
  setShowComplete: (show: boolean) => void
  nextCard: () => void
  previousCard: () => void
  restart: () => Promise<void>
}


export const useReviewSession = (): UseReviewSessionReturn => {
  // 核心複習狀態
  const [currentCard, setCurrentCard] = useState<ExtendedFlashcard | null>(null)
  const [dueCards, setDueCards] = useState<ExtendedFlashcard[]>([])
  const [currentCardIndex, setCurrentCardIndex] = useState(0)
  const [isLoadingCard, setIsLoadingCard] = useState(false)
  const [mode, setMode] = useState<ReviewMode>('flip-memory')
  const [isAutoSelecting, setIsAutoSelecting] = useState(true)
  const [showNoDueCards, setShowNoDueCards] = useState(false)
  const [showComplete, setShowComplete] = useState(false)

  // 載入到期詞卡
  const loadDueCards = async (): Promise<void> => {
    try {
      setIsLoadingCard(true)
      console.log('🔍 開始載入到期詞卡...')

      const apiResult = await flashcardsService.getDueFlashcards(50)
      console.log('📡 API回應結果:', apiResult)

      if (apiResult.success && apiResult.data && apiResult.data.length > 0) {
        const cardsToUse = apiResult.data
        console.log('✅ 載入後端API數據成功:', cardsToUse.length, '張詞卡')

        setDueCards(cardsToUse)
        setCurrentCardIndex(0)
        setCurrentCard(cardsToUse[0])

        // 自動選擇複習模式
        const userCEFRLevel = localStorage.getItem('userEnglishLevel') || 'A2'
        const wordCEFRLevel = cardsToUse[0].difficultyLevel || 'A2'
        const reviewTypes = getReviewTypesByCEFR(userCEFRLevel, wordCEFRLevel)

        if (reviewTypes.length > 0) {
          const selectedMode = reviewTypes[0] as ReviewMode
          setMode(selectedMode)
        }

        setIsAutoSelecting(false)
        setShowNoDueCards(false)
        setShowComplete(false)
      } else {
        console.log('❌ 沒有到期詞卡')
        setDueCards([])
        setCurrentCard(null)
        setShowNoDueCards(true)
        setShowComplete(false)
      }
    } catch (error) {
      console.error('💥 載入到期詞卡失敗:', error)
      setDueCards([])
      setCurrentCard(null)
      setShowNoDueCards(true)
    } finally {
      setIsLoadingCard(false)
    }
  }

  // 下一張詞卡
  const nextCard = (): void => {
    if (currentCardIndex < dueCards.length - 1) {
      const nextIndex = currentCardIndex + 1
      setCurrentCardIndex(nextIndex)
      setCurrentCard(dueCards[nextIndex])
    } else {
      setShowComplete(true)
    }
  }

  // 上一張詞卡
  const previousCard = (): void => {
    if (currentCardIndex > 0) {
      const prevIndex = currentCardIndex - 1
      setCurrentCardIndex(prevIndex)
      setCurrentCard(dueCards[prevIndex])
    }
  }

  // 重新開始
  const restart = async (): Promise<void> => {
    setCurrentCardIndex(0)
    setShowComplete(false)
    setShowNoDueCards(false)
    await loadDueCards()
  }

  return {
    // 狀態
    currentCard,
    dueCards,
    currentCardIndex,
    isLoadingCard,
    mode,
    isAutoSelecting,
    showNoDueCards,
    showComplete,

    // 操作函數
    loadDueCards,
    setCurrentCard,
    setCurrentCardIndex,
    setMode,
    setIsAutoSelecting,
    setShowNoDueCards,
    setShowComplete,
    nextCard,
    previousCard,
    restart
  }
}