const app = getApp()

const getReviewSettings = () => {
  const settings = app.globalData.userSettings || {}
  return {
    autoNextQuestion: Number(settings.auto_next_question || 0) === 1,
    showAnswerAfterSubmit: Number(settings.show_answer_after_submit || 0) === 1,
    blankCount: Number(settings.blank_count || 2),
    blankDifficulty: settings.blank_difficulty || 'normal',
  }
}

Page({
  data: {
    progress: 0,
    current: 1,
    total: 0,
    word: '',
    meaning: '',
    answer: '',
    answers: [],
    clozeAnswers: [],
    feedback: '',
    revealAnswer: '',
    feedbackType: '',
    showFeedback: false,
    completed: false,
    masterHint: false,
    questions: [],
    loading: false,
    error: '',
    settings: getReviewSettings(),
    questionBadge: '',
    entryTypeHint: '',
    isCloze: false,
    currentClozeQuestion: null,
    currentClozeResults: [],
    showClozeFeedback: false,
    clozeSegments: [],
  },
  submitting: false,
  judged: false,
  onLoad() {
    this.loadSettingsAndQuestions()
  },
  loadSettingsAndQuestions() {
    if (!app.globalData.openid) {
      this.setData({ error: '请先登录' })
      return
    }
    wx.request({
      url: `${app.globalData.baseUrl}/api/v1/settings`,
      header: { 'X-OpenID': app.globalData.openid },
      success: (res) => {
        app.globalData.userSettings = res.data?.data || {}
        this.setData({ settings: getReviewSettings() })
        this.loadQuestions()
      },
      fail: () => {
        this.setData({ error: '设置加载失败' })
        this.loadQuestions()
      },
    })
  },
  buildClozeSegments(clozeQuestion) {
    if (!clozeQuestion || !Array.isArray(clozeQuestion.blanks)) return []
    const prompt = clozeQuestion.prompt_text || ''
    const segments = []
    let blankIndex = 0
    if (prompt.includes('____')) {
      prompt.split('____').forEach((text, index, parts) => {
        if (text) segments.push({ type: 'text', text, index: `text-${index}` })
        if (index < parts.length - 1) {
          segments.push({ type: 'blank', blankIndex, index: `blank-${blankIndex}` })
          blankIndex += 1
        }
      })
      return segments
    }

    const blanks = clozeQuestion.blanks || []
    let cursor = 0
    blanks.forEach((blank, idx) => {
      const start = Math.max(0, Number(blank.start || 0))
      const end = Math.max(start, Number(blank.end || start + 1))
      if (start > cursor) {
        segments.push({ type: 'text', text: prompt.slice(cursor, start), index: `text-${idx}` })
      }
      segments.push({ type: 'blank', blankIndex: idx, index: `blank-${idx}` })
      cursor = end
    })
    if (cursor < prompt.length) {
      segments.push({ type: 'text', text: prompt.slice(cursor), index: `text-tail` })
    }
    return segments
  },
  loadQuestions() {
    const session = app.globalData.reviewSessionMeta || wx.getStorageSync('reviewSessionMeta')
    if (!session?.id) {
      this.setData({ error: '暂无复习会话' })
      return
    }
    app.globalData.reviewSessionMeta = session
    this.setData({ loading: true, error: '' })
    wx.request({
      url: `${app.globalData.baseUrl}/api/v1/review/questions?session_id=${session.id}`,
      header: { 'X-OpenID': app.globalData.openid || '' },
      success: (res) => {
        if (res.statusCode < 200 || res.statusCode >= 300) {
          const message = res.data?.detail || res.data?.message || '题目加载失败'
          this.setData({ error: message, questions: [] })
          return
        }
        const questions = (res.data?.data || []).map((item) => {
          if (item.question_mode === 'C') {
            return {
              ...item,
              blank_prompt: item.blank_prompt || item.cloze_question?.prompt_text || item.prompt,
              cloze_question: item.cloze_question || null,
            }
          }
          return {
            ...item,
            entry_type: item.entry_type || 'word',
          }
        })
        if (!questions.length) {
          this.setData({ error: '当前复习会话没有题目，请返回重新选择范围', questions: [] })
          return
        }
        app.globalData.reviewSession = {
          deck: questions,
          currentIndex: 0,
          correctCount: 0,
          wrongCount: 0,
          completed: false,
          currentAnswer: '',
          currentAnswers: [],
          startedAt: Date.now(),
        }
        this.setData({ questions })
        this.syncSession()
      },
      fail: () => this.setData({ error: '题目加载失败' }),
      complete: () => this.setData({ loading: false }),
    })
  },
  syncSession() {
    const session = app.globalData.reviewSession
    const current = session.deck[session.currentIndex]
    const total = session.deck.length || 1
    const isCloze = current?.question_mode === 'C'
    const clozeQuestion = isCloze ? (current?.cloze_question || null) : null
    this.setData({
      progress: Math.round((session.currentIndex / total) * 100),
      current: session.currentIndex + 1,
      total,
      word: isCloze ? (current?.blank_prompt || clozeQuestion?.prompt_text || current?.prompt || '') : (current?.prompt || ''),
      meaning: isCloze ? (current?.answer_hint || '') : '',
      answer: session.currentAnswer || '',
      clozeAnswers: isCloze ? (Array.isArray(session.currentAnswers) ? session.currentAnswers : Array.from({ length: currentClozeQuestion?.blanks?.length || 0 }, () => '')) : [],
      feedback: '',
      revealAnswer: '',
      feedbackType: '',
      showFeedback: false,
      completed: session.completed,
      masterHint: false,
      questionBadge: isCloze ? `填空 · ${current?.entry_type === 'sentence' ? '句子' : '单词'}` : `${current?.entry_type === 'sentence' ? '句子' : '单词'} · ${current?.question_mode || 'A'}`,
      entryTypeHint: isCloze ? '请逐空作答，提交后会显示每个空的结果。' : (current?.entry_type === 'sentence' ? '当前题目来自句子库，注意上下文表达。' : ''),
      isCloze,
      currentClozeQuestion: clozeQuestion,
      currentClozeResults: session.lastClozeResults || [],
      showClozeFeedback: false,
      clozeSegments: isCloze ? this.buildClozeSegments(clozeQuestion) : [],
    })
  },
  onAnswerInput(e) {
    const answer = e.detail.value
    app.globalData.reviewSession.currentAnswer = answer
    this.setData({ answer, showFeedback: false, revealAnswer: '', feedback: '', feedbackType: '', judged: false, showClozeFeedback: false })
  },
  onClozeAnswerInput(e) {
    const { index } = e.currentTarget.dataset
    const value = e.detail.value
    const answers = [...(app.globalData.reviewSession.currentAnswers || [])]
    answers[index] = value
    app.globalData.reviewSession.currentAnswers = answers
    this.setData({
      [`clozeAnswers[${index}]`]: value,
      showFeedback: false,
      revealAnswer: '',
      feedback: '',
      feedbackType: '',
      judged: false,
      showClozeFeedback: false,
    })
  },
  submitAnswer(showExplanation = false, advanceAfterSubmit = false) {
    const session = app.globalData.reviewSession
    const current = session.deck[session.currentIndex]
    if (!current || this.submitting || this.judged) return

    const answer = (this.data.answer || '').trim()
    const clozeQuestion = current.cloze_question
    const payload = {
      session_id: app.globalData.reviewSessionMeta.id,
      record_id: current.record_id,
      user_answer: answer,
    }
    if (current.question_mode === 'C' && clozeQuestion?.blanks?.length) {
      const answers = (this.data.clozeAnswers || []).map((item) => (item || '').trim())
      while (answers.length < clozeQuestion.blanks.length) answers.push('')
      if (!answers.some((item) => item)) {
        wx.showToast({ title: '请先输入答案', icon: 'none' })
        return
      }
      payload.user_answers = answers
    } else if (!answer) {
      wx.showToast({ title: '请先输入答案', icon: 'none' })
      return
    }

    this.submitting = true
    wx.request({
      url: `${app.globalData.baseUrl}/api/v1/review/submit`,
      method: 'POST',
      header: { 'Content-Type': 'application/json', 'X-OpenID': app.globalData.openid || '' },
      data: payload,
      success: (res) => {
        const result = res.data?.data || {}
        session.correctCount += result.is_correct ? 1 : 0
        session.wrongCount += result.is_correct ? 0 : 1
        this.judged = true
        const shouldShowAnswer = showExplanation || this.data.settings.showAnswerAfterSubmit
        const correctAnswerText = result.correct_answer_text || ''
        const clozeResults = Array.isArray(result.cloze_results) ? result.cloze_results : []
        if (clozeResults.length) {
          session.lastClozeResults = clozeResults
          app.globalData.reviewSession.lastClozeResults = clozeResults
        }
        this.setData({
          feedback: result.is_correct ? '回答正确' : '回答错误',
          feedbackType: result.is_correct ? 'correct' : 'wrong',
          revealAnswer: shouldShowAnswer && correctAnswerText ? `正确答案：${correctAnswerText}` : '',
          showFeedback: true,
          showClozeFeedback: clozeResults.length > 0,
          currentClozeResults: clozeResults,
        })
        if (this.data.isCloze) {
          app.globalData.reviewSession.currentAnswers = []
          this.setData({ clozeAnswers: [] })
        }
        if (this.data.settings.autoNextQuestion || advanceAfterSubmit) {
          setTimeout(() => this.nextQuestion(), shouldShowAnswer ? 1200 : 0)
        }
      },
      complete: () => {
        this.submitting = false
      },
    })
  },
  checkAnswer() {
    this.submitAnswer(true)
  },
  nextQuestion() {
    const session = app.globalData.reviewSession
    if (!session.deck.length) return
    if (!this.judged) {
      this.submitAnswer(true, true)
      return
    }
    this.judged = false
    if (session.currentIndex >= session.deck.length - 1) {
      session.completed = true
      session.endedAt = Date.now()
      wx.request({
        url: `${app.globalData.baseUrl}/api/v1/review/finish?session_id=${app.globalData.reviewSessionMeta.id}`,
        method: 'POST',
        header: { 'X-OpenID': app.globalData.openid || '' },
        success: () => wx.navigateTo({ url: '/pages/review-result/review-result' }),
        fail: () => {
          wx.showToast({ title: '提交结果失败，已本地完成', icon: 'none' })
          wx.navigateTo({ url: '/pages/review-result/review-result' })
        },
      })
      return
    }
    session.currentIndex += 1
    session.currentAnswer = ''
    session.currentAnswers = []
    this.syncSession()
  },
  markMastered() {
    this.setData({ masterHint: true })
    wx.showToast({ title: '已标记', icon: 'success' })
  },
})