const audioPages = require('../../data/audioPages')

const SEEK_TIMEOUT_MS = 1600
const PAUSE_LOCK_TIMEOUT_MS = 1200
const RATE_VALUES = Object.freeze([0.8, 1, 1.2])
const RATE_OPTIONS = Object.freeze([
  Object.freeze({ value: 0.8, label: '0.8倍' }),
  Object.freeze({ value: 1, label: '1.0倍' }),
  Object.freeze({ value: 1.2, label: '1.2倍' }),
])
const FALLBACK_RATE_OPTIONS = Object.freeze([
  Object.freeze({ value: 1, label: '1.0倍' }),
])

function formatTime(value) {
  const seconds = Math.max(0, Math.floor(Number(value) || 0))
  return `${Math.floor(seconds / 60)}:${String(seconds % 60).padStart(2, '0')}`
}

function clamp(value, minimum, maximum) {
  return Math.min(maximum, Math.max(minimum, Number(value) || 0))
}

function eventValue(event) {
  return Number(event && event.detail && event.detail.value) || 0
}

Page({
  data: {
    pageId: '',
    pageNumber: 1,
    title: '',
    caption: '',
    imageSrc: '',
    playing: false,
    loading: false,
    audioReady: false,
    hasStarted: false,
    seekLocked: false,
    error: '',
    currentLabel: '0:00',
    durationLabel: '0:00',
    durationSeconds: 1,
    sliderValue: 0,
    progressStyle: 'width:0%',
    playbackRate: 1,
    rateOptions: FALLBACK_RATE_OPTIONS,
    rateControlsVisible: false,
    reviewStatus: 'technical-qa-pass-human-listening-pending',
  },

  onLoad(options = {}) {
    this._unloaded = false
    this._lifecycleGeneration = (Number(this._lifecycleGeneration) || 0) + 1
    this._contextGeneration = 0
    this._intentGeneration = 0
    this._seekOperationGeneration = 0
    this._controlOperationGeneration = 0
    this._desiredPlayback = false
    this._activePlayIntentGeneration = 0
    this._controlLocked = false
    this._scrubbing = false
    this._pendingSeek = null
    this._seekTimer = null
    this._pendingPauseLock = null
    this._pauseLockTimer = null
    this._page = null
    this.bindAudioInterruptionHandlers()
    const pageId = String(options.pageId || '')
    const page = audioPages[pageId]
    if (!page) {
      this.setData({ error: '这一页的声音没有找到，请返回连环画。' })
      return
    }
    this._page = page
    const durationSeconds = Math.max(1, Number(page.durationSeconds) || 1)
    this.setData({
      pageId,
      pageNumber: page.pageNumber,
      title: page.title,
      caption: page.caption,
      imageSrc: page.imageSrc,
      durationLabel: formatTime(durationSeconds),
      durationSeconds,
    })
  },

  onReady() {
    if (!this._page || this._unloaded) return
    this.createAudioContext(this._page.audioSrc)
  },

  isCurrentContext(context, generation) {
    return !this._unloaded
      && this.audioContext === context
      && this._contextGeneration === generation
  },

  setProgress(value, durationValue) {
    const duration = Math.max(
      1,
      Number(durationValue) || Number(this.data.durationSeconds) || 1,
    )
    const current = clamp(value, 0, duration)
    const percent = Math.min(100, current / duration * 100)
    this.setData({
      currentLabel: formatTime(current),
      durationLabel: formatTime(duration),
      durationSeconds: duration,
      sliderValue: current,
      progressStyle: `width:${percent}%`,
    })
  },

  disableRateControls(context) {
    try {
      if (context && typeof context.playbackRate === 'number') {
        context.playbackRate = 1
      }
    } catch (_) {
      // A runtime that rejects playbackRate remains safely at normal speed.
    }
    this.setData({
      playbackRate: 1,
      rateOptions: FALLBACK_RATE_OPTIONS,
      rateControlsVisible: false,
    })
  },

  configureRateControls(context, generation) {
    try {
      if (typeof context.playbackRate !== 'number') {
        this.disableRateControls(context)
        return
      }
      for (const rate of RATE_VALUES) {
        context.playbackRate = rate
        if (Math.abs(Number(context.playbackRate) - rate) > 0.001) {
          this.disableRateControls(context)
          return
        }
      }
      context.playbackRate = 1
      if (
        !this.isCurrentContext(context, generation)
        || Math.abs(Number(context.playbackRate) - 1) > 0.001
      ) {
        this.disableRateControls(context)
        return
      }
      this.setData({
        playbackRate: 1,
        rateOptions: RATE_OPTIONS,
        rateControlsVisible: true,
      })
    } catch (_) {
      this.disableRateControls(context)
    }
  },

  createAudioContext(src) {
    if (this._unloaded) return null
    if (this.audioContext) this.destroyAudioContext()
    const context = wx.createInnerAudioContext()
    const generation = this._contextGeneration + 1
    this._contextGeneration = generation
    this.audioContext = context
    context.autoplay = false
    context.src = src
    this.setData({
      audioReady: true,
      loading: false,
      playing: false,
      error: '',
    })
    this.configureRateControls(context, generation)

    context.onCanplay(() => {
      if (!this.isCurrentContext(context, generation)) return
      this.setData({ audioReady: true, error: '' })
    })
    context.onPlay(() => {
      if (!this.isCurrentContext(context, generation)) return
      if (
        !this._desiredPlayback
        || this._activePlayIntentGeneration !== this._intentGeneration
      ) {
        context.pause()
        this._controlLocked = false
        this.setData({ playing: false, loading: false })
        return
      }
      this._controlLocked = false
      this.setData({
        playing: true,
        loading: false,
        hasStarted: true,
        error: '',
      })
    })
    context.onPause(() => {
      if (!this.isCurrentContext(context, generation)) return
      if (this._desiredPlayback) return
      this.releasePauseLockFromEvent(context, generation)
      this.setData({ playing: false, loading: false })
    })
    context.onStop(() => {
      if (!this.isCurrentContext(context, generation)) return
      this.invalidatePlaybackIntent(false)
      this.setData({ playing: false, loading: false })
    })
    context.onWaiting(() => {
      if (
        !this.isCurrentContext(context, generation)
        || !this._desiredPlayback
      ) return
      this.setData({ playing: false, loading: true })
    })
    context.onEnded(() => {
      if (!this.isCurrentContext(context, generation)) return
      this.invalidatePlaybackIntent(false)
      this.setProgress(this.data.durationSeconds, this.data.durationSeconds)
      this.setData({ playing: false, loading: false })
    })
    context.onTimeUpdate(() => {
      if (
        !this.isCurrentContext(context, generation)
        || this._scrubbing
        || this._pendingSeek
      ) return
      const duration = Number(context.duration) || this.data.durationSeconds
      const current = Number(context.currentTime) || 0
      this.setProgress(current, duration)
    })
    if (typeof context.onSeeked === 'function') {
      context.onSeeked(() => {
        if (!this.isCurrentContext(context, generation)) return
        this.finishSeekFromEvent(context, generation)
      })
    }
    context.onError(() => {
      if (!this.isCurrentContext(context, generation)) return
      this.invalidatePlaybackIntent(false)
      this.setData({
        playing: false,
        loading: false,
        error: '声音暂时没打开，您可以返回继续看连环画。',
      })
    })
    this.bindAudioInterruptionHandlers()
    return context
  },

  beginPlaybackIntent() {
    this._intentGeneration += 1
    this._desiredPlayback = true
    this._activePlayIntentGeneration = this._intentGeneration
    return this._intentGeneration
  },

  clearSeekState(updateData = true) {
    if (this._seekTimer !== null) {
      clearTimeout(this._seekTimer)
      this._seekTimer = null
    }
    this._seekOperationGeneration += 1
    this._pendingSeek = null
    this._scrubbing = false
    if (updateData && !this._unloaded) this.setData({ seekLocked: false })
  },

  clearPauseLock(unlock = true) {
    if (this._pauseLockTimer !== null) {
      clearTimeout(this._pauseLockTimer)
      this._pauseLockTimer = null
    }
    this._controlOperationGeneration += 1
    this._pendingPauseLock = null
    if (unlock) this._controlLocked = false
  },

  beginPauseLock(context) {
    this.clearPauseLock(true)
    const operationGeneration = this._controlOperationGeneration + 1
    this._controlOperationGeneration = operationGeneration
    const pending = {
      operationGeneration,
      contextGeneration: this._contextGeneration,
      intentGeneration: this._intentGeneration,
      lifecycleGeneration: this._lifecycleGeneration,
      context,
    }
    this._pendingPauseLock = pending
    this._controlLocked = true
    this._pauseLockTimer = setTimeout(() => {
      this.releasePauseLock(
        operationGeneration,
        pending.contextGeneration,
        pending.intentGeneration,
        pending.lifecycleGeneration,
        context,
      )
    }, PAUSE_LOCK_TIMEOUT_MS)
  },

  releasePauseLock(
    operationGeneration,
    contextGeneration,
    intentGeneration,
    lifecycleGeneration,
    context,
  ) {
    const pending = this._pendingPauseLock
    if (
      !pending
      || pending.operationGeneration !== operationGeneration
      || pending.contextGeneration !== contextGeneration
      || pending.intentGeneration !== intentGeneration
      || pending.lifecycleGeneration !== lifecycleGeneration
      || pending.context !== context
      || !this.isCurrentContext(context, contextGeneration)
      || this._intentGeneration !== intentGeneration
      || this._lifecycleGeneration !== lifecycleGeneration
      || this._desiredPlayback
    ) return false
    if (this._pauseLockTimer !== null) {
      clearTimeout(this._pauseLockTimer)
      this._pauseLockTimer = null
    }
    this._pendingPauseLock = null
    this._controlLocked = false
    return true
  },

  releasePauseLockFromEvent(context, contextGeneration) {
    const pending = this._pendingPauseLock
    if (!pending) {
      if (this.isCurrentContext(context, contextGeneration)) {
        this._controlLocked = false
      }
      return
    }
    this.releasePauseLock(
      pending.operationGeneration,
      contextGeneration,
      pending.intentGeneration,
      pending.lifecycleGeneration,
      context,
    )
  },

  invalidatePlaybackIntent(pauseContext = true) {
    this._intentGeneration += 1
    this._activePlayIntentGeneration = 0
    this._desiredPlayback = false
    this.clearPauseLock(true)
    this.clearSeekState(!this._unloaded)
    if (
      pauseContext
      && this.audioContext
      && typeof this.audioContext.pause === 'function'
    ) {
      this.audioContext.pause()
    }
  },

  startPlaybackWithIntent(intentGeneration) {
    const context = this.audioContext
    if (
      !context
      || this._unloaded
      || intentGeneration !== this._intentGeneration
      || !this._desiredPlayback
    ) return false
    this._controlLocked = true
    this.setData({
      loading: true,
      playing: false,
      hasStarted: true,
      error: '',
    })
    context.play()
    return true
  },

  bindAudioInterruptionHandlers() {
    if (this._audioInterruptionBeginHandler) return
    const generation = this._lifecycleGeneration
    this._audioInterruptionBeginHandler = () => {
      if (this._unloaded || this._lifecycleGeneration !== generation) return
      this.pauseWithoutAutoResume()
    }
    this._audioInterruptionEndHandler = () => {
      if (this._unloaded || this._lifecycleGeneration !== generation) return
      this.invalidatePlaybackIntent(false)
      this.setData({ playing: false, loading: false })
    }
    if (typeof wx.onAudioInterruptionBegin === 'function') {
      wx.onAudioInterruptionBegin(this._audioInterruptionBeginHandler)
    }
    if (typeof wx.onAudioInterruptionEnd === 'function') {
      wx.onAudioInterruptionEnd(this._audioInterruptionEndHandler)
    }
  },

  unbindAudioInterruptionHandlers() {
    if (
      this._audioInterruptionBeginHandler
      && typeof wx.offAudioInterruptionBegin === 'function'
    ) {
      wx.offAudioInterruptionBegin(this._audioInterruptionBeginHandler)
    }
    if (
      this._audioInterruptionEndHandler
      && typeof wx.offAudioInterruptionEnd === 'function'
    ) {
      wx.offAudioInterruptionEnd(this._audioInterruptionEndHandler)
    }
    this._audioInterruptionBeginHandler = null
    this._audioInterruptionEndHandler = null
  },

  pauseWithoutAutoResume() {
    const context = this.audioContext
    this.invalidatePlaybackIntent(false)
    if (context && typeof context.pause === 'function') {
      this.beginPauseLock(context)
      try {
        context.pause()
      } catch (_) {
        this.clearPauseLock(true)
      }
    }
    if (!this._unloaded) {
      this.setData({ playing: false, loading: false })
    }
  },

  onHide() {
    this.pauseWithoutAutoResume()
  },

  onShow() {
    if (this._unloaded) return
    this.clearPauseLock(true)
    this.setData({ playing: false, loading: false, seekLocked: false })
  },

  togglePlayback() {
    if (this.data.loading || this._controlLocked || this._unloaded) return
    if (!this.audioContext && this._page) {
      this.createAudioContext(this._page.audioSrc)
    }
    if (!this.audioContext) return
    if (this.data.playing || this._desiredPlayback) {
      this.pauseWithoutAutoResume()
      return
    }
    const intentGeneration = this.beginPlaybackIntent()
    this.startPlaybackWithIntent(intentGeneration)
  },

  requestSeek(targetValue, options = {}) {
    const context = this.audioContext
    if (
      !context
      || this._unloaded
      || this.data.loading
      || this._pendingSeek
    ) return false
    const duration = Math.max(
      1,
      Number(context.duration) || Number(this.data.durationSeconds) || 1,
    )
    const target = clamp(targetValue, 0, duration)
    const actualBeforeSeek = Number(context.currentTime)
    const previousValue = clamp(
      Number.isFinite(actualBeforeSeek)
        ? actualBeforeSeek
        : Number(this.data.sliderValue) || 0,
      0,
      duration,
    )
    const operationGeneration = this._seekOperationGeneration + 1
    this._seekOperationGeneration = operationGeneration
    const pending = {
      operationGeneration,
      contextGeneration: this._contextGeneration,
      intentGeneration: this._intentGeneration,
      context,
      target,
      previousValue,
      playAfterSeek: Boolean(options.playAfterSeek),
    }
    this._pendingSeek = pending
    this._scrubbing = false
    this.setProgress(target, duration)
    this.setData({ seekLocked: true, error: '' })
    this._seekTimer = setTimeout(() => {
      this.failSeek(
        operationGeneration,
        pending.contextGeneration,
        pending.intentGeneration,
        context,
      )
    }, SEEK_TIMEOUT_MS)
    try {
      context.seek(target)
    } catch (_) {
      this.failSeek(
        operationGeneration,
        pending.contextGeneration,
        pending.intentGeneration,
        context,
      )
      return false
    }
    return true
  },

  finishSeekFromEvent(context, contextGeneration) {
    const pending = this._pendingSeek
    if (!pending) return
    const actual = Number(context.currentTime)
    if (Number.isFinite(actual) && Math.abs(actual - pending.target) > 1.25) return
    this.finishSeek(
      pending.operationGeneration,
      contextGeneration,
      pending.intentGeneration,
      context,
    )
  },

  finishSeek(
    operationGeneration,
    contextGeneration,
    intentGeneration,
    context,
  ) {
    const pending = this._pendingSeek
    if (
      !pending
      || pending.operationGeneration !== operationGeneration
      || pending.contextGeneration !== contextGeneration
      || pending.intentGeneration !== intentGeneration
      || pending.context !== context
      || !this.isCurrentContext(context, contextGeneration)
      || this._intentGeneration !== intentGeneration
    ) return
    if (this._seekTimer !== null) {
      clearTimeout(this._seekTimer)
      this._seekTimer = null
    }
    this._pendingSeek = null
    this.setData({ seekLocked: false })
    if (
      pending.playAfterSeek
      && this._desiredPlayback
      && this._activePlayIntentGeneration === intentGeneration
    ) {
      this.startPlaybackWithIntent(intentGeneration)
    }
  },

  failSeek(
    operationGeneration,
    contextGeneration,
    intentGeneration,
    context,
  ) {
    const pending = this._pendingSeek
    if (
      !pending
      || pending.operationGeneration !== operationGeneration
      || pending.contextGeneration !== contextGeneration
      || pending.intentGeneration !== intentGeneration
      || pending.context !== context
      || !this.isCurrentContext(context, contextGeneration)
      || this._intentGeneration !== intentGeneration
    ) return false
    if (this._seekTimer !== null) {
      clearTimeout(this._seekTimer)
      this._seekTimer = null
    }
    this._pendingSeek = null
    this._scrubbing = false
    const actual = Number(context.currentTime)
    const restoredValue = Number.isFinite(actual)
      ? actual
      : pending.previousValue
    if (pending.playAfterSeek) this.invalidatePlaybackIntent(false)
    this.setProgress(restoredValue, this.data.durationSeconds)
    this.setData({
      playing: pending.playAfterSeek ? false : this.data.playing,
      loading: false,
      seekLocked: false,
      error: '进度没有调好，请再试一次。',
    })
    return true
  },

  previewSeek(event) {
    if (!this.audioContext || this.data.loading || this._pendingSeek) return
    this._scrubbing = true
    this.setProgress(eventValue(event), this.data.durationSeconds)
  },

  commitSeek(event) {
    if (!this.audioContext || this.data.loading || this._pendingSeek) return
    this._scrubbing = false
    this.requestSeek(eventValue(event))
  },

  rewindTenSeconds() {
    if (!this.audioContext || this.data.loading || this._pendingSeek) return
    const current = Number(this.audioContext.currentTime)
    const fallback = Number(this.data.sliderValue) || 0
    this.requestSeek(Math.max(0, (Number.isFinite(current) ? current : fallback) - 10))
  },

  replay() {
    if (
      !this.audioContext
      || this.data.loading
      || this._controlLocked
      || this._pendingSeek
      || this._unloaded
    ) return
    const alreadyPlaying = this.data.playing && this._desiredPlayback
    const intentGeneration = alreadyPlaying
      ? this._intentGeneration
      : this.beginPlaybackIntent()
    this.setData({ hasStarted: true, error: '' })
    this.requestSeek(0, {
      playAfterSeek: !alreadyPlaying,
      intentGeneration,
    })
  },

  changePlaybackRate(event) {
    const requested = Number(
      event && event.currentTarget && event.currentTarget.dataset.rate,
    )
    if (
      !RATE_VALUES.includes(requested)
      || !this.audioContext
      || !this.data.rateControlsVisible
    ) return
    const allowed = this.data.rateOptions.some((item) => item.value === requested)
    if (!allowed) return
    try {
      this.audioContext.playbackRate = requested
      if (Math.abs(Number(this.audioContext.playbackRate) - requested) > 0.001) {
        this.disableRateControls(this.audioContext)
        return
      }
      this.setData({ playbackRate: requested })
    } catch (_) {
      this.disableRateControls(this.audioContext)
    }
  },

  goBack() {
    const pages = typeof getCurrentPages === 'function' ? getCurrentPages() : []
    const returnToChapter = () => {
      if (typeof wx.reLaunch === 'function') {
        wx.reLaunch({
          url: '/package-game/pages/chapter/chapter?chapter=1',
        })
      }
    }
    if (pages.length > 1 && typeof wx.navigateBack === 'function') {
      wx.navigateBack({ delta: 1, fail: returnToChapter })
      return
    }
    returnToChapter()
  },

  destroyAudioContext() {
    const context = this.audioContext
    if (!context) return
    this.invalidatePlaybackIntent(false)
    this._contextGeneration += 1
    this.audioContext = null
    context.destroy()
    if (!this._unloaded) {
      this.setData({
        audioReady: false,
        playing: false,
        loading: false,
        rateOptions: FALLBACK_RATE_OPTIONS,
        rateControlsVisible: false,
        playbackRate: 1,
      })
    }
  },

  onUnload() {
    this._unloaded = true
    this._lifecycleGeneration += 1
    this._intentGeneration += 1
    this._activePlayIntentGeneration = 0
    this._desiredPlayback = false
    this._controlLocked = true
    this.clearPauseLock(false)
    this.clearSeekState(false)
    this.unbindAudioInterruptionHandlers()
    const context = this.audioContext
    this._contextGeneration += 1
    this.audioContext = null
    if (context) context.destroy()
  },
})