const app = getApp()

function flattenSections(bookData) {
  if (!bookData || !Array.isArray(bookData)) return []
  const out = []
  bookData.forEach(part => {
    if (!part.chapters || !Array.isArray(part.chapters)) return
    part.chapters.forEach(ch => {
      if (!ch.sections || !Array.isArray(ch.sections)) return
      ch.sections.forEach(sec => {
        out.push({ id: sec.id, title: sec.title || sec.id })
      })
    })
  })
  return out
}

Page({
  data: {
    statusBarHeight: 44,
    navBarHeight: 88,
    isLoggedIn: false,
    user: null,
    hasFullBook: false,
    purchasedSections: [],
    purchasedSectionList: [],
    purchasedCount: 0,
    totalSections: 62,
    sectionList: [],
    loading: true
  },

  onLoad() {
    const statusBarHeight = app.globalData.statusBarHeight || 44
    const navBarHeight = app.globalData.navBarHeight || (statusBarHeight + 44)
    this.setData({ statusBarHeight, navBarHeight })
    this.syncUser()
    this.loadBookData()
  },

  onShow() {
    this.syncUser()
  },

  syncUser() {
    const isLoggedIn = !!app.globalData.isLoggedIn
    const user = app.globalData.userInfo || null
    const hasFullBook = !!app.globalData.hasFullBook
    const purchasedSections = app.globalData.purchasedSections || []
    const total = this.data.totalSections || 62
    const purchasedCount = hasFullBook ? total : purchasedSections.length
    const sectionList = this.data.sectionList || []
    const purchasedSectionList = sectionList.filter(s => purchasedSections.indexOf(s.id) >= 0)
    this.setData({
      isLoggedIn,
      user,
      hasFullBook,
      purchasedSections,
      purchasedCount,
      purchasedSectionList
    })
  },

  loadBookData() {
    const bookData = app.globalData.bookData
    if (bookData && Array.isArray(bookData)) {
      const sectionList = flattenSections(bookData)
      const totalSections = sectionList.length || 62
      this.setData({ sectionList, totalSections, loading: false })
      this.syncUser()
      return
    }
    app.request('/api/book/all-chapters').then(res => {
      const raw = (res && res.data) ? res.data : (res && res.chapters) ? res.chapters : []
      const totalSections = res.totalSections || res.total || raw.length || 62
      let sectionList = []
      if (Array.isArray(raw)) {
        raw.forEach(s => {
          sectionList.push({
            id: s.id,
            title: s.sectionTitle || s.title || s.section_title || s.id
          })
        })
      }
      if (sectionList.length === 0 && raw.length > 0) {
        sectionList = raw.map(s => ({ id: s.id, title: s.sectionTitle || s.title || s.id }))
      }
      this.setData({ sectionList, totalSections, loading: false })
      this.syncUser()
    }).catch(() => this.setData({ loading: false }))
  },

  goBack() {
    wx.navigateBack({ fail: () => wx.switchTab({ url: '/pages/my/my' }) })
  },

  goChapters() {
    wx.switchTab({ url: '/pages/chapters/chapters' })
  },

  goToRead(e) {
    const id = e.currentTarget.dataset.id
    if (id) wx.navigateTo({ url: '/pages/read/read?id=' + encodeURIComponent(id) })
  }
})