// calendar.js
const storage = require('../../utils/storage')
const dateUtils = require('../../utils/date')
const lunar = require('../../utils/lunar')
const { TYPE_NAMES, TYPE_ICONS, IMPORTANCE_COLORS } = require('../../utils/constants')

// 算出某条纪念日在指定年份的公历 (month, day)
// 公历纪念日：每年同月同日，直接用录入时的 solarMonth/solarDay
// 农历纪念日：把农历月日转回当年公历，因为农历对应的公历日期每年都不同
function getAnniversaryDateInYear(a, year) {
  if (a.isLunar && a.lunarMonth && a.lunarDay) {
    const date = lunar.lunarToSolar(year, a.lunarMonth, a.lunarDay, !!a.isLeapMonth)
    return { month: date.getMonth() + 1, day: date.getDate() }
  }
  return { month: a.solarMonth, day: a.solarDay }
}

Page({
  data: {
    currentYear: new Date().getFullYear(),
    currentMonth: new Date().getMonth() + 1,
    calendarDays: [],
    monthEvents: []
  },

  onLoad() {
    const today = new Date()
    this.setData({
      currentYear: today.getFullYear(),
      currentMonth: today.getMonth() + 1
    })
    this.renderCalendar()
    this.loadMonthEvents()
  },

  /**
   * 构建当月事件索引 { "day": [anniversary, ...] }
   */
  buildEventIndex(anniversaries, year, month) {
    const index = {}
    for (const a of anniversaries) {
      const { month: m, day: d } = getAnniversaryDateInYear(a, year)
      if (m === month) {
        const key = String(d)
        if (!index[key]) index[key] = []
        index[key].push(a)
      }
    }
    return index
  },

  /**
   * 渲染日历
   */
  renderCalendar() {
    const { currentYear, currentMonth } = this.data
    const anniversaries = storage.getAnniversaries()

    // 预建事件索引，避免 O(n×m) 过滤
    const eventIndex = this.buildEventIndex(anniversaries, currentYear, currentMonth)

    const firstDay = new Date(currentYear, currentMonth - 1, 1)
    const startWeekday = firstDay.getDay()
    const daysInMonth = new Date(currentYear, currentMonth, 0).getDate()
    const prevMonthDays = new Date(currentYear, currentMonth - 1, 0).getDate()

    const calendarDays = []

    // 填充上个月的日期
    for (let i = startWeekday - 1; i >= 0; i--) {
      const day = prevMonthDays - i
      calendarDays.push({ day, isToday: false, isOtherMonth: true, events: [], hasMore: false })
    }

    // 填充本月的日期
    for (let day = 1; day <= daysInMonth; day++) {
      const date = new Date(currentYear, currentMonth - 1, day)
      const isToday = dateUtils.isToday(date)
      const allEvents = eventIndex[String(day)] || []
      const events = allEvents.slice(0, 3).map(a => ({ id: a.id, color: this.getEventColor(a) }))

      calendarDays.push({
        day,
        isToday,
        isOtherMonth: false,
        events,
        hasMore: allEvents.length > 3,
        moreCount: allEvents.length - 3
      })
    }

    // 填充下个月的日期（补全6行）
    const remainingDays = 42 - calendarDays.length
    for (let day = 1; day <= remainingDays; day++) {
      calendarDays.push({ day, isToday: false, isOtherMonth: true, events: [], hasMore: false })
    }

    this.setData({ calendarDays })
  },

  /**
   * 获取事件颜色
   */
  getEventColor(anniversary) {
    return IMPORTANCE_COLORS[anniversary.importance] || '#07c160'
  },

  /**
   * 加载本月事件
   */
  loadMonthEvents() {
    const { currentYear, currentMonth } = this.data
    const persons = storage.getPersons()
    const anniversaries = storage.getAnniversaries()

    const monthEvents = anniversaries
      .map(a => {
        const { month: m, day: d } = getAnniversaryDateInYear(a, currentYear)
        return { ...a, _displayMonth: m, _displayDay: d }
      })
      .filter(x => x._displayMonth === currentMonth)
      .map(x => {
        const person = persons.find(p => p.id === x.personId)
        const date = new Date(currentYear, x._displayMonth - 1, x._displayDay)
        const ld = lunar.solarToLunar(date)
        return {
          ...x,
          personName: person ? person.name : '未知',
          typeIcon: this.getTypeIcon(x.type),
          typeName: x.customTypeName || this.getTypeName(x.type),
          dateText: dateUtils.formatDate(date, 'MM月DD日'),
          lunarMD: ld.lunarText,
          daysUntil: dateUtils.getDaysUntil(date)
        }
      })
      .sort((a, b) => a._displayDay - b._displayDay)

    this.setData({ monthEvents })
  },

  /**
   * 获取类型图标
   */
  getTypeIcon(type) {
    return TYPE_ICONS[type] || '📅'
  },

  /**
   * 获取类型名称
   */
  getTypeName(type) {
    return TYPE_NAMES[type] || '其他'
  },

  /**
   * 上一个月
   */
  onPrevMonth() {
    let { currentYear, currentMonth } = this.data
    if (currentMonth === 1) {
      currentYear--
      currentMonth = 12
    } else {
      currentMonth--
    }
    this.setData({ currentYear, currentMonth })
    this.renderCalendar()
    this.loadMonthEvents()
  },

  /**
   * 下一个月
   */
  onNextMonth() {
    let { currentYear, currentMonth } = this.data
    if (currentMonth === 12) {
      currentYear++
      currentMonth = 1
    } else {
      currentMonth++
    }
    this.setData({ currentYear, currentMonth })
    this.renderCalendar()
    this.loadMonthEvents()
  },

  /**
   * 回到今天
   */
  onGoToday() {
    const today = new Date()
    this.setData({
      currentYear: today.getFullYear(),
      currentMonth: today.getMonth() + 1
    })
    this.renderCalendar()
    this.loadMonthEvents()
  },

  /**
   * 点击事件
   */
  onEventTap(e) {
    const id = e.currentTarget.dataset.id
    const anniversary = storage.getAnniversaries().find(a => a.id === id)
    if (anniversary) {
      wx.navigateTo({
        url: `/pages/person-detail/person-detail?id=${anniversary.personId}`
      })
    }
  }
})