const { getDayInfo, getAlmanacInfo, getMonthCalendar } = require('../../utils/core/index.js');

function pad(n) { return String(n).padStart(2, '0'); }
function fmt(y, m, d) { return `${y}-${pad(m)}-${pad(d)}`; }

Page({
  data: {
    statusBarHeight: 20,
    navBarHeight: 44,
    viewMode: 'day',          // day | month
    dayInfo: {},
    almanac: {},
    // 月历
    year: 0,
    month: 0,
    weekHeaders: ['日', '一', '二', '三', '四', '五', '六'],
    calendarDays: [],
    selectedDay: null
  },

  onLoad() {
    const sys = wx.getWindowInfo ? wx.getWindowInfo() : wx.getSystemInfoSync();
    const menu = wx.getMenuButtonBoundingClientRect ? wx.getMenuButtonBoundingClientRect() : null;
    const statusBarHeight = sys.statusBarHeight || 20;
    let navBarHeight = 44;
    if (menu && menu.top) {
      navBarHeight = (menu.top - statusBarHeight) * 2 + menu.height;
    }
    this.setData({ statusBarHeight, navBarHeight });
    this.loadDay(new Date());
  },

  onPullDownRefresh() {
    if (this.data.viewMode === 'day') {
      this.loadDay(new Date());
    } else {
      this.loadCalendar();
    }
    wx.stopPullDownRefresh();
  },

  /** 加载某日的老黄历 */
  loadDay(date) {
    const y = date.getFullYear();
    const m = date.getMonth() + 1;
    const d = date.getDate();
    const dayInfo = getDayInfo(y, m, d);
    const almanac = getAlmanacInfo(y, m, d);
    this.setData({ dayInfo, almanac, year: y, month: m });
  },

  /** 前一天 / 后一天 */
  prevDay() { this.shiftDay(-1); },
  nextDay() { this.shiftDay(1); },
  shiftDay(delta) {
    const { dayInfo } = this.data;
    const date = new Date(dayInfo.solarYear, dayInfo.solarMonth - 1, dayInfo.solarDay + delta);
    this.loadDay(date);
  },

  /** 回到今天 */
  backToday() {
    this.loadDay(new Date());
  },

  /** 切换 日视图/月历视图 */
  toggleView() {
    const mode = this.data.viewMode === 'day' ? 'month' : 'day';
    this.setData({ viewMode: mode });
    if (mode === 'month') {
      const { dayInfo } = this.data;
      this.setData({ year: dayInfo.solarYear, month: dayInfo.solarMonth }, () => this.loadCalendar());
    }
  },

  /** 月历 */
  loadCalendar() {
    const { year, month } = this.data;
    const weeks = getMonthCalendar(year, month);
    const calendarDays = [];
    weeks.forEach(w => w.forEach(d => calendarDays.push(d)));
    this.setData({ calendarDays });
  },

  prevMonth() {
    let { year, month } = this.data;
    month--;
    if (month < 1) { month = 12; year--; }
    this.setData({ year, month }, () => this.loadCalendar());
  },

  nextMonth() {
    let { year, month } = this.data;
    month++;
    if (month > 12) { month = 1; year++; }
    this.setData({ year, month }, () => this.loadCalendar());
  },

  /** 月历中选中某天 → 切回日视图 */
  selectDay(e) {
    const date = e.currentTarget.dataset.date;
    const [y, m, d] = date.split('-').map(Number);
    this.loadDay(new Date(y, m - 1, d));
    this.setData({ viewMode: 'day' });
  },

  /** 跳详情页 */
  goDetail() {
    const { dayInfo } = this.data;
    wx.navigateTo({ url: `/pages/day-detail/day-detail?date=${fmt(dayInfo.solarYear, dayInfo.solarMonth, dayInfo.solarDay)}` });
  },

  navTo(e) {
    wx.navigateTo({ url: e.currentTarget.dataset.url });
  }
});