const store = require('../../utils/store.js');
const api = require('../../utils/api.js');
const { toastErr } = require('../../utils/ui.js');

function pad2(n) {
  return n < 10 ? '0' + n : '' + n;
}
function ymd(d) {
  return d.getFullYear() + '-' + pad2(d.getMonth() + 1) + '-' + pad2(d.getDate());
}
// "2026-07-04" → "7月4日"
function fmtMD(date) {
  const p = (date || '').split('-');
  return p.length < 3 ? '' : +p[1] + '月' + +p[2] + '日';
}
function parseYMD(s) {
  const p = (s || '').split('-');
  return p.length < 3 ? null : new Date(+p[0], +p[1] - 1, +p[2]);
}

// 计划覆盖的天数。内置模板会生成 day=30 的节点（第 31 天），所以是 31 格不是 30 格；
// 按 30 画的话模板自己的最后一个节点在日历上没有格子——看得到、点不到。
// 和后端 service/plan.go 的 planSpanDays 必须一致。
const SPAN = 31;

// 只画计划覆盖的这段，不画整月：整月会多出一堆空白格子、跨月还要翻页。
// 按周对齐排 31 天，首尾补几个空格就够，一屏看完。
function buildCells(startStr, byDate, todayStr) {
  const start = parseYMD(startStr);
  if (!start) return [];
  const lead = (start.getDay() + 6) % 7; // 周一为一周起点
  const cells = [];
  for (let i = 0; i < lead; i++) cells.push({ blank: true });
  for (let i = 0; i < SPAN; i++) {
    const d = new Date(start.getFullYear(), start.getMonth(), start.getDate() + i);
    const s = ymd(d);
    cells.push({ day: d.getDate(), date: s, count: (byDate[s] || []).length, today: s === todayStr });
  }
  // 末尾补齐整周，否则最后一行格子宽度会被 grid 拉歪
  while (cells.length % 7) cells.push({ blank: true });
  return cells;
}

Page({
  data: {
    pet: {},
    plan: null,
    doneCount: 0,
    cells: [],
    calRange: '',
    planStart: '',
    planEnd: '',
    selDate: '',
    selLabel: '',
    dayTasks: [],
    allOpen: false,
    editShow: false,
    editId: '',
    form: { title: '', date: '', description: '' },
    saving: false,
    sheetShow: false,
    sheetType: '',
  },
  onLoad() {
    this._unsub = store.subscribe((pet) => {
      this.setData({ pet });
      if (this._inited) this.load();
    });
  },
  onUnload() {
    if (this._unsub) this._unsub();
  },
  onShow() {
    store
      .ready()
      .then(() => {
        this._inited = true;
        this.setData({ pet: store.getPet() });
        this.load();
      })
      .catch((e) => toastErr(e));
  },
  load() {
    const id = store.currentPetId();
    if (!id) return;
    api
      .getPlan(id)
      .then((plan) => this.apply(plan))
      .catch(() => this.setData({ plan: null, cells: [], dayTasks: [] }));
  },
  apply(plan) {
    const tasks = (plan.tasks || []).map((t) => ({ ...t, dateLabel: fmtMD(t.date) }));
    const byDate = {};
    tasks.forEach((t) => {
      if (!t.date) return;
      (byDate[t.date] = byDate[t.date] || []).push(t);
    });
    const start = (plan.start_date || '').slice(0, 10);
    const end = start ? ymd(new Date(parseYMD(start).getTime() + (SPAN - 1) * 86400000)) : '';
    const todayStr = ymd(new Date());
    this._byDate = byDate;

    // 默认选今天；今天不在计划范围内（计划早就过期了）就选开始那天
    const sel = byDate[todayStr] !== undefined || (todayStr >= start && todayStr <= end) ? todayStr : start;
    this.setData({
      plan: { ...plan, tasks },
      doneCount: tasks.filter((t) => t.done).length,
      cells: buildCells(start, byDate, todayStr),
      calRange: start ? fmtMD(start) + ' — ' + fmtMD(end) : '',
      planStart: start,
      planEnd: end,
    });
    this.selectDay(sel, todayStr);
  },
  selectDay(date, todayStr) {
    const t = todayStr || ymd(new Date());
    this.setData({
      selDate: date,
      selLabel: date === t ? '今天的安排' : fmtMD(date) + '的安排',
      dayTasks: (this._byDate || {})[date] || [],
    });
  },
  onTapDay(e) {
    const d = e.currentTarget.dataset.date;
    if (d) this.selectDay(d);
  },
  backToToday() {
    const t = ymd(new Date());
    // 今天不在这 30 天里就退回开始日，否则选中一个日历上不存在的格子
    this.selectDay(t >= this.data.planStart && t <= this.data.planEnd ? t : this.data.planStart);
  },
  toggleAll() {
    this.setData({ allOpen: !this.data.allOpen });
  },
  toggleTask(e) {
    api
      .togglePlanTask(e.currentTarget.dataset.id)
      .then(() => this.load())
      .catch((err) => toastErr(err, '操作失败'));
  },

  // ── 加 / 改 ──
  openAdd() {
    this.setData({
      editShow: true, editId: '',
      form: { title: '', date: this.data.selDate || this.data.planStart, description: '' },
    });
  },
  openEdit(e) {
    const t = (this.data.dayTasks || []).find((x) => x.id === e.currentTarget.dataset.id);
    if (!t) return;
    this.setData({
      editShow: true, editId: t.id,
      form: { title: t.title, date: t.date || this.data.selDate, description: t.description || '' },
    });
  },
  closeEdit() {
    this.setData({ editShow: false });
  },
  noop() {},
  onFormTitle(e) {
    this.setData({ 'form.title': e.detail.value });
  },
  onFormDate(e) {
    this.setData({ 'form.date': e.detail.value });
  },
  onFormDesc(e) {
    this.setData({ 'form.description': e.detail.value });
  },
  onSubmit() {
    if (this.data.saving) return;
    const f = this.data.form;
    if (!(f.title || '').trim()) return wx.showToast({ title: '写一下做什么', icon: 'none' });
    const id = store.currentPetId();
    if (!id) return;
    this.setData({ saving: true });
    const req = this.data.editId
      ? api.updatePlanTask(this.data.editId, f)
      : api.addPlanTask(id, f);
    req
      .then(() => {
        this.setData({ saving: false, editShow: false });
        // 加完/改完要跳到那一天，不然用户改了日期却看不到东西去哪了
        this._pendingSel = f.date;
        this.load();
      })
      .catch((e) => {
        this.setData({ saving: false });
        toastErr(e, '保存失败');
      });
  },
  onDelete(e) {
    const { id, title } = e.currentTarget.dataset;
    wx.showModal({
      title: '删掉这件事？',
      content: title || '',
      confirmColor: '#EE7D73',
      success: (r) => {
        if (!r.confirm) return;
        api
          .deletePlanTask(id)
          .then(() => this.load())
          .catch((err) => toastErr(err, '删除失败'));
      },
    });
  },

  openSheet(e) {
    const type = e.currentTarget.dataset.type;
    if (!type) return;
    this.setData({ sheetType: type, sheetShow: true });
  },
  closeSheet() {
    this.setData({ sheetShow: false });
  },
  onAddPet() {
    this.setData({ sheetType: 'addPet', sheetShow: true });
  },
  onShareAppMessage() {
    return { title: '我给毛孩子做了份养护计划', path: '/pages/plan/plan' };
  },
  onShareTimeline() {
    return { title: '我给毛孩子做了份养护计划' };
  },
});