import { useCallback, useEffect, useMemo, useState } from 'react'
import {
  Button, Dialog, DotLoading, Empty, Input, Popup, Selector, Stepper, Toast,
} from 'antd-mobile'
import RingProgress, { Celebrate } from '../../components/RingProgress.jsx'
import { checkinApi } from '../../api/checkin.js'
import useRefreshOnVisible from '../../hooks/useRefreshOnVisible.js'
import { toDateStr, dayLabel } from './date.js'

const PERIOD_OPTIONS = [
  { label: '每天', value: 'day' },
  { label: '每周', value: 'week' },
  { label: '每月', value: 'month' },
  { label: '每年', value: 'year' },
]

const COLORS = ['#1677ff', '#00b578', '#ff8f1f', '#ff3141', '#a855f7', '#14b8a6', '#f43f9e']

const EMPTY_FORM = { id: null, name: '', period: 'day', target: 1, color: COLORS[0], note: '' }

// 打卡视图: 今日待办列表 + 环形进度 + 打卡/撤销 + 新建/编辑
export default function HabitView({ date, onDateChange }) {
  const [data, setData] = useState(null)          // { today, date, items, summary }
  const [err, setErr] = useState('')
  const [bursts, setBursts] = useState({})        // { habitId: 触发计数 }
  const [form, setForm] = useState(EMPTY_FORM)
  const [showForm, setShowForm] = useState(false)

  const load = useCallback((silent) => {
    if (!silent) setErr('')
    checkinApi.habits(date)
      .then((d) => setData(d))
      .catch((e) => { if (!silent) setErr(e.message) })
  }, [date])

  useEffect(() => { load(false) }, [load])
  useRefreshOnVisible(() => load(true))

  const items = useMemo(() => {
    const list = data?.items || []
    // 未完成在前, 已完成在后 (F-CK-16 默认排序)
    return [...list].sort((a, b) => Number(a.completed) - Number(b.completed) || a.id - b.id)
  }, [data])

  const fireBurst = (id) => setBursts((m) => ({ ...m, [id]: (m[id] || 0) + 1 }))

  // 乐观更新: 先本地 +1, 成功用服务端结果覆盖, 失败回滚 (F-SY-06/E-02)
  async function doCheck(item) {
    const before = data
    const patch = (it) => {
      const done = it.done + 1
      return {
        ...it,
        done,
        remaining: Math.max(0, it.target - done),
        percent: Math.min(1, done / it.target),
        completed: done >= it.target,
        over: Math.max(0, done - it.target),
        countOnDate: (it.countOnDate || 0) + 1,
        dayDone: (it.countOnDate || 0) + 1 >= it.expectedPerDay,
      }
    }
    setData((d) => ({ ...d, items: d.items.map((x) => (x.id === item.id ? patch(x) : x)) }))
    try {
      const res = await checkinApi.check(item.id, date)
      setData((d) => ({ ...d, items: d.items.map((x) => (x.id === item.id ? res.item : x)) }))
      if (res.item.completed) fireBurst(item.id)
    } catch (e) {
      setData(before)
      Toast.show({ content: e.message || '打卡失败' })
    }
  }

  async function doUncheck(item) {
    const before = data
    setData((d) => ({
      ...d,
      items: d.items.map((x) => {
        if (x.id !== item.id) return x
        const done = Math.max(0, x.done - 1)
        return {
          ...x,
          done,
          remaining: Math.max(0, x.target - done),
          percent: Math.min(1, done / x.target),
          completed: done >= x.target,
          over: Math.max(0, done - x.target),
          countOnDate: Math.max(0, (x.countOnDate || 0) - 1),
        }
      }),
    }))
    try {
      const res = await checkinApi.uncheck(item.id, date)
      setData((d) => ({ ...d, items: d.items.map((x) => (x.id === item.id ? res.item : x)) }))
    } catch (e) {
      setData(before)
      Toast.show({ content: e.message || '撤销失败' })
    }
  }

  async function submitForm() {
    const name = String(form.name || '').trim()
    if (!name) return Toast.show({ content: '请填写名称' })
    if (name.length > 20) return Toast.show({ content: '名称不能超过 20 个字' })
    const payload = { name, period: form.period, target: Number(form.target) || 1, color: form.color, note: form.note }
    try {
      if (form.id) await checkinApi.updateHabit(form.id, payload)
      else await checkinApi.createHabit(payload)
      setShowForm(false)
      setForm(EMPTY_FORM)
      load(true)
    } catch (e) {
      Toast.show({ content: e.message || '保存失败' })
    }
  }

  async function removeHabit(item) {
    const ok = await Dialog.confirm({
      content: `归档「${item.name}」？归档后不再出现在待办，历史记录保留。`,
      confirmText: '归档',
      cancelText: '取消',
    })
    if (!ok) return
    try {
      await checkinApi.deleteHabit(item.id)
      Toast.show({ content: '已归档' })
      load(true)
    } catch (e) {
      Toast.show({ content: e.message || '操作失败' })
    }
  }

  const summary = data?.summary || { total: 0, done: 0 }
  const isToday = data ? data.date === data.today : true

  return (
    <div className="habit-view">
      <div className="habit-head">
        <div className="habit-head-left">
          <div className="habit-date">{dayLabel(date, data?.today || toDateStr())}</div>
          <div className="habit-summary">
            已完成 <strong>{summary.done}</strong> / {summary.total}
            {!isToday && <span className="habit-badge">非今天</span>}
          </div>
        </div>
        <div className="habit-head-right">
          <Button size="mini" color="primary" onClick={() => { setForm(EMPTY_FORM); setShowForm(true) }}>
            + 新建
          </Button>
        </div>
      </div>

      {err && (
        <div className="error-banner">
          {err}
          <span className="retry-link" onClick={() => load(false)}>重试</span>
        </div>
      )}

      {data === null && !err && <div className="monitor-loading"><DotLoading /> 加载中...</div>}

      {data !== null && !err && items.length === 0 && (
        <div className="checkin-empty">
          <Empty description="还没有打卡项" />
          <Button color="primary" size="small" onClick={() => { setForm(EMPTY_FORM); setShowForm(true) }}>
            创建第一个打卡项
          </Button>
        </div>
      )}

      <div className="habit-list">
        {items.map((item) => (
          <div key={item.id} className={'habit-card' + (item.completed ? ' done' : '')}>
            <RingProgress
              percent={item.percent}
              done={item.done}
              target={item.target}
              over={item.over}
              completed={item.completed}
              color={item.color}
              onClick={() => doCheck(item)}
            />
            <div className="habit-main">
              <div className="habit-name">{item.name}</div>
              <div className="habit-meta">
                {item.periodLabel} {item.target} 次
                {item.streak > 0 && <span className="habit-streak">连续 {item.streak}</span>}
              </div>
              {item.note && <div className="habit-note">{item.note}</div>}
              <div className="habit-range">
                {item.periodStart === item.periodEnd
                  ? '今日'
                  : `${item.periodStart.slice(5)} ~ ${item.periodEnd.slice(5)}`}
                {item.over > 0 && <span className="habit-over">超额 {item.over}</span>}
              </div>
            </div>
            <div className="habit-actions">
              <Button
                size="mini"
                color={item.completed ? 'default' : 'primary'}
                onClick={() => doCheck(item)}
              >
                {item.completed ? '再打一次' : '打卡'}
              </Button>
            </div>
            <div className="habit-foot">
              {item.done > 0 && (
                <span className="habit-link" onClick={() => doUncheck(item)}>撤销</span>
              )}
              <span
                className="habit-link"
                onClick={() => {
                  setForm({ id: item.id, name: item.name, period: item.period, target: item.target, color: item.color, note: item.note })
                  setShowForm(true)
                }}
              >编辑</span>
              <span className="habit-link danger" onClick={() => removeHabit(item)}>归档</span>
            </div>
            <Celebrate fire={bursts[item.id] || 0} color={item.color} />
          </div>
        ))}
      </div>

      {/* 新建 / 编辑 */}
      <Popup
        visible={showForm}
        onMaskClick={() => setShowForm(false)}
        bodyStyle={{ borderTopLeftRadius: 12, borderTopRightRadius: 12, paddingBottom: 16 }}
      >
        <div className="form-popup">
          <div className="form-title">{form.id ? '编辑打卡项' : '新建打卡项'}</div>
          <div className="form-field">
            <label>名称</label>
            <Input
              placeholder="例如：喝水 / 健身 / 读书"
              value={form.name}
              maxLength={20}
              onChange={(v) => setForm((f) => ({ ...f, name: v }))}
            />
          </div>
          <div className="form-field">
            <label>周期</label>
            <Selector
              options={PERIOD_OPTIONS}
              value={[form.period]}
              onChange={(v) => setForm((f) => ({ ...f, period: v[0] }))}
            />
          </div>
          <div className="form-field">
            <label>目标次数（周期内）</label>
            <Stepper min={1} max={999} value={form.target} onChange={(v) => setForm((f) => ({ ...f, target: v }))} />
          </div>
          <div className="form-field">
            <label>颜色</label>
            <div className="color-row">
              {COLORS.map((c) => (
                <span
                  key={c}
                  className={'color-dot' + (form.color === c ? ' active' : '')}
                  style={{ background: c }}
                  onClick={() => setForm((f) => ({ ...f, color: c }))}
                />
              ))}
            </div>
          </div>
          <div className="form-field">
            <label>备注（可选）</label>
            <Input
              placeholder="补充说明"
              value={form.note}
              onChange={(v) => setForm((f) => ({ ...f, note: v }))}
            />
          </div>
          <div className="form-actions">
            <Button block color="primary" onClick={submitForm}>保存</Button>
            <Button block fill="outline" onClick={() => setShowForm(false)} style={{ marginTop: 8 }}>取消</Button>
          </div>
        </div>
      </Popup>
    </div>
  )
}