import { useState, useMemo, useEffect, useRef } from 'react'
import { useNavigate, useLocation } from 'react-router-dom'
import { useTranslation } from 'react-i18next'
import { DatePicker, Input, Toast, Dialog, TextArea, Selector } from 'antd-mobile'
import { AddOutline, DeleteOutline } from 'antd-mobile-icons'
import dayjs from 'dayjs'
import { businessTripApi, userApi } from '../../services/api'
import { useUserStore } from '@/stores/user'
import styles from './apply.module.css'

interface ItineraryItem {
  startTime: Date | null
  endTime: Date | null
  departure: string
  destination: string
  transport: string
  tripType: 'oneway' | 'roundtrip' | ''
  remark: string
}

interface ApproverItem {
  id: number
  name: string
  avatar?: string
  position?: string
}

// 计算时长（天数）
const calculateDuration = (start: Date | null, end: Date | null): number => {
  if (!start || !end) return 0
  const startDate = dayjs(start)
  const endDate = dayjs(end)
  return endDate.diff(startDate, 'day') + 1
}

// 格式化时长显示
const formatDuration = (days: number): string => {
  if (days <= 0) return ''
  return `${days}天`
}

// 行程类型选项
const tripTypeOptions = [
  { label: '单程', value: 'oneway' },
  { label: '往返', value: 'roundtrip' },
]

// 交通工具选项
const transportOptions = [
  { label: '飞机', value: '飞机' },
  { label: '高铁', value: '高铁' },
  { label: '火车', value: '火车' },
  { label: '自驾', value: '自驾' },
  { label: '其他', value: '其他' },
]

export default function BusinessTripApply() {
  const { t } = useTranslation()
  const navigate = useNavigate()
  const location = useLocation()

  const [reason, setReason] = useState('')
  const [itineraries, setItineraries] = useState<ItineraryItem[]>([
    { startTime: null, endTime: null, departure: '', destination: '', transport: '', tripType: '' as 'oneway' | 'roundtrip' | '', remark: '' }
  ])
  const [approvers, setApprovers] = useState<ApproverItem[]>([])
  const [ccUsers, setCcUsers] = useState<ApproverItem[]>([])
  const [defaultLoaded, setDefaultLoaded] = useState(false)

  // 手动保存草稿的函数
  const saveDraft = () => {
    const draftData = {
      reason,
      itineraries,
    }
    sessionStorage.setItem('businessTripDraft', JSON.stringify(draftData))
    console.log('💾 Manually saved draft:', { reason, itineraries })
  }

  // DatePicker 可见性状态
  const [datePickerVisible, setDatePickerVisible] = useState<{
    index: number
    field: 'startTime' | 'endTime'
  } | null>(null)

  // 使用 ref 来跟踪是否已经恢复过草稿
  const hasRestoredRef = useRef(false)

  // 统一处理：草稿恢复、默认审批人加载、选择页面返回
  const initRef = useRef(false)

  useEffect(() => {
    const fromSelection = location.state?.fromSelection

    console.log('📍 Page init:', { fromSelection, locationState: location.state, initRef: initRef.current })

    // 1. 从选择页面返回：恢复所有数据（草稿 + 人员）
    if (fromSelection) {
      console.log('🔄 Returning from selection page')
      // 恢复草稿数据
      const draftData = sessionStorage.getItem('businessTripDraft')
      if (draftData) {
        const draft = JSON.parse(draftData)
        setReason(draft.reason || '')
        // 将日期字符串转换回 Date 对象
        const restoredItineraries = (draft.itineraries || [{ startTime: null, endTime: null, departure: '', destination: '', transport: '', tripType: '' as 'oneway' | 'roundtrip' | '', remark: '' }]).map((item: any) => ({
          ...item,
          startTime: item.startTime ? new Date(item.startTime) : null,
          endTime: item.endTime ? new Date(item.endTime) : null,
        }))
        setItineraries(restoredItineraries)
        console.log('✅ Restored draft')
      }

      // 恢复人员数据
      const approversData = sessionStorage.getItem('selectedApprovers')
      if (approversData) {
        setApprovers(JSON.parse(approversData))
        console.log('✅ Restored approvers')
      } else {
        setApprovers([])
      }

      const ccData = sessionStorage.getItem('selectedCc')
      if (ccData) {
        setCcUsers(JSON.parse(ccData))
        console.log('✅ Restored CC')
      } else {
        setCcUsers([])
      }
      return
    }

    // 2. 非首次进入且已初始化过：跳过
    if (initRef.current) {
      console.log('⏭️ Already initialized, skipping')
      return
    }
    initRef.current = true

    // 3. 从列表页新建申请：清除旧数据，加载默认配置
    console.log('🆕 New application - clearing old data and loading defaults')
    sessionStorage.removeItem('businessTripDraft')
    sessionStorage.removeItem('selectedApprovers')
    sessionStorage.removeItem('selectedCc')
    setReason('')
    setItineraries([{ startTime: null, endTime: null, departure: '', destination: '', transport: '', tripType: '' as 'oneway' | 'roundtrip' | '', remark: '' }])
    setApprovers([])
    setCcUsers([])

    // 4. 加载默认审批人和抄送人
    const loadDefaultApprovers = async () => {
      console.log('📡 Calling API...')

      try {
        const defaultData = await businessTripApi.getDefaultApprovers()
        console.log('✅ API Response:', defaultData)

        if (defaultData.approvers && defaultData.approvers.length > 0) {
          console.log('✅ Setting approvers:', defaultData.approvers)
          setApprovers(defaultData.approvers)
          sessionStorage.setItem('selectedApprovers', JSON.stringify(defaultData.approvers))
        }
        if (defaultData.cc_users && defaultData.cc_users.length > 0) {
          console.log('✅ Setting cc_users:', defaultData.cc_users)
          setCcUsers(defaultData.cc_users)
          sessionStorage.setItem('selectedCc', JSON.stringify(defaultData.cc_users))
        }
      } catch (error: any) {
        console.error('❌ Failed to load default approvers:', error.message)
      }
    }

    loadDefaultApprovers()
  }, [location.state?.fromSelection])

  // 计算总时长（累加所有行程的天数）
  const totalDuration = useMemo(() => {
    let total = 0
    itineraries.forEach(item => {
      const duration = calculateDuration(item.startTime, item.endTime)
      total += duration
    })
    return total
  }, [itineraries])

  const handleAddItinerary = () => {
    const newItineraries = [...itineraries, {
      startTime: null,
      endTime: null,
      departure: '',
      destination: '',
      transport: '',
      tripType: '' as 'oneway' | 'roundtrip' | '',
      remark: ''
    }]
    setItineraries(newItineraries)
    saveDraft()
  }

  const handleRemoveItinerary = (index: number) => {
    if (itineraries.length === 1) {
      Toast.show('至少保留一条行程')
      return
    }
    const newItineraries = itineraries.filter((_, i) => i !== index)
    setItineraries(newItineraries)
    saveDraft()
  }

  const handleUpdateItinerary = (index: number, field: keyof ItineraryItem, value: any) => {
    const updated = [...itineraries]
    updated[index] = { ...updated[index], [field]: value }
    setItineraries(updated)
    saveDraft()
  }

  const handleSelectApprovers = () => {
    console.log('🚀 Navigating to select approvers')
    saveDraft() // 导航前保存草稿
    navigate('/business-trip/apply/select-approver', { state: { selected: approvers, type: 'approver' } })
  }

  const handleSelectCc = () => {
    console.log('🚀 Navigating to select CC')
    saveDraft() // 导航前保存草稿
    navigate('/business-trip/apply/select-cc', { state: { selected: ccUsers, type: 'cc' } })
  }

  const handleSave = async () => {
    // 移除当前焦点，避免按钮保持高亮状态
    if (document.activeElement instanceof HTMLElement) {
      document.activeElement.blur()
    }

    try {
      // 验证必填字段
      if (!reason.trim()) {
        Toast.show(t('businessTrip.pleaseEnterReason'))
        return
      }

      const hasValidItinerary = itineraries.some(item => item.startTime && item.destination.trim())
      if (!hasValidItinerary) {
        Toast.show('请至少填写一条完整行程')
        return
      }

      // 准备行程数据
      const itineraryData = itineraries
        .filter(item => item.startTime) // 只保存有开始时间的行程
        .map(item => ({
          start_time: dayjs(item.startTime).format('YYYY-MM-DD HH:mm:ss'),
          end_time: item.endTime ? dayjs(item.endTime).format('YYYY-MM-DD HH:mm:ss') : '',
          departure: item.departure || '',
          destination: item.destination || '',
          transport: item.transport || '',
          trip_type: item.tripType || 'oneway',
          remark: item.remark || '',
        }))

      await businessTripApi.create({
        reason,
        itineraries: itineraryData,
      })

      // 保存成功后清除 sessionStorage
      sessionStorage.removeItem('selectedApprovers')
      sessionStorage.removeItem('selectedCc')
      sessionStorage.removeItem('businessTripDraft')

      Toast.show('草稿已保存')
      navigate('/approval')
    } catch (error: any) {
      Toast.show(error.message || '保存失败')
    }
  }

  const handleSubmit = () => {
    // 移除当前焦点，避免按钮保持高亮状态
    if (document.activeElement instanceof HTMLElement) {
      document.activeElement.blur()
    }

    if (!reason.trim()) {
      Toast.show(t('businessTrip.pleaseEnterReason'))
      return
    }

    const hasValidItinerary = itineraries.some(item => item.startTime && item.destination.trim())
    if (!hasValidItinerary) {
      Toast.show('请至少填写一条完整行程')
      return
    }

    if (approvers.length === 0) {
      Toast.show('请选择审批人')
      return
    }

    Dialog.confirm({
      content: t('businessTrip.confirmSubmit'),
      confirmText: '确认',
      cancelText: '取消',
      onConfirm: async () => {
        try {
          // 准备行程数据
          const itineraryData = itineraries
            .filter(item => item.startTime) // 只保存有开始时间的行程
            .map(item => ({
              start_time: dayjs(item.startTime).format('YYYY-MM-DD HH:mm:ss'),
              end_time: item.endTime ? dayjs(item.endTime).format('YYYY-MM-DD HH:mm:ss') : '',
              departure: item.departure || '',
              destination: item.destination || '',
              transport: item.transport || '',
              trip_type: item.tripType || 'oneway',
              remark: item.remark || '',
            }))

          // 先创建草稿
          const result = await businessTripApi.create({
            reason,
            itineraries: itineraryData,
          })

          // 再提交
          await businessTripApi.submit(
            result.id,
            approvers.map(a => a.id),
            ccUsers.map(u => u.id)
          )

          // 提交成功后清除 sessionStorage
          sessionStorage.removeItem('selectedApprovers')
          sessionStorage.removeItem('selectedCc')
          sessionStorage.removeItem('businessTripDraft')

          Toast.show(t('businessTrip.submitSuccess'))
          navigate('/approval')
        } catch (error: any) {
          Toast.show(error.message || '提交失败')
        }
      }
    })
  }

  return (
    <div className={styles.apply}>
      <div className={styles.form}>
        <div className={styles.group}>
          <label className={styles.required}>
            {t('businessTrip.reason')}
          </label>
          <TextArea
            placeholder={t('businessTrip.pleaseEnterReason')}
            value={reason}
            onChange={(val) => {
              setReason(val)
              saveDraft()
            }}
            rows={3}
            maxLength={500}
          />
        </div>

        <div className={styles.group}>
          <label>{t('businessTrip.totalDuration')}</label>
          <div className={styles.readonlyInput}>
            {formatDuration(totalDuration) || '-'}
          </div>
        </div>

        <div className={styles.section}>
          <div className={styles.sectionHeader}>
            <span className={styles.sectionTitle}>{t('businessTrip.itinerary')}</span>
          </div>
          {itineraries.map((item, index) => {
            const itemDuration = calculateDuration(item.startTime, item.endTime)
            return (
              <div key={index} className={styles.itineraryItem}>
                {itineraries.length > 1 && (
                  <div className={styles.itineraryHeader}>
                    <span className={styles.itineraryIndex}>行程{index + 1}</span>
                    <button
                      className={styles.removeBtn}
                      onClick={() => handleRemoveItinerary(index)}
                    >
                      <DeleteOutline />
                    </button>
                  </div>
                )}

                <div className={styles.dateField}>
                  <label className={styles.required}>{t('businessTrip.itineraryStartTime')}</label>
                  <div
                    className={styles.dateClickable}
                    onClick={() => setDatePickerVisible({ index, field: 'startTime' })}
                  >
                    {item.startTime ? dayjs(item.startTime).format('YYYY-MM-DD HH:mm') : t('common.select')}
                  </div>
                  <DatePicker
                    visible={datePickerVisible?.index === index && datePickerVisible?.field === 'startTime'}
                    onConfirm={(val) => {
                      const updated = [...itineraries]
                      updated[index] = { ...updated[index], startTime: val }
                      setItineraries(updated)
                      setDatePickerVisible(null)
                      saveDraft()
                    }}
                    onClose={() => setDatePickerVisible(null)}
                    onCancel={() => setDatePickerVisible(null)}
                    precision="minute"
                  />
                </div>

                <div className={styles.dateField}>
                  <label className={styles.required}>{t('businessTrip.itineraryEndTime')}</label>
                  <div
                    className={styles.dateClickable}
                    onClick={() => setDatePickerVisible({ index, field: 'endTime' })}
                  >
                    {item.endTime ? dayjs(item.endTime).format('YYYY-MM-DD HH:mm') : t('common.select')}
                  </div>
                  <DatePicker
                    visible={datePickerVisible?.index === index && datePickerVisible?.field === 'endTime'}
                    onConfirm={(val) => {
                      const updated = [...itineraries]
                      updated[index] = { ...updated[index], endTime: val }
                      setItineraries(updated)
                      setDatePickerVisible(null)
                      saveDraft()
                    }}
                    onClose={() => setDatePickerVisible(null)}
                    onCancel={() => setDatePickerVisible(null)}
                    precision="minute"
                    {...(item.startTime && { min: item.startTime })}
                  />
                </div>

                <div className={styles.field}>
                  <label>{t('businessTrip.duration')}</label>
                  <div className={styles.readonlyInput}>
                    {formatDuration(itemDuration) || '-'}
                  </div>
                </div>

                <div className={styles.field}>
                  <label className={styles.required}>{t('businessTrip.itineraryDeparture')}</label>
                  <Input
                    placeholder={t('businessTrip.itineraryDeparture')}
                    value={item.departure}
                    onChange={val => handleUpdateItinerary(index, 'departure', val)}
                    clearable
                  />
                </div>

                <div className={styles.field}>
                  <label className={styles.required}>{t('businessTrip.itineraryDestination')}</label>
                  <Input
                    placeholder={t('businessTrip.itineraryDestination')}
                    value={item.destination}
                    onChange={val => handleUpdateItinerary(index, 'destination', val)}
                    clearable
                  />
                </div>

                <div className={styles.field}>
                  <label className={styles.required}>{t('businessTrip.itineraryTransport')}</label>
                  <Selector
                    options={transportOptions}
                    value={item.transport ? [item.transport] : []}
                    onChange={(val) => handleUpdateItinerary(index, 'transport', val[0] || '')}
                    showCheckMark={false}
                  />
                </div>

                <div className={styles.field}>
                  <label className={styles.required}>{t('businessTrip.tripType')}</label>
                  <Selector
                    options={tripTypeOptions}
                    value={item.tripType ? [item.tripType] : []}
                    onChange={(val) => handleUpdateItinerary(index, 'tripType', val[0] as 'oneway' | 'roundtrip')}
                    showCheckMark={false}
                  />
                </div>

                <div className={styles.field}>
                  <label>{t('businessTrip.itineraryRemark')}</label>
                  <Input
                    placeholder={t('businessTrip.itineraryRemark')}
                    value={item.remark}
                    onChange={val => handleUpdateItinerary(index, 'remark', val)}
                    clearable
                  />
                </div>
              </div>
            )
          })}
          <button className={styles.addBtn} onClick={handleAddItinerary}>
            <AddOutline />
            {t('businessTrip.addItinerary')}
          </button>
        </div>

        <div className={styles.section}>
          <div className={styles.selector} onClick={handleSelectApprovers}>
            <span className={styles.label}>{t('businessTrip.approvers')}</span>
            <div className={styles.value}>
              {approvers.length > 0 ? (
                <div className={styles.selectedUsers}>
                  {approvers.map(u => (
                    <img key={`approver-${u.id}`} src={u.avatar || '/default-avatar.png'} alt={u.name} className={styles.avatar} />
                  ))}
                </div>
              ) : (
                <span className={styles.placeholder}>{t('businessTrip.selectApprovers')}</span>
              )}
              <AddOutline className={styles.icon} />
            </div>
          </div>

          <div className={styles.selector} onClick={handleSelectCc}>
            <span className={styles.label}>{t('businessTrip.cc')}</span>
            <div className={styles.value}>
              {ccUsers.length > 0 ? (
                <div className={styles.selectedUsers}>
                  {ccUsers.map(u => (
                    <img key={`cc-${u.id}`} src={u.avatar || '/default-avatar.png'} alt={u.name} className={styles.avatar} />
                  ))}
                </div>
              ) : (
                <span className={styles.placeholder}>{t('businessTrip.selectCc')}</span>
              )}
              <AddOutline className={styles.icon} />
            </div>
          </div>
        </div>
      </div>

      <div className={styles.footer}>
        <button className={styles.saveBtn} onClick={handleSave}>
          {t('common.save')}
        </button>
        <button className={styles.submitBtn} onClick={handleSubmit}>
          {t('common.submit')}
        </button>
      </div>
    </div>
  )
}