import { useState } from 'react'
import { toast } from 'sonner'
import { useQuery, useMutation, useQueryClient } from '@tanstack/react-query'
import { useConfirm } from '../hooks/useConfirm'
import { Gift, Plus, Settings as SettingsIcon, X, Users } from 'lucide-react'
import { benefitApi, employeeApi } from '../lib/api-services'
import PageGuide from '../components/ui/PageGuide'
import Card from '../components/ui/Card'
import Button from '../components/ui/Button'
import { Input, Label } from '../components/ui/Input'
import { InlineAlert } from '../components/ui/InlineAlert'
import Modal from '../components/ui/Modal'

const fmt = (n: number) => (n || 0).toLocaleString('zh-CN', { minimumFractionDigits: 2, maximumFractionDigits: 2 })

const BENEFIT_CATEGORIES: Record<string, { label: string; color: string }> = {
  TRANSPORT: { label: '交通补贴', color: 'bg-blue-50 text-blue-700 border border-blue-200' },
  MEAL: { label: '餐补', color: 'bg-orange-50 text-orange-700 border border-orange-200' },
  HOUSING: { label: '住房补贴', color: 'bg-teal-50 text-teal-700 border border-teal-200' },
  COMMUNICATION: { label: '通讯补贴', color: 'bg-purple-50 text-purple-700 border border-purple-200' },
  HEALTH_CHECK: { label: '体检', color: 'bg-green-50 text-green-700 border border-green-200' },
  HOLIDAY: { label: '节日福利', color: 'bg-red-50 text-red-700 border border-red-200' },
  BIRTHDAY: { label: '生日福利', color: 'bg-pink-50 text-pink-700 border border-pink-200' },
  OTHER: { label: '其他', color: 'bg-gray-50 text-gray-700 border border-gray-200' },
}

const FREQUENCY_LABELS: Record<string, string> = {
  MONTHLY: '每月',
  QUARTERLY: '每季',
  YEARLY: '每年',
  ONE_TIME: '一次性',
}

const DEFAULT_PLAN = {
  name: '', category: 'TRANSPORT', amount: 0, frequency: 'MONTHLY',
  taxDeductible: false, description: '',
}

export default function EmployeeBenefits() {
  const queryClient = useQueryClient()
  const confirm = useConfirm()
  const [tab, setTab] = useState<'plans' | 'summary'>('plans')
  const [showAddPlan, setShowAddPlan] = useState(false)
  const [editingPlan, setEditingPlan] = useState<any>(null)
  const [selectedPlanId, setSelectedPlanId] = useState<string | null>(null)
  const [newPlan, setNewPlan] = useState<any>({ ...DEFAULT_PLAN })
  const [showEnrollModal, setShowEnrollModal] = useState(false)
  const [enrollEmployeeIds, setEnrollEmployeeIds] = useState<string[]>([])
  const [enrollEffectiveFrom, setEnrollEffectiveFrom] = useState(new Date().toISOString().slice(0, 7))

  const { data: plans = [], isLoading } = useQuery<any[]>({
    queryKey: ['benefit-plans'],
    queryFn: async () => {
      return await benefitApi.plans()
    },
  })

  const { data: enrollments = [], isLoading: enrollLoading } = useQuery<any[]>({
    queryKey: ['benefit-enrollments', selectedPlanId],
    queryFn: async () => {
      if (!selectedPlanId) return []
      return await benefitApi.enrollments(selectedPlanId)
    },
    enabled: !!selectedPlanId,
  })

  const { data: employeeSummary = [] } = useQuery<any[]>({
    queryKey: ['benefit-employee-summary'],
    queryFn: async () => {
      return await benefitApi.employeeSummary()
    },
    enabled: tab === 'summary',
  })

  const { data: rosterData } = useQuery<any[]>({
    queryKey: ['employees-for-benefit'],
    queryFn: async () => {
      return await employeeApi.allLite({ status: 'ACTIVE' })
    },
    enabled: showEnrollModal,
  })

  const savePlanMutation = useMutation({
    mutationFn: async (data: any) => {
      if (editingPlan) {
        return benefitApi.savePlan(data, editingPlan.id) as any
      }
      return benefitApi.savePlan(data) as any
    },
    onSuccess: () => {
      queryClient.invalidateQueries({ queryKey: ['benefit-plans'] })
      setShowAddPlan(false)
      setEditingPlan(null)
      setNewPlan({ ...DEFAULT_PLAN })
      toast.success(editingPlan ? '福利方案已更新' : '福利方案已创建')
    },
    onError: () => toast.error('保存失败'),
  })

  const deletePlanMutation = useMutation({
    mutationFn: (id: string) => benefitApi.removePlan(id),
    onSuccess: () => {
      queryClient.invalidateQueries({ queryKey: ['benefit-plans'] })
      setSelectedPlanId(null)
      toast.success('福利方案已删除')
    },
  })

  const enrollMutation = useMutation({
    mutationFn: async (data: { employeeIds: string[]; effectiveFrom: string }) =>
      benefitApi.enroll(selectedPlanId!, data) as any,
    onSuccess: (res: any) => {
      queryClient.invalidateQueries({ queryKey: ['benefit-enrollments'] })
      queryClient.invalidateQueries({ queryKey: ['benefit-employee-summary'] })
      setShowEnrollModal(false)
      setEnrollEmployeeIds([])
      toast.success(`已添加 ${res.data?.enrolled || 0} 名员工`)
    },
    onError: () => toast.error('参保失败'),
  })

  const terminateMutation = useMutation({
    mutationFn: (enrollmentId: string) => benefitApi.terminateEnrollment(enrollmentId),
    onSuccess: () => {
      queryClient.invalidateQueries({ queryKey: ['benefit-enrollments'] })
      queryClient.invalidateQueries({ queryKey: ['benefit-employee-summary'] })
      toast.success('已终止福利')
    },
  })

  const handleEdit = (plan: any) => {
    setEditingPlan(plan)
    setNewPlan({ ...plan })
    setShowAddPlan(true)
  }

  const handleSave = () => {
    if (!newPlan.name?.trim()) { toast.error('请填写方案名称'); return }
    savePlanMutation.mutate(newPlan)
  }

  return (
    <div className="space-y-4">
      <div className="flex items-center gap-2">
        <Gift className="h-5 w-5 text-primary" />
        <div>
          <h1 className="text-base font-semibold">员工福利</h1>
          <p className="mt-1 text-sm text-gray-500">管理员工福利方案、参保人员及福利汇总</p>
        </div>
      </div>

      <PageGuide>
        员工福利包括交通补贴、餐补、住房补贴、通讯补贴、体检、节日福利等。
        管理福利方案、批量参保、查看员工福利汇总。
        <span className="text-primary"> 员工福利是系统增值服务模块，支持按方案/按员工维度管理福利，可关联薪资计算。</span>
      </PageGuide>

      {/* Tab 切换 */}
      <div className="flex items-center gap-4 border-b">
        {(['plans', 'summary'] as const).map((t) => (
          <button
            key={t}
            className={`px-4 py-2 text-sm font-medium border-b-2 transition-colors ${
              tab === t ? 'border-primary text-primary' : 'border-transparent text-gray-500 hover:text-gray-700'
            }`}
            onClick={() => setTab(t)}
          >
            {t === 'plans' ? '福利方案' : '员工汇总'}
          </button>
        ))}
        {tab === 'plans' && (
          <Button size="sm" className="ml-auto" onClick={() => { setEditingPlan(null); setNewPlan({ ...DEFAULT_PLAN }); setShowAddPlan(true) }}>
            <Plus className="w-4 h-4 mr-1" />新增方案
          </Button>
        )}
      </div>

      {/* ========== 福利方案 Tab ========== */}
      {tab === 'plans' && (
        <>
          {isLoading ? (
            <Card><div className="text-center py-8 text-gray-400">加载中...</div></Card>
          ) : plans.length === 0 ? (
            <Card><div className="text-center py-8 text-gray-400 text-sm">暂无福利方案，点击「新增方案」创建</div></Card>
          ) : (
            <div className="grid gap-3 md:grid-cols-2 lg:grid-cols-3">
              {plans.map((plan: any) => {
                const catCfg = BENEFIT_CATEGORIES[plan.category] || BENEFIT_CATEGORIES.OTHER
                const isSelected = selectedPlanId === plan.id
                return (
                  <Card
                    key={plan.id}
                    className={`cursor-pointer transition-all ${isSelected ? 'ring-2 ring-primary/20' : 'hover:shadow-md'}`}
                  >
                    <div onClick={() => setSelectedPlanId(isSelected ? null : plan.id)}>
                      <div className="flex items-start justify-between mb-2">
                        <div>
                          <span className={`px-2 py-0.5 rounded text-xs ${catCfg.color}`}>{catCfg.label}</span>
                          <h3 className="text-sm font-medium mt-1">{plan.name}</h3>
                        </div>
                        <div className="flex gap-1" onClick={(e) => e.stopPropagation()}>
                          <button className="text-xs text-gray-400 hover:text-primary" onClick={() => handleEdit(plan)}>
                            <SettingsIcon className="w-3.5 h-3.5" />
                          </button>
                          <button className="text-xs text-gray-400 hover:text-danger" onClick={async () => {
                            if (await confirm({ title: '确认删除', message: `确定删除福利方案「${plan.name}」吗？` })) {
                              deletePlanMutation.mutate(plan.id)
                            }
                          }}>
                            <X className="w-3.5 h-3.5" />
                          </button>
                        </div>
                      </div>
                      <div className="space-y-1 text-xs text-gray-500">
                        <div className="flex justify-between"><span>金额</span><span className="text-gray-700">¥{fmt(plan.amount)} / {FREQUENCY_LABELS[plan.frequency] || plan.frequency}</span></div>
                        <div className="flex justify-between"><span>税前扣除</span><span className="text-gray-700">{plan.taxDeductible ? '是' : '否'}</span></div>
                        <div className="flex justify-between"><span>参保人数</span><span className="text-gray-700">{plan._count?.enrollments || 0} 人</span></div>
                      </div>
                      {plan.description && <p className="text-xs text-gray-400 mt-2 line-clamp-2">{plan.description}</p>}
                    </div>
                  </Card>
                )
              })}
            </div>
          )}

          {/* 参保人员 */}
          {selectedPlanId && (
            <Card>
              <div className="flex items-center justify-between mb-3">
                <h3 className="text-sm font-medium">参保人员（{enrollments.length}人）</h3>
                <Button size="sm" variant="secondary" onClick={() => { setEnrollEmployeeIds([]); setShowEnrollModal(true) }}>
                  <Users className="w-3.5 h-3.5 mr-1" />为员工添加福利
                </Button>
              </div>
              {enrollLoading ? (
                <div className="text-center py-4 text-gray-400 text-sm">加载中...</div>
              ) : enrollments.length === 0 ? (
                <div className="text-center py-4 text-gray-400 text-sm">暂无参保人员</div>
              ) : (
                <div className="overflow-x-auto">
                  <table className="w-full text-sm">
                    <thead>
                      <tr className="border-b text-xs text-gray-500">
                        <th className="py-2 text-left">姓名</th>
                        <th className="py-2 text-left">部门</th>
                        <th className="py-2 text-left">生效月份</th>
                        <th className="py-2 text-left">截止月份</th>
                        <th className="py-2 text-left">状态</th>
                        <th className="py-2 text-right">操作</th>
                      </tr>
                    </thead>
                    <tbody>
                      {enrollments.map((e: any) => (
                        <tr key={e.id || e.employeeId} className="border-b last:border-0 hover:bg-gray-50">
                          <td className="py-2 font-medium">{e.name}</td>
                          <td className="py-2 text-gray-500">{e.department}</td>
                          <td className="py-2 text-gray-500 text-xs">{e.effectiveFrom || '—'}</td>
                          <td className="py-2 text-gray-500 text-xs">{e.effectiveTo || '至今'}</td>
                          <td className="py-2">
                            <span className={`px-2 py-0.5 rounded text-xs ${e.status === 'ACTIVE' ? 'bg-green-50 text-safe' : 'bg-gray-100 text-gray-500'}`}>
                              {e.status === 'ACTIVE' ? '有效' : '已终止'}
                            </span>
                          </td>
                          <td className="py-2 text-right">
                            {e.status === 'ACTIVE' && (
                              <button className="text-xs text-gray-400 hover:text-danger" onClick={async () => {
                                if (await confirm({ title: '确认终止', message: `确定终止${e.name}的福利吗？` })) {
                                  terminateMutation.mutate(e.id)
                                }
                              }}>终止</button>
                            )}
                          </td>
                        </tr>
                      ))}
                    </tbody>
                  </table>
                </div>
              )}
            </Card>
          )}
        </>
      )}

      {/* ========== 员工汇总 Tab ========== */}
      {tab === 'summary' && (
        <Card>
          {employeeSummary.length === 0 ? (
            <div className="text-center py-8 text-gray-400 text-sm">暂无员工福利数据</div>
          ) : (
            <div className="overflow-x-auto">
              <table className="w-full text-sm">
                <thead>
                  <tr className="border-b text-xs text-gray-500">
                    <th className="py-2 text-left">姓名</th>
                    <th className="py-2 text-left">部门</th>
                    <th className="py-2 text-left">福利项</th>
                    <th className="py-2 text-right">月度合计</th>
                  </tr>
                </thead>
                <tbody>
                  {employeeSummary.map((e: any) => (
                    <tr key={e.employeeId} className="border-b last:border-0 hover:bg-gray-50">
                      <td className="py-2 font-medium">{e.name}</td>
                      <td className="py-2 text-gray-500">{e.department}</td>
                      <td className="py-2">
                        <div className="flex flex-wrap gap-1">
                          {e.benefits.map((b: any, i: number) => (
                            <span key={i} className={`px-1.5 py-0.5 rounded text-xs ${BENEFIT_CATEGORIES[b.category]?.color || BENEFIT_CATEGORIES.OTHER.color}`}>
                              {b.planName} ¥{fmt(b.amount)}
                            </span>
                          ))}
                        </div>
                      </td>
                      <td className="py-2 text-right font-medium text-primary">¥{fmt(e.totalMonthly)}</td>
                    </tr>
                  ))}
                </tbody>
              </table>
            </div>
          )}
        </Card>
      )}

      {/* 新增/编辑方案 Modal */}
      {showAddPlan && (
        <div className="fixed inset-0 z-50 flex items-center justify-center bg-black/30" onClick={() => setShowAddPlan(false)}>
          <Card className="w-full max-w-lg mx-4">
            <div onClick={(e) => e.stopPropagation()}>
              <div className="flex items-center justify-between mb-4">
                <h3 className="text-sm font-medium">{editingPlan ? '编辑福利方案' : '新增福利方案'}</h3>
                <button onClick={() => setShowAddPlan(false)} className="text-gray-400 hover:text-gray-600"><X className="w-4 h-4" /></button>
              </div>
              <div className="space-y-3">
                <div>
                  <Label>方案名称 *</Label>
                  <Input value={newPlan.name} onChange={(e) => setNewPlan({ ...newPlan, name: e.target.value })} placeholder="如：2024年度交通补贴" />
                </div>
                <div className="grid grid-cols-2 gap-3">
                  <div>
                    <Label>福利类型</Label>
                    <select
                      className="h-9 w-full rounded-md border border-gray-200 bg-white px-3 text-sm text-gray-700 shadow-sm outline-none transition focus:border-primary focus:ring-2 focus:ring-primary/10"
                      value={newPlan.category}
                      onChange={(e) => setNewPlan({ ...newPlan, category: e.target.value })}
                    >
                      {Object.entries(BENEFIT_CATEGORIES).map(([k, v]) => <option key={k} value={k}>{v.label}</option>)}
                    </select>
                  </div>
                  <div>
                    <Label>发放频率</Label>
                    <select
                      className="h-9 w-full rounded-md border border-gray-200 bg-white px-3 text-sm text-gray-700 shadow-sm outline-none transition focus:border-primary focus:ring-2 focus:ring-primary/10"
                      value={newPlan.frequency}
                      onChange={(e) => setNewPlan({ ...newPlan, frequency: e.target.value })}
                    >
                      {Object.entries(FREQUENCY_LABELS).map(([k, v]) => <option key={k} value={k}>{v}</option>)}
                    </select>
                  </div>
                </div>
                <div className="grid grid-cols-2 gap-3">
                  <div>
                    <Label>金额（元）</Label>
                    <Input type="number" value={newPlan.amount} onChange={(e) => setNewPlan({ ...newPlan, amount: parseFloat(e.target.value) || 0 })} />
                  </div>
                  <div>
                    <Label>是否税前扣除</Label>
                    <select
                      className="h-9 w-full rounded-md border border-gray-200 bg-white px-3 text-sm text-gray-700 shadow-sm outline-none transition focus:border-primary focus:ring-2 focus:ring-primary/10"
                      value={newPlan.taxDeductible ? 'true' : 'false'}
                      onChange={(e) => setNewPlan({ ...newPlan, taxDeductible: e.target.value === 'true' })}
                    >
                      <option value="false">否</option>
                      <option value="true">是</option>
                    </select>
                  </div>
                </div>
                <div>
                  <Label>备注</Label>
                  <Input value={newPlan.description || ''} onChange={(e) => setNewPlan({ ...newPlan, description: e.target.value })} placeholder="适用条件、发放规则等" />
                </div>
                <div className="flex justify-end gap-2 pt-2">
                  <Button variant="secondary" size="sm" onClick={() => setShowAddPlan(false)}>取消</Button>
                  <Button size="sm" onClick={handleSave} disabled={savePlanMutation.isPending}>
                    {savePlanMutation.isPending ? '保存中...' : '保存'}
                  </Button>
                </div>
              </div>
            </div>
          </Card>
        </div>
      )}

      {/* 批量参保 Modal */}
      {showEnrollModal && (
        <Modal open={true} onClose={() => setShowEnrollModal(false)} title="为员工添加福利" size="lg">
          <div className="space-y-3">
            <InlineAlert type="info">
              选择需要参保的员工，设置生效月份后点击「确认参保」。
            </InlineAlert>
            <div className="flex items-center gap-2">
              <Label className="shrink-0">生效月份</Label>
              <Input type="month" value={enrollEffectiveFrom} onChange={(e) => setEnrollEffectiveFrom(e.target.value)} className="!w-32" />
            </div>
            <div className="max-h-80 overflow-y-auto border rounded-md">
              <table className="w-full text-sm">
                <thead className="sticky top-0 bg-white">
                  <tr className="border-b text-xs text-gray-500">
                    <th className="py-2 px-3 text-left w-8">
                      <input type="checkbox" checked={enrollEmployeeIds.length === (rosterData?.length || 0) && enrollEmployeeIds.length > 0}
                        onChange={(e) => {
                          if (e.target.checked) {
                            setEnrollEmployeeIds(rosterData?.map((emp: any) => emp.id) || [])
                          } else {
                            setEnrollEmployeeIds([])
                          }
                        }} />
                    </th>
                    <th className="py-2 px-3 text-left">姓名</th>
                    <th className="py-2 px-3 text-left">部门</th>
                    <th className="py-2 px-3 text-left">状态</th>
                  </tr>
                </thead>
                <tbody>
                  {rosterData?.map((emp: any) => (
                    <tr key={emp.id} className="border-b last:border-0 hover:bg-gray-50">
                      <td className="py-2 px-3">
                        <input type="checkbox" checked={enrollEmployeeIds.includes(emp.id)}
                          onChange={(e) => {
                            if (e.target.checked) setEnrollEmployeeIds([...enrollEmployeeIds, emp.id])
                            else setEnrollEmployeeIds(enrollEmployeeIds.filter((id) => id !== emp.id))
                          }} />
                      </td>
                      <td className="py-2 px-3 font-medium">{emp.name}</td>
                      <td className="py-2 px-3 text-gray-500">{emp.department}</td>
                      <td className="py-2 px-3">
                        <span className="px-2 py-0.5 rounded text-xs bg-green-50 text-safe">在职</span>
                      </td>
                    </tr>
                  ))}
                </tbody>
              </table>
            </div>
            <div className="flex items-center justify-between">
              <span className="text-xs text-gray-400">已选 {enrollEmployeeIds.length} 人</span>
              <div className="flex gap-2">
                <Button variant="secondary" size="sm" onClick={() => setShowEnrollModal(false)}>取消</Button>
                <Button size="sm" onClick={() => enrollMutation.mutate({ employeeIds: enrollEmployeeIds, effectiveFrom: enrollEffectiveFrom })}
                  disabled={enrollEmployeeIds.length === 0 || enrollMutation.isPending}>
                  {enrollMutation.isPending ? '参保中...' : '确认参保'}
                </Button>
              </div>
            </div>
          </div>
        </Modal>
      )}
    </div>
  )
}
