'use client'

import { useEffect, useState } from 'react'
import { useSession } from 'next-auth/react'
import { useRouter, useParams } from 'next/navigation'
import EmailAccountsTab from '@/components/employees/email-accounts-tab'
import PermissionsTab from '@/components/employees/permissions-tab'

interface DepartmentMembership {
  id: number
  department_id: number
  department_name: string
  department_code: string
  department_depth: number
  effective_email_domain?: string
  position?: string
  membership_type: string
  is_active: boolean
  joined_at: string
  ended_at?: string
}

interface Employee {
  id: number
  employee_id: string
  username_base: string
  legal_name: string
  english_name: string | null
  phone: string | null
  mobile: string | null
  hire_date: string
  termination_date: string | null
  status: string
  has_network_drive: boolean
  created_at: string
  updated_at: string
}

type TabType = 'basic' | 'departments' | 'email' | 'permissions'

interface OffboardResult {
  disabled?: boolean
  handled?: boolean
  created?: boolean
  error?: string | null
  message?: string
  method?: string
}

export default function EmployeeDetailPage() {
  const { data: session, status } = useSession()
  const router = useRouter()
  const params = useParams()
  const employeeId = params.id as string

  const [employee, setEmployee] = useState<Employee | null>(null)
  const [memberships, setMemberships] = useState<DepartmentMembership[]>([])
  const [loading, setLoading] = useState(true)
  const [error, setError] = useState<string | null>(null)
  const [activeTab, setActiveTab] = useState<TabType>('basic')

  // 離職處理 Dialog 狀態
  const [showOffboardDialog, setShowOffboardDialog] = useState(false)
  const [offboardConfirmText, setOffboardConfirmText] = useState('')
  const [offboardLoading, setOffboardLoading] = useState(false)
  const [offboardEmailHandling, setOffboardEmailHandling] = useState<'forward' | 'disable'>('forward')
  const [offboardResults, setOffboardResults] = useState<{
    keycloak: OffboardResult
    email: OffboardResult
    drive: OffboardResult
  } | null>(null)

  useEffect(() => {
    if (status === 'unauthenticated') {
      router.push('/auth/signin')
    }
  }, [status, router])

  useEffect(() => {
    if (status === 'authenticated' && employeeId) {
      fetchEmployee()
      fetchMemberships()
    }
  }, [status, employeeId])

  const fetchEmployee = async () => {
    try {
      setLoading(true)
      setError(null)

      const response = await fetch(
        `${process.env.NEXT_PUBLIC_API_BASE_URL}/employees/${employeeId}`
      )

      if (!response.ok) {
        throw new Error('無法載入員工資料')
      }

      const data = await response.json()
      setEmployee(data)
    } catch (err) {
      setError(err instanceof Error ? err.message : '載入失敗')
    } finally {
      setLoading(false)
    }
  }

  const fetchMemberships = async () => {
    try {
      const response = await fetch(
        `${process.env.NEXT_PUBLIC_API_BASE_URL}/department-members/?employee_id=${employeeId}`
      )
      if (response.ok) {
        const data = await response.json()
        setMemberships(Array.isArray(data) ? data : data.items || [])
      }
    } catch (err) {
      console.error('載入部門成員資料失敗:', err)
    }
  }

  // 執行離職流程
  const handleOffboard = async () => {
    if (!employee) return
    if (offboardConfirmText !== employee.employee_id) return

    setOffboardLoading(true)
    try {
      const searchParams = new URLSearchParams({
        disable_keycloak: 'true',
        email_handling: offboardEmailHandling,
        disable_drive: 'true',
      })

      const response = await fetch(
        `${process.env.NEXT_PUBLIC_API_BASE_URL}/employees/${employeeId}/offboard?${searchParams.toString()}`,
        { method: 'POST' }
      )

      if (!response.ok) {
        const data = await response.json()
        throw new Error(data.detail || '離職流程執行失敗')
      }

      const data = await response.json()
      setOffboardResults(data.results)
      setEmployee((prev) => prev ? { ...prev, status: 'terminated' } : null)
    } catch (err) {
      alert(err instanceof Error ? err.message : '操作失敗')
    } finally {
      setOffboardLoading(false)
    }
  }

  if (status === 'loading' || loading) {
    return (
      <div className="flex items-center justify-center min-h-screen">
        <div className="text-lg">載入中...</div>
      </div>
    )
  }

  if (!session) return null

  if (error) {
    return (
      <div className="container mx-auto px-4 py-8">
        <div className="p-4 bg-red-50 border border-red-200 rounded-lg text-red-700">
          {error}
        </div>
        <button
          onClick={() => router.back()}
          className="mt-4 text-blue-600 hover:text-blue-800"
        >
          ← 返回
        </button>
      </div>
    )
  }

  if (!employee) return null

  const tabs: { id: TabType; label: string; icon: string }[] = [
    { id: 'basic', label: '基本資料', icon: '👤' },
    { id: 'departments', label: '部門成員', icon: '🏢' },
    { id: 'email', label: '郵件帳號', icon: '📧' },
    { id: 'permissions', label: '系統權限', icon: '🔐' },
  ]

  // 找到主要郵件網域 (取第一個啟用中的成員紀錄的有效網域)
  const primaryMembership = memberships.find((m) => m.is_active)
  const primaryEmailDomain = primaryMembership?.effective_email_domain

  const membershipTypeLabel = (type: string) => {
    switch (type) {
      case 'permanent': return '正式'
      case 'temporary': return '臨時'
      case 'project': return '專案'
      default: return type
    }
  }

  return (
    <div className="container mx-auto px-4 py-8 max-w-6xl">
      {/* 頁首 */}
      <div className="mb-8 flex items-center justify-between">
        <div>
          <button
            onClick={() => router.back()}
            className="text-blue-600 hover:text-blue-800 mb-2"
          >
            ← 返回列表
          </button>
          <h1 className="text-3xl font-bold text-gray-900">
            {employee.legal_name}
          </h1>
          <p className="mt-1 text-gray-600">員工編號: {employee.employee_id}</p>
        </div>
        <div className="flex gap-2">
          <button
            onClick={() => router.push(`/employees/${employee.id}/edit`)}
            className="px-4 py-2 bg-blue-600 text-white rounded-lg hover:bg-blue-700 transition-colors"
          >
            編輯資料
          </button>
          {employee.status === 'active' && (
            <button
              onClick={() => {
                setOffboardConfirmText('')
                setOffboardResults(null)
                setShowOffboardDialog(true)
              }}
              className="px-4 py-2 bg-red-600 text-white rounded-lg hover:bg-red-700 transition-colors"
            >
              離職處理
            </button>
          )}
        </div>
      </div>

      {/* Tab 切換 */}
      <div className="mb-6">
        <div className="border-b border-gray-200">
          <nav className="-mb-px flex gap-8">
            {tabs.map((tab) => (
              <button
                key={tab.id}
                onClick={() => setActiveTab(tab.id)}
                className={`
                  py-4 px-1 border-b-2 font-medium text-sm flex items-center gap-2
                  ${
                    activeTab === tab.id
                      ? 'border-blue-500 text-blue-600'
                      : 'border-transparent text-gray-500 hover:text-gray-700 hover:border-gray-300'
                  }
                `}
              >
                <span>{tab.icon}</span>
                {tab.label}
                {tab.id === 'departments' && memberships.length > 0 && (
                  <span className="ml-1 bg-blue-100 text-blue-700 text-xs px-1.5 py-0.5 rounded-full">
                    {memberships.filter((m) => m.is_active).length}
                  </span>
                )}
              </button>
            ))}
          </nav>
        </div>
      </div>

      {/* 基本資料 Tab */}
      {activeTab === 'basic' && (
        <div>
          <div className="bg-white shadow rounded-lg p-6 mb-6">
            <h2 className="text-xl font-semibold text-gray-900 mb-4">基本資料</h2>
            <div className="grid grid-cols-1 md:grid-cols-2 gap-6">
              <div>
                <label className="block text-sm font-medium text-gray-500">員工編號</label>
                <p className="mt-1 text-lg text-gray-900">{employee.employee_id}</p>
              </div>
              <div>
                <label className="block text-sm font-medium text-gray-500">狀態</label>
                <span
                  className={`mt-1 inline-flex px-2 py-1 text-sm font-semibold rounded-full ${
                    employee.status === 'active'
                      ? 'bg-green-100 text-green-800'
                      : employee.status === 'inactive'
                      ? 'bg-yellow-100 text-yellow-800'
                      : 'bg-red-100 text-red-800'
                  }`}
                >
                  {employee.status === 'active' ? '在職' : employee.status === 'inactive' ? '停用' : '離職'}
                </span>
              </div>
              <div>
                <label className="block text-sm font-medium text-gray-500">中文姓名</label>
                <p className="mt-1 text-lg text-gray-900">{employee.legal_name}</p>
              </div>
              <div>
                <label className="block text-sm font-medium text-gray-500">英文姓名</label>
                <p className="mt-1 text-lg text-gray-900">{employee.english_name || '-'}</p>
              </div>
              <div>
                <label className="block text-sm font-medium text-gray-500">帳號基底</label>
                <p className="mt-1 text-lg text-gray-900 font-mono">{employee.username_base}</p>
              </div>
              <div>
                <label className="block text-sm font-medium text-gray-500">到職日</label>
                <p className="mt-1 text-lg text-gray-900">
                  {new Date(employee.hire_date).toLocaleDateString('zh-TW')}
                </p>
              </div>
              {employee.termination_date && (
                <div>
                  <label className="block text-sm font-medium text-gray-500">離職日</label>
                  <p className="mt-1 text-lg text-gray-900">
                    {new Date(employee.termination_date).toLocaleDateString('zh-TW')}
                  </p>
                </div>
              )}
            </div>
          </div>

          {/* 聯絡資訊 */}
          <div className="bg-white shadow rounded-lg p-6 mb-6">
            <h2 className="text-xl font-semibold text-gray-900 mb-4">聯絡資訊</h2>
            <div className="grid grid-cols-1 md:grid-cols-2 gap-6">
              <div>
                <label className="block text-sm font-medium text-gray-500">辦公室電話</label>
                <p className="mt-1 text-lg text-gray-900">{employee.phone || '-'}</p>
              </div>
              <div>
                <label className="block text-sm font-medium text-gray-500">手機</label>
                <p className="mt-1 text-lg text-gray-900">{employee.mobile || '-'}</p>
              </div>
            </div>
          </div>

          {/* 系統帳號資訊 */}
          <div className="bg-white shadow rounded-lg p-6 mb-6">
            <h2 className="text-xl font-semibold text-gray-900 mb-4">系統帳號資訊</h2>
            <div className="grid grid-cols-1 md:grid-cols-2 gap-6">
              <div className="flex items-center justify-between p-4 bg-gray-50 rounded-lg">
                <div>
                  <p className="text-sm font-medium text-gray-500">所屬部門數量</p>
                  <p className="mt-1 text-2xl font-semibold text-gray-900">
                    {memberships.filter((m) => m.is_active).length}
                  </p>
                  <p className="text-xs text-gray-500 mt-1">
                    {memberships.filter((m) => m.is_active).length > 1 ? '多部門任職' : '單一部門'}
                  </p>
                </div>
                <button
                  onClick={() => setActiveTab('departments')}
                  className="px-3 py-1.5 bg-blue-600 text-white text-sm rounded hover:bg-blue-700 transition-colors"
                >
                  管理部門 →
                </button>
              </div>
              <div className="flex items-center justify-between p-4 bg-gray-50 rounded-lg">
                <div>
                  <p className="text-sm font-medium text-gray-500">NAS 帳號</p>
                  <p className="mt-1 text-lg font-semibold text-gray-900">
                    {employee.has_network_drive ? '已建立' : '未建立'}
                  </p>
                </div>
                {employee.has_network_drive && (
                  <span className="text-green-600">✓</span>
                )}
              </div>
            </div>
          </div>

          {/* 系統資訊 */}
          <div className="bg-gray-50 rounded-lg p-4 text-sm text-gray-600">
            <div className="grid grid-cols-1 md:grid-cols-2 gap-2">
              <div>建立時間: {new Date(employee.created_at).toLocaleString('zh-TW')}</div>
              <div>更新時間: {new Date(employee.updated_at).toLocaleString('zh-TW')}</div>
            </div>
          </div>
        </div>
      )}

      {/* 部門成員 Tab */}
      {activeTab === 'departments' && (
        <div>
          <div className="bg-white shadow rounded-lg p-6 mb-6">
            <div className="flex items-center justify-between mb-4">
              <h2 className="text-xl font-semibold text-gray-900">部門成員紀錄</h2>
              <p className="text-sm text-gray-500">
                員工可同時隸屬多個部門
              </p>
            </div>

            {memberships.length === 0 ? (
              <div className="text-center py-8">
                <p className="text-gray-500">尚未加入任何部門</p>
                <p className="text-sm text-gray-400 mt-1">
                  請至「組織架構」頁面將員工加入部門
                </p>
              </div>
            ) : (
              <div className="space-y-3">
                {memberships.map((membership) => (
                  <div
                    key={membership.id}
                    className={`border rounded-lg p-4 ${
                      membership.is_active
                        ? 'border-blue-200 bg-blue-50'
                        : 'border-gray-200 bg-gray-50 opacity-60'
                    }`}
                  >
                    <div className="flex items-start justify-between">
                      <div className="flex-1">
                        <div className="flex items-center gap-2 mb-1">
                          <span className="font-medium text-gray-900">
                            {membership.department_name}
                          </span>
                          <span className="text-xs text-gray-500 bg-gray-200 px-2 py-0.5 rounded">
                            {membership.department_code}
                          </span>
                          {membership.department_depth === 0 && (
                            <span className="text-xs text-blue-600 bg-blue-100 px-2 py-0.5 rounded">
                              第一層
                            </span>
                          )}
                          <span
                            className={`text-xs px-2 py-0.5 rounded ${
                              membership.is_active
                                ? 'text-green-700 bg-green-100'
                                : 'text-gray-600 bg-gray-200'
                            }`}
                          >
                            {membership.is_active ? '啟用中' : '已結束'}
                          </span>
                        </div>

                        <div className="flex flex-wrap gap-4 text-sm text-gray-600 mt-2">
                          {membership.position && (
                            <div>
                              <span className="text-gray-400">職位: </span>
                              <span>{membership.position}</span>
                            </div>
                          )}
                          <div>
                            <span className="text-gray-400">類型: </span>
                            <span>{membershipTypeLabel(membership.membership_type)}</span>
                          </div>
                          {membership.effective_email_domain && (
                            <div>
                              <span className="text-gray-400">郵件網域: </span>
                              <span className="font-mono text-blue-600">
                                @{membership.effective_email_domain}
                              </span>
                            </div>
                          )}
                        </div>

                        <div className="flex flex-wrap gap-4 text-xs text-gray-500 mt-1">
                          <div>
                            加入: {new Date(membership.joined_at).toLocaleDateString('zh-TW')}
                          </div>
                          {membership.ended_at && (
                            <div>
                              結束: {new Date(membership.ended_at).toLocaleDateString('zh-TW')}
                            </div>
                          )}
                        </div>
                      </div>
                    </div>
                  </div>
                ))}
              </div>
            )}
          </div>

          <div className="bg-blue-50 border border-blue-200 rounded-lg p-4 text-sm text-blue-700">
            <p className="font-medium mb-1">部門成員管理說明</p>
            <ul className="space-y-1 text-blue-600">
              <li>• 員工可同時隸屬多個部門 (主要職務 + 兼任)</li>
              <li>• 郵件網域由所屬第一層部門決定</li>
              <li>• 員工編號不因部門轉換而改變</li>
              <li>• 若需調整部門成員，請至「組織架構」頁面操作</li>
            </ul>
          </div>
        </div>
      )}

      {/* 郵件帳號 Tab */}
      {activeTab === 'email' && (
        <EmailAccountsTab
          employeeId={employee.id}
          primaryIdentity={
            primaryEmailDomain
              ? {
                  email_domain: primaryEmailDomain,
                  business_unit_name: primaryMembership?.department_name || '',
                  email_quota_mb: 5120,
                }
              : undefined
          }
        />
      )}

      {/* 系統權限 Tab */}
      {activeTab === 'permissions' && <PermissionsTab employeeId={employee.id} />}

      {/* 離職處理 Dialog */}
      {showOffboardDialog && (
        <div className="fixed inset-0 z-50 flex items-center justify-center bg-black/50">
          <div className="bg-white rounded-xl shadow-2xl w-full max-w-lg mx-4 p-6">
            {offboardResults ? (
              <div>
                <h2 className="text-xl font-bold text-gray-900 mb-4">離職流程執行完成</h2>
                <div className="space-y-3 mb-6">
                  <div className={`flex items-start gap-2 p-3 rounded-lg ${offboardResults.keycloak?.disabled ? 'bg-green-50' : 'bg-amber-50'}`}>
                    <span className="text-lg">{offboardResults.keycloak?.disabled ? '✓' : '⚠'}</span>
                    <div>
                      <p className="text-sm font-medium">Keycloak SSO 帳號</p>
                      <p className="text-xs text-gray-600">{offboardResults.keycloak?.message}</p>
                      {offboardResults.keycloak?.error && (
                        <p className="text-xs text-red-600">{offboardResults.keycloak.error}</p>
                      )}
                    </div>
                  </div>
                  <div className={`flex items-start gap-2 p-3 rounded-lg ${offboardResults.email?.handled ? 'bg-green-50' : 'bg-amber-50'}`}>
                    <span className="text-lg">{offboardResults.email?.handled ? '✓' : '⚠'}</span>
                    <div>
                      <p className="text-sm font-medium">郵件帳號 ({offboardResults.email?.method === 'forward' ? '轉發' : '停用'})</p>
                      <p className="text-xs text-gray-600">{offboardResults.email?.message}</p>
                    </div>
                  </div>
                  <div className={`flex items-start gap-2 p-3 rounded-lg ${offboardResults.drive?.disabled ? 'bg-green-50' : 'bg-amber-50'}`}>
                    <span className="text-lg">{offboardResults.drive?.disabled ? '✓' : '⚠'}</span>
                    <div>
                      <p className="text-sm font-medium">雲端硬碟帳號</p>
                      <p className="text-xs text-gray-600">{offboardResults.drive?.message}</p>
                    </div>
                  </div>
                </div>
                <div className="flex justify-end gap-3">
                  <button
                    onClick={() => {
                      setShowOffboardDialog(false)
                      router.push('/employees')
                    }}
                    className="px-4 py-2 bg-gray-600 text-white rounded-lg hover:bg-gray-700 transition-colors"
                  >
                    返回列表
                  </button>
                  <button
                    onClick={() => setShowOffboardDialog(false)}
                    className="px-4 py-2 bg-blue-600 text-white rounded-lg hover:bg-blue-700 transition-colors"
                  >
                    留在此頁
                  </button>
                </div>
              </div>
            ) : (
              <div>
                <div className="flex items-center gap-3 mb-4">
                  <div className="w-10 h-10 bg-red-100 rounded-full flex items-center justify-center">
                    <span className="text-red-600 text-xl">⚠</span>
                  </div>
                  <h2 className="text-xl font-bold text-gray-900">員工離職處理</h2>
                </div>

                <div className="bg-red-50 border border-red-200 rounded-lg p-4 mb-4">
                  <p className="text-sm text-red-700 font-medium">此操作將自動執行以下操作：</p>
                  <ul className="mt-2 text-sm text-red-600 space-y-1">
                    <li>• 停用 Keycloak SSO 帳號 (帳號保留以維持審計記錄)</li>
                    <li>• 處理郵件帳號 (轉發或停用)</li>
                    <li>• 停用雲端硬碟帳號</li>
                    <li>• 將員工狀態設為「離職」</li>
                  </ul>
                </div>

                <div className="mb-4">
                  <label className="block text-sm font-medium text-gray-700 mb-2">
                    郵件帳號處理方式
                  </label>
                  <div className="flex gap-4">
                    <label className="flex items-center gap-2 cursor-pointer">
                      <input
                        type="radio"
                        name="email_handling"
                        value="forward"
                        checked={offboardEmailHandling === 'forward'}
                        onChange={() => setOffboardEmailHandling('forward')}
                        className="w-4 h-4 text-blue-600"
                      />
                      <span className="text-sm text-gray-700">轉發給 HR (建議)</span>
                    </label>
                    <label className="flex items-center gap-2 cursor-pointer">
                      <input
                        type="radio"
                        name="email_handling"
                        value="disable"
                        checked={offboardEmailHandling === 'disable'}
                        onChange={() => setOffboardEmailHandling('disable')}
                        className="w-4 h-4 text-blue-600"
                      />
                      <span className="text-sm text-gray-700">直接停用</span>
                    </label>
                  </div>
                </div>

                <div className="mb-6">
                  <label className="block text-sm font-medium text-gray-700 mb-2">
                    請輸入員工編號 <span className="font-mono text-red-600">{employee.employee_id}</span> 以確認
                  </label>
                  <input
                    type="text"
                    value={offboardConfirmText}
                    onChange={(e) => setOffboardConfirmText(e.target.value)}
                    className="w-full px-3 py-2 border border-gray-300 rounded-md focus:ring-red-500 focus:border-red-500 font-mono"
                    placeholder={employee.employee_id}
                  />
                </div>

                <div className="flex justify-end gap-3">
                  <button
                    onClick={() => setShowOffboardDialog(false)}
                    disabled={offboardLoading}
                    className="px-4 py-2 border border-gray-300 rounded-lg text-gray-700 hover:bg-gray-50 transition-colors disabled:opacity-50"
                  >
                    取消
                  </button>
                  <button
                    onClick={handleOffboard}
                    disabled={offboardLoading || offboardConfirmText !== employee.employee_id}
                    className="px-4 py-2 bg-red-600 text-white rounded-lg hover:bg-red-700 transition-colors disabled:opacity-50 disabled:cursor-not-allowed"
                  >
                    {offboardLoading ? '執行中...' : '確認離職'}
                  </button>
                </div>
              </div>
            )}
          </div>
        </div>
      )}
    </div>
  )
}