/**
 * 認證 Hook
 * 提供認證狀態和權限檢查功能
 */
import { useSession } from 'next-auth/react'
import { hasRole, hasAnyRole, hasAllRoles, inGroup } from '@/lib/auth'

export function useAuth() {
  const { data: session, status } = useSession()

  return {
    // 認證狀態
    session,
    status,
    isLoading: status === 'loading',
    isAuthenticated: status === 'authenticated',
    isUnauthenticated: status === 'unauthenticated',

    // 用戶資訊
    user: session?.user,
    accessToken: session?.accessToken,
    error: session?.error,

    // 權限檢查
    hasRole: (role: string) => hasRole(session, role),
    hasAnyRole: (roles: string[]) => hasAnyRole(session, roles),
    hasAllRoles: (roles: string[]) => hasAllRoles(session, roles),
    inGroup: (group: string) => inGroup(session, group),

    // 角色檢查快捷方式
    isAdmin: hasRole(session, 'admin'),
    isHR: hasRole(session, 'hr'),
    isManager: hasRole(session, 'manager'),
    isEmployee: hasRole(session, 'employee'),
  }
}

/**
 * 權限保護 Hook
 * 檢查使用者是否有必要的權限,沒有則導向錯誤頁
 */
export function useRequireAuth(requiredRoles?: string[]) {
  const auth = useAuth()

  if (auth.isLoading) {
    return { ...auth, isAuthorized: false }
  }

  if (!auth.isAuthenticated) {
    // 未登入,導向登入頁
    if (typeof window !== 'undefined') {
      window.location.href = '/auth/signin'
    }
    return { ...auth, isAuthorized: false }
  }

  if (requiredRoles && requiredRoles.length > 0) {
    // 檢查是否有任一必要角色
    const isAuthorized = auth.hasAnyRole(requiredRoles)
    if (!isAuthorized) {
      // 無權限,導向錯誤頁
      if (typeof window !== 'undefined') {
        window.location.href = '/auth/error?error=Unauthorized'
      }
      return { ...auth, isAuthorized: false }
    }
  }

  return { ...auth, isAuthorized: true }
}

/**
 * 系統權限 Hook
 * 檢查使用者對特定系統的存取權限
 */
export function useSystemPermission(systemName?: string) {
  const auth = useAuth()

  if (!systemName || !auth.user) {
    return {
      hasAccess: false,
      accessLevel: null,
      isAdmin: false,
      isUser: false,
      isReadonly: false,
    }
  }

  // 從用戶的 groups 中解析系統權限
  // 格式: /systems/{system_name}/{access_level}
  const systemGroups = auth.user.groups?.filter((group: string) =>
    group.startsWith(`/systems/${systemName}/`)
  )

  if (!systemGroups || systemGroups.length === 0) {
    return {
      hasAccess: false,
      accessLevel: null,
      isAdmin: false,
      isUser: false,
      isReadonly: false,
    }
  }

  // 取得最高權限
  const accessLevels = systemGroups.map((group: string) => {
    const parts = group.split('/')
    return parts[parts.length - 1]
  })

  const hasAdmin = accessLevels.includes('admin')
  const hasUser = accessLevels.includes('user')
  const hasReadonly = accessLevels.includes('readonly')

  const accessLevel = hasAdmin ? 'admin' : hasUser ? 'user' : 'readonly'

  return {
    hasAccess: true,
    accessLevel,
    isAdmin: hasAdmin,
    isUser: hasUser || hasAdmin,
    isReadonly: hasReadonly || hasUser || hasAdmin,
  }
}