"use client"

import { useState, useEffect } from "react"
import { Button } from "@/components/ui/button"
import { Input } from "@/components/ui/input"
import { Label } from "@/components/ui/label"
import { Table, TableBody, TableCell, TableHead, TableHeader, TableRow } from "@/components/ui/table"
import { Card, CardContent, CardHeader, CardTitle } from "@/components/ui/card"
import { Alert, AlertDescription } from "@/components/ui/alert"
import { Badge } from "@/components/ui/badge"
import { Checkbox } from "@/components/ui/checkbox"
import {
  Dialog,
  DialogContent,
  DialogDescription,
  DialogHeader,
  DialogTitle,
  DialogTrigger,
} from "@/components/ui/dialog"
import { Edit2, Plus, Save, X, Loader2, RefreshCw, Users, Shield, Trash2 } from "lucide-react"
import { isAdmin, getCurrentUserEmail } from "@/lib/auth"

const API_BASE_URL = process.env.NEXT_PUBLIC_API_URL || "http://localhost:5000/api/v1"

interface User {
  _id: {
    $oid: string
  }
  email: string
  roles: string[]
}

interface UsersResponse {
  success: boolean
  data: User[]
}

interface UserResponse {
  success: boolean
  user: User
}

interface CreateUserRequest {
  email: string
  password: string
  roles: string[]
}

interface UpdateUserRequest {
  email: string
  password?: string
  roles: string[]
}

interface DeleteUserResponse {
  success: boolean
  message: string
}

interface UpdateUserResponse {
  success: boolean
  message: string
}

// Roles disponíveis no sistema
const AVAILABLE_ROLES = [
  { id: "admin", label: "Administrador", description: "Acesso total ao sistema" },
  { id: "user", label: "Usuário", description: "Acesso parcial, não pode gerenciar usuários" }, 
]

export default function UserManagement() {
  const [users, setUsers] = useState<User[]>([])
  const [isLoading, setIsLoading] = useState(false)
  const [error, setError] = useState("")
  const [success, setSuccess] = useState("")

  // Estados para criação de usuário
  const [isCreateDialogOpen, setIsCreateDialogOpen] = useState(false)
  const [isCreating, setIsCreating] = useState(false)
  const [createForm, setCreateForm] = useState<CreateUserRequest>({
    email: "",
    password: "",
    roles: [],
  })

  // Estados para edição de usuário
  const [editingUser, setEditingUser] = useState<string | null>(null)
  const [editForm, setEditForm] = useState<UpdateUserRequest>({
    email: "",
    password: "",
    roles: [],
  })
  const [isUpdating, setIsUpdating] = useState(false)

  // Estados para exclusão
  const [isDeleting, setIsDeleting] = useState<string | null>(null)

  const getAuthHeaders = () => {
    const token = localStorage.getItem("access_token")
    return {
      Authorization: `Bearer ${token}`,
      "Content-Type": "application/json",
    }
  }

  const fetchUsers = async () => {
    setIsLoading(true)
    setError("")

    try {
      const response = await fetch(`${API_BASE_URL}/users`, {
        method: "GET",
        headers: getAuthHeaders(),
      })

      if (response.ok) {
        const result: UsersResponse = await response.json()
        setUsers(result.data || [])
      } else {
        const errorData = await response.json()
        setError(errorData.message || "Erro ao buscar usuários")
      }
    } catch (err) {
      setError("Erro de conexão com o servidor")
    } finally {
      setIsLoading(false)
    }
  }

  const createUser = async () => {
    if (!createForm.email || !createForm.password || createForm.roles.length === 0) {
      setError("Preencha todos os campos obrigatórios")
      return
    }

    setIsCreating(true)
    setError("")
    setSuccess("")

    try {
      const response = await fetch(`${API_BASE_URL}/auth/signup`, {
        method: "POST",
        headers: getAuthHeaders(),
        body: JSON.stringify(createForm),
      })

      if (response.ok) {
        const result = await response.json()
        setSuccess("Usuário criado com sucesso!")
        setCreateForm({ email: "", password: "", roles: [] })
        setIsCreateDialogOpen(false)
        await fetchUsers()
      } else {
        const errorData = await response.json()
        setError(errorData.message || "Erro ao criar usuário")
      }
    } catch (err) {
      setError("Erro de conexão com o servidor")
    } finally {
      setIsCreating(false)
    }
  }

  const updateUser = async (userId: string) => {
    if (!editForm.email || editForm.roles.length === 0) {
      setError("Preencha todos os campos obrigatórios")
      return
    }

    setIsUpdating(true)
    setError("")
    setSuccess("")

    try {
      const updateData: UpdateUserRequest = {
        email: editForm.email,
        roles: editForm.roles,
      }

      // Só incluir password se foi preenchido
      if (editForm.password && editForm.password.trim() !== "") {
        updateData.password = editForm.password
      }

      const response = await fetch(`${API_BASE_URL}/users/${userId}`, {
        method: "PATCH",
        headers: getAuthHeaders(),
        body: JSON.stringify(updateData),
      })

      if (response.ok) {
        const result: UpdateUserResponse = await response.json()
        setSuccess("Usuário atualizado com sucesso!")
        setEditingUser(null)
        setEditForm({ email: "", password: "", roles: [] })
        await fetchUsers()
      } else {
        const errorData = await response.json()
        setError(errorData.message || "Erro ao atualizar usuário")
      }
    } catch (err) {
      setError("Erro de conexão com o servidor")
    } finally {
      setIsUpdating(false)
    }
  }

  const deleteUser = async (userId: string) => {
    if (!confirm("Tem certeza que deseja excluir este usuário? Esta ação não pode ser desfeita.")) {
      return
    }

    setIsDeleting(userId)
    setError("")
    setSuccess("")

    try {
      const response = await fetch(`${API_BASE_URL}/users/${userId}`, {
        method: "DELETE",
        headers: getAuthHeaders(),
      })

      if (response.ok) {
        const result: DeleteUserResponse = await response.json()
        setSuccess("Usuário excluído com sucesso!")
        await fetchUsers()
      } else {
        const errorData = await response.json()
        setError(errorData.message || "Erro ao excluir usuário")
      }
    } catch (err) {
      setError("Erro de conexão com o servidor")
    } finally {
      setIsDeleting(null)
    }
  }

  const startEditUser = (user: User) => {
    setEditingUser(user._id.$oid)
    setEditForm({
      email: user.email,
      password: "", // Deixar vazio para não alterar a senha
      roles: [...user.roles],
    })
  }

  const cancelEditUser = () => {
    setEditingUser(null)
    setEditForm({ email: "", password: "", roles: [] })
  }

  const handleEditRoleChange = (roleId: string, checked: boolean | "indeterminate") => {
    if (checked === true) {
      setEditForm((prev) => ({ ...prev, roles: [...prev.roles, roleId] }))
    } else {
      setEditForm((prev) => ({ ...prev, roles: prev.roles.filter((role) => role !== roleId) }))
    }
  }

  const handleCreateRoleChange = (roleId: string, checked: boolean | "indeterminate") => {
    if (checked === true) {
      setCreateForm((prev) => ({ ...prev, roles: [...prev.roles, roleId] }))
    } else {
      setCreateForm((prev) => ({ ...prev, roles: prev.roles.filter((role) => role !== roleId) }))
    }
  }

  const getRoleBadgeVariant = (role: string) => {
    switch (role) {
      case "admin":
        return "destructive" as const
      case "financeiro":
        return "default" as const
      case "user":
        return "secondary" as const
      default:
        return "outline" as const
    }
  }

  const getRoleLabel = (roleId: string) => {
    const role = AVAILABLE_ROLES.find((r) => r.id === roleId)
    return role ? role.label : roleId
  }

  const canDeleteUser = (user: User) => {
    const currentUserEmail = getCurrentUserEmail()
    // Não permitir que o usuário delete a si mesmo
    return user.email !== currentUserEmail
  }

  useEffect(() => {
    fetchUsers()
  }, [])

  // Verificar se o usuário tem permissão para gerenciar usuários
  if (!isAdmin()) {
    return (
      <div className="flex flex-col items-center justify-center py-12 text-center">
        <div className="rounded-full bg-red-100 p-6 mb-4">
          <Shield className="h-8 w-8 text-red-600" />
        </div>
        <h3 className="text-lg font-medium mb-2">Acesso Negado</h3>
        <p className="text-gray-500 max-w-md">
          Você não tem permissão para acessar o gerenciamento de usuários. Entre em contato com um administrador.
        </p>
      </div>
    )
  }

  return (
    <div className="space-y-6">
      {/* Cabeçalho com botão de criar */}
      <div className="flex justify-end items-center">
        <div className="flex gap-2">
          <Button onClick={fetchUsers} disabled={isLoading} variant="outline">
            {isLoading ? <Loader2 className="mr-2 h-4 w-4 animate-spin" /> : <RefreshCw className="mr-2 h-4 w-4" />}
            Atualizar
          </Button>
          <Dialog open={isCreateDialogOpen} onOpenChange={setIsCreateDialogOpen}>
            <DialogTrigger asChild>
              <Button>
                <Plus className="mr-2 h-4 w-4" />
                Novo Usuário
              </Button>
            </DialogTrigger>
            <DialogContent>
              <DialogHeader>
                <DialogTitle>Criar Novo Usuário</DialogTitle>
                <DialogDescription>Preencha as informações do novo usuário e suas permissões</DialogDescription>
              </DialogHeader>
              <div className="space-y-4">
                <div className="space-y-2">
                  <Label htmlFor="email">Email *</Label>
                  <Input
                    id="email"
                    type="email"
                    value={createForm.email}
                    onChange={(e) => setCreateForm((prev) => ({ ...prev, email: e.target.value }))}
                    placeholder="usuario@exemplo.com"
                  />
                </div>
                <div className="space-y-2">
                  <Label htmlFor="password">Senha *</Label>
                  <Input
                    id="password"
                    type="password"
                    value={createForm.password}
                    onChange={(e) => setCreateForm((prev) => ({ ...prev, password: e.target.value }))}
                    placeholder="Senha do usuário"
                    minLength={8}
                  />
                </div>
                <div className="space-y-2">
                  <Label>Permissões *</Label>
                  <div className="space-y-2">
                    {AVAILABLE_ROLES.map((role) => (
                      <div key={role.id} className="flex items-center space-x-2">
                        <Checkbox
                          id={`create-${role.id}`}
                          checked={createForm.roles.includes(role.id)}
                          onCheckedChange={(checked) => handleCreateRoleChange(role.id, checked as boolean)}
                        />
                        <div className="flex-1">
                          <Label htmlFor={`create-${role.id}`} className="text-sm font-medium">
                            {role.label}
                          </Label>
                          <p className="text-xs text-gray-500">{role.description}</p>
                        </div>
                      </div>
                    ))}
                  </div>
                </div>
                <div className="flex gap-2 pt-4">
                  <Button onClick={createUser} disabled={isCreating} className="flex-1">
                    {isCreating ? <Loader2 className="mr-2 h-4 w-4 animate-spin" /> : <Save className="mr-2 h-4 w-4" />}
                    Criar Usuário
                  </Button>
                  <Button variant="outline" onClick={() => setIsCreateDialogOpen(false)} disabled={isCreating}>
                    Cancelar
                  </Button>
                </div>
              </div>
            </DialogContent>
          </Dialog>
        </div>
      </div>

      {error && (
        <Alert variant="destructive">
          <AlertDescription>{error}</AlertDescription>
        </Alert>
      )}

      {success && (
        <Alert>
          <AlertDescription>{success}</AlertDescription>
        </Alert>
      )}

      {/* Tabela de Usuários */}
      <Card>
        <CardHeader>
          <CardTitle className="flex items-center gap-2">
            <Users className="h-5 w-5" />
            Lista de Usuários ({users.length} usuários)
          </CardTitle>
        </CardHeader>
        <CardContent>
          {users.length > 0 ? (
            <div className="overflow-x-auto">
              <Table>
                <TableHeader>
                  <TableRow>
                    <TableHead>Email</TableHead>
                    <TableHead>Permissões</TableHead>
                    <TableHead>Ações</TableHead>
                  </TableRow>
                </TableHeader>
                <TableBody>
                  {users.map((user) => (
                    <TableRow key={user._id.$oid}>
                      <TableCell>
                        {editingUser === user._id.$oid ? (
                          <Input
                            type="email"
                            value={editForm.email}
                            onChange={(e) => setEditForm((prev) => ({ ...prev, email: e.target.value }))}
                            placeholder="Email do usuário"
                          />
                        ) : (
                          <div className="font-medium">{user.email}</div>
                        )}
                        {editingUser === user._id.$oid && (
                          <div className="mt-2">
                            <Input
                              type="password"
                              value={editForm.password}
                              onChange={(e) => setEditForm((prev) => ({ ...prev, password: e.target.value }))}
                              placeholder="Nova senha (deixe vazio para não alterar)"
                            />
                          </div>
                        )}
                      </TableCell>
                      <TableCell>
                        {editingUser === user._id.$oid ? (
                          <div className="space-y-2">
                            {AVAILABLE_ROLES.map((role) => (
                              <div key={role.id} className="flex items-center space-x-2">
                                <Checkbox
                                  id={`edit-${role.id}-${user._id.$oid}`}
                                  checked={editForm.roles.includes(role.id)}
                                  onCheckedChange={(checked) => handleEditRoleChange(role.id, checked as boolean)}
                                />
                                <Label htmlFor={`edit-${role.id}-${user._id.$oid}`} className="text-sm">
                                  {role.label}
                                </Label>
                              </div>
                            ))}
                          </div>
                        ) : (
                          <div className="flex flex-wrap gap-1">
                            {user.roles.map((role) => (
                              <Badge key={role} variant={getRoleBadgeVariant(role)}>
                                {getRoleLabel(role)}
                              </Badge>
                            ))}
                          </div>
                        )}
                      </TableCell>
                      <TableCell>
                        <div className="flex gap-2">
                          {editingUser === user._id.$oid ? (
                            <>
                              <Button size="sm" onClick={() => updateUser(user._id.$oid)} disabled={isUpdating}>
                                {isUpdating ? (
                                  <Loader2 className="h-4 w-4 animate-spin" />
                                ) : (
                                  <Save className="h-4 w-4" />
                                )}
                              </Button>
                              <Button size="sm" variant="outline" onClick={cancelEditUser} disabled={isUpdating}>
                                <X className="h-4 w-4" />
                              </Button>
                            </>
                          ) : (
                            <>
                              <Button size="sm" variant="outline" onClick={() => startEditUser(user)}>
                                <Edit2 className="h-4 w-4" />
                              </Button>
                              {canDeleteUser(user) && (
                                <Button
                                  size="sm"
                                  variant="outline"
                                  onClick={() => deleteUser(user._id.$oid)}
                                  disabled={isDeleting === user._id.$oid}
                                >
                                  {isDeleting === user._id.$oid ? (
                                    <Loader2 className="h-4 w-4 animate-spin" />
                                  ) : (
                                    <Trash2 className="h-4 w-4" />
                                  )}
                                </Button>
                              )}
                            </>
                          )}
                        </div>
                      </TableCell>
                    </TableRow>
                  ))}
                </TableBody>
              </Table>
            </div>
          ) : (
            <div className="text-center py-8 text-gray-500">
              {isLoading ? "Carregando..." : "Nenhum usuário encontrado."}
            </div>
          )}
        </CardContent>
      </Card>
    </div>
  )
}