"use client";

import { useState, useEffect, useMemo } from "react";
import {
  Table,
  TableBody,
  TableCell,
  TableHead,
  TableHeader,
  TableRow,
} from "@/components/ui/table";
import { Button } from "@/components/ui/button";
import { useSession } from "next-auth/react";
import { AddUserButton } from "./add-user-button";
import { SimplePagination } from "@/components/ui/pagination";
import { Input } from "@/components/ui/input";
import { MoreHorizontal, Trash, Edit, UserPlus } from "lucide-react";
import {
  DropdownMenu,
  DropdownMenuContent,
  DropdownMenuItem,
  DropdownMenuLabel,
  DropdownMenuSeparator,
  DropdownMenuTrigger,
} from "@/components/ui/dropdown-menu";

interface User {
  id: string;
  username: string;
  firstName: string;
  lastName: string;
  email: string;
  createdTimestamp: number;
  roles: string[];
}

interface UsersTableProps {
  userRole?: string[];
}

// Constants for role names
const ROLES = {
  ADMIN: "Admin",
  TEACHER: "Teacher",
  STUDENT: "Students"
} as const;

const ITEMS_PER_PAGE = 10;

export function UsersTable({ userRole = [] }: UsersTableProps) {
  const { data: session, status } = useSession();
  const [users, setUsers] = useState<User[]>([]);
  const [loading, setLoading] = useState(true);
  const [currentPage, setCurrentPage] = useState(1);
  const [searchTerm, setSearchTerm] = useState("");

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

  const fetchUsers = async () => {
    try {
      setLoading(true);
      const response = await fetch("/api/users");
      const data = await response.json();
      console.log("Fetched users:", data);
      console.log("Current user role:", session?.user?.role); // Debug log
      setUsers(data);
    } catch (error) {
      console.error("Error fetching users:", error);
    } finally {
      setLoading(false);
    }
  };

  const filterUsers = (users: User[]) => {
    console.log("Filtering users with role:", userRole); // Debug log
    
    if (!Array.isArray(users)) return [];
    
    // If no role specified or user is admin, show all users
    if (!userRole?.length || userRole.includes(ROLES.ADMIN)) {
      console.log("Showing all users - admin or no role");
      return users;
    }
    
    // If user is teacher, show teachers and students
    if (userRole.includes(ROLES.TEACHER)) {
      console.log("Filtering for teacher view");
      return users.filter(user =>
        user.roles?.includes(ROLES.TEACHER) || user.roles?.includes(ROLES.STUDENT)
      );
    }
    
    // If user is student, show only students
    if (userRole.includes(ROLES.STUDENT)) {
      console.log("Filtering for student view");
      return users.filter(user => user.roles?.includes(ROLES.STUDENT));
    }
    
    // Default: show all users
    console.log("Default case: showing all users");
    return users;
  };

  const canDelete = (targetUserRole: string[]) => {
    if (!userRole?.length) return false;
    
    if (userRole.includes(ROLES.ADMIN)) return true;
    if (userRole.includes(ROLES.TEACHER)) {
      return targetUserRole.includes(ROLES.STUDENT);
    }
    return false;
  };

  const handleDelete = async (userId: string) => {
    try {
      const response = await fetch(`/api/users/${userId}`, {
        method: "DELETE",
      });

      const data = await response.json();

      if (!response.ok) {
        console.error("Delete error:", data);
        // You might want to show an error message to the user here
        return;
      }

      // Remove the user from the local state
      setUsers(prevUsers => prevUsers.filter(user => user.id !== userId));
      
      // Optional: Show success message
      console.log("User deleted successfully");
    } catch (error) {
      console.error("Error deleting user:", error);
      // You might want to show an error message to the user here
    }
  };

  const filteredUsers = useMemo(() => {
    let filtered = filterUsers(users);
    
    // Apply search filter
    if (searchTerm) {
      filtered = filtered.filter(user => 
        user.username.toLowerCase().includes(searchTerm.toLowerCase()) ||
        user.email.toLowerCase().includes(searchTerm.toLowerCase()) ||
        user.firstName.toLowerCase().includes(searchTerm.toLowerCase()) ||
        user.lastName.toLowerCase().includes(searchTerm.toLowerCase())
      );
    }
    
    return filtered;
  }, [users, searchTerm, userRole]);

  // Calculate pagination
  const totalPages = Math.ceil(filteredUsers.length / ITEMS_PER_PAGE);
  const paginatedUsers = filteredUsers.slice(
    (currentPage - 1) * ITEMS_PER_PAGE,
    currentPage * ITEMS_PER_PAGE
  );

  const handlePageChange = (page: number) => {
    setCurrentPage(page);
  };

  const handleAddUser = (newUser: User) => {
    setUsers(prev => {
      const updated = [...prev, newUser];
      // Sort users by username
      return updated.sort((a, b) => a.username.localeCompare(b.username));
    });
    // Reset to first page when adding new user
    setCurrentPage(1);
  };

  // First, let's debug the roles
  console.log("Current session:", {
    role: session?.user?.role,
    isAdmin: session?.user?.role?.includes("Admin"),
    isTeacher: session?.user?.role?.includes("Teacher")
  });

  // Add this function for editing user
  const handleEdit = async (userId: string) => {
    // TODO: Implement edit functionality
    console.log("Edit user:", userId);
  };

  // Add this function for managing roles
  const handleManageRoles = async (userId: string) => {
    // TODO: Implement role management
    console.log("Manage roles for user:", userId);
  };

  if (!session) return null;
  if (loading) return <div className="text-center p-4">Loading...</div>;

  return (
    <div>
      {/* Search and Add User row */}
      <div className="flex justify-between items-center mb-6">
        <input
          type="text"
          placeholder="Rechercher un utilisateur..."
          className="bg-black/20 border-0 rounded-md text-white/80 w-96"
        />
        <Button variant="secondary">
          Ajouter un utilisateur
        </Button>
      </div>

      {/* Table content */}
      <div className="space-y-4">
        <Table>
          <TableHeader>
            <TableRow>
              <TableHead>Nom d'utilisateur</TableHead>
              <TableHead>Prénom</TableHead>
              <TableHead>Nom</TableHead>
              <TableHead>Email</TableHead>
              <TableHead>Date d'inscription</TableHead>
              <TableHead>Roles</TableHead>
              <TableHead className="text-right">Actions</TableHead>
            </TableRow>
          </TableHeader>
          <TableBody>
            {paginatedUsers.map((user) => (
              <TableRow key={user.id}>
                <TableCell>{user.username}</TableCell>
                <TableCell>{user.firstName}</TableCell>
                <TableCell>{user.lastName}</TableCell>
                <TableCell>{user.email}</TableCell>
                <TableCell>
                  {new Date(user.createdTimestamp).toLocaleDateString()}
                </TableCell>
                <TableCell>{user.roles.join(", ")}</TableCell>
                <TableCell className="text-right">
                  <DropdownMenu>
                    <DropdownMenuTrigger asChild>
                      <Button variant="ghost" className="h-8 w-8 p-0">
                        <span className="sr-only">Open menu</span>
                        <MoreHorizontal className="h-4 w-4" />
                      </Button>
                    </DropdownMenuTrigger>
                    <DropdownMenuContent align="end">
                      <DropdownMenuLabel>Actions</DropdownMenuLabel>
                      <DropdownMenuItem onClick={() => handleEdit(user.id)}>
                        <Edit className="mr-2 h-4 w-4" />
                        Modifier
                      </DropdownMenuItem>
                      <DropdownMenuItem onClick={() => handleManageRoles(user.id)}>
                        <UserPlus className="mr-2 h-4 w-4" />
                        Gérer les rôles
                      </DropdownMenuItem>
                      <DropdownMenuSeparator />
                      <DropdownMenuItem
                        className="text-red-600"
                        onClick={() => handleDelete(user.id)}
                      >
                        <Trash className="mr-2 h-4 w-4" />
                        Supprimer
                      </DropdownMenuItem>
                    </DropdownMenuContent>
                  </DropdownMenu>
                </TableCell>
              </TableRow>
            ))}
          </TableBody>
        </Table>

        <SimplePagination
          currentPage={currentPage}
          totalPages={totalPages}
          onPageChange={handlePageChange}
        />

        <div className="text-sm text-gray-500 text-center mt-2">
          Affichage de {Math.min(currentPage * ITEMS_PER_PAGE, filteredUsers.length)} sur {filteredUsers.length} utilisateurs
        </div>
      </div>
    </div>
  );
}