/**
 * User Management Page
 *
 * Manage organization users, roles, and invitations
 */

'use client';

import { useState, useEffect } from 'react';
import { useRouter } from 'next/navigation';
import { useQuery, useMutation, useQueryClient } from '@tanstack/react-query';
import { listUsers, updateUser, deleteUser } from '@/lib/api';
import { createInvitation } from '@/lib/api/invitations';
import { useAuth } from '@/lib/context/auth-context';

export default function UsersManagementPage() {
  const router = useRouter();
  const queryClient = useQueryClient();
  const { user: currentUser } = useAuth();
  const [showInviteModal, setShowInviteModal] = useState(false);
  const [inviteForm, setInviteForm] = useState({
    email: '',
    firstName: '',
    lastName: '',
    role: 'USER' as 'MANAGER' | 'USER' | 'VIEWER',
  });
  const [error, setError] = useState('');
  const [success, setSuccess] = useState('');

  const { data: users, isLoading } = useQuery({
    queryKey: ['users'],
    queryFn: () => listUsers(),
  });

  const inviteMutation = useMutation({
    mutationFn: (data: typeof inviteForm) => {
      return createInvitation({
        email: data.email,
        firstName: data.firstName,
        lastName: data.lastName,
        role: data.role,
      });
    },
    onSuccess: () => {
      queryClient.invalidateQueries({ queryKey: ['users'] });
      setSuccess('Invitation sent successfully! The user will receive an email with a registration link.');
      setShowInviteModal(false);
      setInviteForm({
        email: '',
        firstName: '',
        lastName: '',
        role: 'USER',
      });
      setTimeout(() => setSuccess(''), 5000);
    },
    onError: (err: any) => {
      setError(err.response?.data?.message || 'Failed to send invitation');
      setTimeout(() => setError(''), 5000);
    },
  });

  const changeRoleMutation = useMutation({
    mutationFn: ({ id, role }: { id: string; role: 'ADMIN' | 'MANAGER' | 'USER' | 'VIEWER' }) => {
      return updateUser(id, { role });
    },
    onSuccess: () => {
      queryClient.invalidateQueries({ queryKey: ['users'] });
      setSuccess('Role updated successfully');
      setTimeout(() => setSuccess(''), 3000);
    },
    onError: (err: any) => {
      setError(err.response?.data?.message || 'Failed to update role');
      setTimeout(() => setError(''), 5000);
    },
  });

  const toggleActiveMutation = useMutation({
    mutationFn: ({ id, isActive }: { id: string; isActive: boolean }) => {
      return updateUser(id, { isActive: !isActive });
    },
    onSuccess: () => {
      queryClient.invalidateQueries({ queryKey: ['users'] });
      setSuccess('User status updated successfully');
      setTimeout(() => setSuccess(''), 3000);
    },
    onError: (err: any) => {
      setError(err.response?.data?.message || 'Failed to update user status');
      setTimeout(() => setError(''), 5000);
    },
  });

  const deleteMutation = useMutation({
    mutationFn: (id: string) => deleteUser(id),
    onSuccess: () => {
      queryClient.invalidateQueries({ queryKey: ['users'] });
      setSuccess('User deleted successfully');
      setTimeout(() => setSuccess(''), 3000);
    },
    onError: (err: any) => {
      setError(err.response?.data?.message || 'Failed to delete user');
      setTimeout(() => setError(''), 5000);
    },
  });

  // Restrict access to ADMIN and MANAGER only
  useEffect(() => {
    if (currentUser && currentUser.role !== 'ADMIN' && currentUser.role !== 'MANAGER') {
      router.push('/dashboard');
    }
  }, [currentUser, router]);

  // Don't render until we've checked permissions
  if (!currentUser || (currentUser.role !== 'ADMIN' && currentUser.role !== 'MANAGER')) {
    return (
      <div className="flex items-center justify-center min-h-screen">
        <div className="animate-spin rounded-full h-12 w-12 border-b-2 border-blue-600"></div>
      </div>
    );
  }

  const handleInvite = (e: React.FormEvent) => {
    e.preventDefault();
    setError('');

    inviteMutation.mutate(inviteForm);
  };

  const handleRoleChange = (userId: string, newRole: string) => {
    changeRoleMutation.mutate({ id: userId, role: newRole as 'ADMIN' | 'MANAGER' | 'USER' | 'VIEWER' });
  };

  const handleToggleActive = (userId: string, isActive: boolean) => {
    if (
      window.confirm(`Are you sure you want to ${isActive ? 'deactivate' : 'activate'} this user?`)
    ) {
      toggleActiveMutation.mutate({ id: userId, isActive });
    }
  };

  const handleDelete = (userId: string) => {
    if (
      window.confirm('Are you sure you want to delete this user? This action cannot be undone.')
    ) {
      deleteMutation.mutate(userId);
    }
  };

  const getRoleBadgeColor = (role: string) => {
    const colors: Record<string, string> = {
      ADMIN: 'bg-red-100 text-red-800',
      MANAGER: 'bg-blue-100 text-blue-800',
      USER: 'bg-green-100 text-green-800',
      VIEWER: 'bg-gray-100 text-gray-800',
    };
    return colors[role] || 'bg-gray-100 text-gray-800';
  };

  return (
    <div className="space-y-6">
      {/* Header */}
      <div className="flex items-center justify-between">
        <div>
          <h1 className="text-2xl font-bold text-gray-900">User Management</h1>
          <p className="text-sm text-gray-500 mt-1">Manage team members and their permissions</p>
        </div>
        <button
          onClick={() => setShowInviteModal(true)}
          className="inline-flex items-center px-4 py-2 border border-transparent text-sm font-medium rounded-md text-white bg-blue-600 hover:bg-blue-700"
        >
          <span className="mr-2">➕</span>
          Invite User
        </button>
      </div>

      {success && (
        <div className="rounded-md bg-green-50 p-4">
          <div className="text-sm text-green-800">{success}</div>
        </div>
      )}

      {error && (
        <div className="rounded-md bg-red-50 p-4">
          <div className="text-sm text-red-800">{error}</div>
        </div>
      )}

      {/* Users Table */}
      <div className="bg-white rounded-lg shadow overflow-hidden">
        {isLoading ? (
          <div className="px-6 py-12 text-center text-gray-500">
            <div className="animate-spin rounded-full h-12 w-12 border-b-2 border-blue-600 mx-auto mb-4"></div>
            Loading users...
          </div>
        ) : users?.users && users.users.length > 0 ? (
          <div className="overflow-x-auto">
            <table className="min-w-full divide-y divide-gray-200">
              <thead className="bg-gray-50">
                <tr>
                  <th className="px-6 py-3 text-left text-xs font-medium text-gray-500 uppercase tracking-wider">
                    User
                  </th>
                  <th className="px-6 py-3 text-left text-xs font-medium text-gray-500 uppercase tracking-wider">
                    Email
                  </th>
                  <th className="px-6 py-3 text-left text-xs font-medium text-gray-500 uppercase tracking-wider">
                    Role
                  </th>
                  <th className="px-6 py-3 text-left text-xs font-medium text-gray-500 uppercase tracking-wider">
                    Status
                  </th>
                  <th className="px-6 py-3 text-left text-xs font-medium text-gray-500 uppercase tracking-wider">
                    Last Login
                  </th>
                  <th className="px-6 py-3 text-right text-xs font-medium text-gray-500 uppercase tracking-wider">
                    Actions
                  </th>
                </tr>
              </thead>
              <tbody className="bg-white divide-y divide-gray-200">
                {users.users.map(user => (
                  <tr key={user.id} className="hover:bg-gray-50">
                    <td className="px-6 py-4 whitespace-nowrap">
                      <div className="flex items-center">
                        <div className="flex-shrink-0 h-10 w-10 bg-blue-600 rounded-full flex items-center justify-center text-white font-semibold">
                          {user.firstName[0]}
                          {user.lastName[0]}
                        </div>
                        <div className="ml-4">
                          <div className="text-sm font-medium text-gray-900">
                            {user.firstName} {user.lastName}
                          </div>
                          <div className="text-sm text-gray-500">
                            {user.email}
                          </div>
                        </div>
                      </div>
                    </td>
                    <td className="px-6 py-4 whitespace-nowrap">
                      <div className="text-sm text-gray-900">{user.email}</div>
                    </td>
                    <td className="px-6 py-4 whitespace-nowrap">
                      <select
                        value={user.role}
                        onChange={e => handleRoleChange(user.id, e.target.value)}
                        className={`text-xs font-semibold rounded-full px-3 py-1 ${getRoleBadgeColor(
                          user.role
                        )}`}
                        disabled={changeRoleMutation.isPending || (user.role === 'ADMIN' && currentUser?.role !== 'ADMIN')}
                      >
                        {currentUser?.role === 'ADMIN' && <option value="ADMIN">Admin</option>}
                        <option value="MANAGER">Manager</option>
                        <option value="USER">User</option>
                        <option value="VIEWER">Viewer</option>
                      </select>
                    </td>
                    <td className="px-6 py-4 whitespace-nowrap">
                      <button
                        onClick={() => handleToggleActive(user.id, user.isActive)}
                        disabled={toggleActiveMutation.isPending}
                        className={`px-3 py-1 inline-flex text-xs leading-5 font-semibold rounded-full ${
                          user.isActive
                            ? 'bg-green-100 text-green-800 hover:bg-green-200'
                            : 'bg-red-100 text-red-800 hover:bg-red-200'
                        } disabled:opacity-50 disabled:cursor-not-allowed`}
                      >
                        {user.isActive ? 'Active' : 'Inactive'}
                      </button>
                    </td>
                    <td className="px-6 py-4 whitespace-nowrap text-sm text-gray-500">
                      {new Date(user.createdAt).toLocaleDateString()}
                    </td>
                    <td className="px-6 py-4 whitespace-nowrap text-right text-sm font-medium">
                      <button
                        onClick={() => handleDelete(user.id)}
                        disabled={deleteMutation.isPending}
                        className="text-red-600 hover:text-red-900 ml-4 disabled:opacity-50 disabled:cursor-not-allowed"
                      >
                        Delete
                      </button>
                    </td>
                  </tr>
                ))}
              </tbody>
            </table>
          </div>
        ) : (
          <div className="px-6 py-12 text-center">
            <svg
              className="mx-auto h-12 w-12 text-gray-400"
              fill="none"
              stroke="currentColor"
              viewBox="0 0 24 24"
            >
              <path
                strokeLinecap="round"
                strokeLinejoin="round"
                strokeWidth={2}
                d="M12 4.354a4 4 0 110 5.292M15 21H3v-1a6 6 0 0112 0v1zm0 0h6v-1a6 6 0 00-9-5.197M13 7a4 4 0 11-8 0 4 4 0 018 0z"
              />
            </svg>
            <h3 className="mt-2 text-sm font-medium text-gray-900">No users</h3>
            <p className="mt-1 text-sm text-gray-500">Get started by inviting a team member</p>
            <div className="mt-6">
              <button
                onClick={() => setShowInviteModal(true)}
                className="inline-flex items-center px-4 py-2 border border-transparent shadow-sm text-sm font-medium rounded-md text-white bg-blue-600 hover:bg-blue-700"
              >
                <span className="mr-2">➕</span>
                Invite User
              </button>
            </div>
          </div>
        )}
      </div>

      {/* Invite Modal */}
      {showInviteModal && (
        <div className="fixed inset-0 z-50 overflow-y-auto">
          <div className="flex items-center justify-center min-h-screen px-4 pt-4 pb-20 text-center sm:block sm:p-0">
            <div
              className="fixed inset-0 transition-opacity bg-gray-500 bg-opacity-75"
              onClick={() => setShowInviteModal(false)}
            />

            <div className="inline-block align-bottom bg-white rounded-lg px-4 pt-5 pb-4 text-left overflow-hidden shadow-xl transform transition-all sm:my-8 sm:align-middle sm:max-w-lg sm:w-full sm:p-6">
              <div>
                <div className="flex items-center justify-between mb-4">
                  <h3 className="text-lg font-medium text-gray-900">Invite User</h3>
                  <button
                    onClick={() => setShowInviteModal(false)}
                    className="text-gray-400 hover:text-gray-500"
                  >
                    <svg className="h-6 w-6" fill="none" stroke="currentColor" viewBox="0 0 24 24">
                      <path
                        strokeLinecap="round"
                        strokeLinejoin="round"
                        strokeWidth={2}
                        d="M6 18L18 6M6 6l12 12"
                      />
                    </svg>
                  </button>
                </div>

                <form onSubmit={handleInvite} className="space-y-4">
                  <div className="grid grid-cols-2 gap-4">
                    <div>
                      <label className="block text-sm font-medium text-gray-700">
                        First Name *
                      </label>
                      <input
                        type="text"
                        required
                        value={inviteForm.firstName}
                        onChange={e => setInviteForm({ ...inviteForm, firstName: e.target.value })}
                        className="mt-1 block w-full rounded-md border-gray-300 shadow-sm focus:border-blue-500 focus:ring-blue-500 sm:text-sm px-3 py-2 border"
                      />
                    </div>
                    <div>
                      <label className="block text-sm font-medium text-gray-700">Last Name *</label>
                      <input
                        type="text"
                        required
                        value={inviteForm.lastName}
                        onChange={e => setInviteForm({ ...inviteForm, lastName: e.target.value })}
                        className="mt-1 block w-full rounded-md border-gray-300 shadow-sm focus:border-blue-500 focus:ring-blue-500 sm:text-sm px-3 py-2 border"
                      />
                    </div>
                  </div>

                  <div>
                    <label className="block text-sm font-medium text-gray-700">Email *</label>
                    <input
                      type="email"
                      required
                      value={inviteForm.email}
                      onChange={e => setInviteForm({ ...inviteForm, email: e.target.value })}
                      className="mt-1 block w-full rounded-md border-gray-300 shadow-sm focus:border-blue-500 focus:ring-blue-500 sm:text-sm px-3 py-2 border"
                    />
                  </div>

                  <div>
                    <label className="block text-sm font-medium text-gray-700">Role *</label>
                    <select
                      value={inviteForm.role}
                      onChange={e => setInviteForm({ ...inviteForm, role: e.target.value as any })}
                      className="mt-1 block w-full rounded-md border-gray-300 shadow-sm focus:border-blue-500 focus:ring-blue-500 sm:text-sm px-3 py-2 border"
                    >
                      <option value="USER">User</option>
                      <option value="MANAGER">Manager</option>
                      {currentUser?.role === 'ADMIN' && <option value="ADMIN">Admin</option>}
                      <option value="VIEWER">Viewer</option>
                    </select>
                    {currentUser?.role !== 'ADMIN' && (
                      <p className="mt-1 text-xs text-gray-500">
                        Only platform administrators can assign the ADMIN role
                      </p>
                    )}
                  </div>

                  <div className="mt-5 sm:mt-6 sm:grid sm:grid-cols-2 sm:gap-3 sm:grid-flow-row-dense">
                    <button
                      type="submit"
                      disabled={inviteMutation.isPending}
                      className="w-full inline-flex justify-center rounded-md border border-transparent shadow-sm px-4 py-2 bg-blue-600 text-base font-medium text-white hover:bg-blue-700 focus:outline-none focus:ring-2 focus:ring-offset-2 focus:ring-blue-500 sm:col-start-2 sm:text-sm disabled:bg-gray-400"
                    >
                      {inviteMutation.isPending ? 'Inviting...' : 'Send Invitation'}
                    </button>
                    <button
                      type="button"
                      onClick={() => setShowInviteModal(false)}
                      className="mt-3 w-full inline-flex justify-center rounded-md border border-gray-300 shadow-sm px-4 py-2 bg-white text-base font-medium text-gray-700 hover:bg-gray-50 focus:outline-none focus:ring-2 focus:ring-offset-2 focus:ring-blue-500 sm:mt-0 sm:col-start-1 sm:text-sm"
                    >
                      Cancel
                    </button>
                  </div>
                </form>
              </div>
            </div>
          </div>
        </div>
      )}
    </div>
  );
}