将请求分发器的注册与退出登录完善

<?php
session_start();
//连接数据库
require '1-connect.php';
// 接受前端传过来的参数
$name   = isset($_POST['uname']) ? $_POST['uname'] : null;
$pwd    = isset($_POST['pwd']) ? $_POST['pwd'] : null;
$gender = isset($_POST['gender']) ? $_POST['gender'] : null;
$created_at = time();
$type       = strtolower($_GET['type']);
// 请求分发器  注册 登录 退出
switch ($type) {
    case 'login':
        $res = loginCheck($name, $pwd);
        if ($res) {
            echo json_encode(['status' => 1, 'msg' => '登录成功'], 320);
            exit;
        }
        echo json_encode(['status' => 0, 'msg' => '用户名或密码错误'], 320);
        break;
    case 'reg':
        $res = insertData($name, $pwd, $gender, $created_at);
        if ($res) {
            echo json_encode(['status' => 1, 'msg' => '注册成功'], 320);
            exit;
        }
        echo json_encode(['status' => 0, 'msg' => '注册失败'], 320);
        break;
    case 'logout':
        session_destroy();
        header('Location:index.php');
        break;
    default:
           exit('非法请求');
}
function loginCheck($name, $pwd)
{
    global $pdo;
    $sql = "SELECT `username`,`password` FROM `user` WHERE `username` = ? AND `password` = ? ";
    $stmt = $pdo->prepare($sql);
    $res = $stmt->execute([$name, md5($pwd)]);
    if ($res) {
        $res = $stmt->fetch(PDO::FETCH_ASSOC);
        if ($res) {
            $_SESSION['username'] = $res['username'];
            return true;
        } else {
            return false;
        }
    }
}
function insertData($name, $pwd, $gender, $created_at)
{
    global $pdo;
    $flag = false;
    $sql = "INSERT INTO `user` SET `username` =?,`password`=?, `gender`=?,`created_at`=?  ";
    $stmt = $pdo->prepare($sql);
    $stmt->execute([$name, $pwd, $gender, $created_at]);
    if ($stmt->rowCount() == 1) {
        $flag = true;
    }
    return $flag;
}
?>