PHPを使用してWeChatアプレットのタスク報酬機能を実装するにはどうすればよいですか?

CREATE TABLE `user` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `openid` varchar(50) NOT NULL,
  `nickname` varchar(50) NOT NULL,
  `avatar` varchar(100) NOT NULL,
  `points` int(11) NOT NULL DEFAULT '0',
  PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

CREATE TABLE `reward` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `openid` varchar(50) NOT NULL,
  `task_name` varchar(100) NOT NULL,
  `points` int(11) NOT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

// 获取用户openid
$code = $_GET['code'];
$appid = 'your_appid';
$secret = 'your_secret';
$url = "https://api.weixin.qq.com/sns/jscode2session?appid=$appid&secret=$secret&js_code=$code&grant_type=authorization_code";
$res = json_decode(file_get_contents($url), true);
$openid = $res['openid'];

// 获取用户信息
$nickname = $_GET['nickname'];
$avatar = $_GET['avatar'];

// 保存用户信息到数据库
$conn = mysqli_connect('localhost', 'your_username', 'your_password', 'your_database');
$sql = "INSERT INTO user (openid, nickname, avatar) VALUES ('$openid', '$nickname', '$avatar')";
mysqli_query($conn, $sql);

$task_name = $_GET['task_name'];
$points = $_GET['points'];

$conn = mysqli_connect('localhost', 'your_username', 'your_password', 'your_database');
$sql = "INSERT INTO reward (openid, task_name, points) VALUES ('$openid', '$task_name', $points)";
mysqli_query($conn, $sql);

$reward_id = $_GET['reward_id'];

$conn = mysqli_connect('localhost', 'your_username', 'your_password', 'your_database');
$sql = "SELECT points FROM reward WHERE id = $reward_id";
$result = mysqli_query($conn, $sql);
$row = mysqli_fetch_assoc($result);
$points = $row['points'];

// 更新用户积分
$sql = "UPDATE user SET points = points + $points WHERE openid = '$openid'";
mysqli_query($conn, $sql);

// 删除任务记录
$sql = "DELETE FROM reward WHERE id = $reward_id";
mysqli_query($conn, $sql);

$conn = mysqli_connect('localhost', 'your_username', 'your_password', 'your_database');
$sql = "SELECT points FROM user WHERE openid = '$openid'";
$result = mysqli_query($conn, $sql);
$row = mysqli_fetch_assoc($result);
$points = $row['points'];