<?php
// 获取参数
$student_id = $_GET['student_id'] ?? null;
$english = $_GET['english'] ?? null;
$math = $_GET['math'] ?? null;
$computer = $_GET['computer'] ?? null;

// 校验参数是否完整
if ($student_id === null || $english === null || $math === null || $computer === null) {
    // 返回错误信息
    echo json_encode([
        "error" => "Missing required parameters: student_id, english, math, computer"
    ]);
    exit;
}

// 验证分数是否为数字
if (!is_numeric($english) || !is_numeric($math) || !is_numeric($computer)) {
    // 返回错误信息
    echo json_encode([
        "error" => "Parameters english, math, and computer must be numeric"
    ]);
    exit;
}

// 计算总分
$sum = $english + $math + $computer;

// 封装为 JSON 格式
$response = [
    "student_id" => $student_id,
    "sum" => (string)$sum // 转为字符串以匹配返回格式
];

// 输出 JSON
header('Content-Type: application/json');
echo json_encode($response);
?>