<?php
require_once 'includes/header.php';
require_once 'db/config.php';

// Redirect if not logged in
if (!isset($_SESSION['user_id'])) {
    header('Location: login.php');
    exit();
}

// Check for test ID
if (!isset($_GET['test_id']) || !is_numeric($_GET['test_id'])) {
    // Redirect to home or show an error
    header('Location: index.php');
    exit();
}

$test_id = intval($_GET['test_id']);
$user_id = $_SESSION['user_id'];

try {
    $db = db();

    // Start a transaction
    $db->beginTransaction();

    // Delete from user_answers
    $stmt_answers = $db->prepare("DELETE FROM user_answers WHERE user_id = :user_id AND question_id IN (SELECT id FROM questions WHERE test_id = :test_id)");
    $stmt_answers->execute(['user_id' => $user_id, 'test_id' => $test_id]);

    // Delete from user_tests
    $stmt_tests = $db->prepare("DELETE FROM user_tests WHERE user_id = :user_id AND test_id = :test_id");
    $stmt_tests->execute(['user_id' => $user_id, 'test_id' => $test_id]);

    // Commit the transaction
    $db->commit();

    // Redirect to the test page
    header('Location: take_test.php?test_id=' . $test_id);
    exit();

} catch (PDOException $e) {
    // Rollback the transaction if something failed
    if ($db->inTransaction()) {
        $db->rollBack();
    }
    // You might want to log this error instead of showing it to the user
    die("Database error while trying to reset the test. Please try again.");
}

// No need for footer as we are redirecting
?>