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

// Redirect if not logged in or if it's not a POST request
if (!isset($_SESSION['user_id']) || $_SERVER['REQUEST_METHOD'] !== 'POST') {
    header('Location: login.php');
    exit();
}

// Basic validation
if (!isset($_POST['test_id']) || !is_numeric($_POST['test_id']) || !isset($_POST['answers']) || !is_array($_POST['answers'])) {
    die("Invalid data submitted.");
}

$user_id = $_SESSION['user_id'];
$test_id = intval($_POST['test_id']);
$answers = $_POST['answers'];
$total_score = 0;

try {
    $db = db();
    
    // Get the scores for the selected options
    $option_ids = array_values($answers);
    $placeholders = implode(',', array_fill(0, count($option_ids), '?'));

    $scoreStmt = $db->prepare("SELECT id, score FROM options WHERE id IN ($placeholders)");
    $scoreStmt->execute($option_ids);
    $scores = $scoreStmt->fetchAll(PDO::FETCH_KEY_PAIR);

    // Begin transaction
    $db->beginTransaction();


    // Calculate total score
    foreach ($answers as $question_id => $option_id) {
        if (isset($scores[$option_id])) {
            $total_score += $scores[$option_id];
        }
    }

    // Save the final score in the user_tests table
    $userTestStmt = $db->prepare("
        INSERT INTO user_tests (user_id, test_id, score) 
        VALUES (:user_id, :test_id, :score)
        ON DUPLICATE KEY UPDATE score = :score
    ");
    $userTestStmt->execute([
        'user_id' => $user_id,
        'test_id' => $test_id,
        'score' => $total_score
    ]);

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

    // Redirect to results page
    header("Location: test_results.php?test_id=" . $test_id);
    exit();

} catch (PDOException $e) {
    // Rollback on error
    if ($db->inTransaction()) {
        $db->rollBack();
    }
    // A generic error message is better for production
    die("An error occurred while submitting your test. Please try again later. Error: " . $e->getMessage());
}

?>