134 lines
4.9 KiB
PHP
134 lines
4.9 KiB
PHP
<?php
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session_start();
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require_once 'db/config.php';
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if (!isset($_SESSION['user_id']) || $_SESSION['role'] !== 'student') {
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header('Location: login.php');
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exit();
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}
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$user_id = $_SESSION['user_id'];
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$pdo = db();
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if (!isset($_GET['student_exam_id'])) {
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header('Location: exams.php');
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exit();
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}
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$student_exam_id = $_GET['student_exam_id'];
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// Verify student is assigned to this exam
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$stmt = $pdo->prepare('SELECT * FROM student_exams WHERE id = ? AND student_id = ?');
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$stmt->execute([$student_exam_id, $user_id]);
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$student_exam = $stmt->fetch();
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if (!$student_exam) {
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echo "You are not assigned to this exam.";
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exit();
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}
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// Prevent re-taking a completed exam
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if ($student_exam['status'] === 'completed') {
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echo "You have already completed this exam.";
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// Maybe redirect to a results page in the future
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echo '<br><a href="exams.php">Back to Exams</a>';
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exit();
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}
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// Fetch exam details
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$stmt = $pdo->prepare('SELECT * FROM exams WHERE id = ?');
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$stmt->execute([$student_exam['exam_id']]);
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$exam = $stmt->fetch();
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// Fetch exam questions
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$stmt = $pdo->prepare('SELECT * FROM exam_questions WHERE exam_id = ? ORDER BY id ASC');
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$stmt->execute([$exam['id']]);
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$questions = $stmt->fetchAll();
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// Handle exam submission
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if ($_SERVER['REQUEST_METHOD'] === 'POST' && isset($_POST['answers'])) {
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$answers = $_POST['answers'];
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$pdo->beginTransaction();
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try {
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foreach ($answers as $question_id => $answer_text) {
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// Use INSERT ... ON DUPLICATE KEY UPDATE to prevent duplicate answer submissions
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$sql = 'INSERT INTO student_answers (student_exam_id, question_id, answer_text) VALUES (?, ?, ?) ON DUPLICATE KEY UPDATE answer_text = VALUES(answer_text)';
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$stmt = $pdo->prepare($sql);
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$stmt->execute([$student_exam_id, $question_id, trim($answer_text)]);
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}
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// Mark exam as completed
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$stmt = $pdo->prepare('UPDATE student_exams SET status = \'completed\' WHERE id = ?');
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$stmt->execute([$student_exam_id]);
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$pdo->commit();
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header('Location: exams.php');
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exit();
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} catch (Exception $e) {
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$pdo->rollBack();
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// Log error properly in a real application
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die("An error occurred while submitting your exam. Please try again. Error: " . $e->getMessage());
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}
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}
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// If student is starting the exam, mark it as 'in-progress'
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if ($student_exam['status'] === 'assigned') {
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$stmt = $pdo->prepare('UPDATE student_exams SET status = \'in-progress\' WHERE id = ?');
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$stmt->execute([$student_exam_id]);
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}
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?>
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<!DOCTYPE html>
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<html lang="en">
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<head>
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<meta charset="UTF-8">
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<meta name="viewport" content="width=device-width, initial-scale=1.0">
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<title>Take Exam: <?php echo htmlspecialchars($exam['name']); ?></title>
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<link rel="stylesheet" href="assets/css/custom.css?v=<?php echo time(); ?>">
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</head>
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<body>
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<header>
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<h1><?php echo htmlspecialchars($exam['name']); ?></h1>
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<nav>
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<ul>
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<li><a href="exams.php">Back to Exams</a></li>
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<li><a href="logout.php">Logout</a></li>
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</ul>
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</nav>
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</header>
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<main>
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<form action="take_exam.php?student_exam_id=<?php echo $student_exam_id; ?>" method="POST">
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<?php foreach ($questions as $index => $q): ?>
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<div class="question-block">
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<p><strong>Question <?php echo $index + 1; ?>:</strong> <?php echo nl2br(htmlspecialchars($q['question_text'])); ?></p>
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<?php if ($q['question_type'] === 'multiple_choice'): ?>
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<?php $options = json_decode($q['options']); ?>
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<?php if($options):
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foreach ($options as $option):
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?>
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<div>
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<input type="radio" id="q_<?php echo $q['id'] . '_' . htmlspecialchars($option); ?>" name="answers[<?php echo $q['id']; ?>]" value="<?php echo htmlspecialchars($option); ?>" required>
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<label for="q_<?php echo $q['id'] . '_' . htmlspecialchars($option); ?>"><?php echo htmlspecialchars($option); ?></label>
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</div>
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<?php endforeach; ?>
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<?php endif; ?>
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<?php else: // free_text ?>
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<textarea name="answers[<?php echo $q['id']; ?>]" rows="5" required></textarea>
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<?php endif; ?>
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</div>
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<?php endforeach; ?>
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<?php if (empty($questions)): ?>
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<p>This exam has no questions.</p>
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<?php else: ?>
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<button type="submit" onclick="return confirm('Are you sure you want to submit your answers?');">Submit Exam</button>
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<?php endif; ?>
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</form>
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</main>
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</body>
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</html>
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