<?php
// students_crud.php
require_once '../includes/dbcon.php';

// Check if user is logged in
if (!is_logged_in()) {
    redirect('login.php');
}

// Get classes and academic years for dropdowns
function getClasses() {
    global $DBcon;
    try {
        $sql = "SELECT classid FROM class ORDER BY classid";
        $stmt = $DBcon->prepare($sql);
        $stmt->execute();
        return $stmt->fetchAll(PDO::FETCH_ASSOC);
    } catch (PDOException $e) {
        error_log("Get classes error: " . $e->getMessage());
        return [];
    }
}

function getAcademicYears() {
    global $DBcon;
    try {
        $sql = "SELECT academic_year FROM calender ORDER BY academic_year DESC";
        $stmt = $DBcon->prepare($sql);
        $stmt->execute();
        return $stmt->fetchAll(PDO::FETCH_ASSOC);
    } catch (PDOException $e) {
        error_log("Get academic years error: " . $e->getMessage());
        return [];
    }
}

$classes = getClasses();
$academic_years = getAcademicYears();

// Initialize variables
$action = isset($_GET['action']) ? sanitize_input($_GET['action']) : 'list';
$id = isset($_GET['id']) ? intval($_GET['id']) : 0;
$message = '';
$message_type = '';
$student = null;

// Handle form submissions
if ($_SERVER['REQUEST_METHOD'] === 'POST') {
    // Validate CSRF token
    if (!validate_csrf_token($_POST['csrf_token'])) {
        $message = 'Security token validation failed.';
        $message_type = 'error';
    } else {
        // DEBUG: Log the POST data
        error_log("POST Data: " . print_r($_POST, true));
        error_log("FILES Data: " . print_r($_FILES, true));
        
        // Process different actions
        switch ($_POST['action']) {
            case 'create':
                $result = createStudent($_POST, $_FILES);
                if ($result) {
                    $message = 'Student created successfully.';
                    $message_type = 'success';
                    $action = 'list';
                } else {
                    $message = 'Failed to create student. Please try again.';
                    $message_type = 'error';
                }
                break;
                
            case 'update':
                $result = updateStudent($_POST, $_FILES);
                if ($result) {
                    $message = 'Student updated successfully.';
                    $message_type = 'success';
                    $action = 'list';
                } else {
                    $message = 'Failed to update student. Please try again.';
                    $message_type = 'error';
                }
                break;
                
            case 'delete':
                $result = deleteStudent($_POST['id']);
                if ($result) {
                    $message = 'Student deleted successfully.';
                    $message_type = 'success';
                } else {
                    $message = 'Failed to delete student. Please try again.';
                    $message_type = 'error';
                }
                break;
        }
    }
}

// If editing, get student data
if ($action === 'edit') {
    $student = getStudent($id);
    if (!$student) {
        $message = 'Student not found.';
        $message_type = 'error';
        $action = 'list';
    }
}

// CRUD Functions
function createStudent($data, $files) {
    global $DBcon;
    
    try {
        $image_path = handleImageUpload($files, $data);
        
        $sql = "INSERT INTO students_info (fullname, regno, class_id, admin_year, image) 
                VALUES (:fullname, :regno, :class_id, :admin_year, :image)";
        $stmt = $DBcon->prepare($sql);
        
        $result = $stmt->execute([
            ':fullname' => sanitize_input($data['fullname']),
            ':regno' => sanitize_input($data['regno']),
            ':class_id' => sanitize_input($data['class_id']),
            ':admin_year' => sanitize_input($data['admin_year']),
            ':image' => $image_path
        ]);
        
        error_log("Create student result: " . ($result ? 'SUCCESS' : 'FAILED'));
        return $result;
        
    } catch (PDOException $e) {
        error_log("Create student error: " . $e->getMessage());
        return false;
    }
}

function updateStudent($data, $files) {
    global $DBcon;
    
    try {
        // Get current student data first
        $current_student = getStudent($data['id']);
        if (!$current_student) {
            error_log("Update failed: Student not found with ID: " . $data['id']);
            return false;
        }
        
        error_log("Current student data: " . print_r($current_student, true));
        
        // Handle image upload
        $image_path = handleImageUpload($files, $data);
        error_log("Image path after upload handling: " . $image_path);
        
        // If no new image was uploaded, keep the current image
        if ($image_path === '') {
            $image_path = $current_student['image'];
            error_log("Using current image: " . $image_path);
        } else if ($image_path !== false) {
            // New image was uploaded successfully, delete old image if it exists
            if (!empty($current_student['image']) && file_exists('../' . $current_student['image'])) {
                unlink('../' . $current_student['image']);
                error_log("Deleted old image: " . $current_student['image']);
            }
        } else {
            // Image upload failed
            error_log("Image upload failed, keeping current image");
            $image_path = $current_student['image'];
        }
        
        $sql = "UPDATE students_info 
                SET fullname = :fullname, 
                    regno = :regno, 
                    class_id = :class_id, 
                    admin_year = :admin_year, 
                    image = :image 
                WHERE sn = :id";
        
        $stmt = $DBcon->prepare($sql);
        
        $params = [
            ':fullname' => sanitize_input($data['fullname']),
            ':regno' => sanitize_input($data['regno']),
            ':class_id' => sanitize_input($data['class_id']),
            ':admin_year' => sanitize_input($data['admin_year']),
            ':image' => $image_path,
            ':id' => intval($data['id'])
        ];
        
        error_log("Update params: " . print_r($params, true));
        
        $result = $stmt->execute($params);
        
        error_log("Update student result: " . ($result ? 'SUCCESS' : 'FAILED'));
        error_log("Rows affected: " . $stmt->rowCount());
        
        return $result;
        
    } catch (PDOException $e) {
        error_log("Update student error: " . $e->getMessage());
        return false;
    }
}

function handleImageUpload($files, $data) {
    error_log("Starting image upload handling");
    
    // Check for webcam image first
    if (!empty($data['webcam_image']) && $data['webcam_image'] !== 'data:,') {
        error_log("Webcam image detected");
        $result = saveWebcamImage($data['webcam_image']);
        error_log("Webcam image save result: " . $result);
        return $result;
    }
    
    // Check for file upload
    if (isset($files['image_upload']) && $files['image_upload']['error'] === UPLOAD_ERR_OK) {
        error_log("File upload detected: " . $files['image_upload']['name']);
        $result = saveUploadedImage($files['image_upload']);
        error_log("File upload save result: " . $result);
        return $result;
    }
    
    error_log("No image provided, returning empty string");
    // No image provided - return empty string
    return '';
}

function saveWebcamImage($base64_image) {
    $upload_dir = '../uploads/students/';
    
    // Create upload directory if it doesn't exist
    if (!file_exists($upload_dir)) {
        mkdir($upload_dir, 0755, true);
    }
    
    // Extract base64 data
    if (preg_match('/^data:image\/(\w+);base64,/', $base64_image, $type)) {
        $image_data = substr($base64_image, strpos($base64_image, ',') + 1);
        $type = strtolower($type[1]); // jpg, png, gif
        
        if (!in_array($type, ['jpg', 'jpeg', 'png', 'gif'])) {
            error_log("Invalid image type: " . $type);
            return false;
        }
        
        $image_data = base64_decode($image_data);
        
        if ($image_data === false) {
            error_log("Failed to decode base64 image data");
            return false;
        }
    } else {
        error_log("Invalid base64 image format");
        return false;
    }
    
    $filename = 'student_' . uniqid() . '.' . $type;
    $filepath = $upload_dir . $filename;
    
    if (file_put_contents($filepath, $image_data)) {
        $result_path = 'uploads/students/' . $filename;
        error_log("Webcam image saved successfully: " . $result_path);
        return $result_path;
    }
    
    error_log("Failed to save webcam image to: " . $filepath);
    return false;
}

function saveUploadedImage($file) {
    $upload_dir = '../uploads/students/';
    $allowed_types = ['image/jpeg', 'image/jpg', 'image/png', 'image/gif'];
    $max_size = 2 * 1024 * 1024; // 2MB
    
    // Create upload directory if it doesn't exist
    if (!file_exists($upload_dir)) {
        mkdir($upload_dir, 0755, true);
    }
    
    // Validate file
    if (!in_array($file['type'], $allowed_types)) {
        error_log("Invalid file type: " . $file['type']);
        return false;
    }
    
    if ($file['size'] > $max_size) {
        error_log("File too large: " . $file['size']);
        return false;
    }
    
    // Generate unique filename
    $extension = pathinfo($file['name'], PATHINFO_EXTENSION);
    $filename = 'student_' . uniqid() . '.' . $extension;
    $filepath = $upload_dir . $filename;
    
    if (move_uploaded_file($file['tmp_name'], $filepath)) {
        $result_path = 'uploads/students/' . $filename;
        error_log("File uploaded successfully: " . $result_path);
        return $result_path;
    }
    
    error_log("Failed to move uploaded file to: " . $filepath);
    return false;
}

function deleteStudent($id) {
    global $DBcon;
    
    try {
        // Get student image path to delete the file
        $student = getStudent($id);
        if ($student && !empty($student['image']) && file_exists('../' . $student['image'])) {
            unlink('../' . $student['image']);
        }
        
        $sql = "DELETE FROM students_info WHERE sn = :id";
        $stmt = $DBcon->prepare($sql);
        return $stmt->execute([':id' => intval($id)]);
    } catch (PDOException $e) {
        error_log("Delete student error: " . $e->getMessage());
        return false;
    }
}

function getStudent($id) {
    global $DBcon;
    
    try {
        $sql = "SELECT * FROM students_info WHERE sn = :id";
        $stmt = $DBcon->prepare($sql);
        $stmt->execute([':id' => intval($id)]);
        $result = $stmt->fetch(PDO::FETCH_ASSOC);
        error_log("Get student with ID $id: " . ($result ? 'FOUND' : 'NOT FOUND'));
        return $result;
    } catch (PDOException $e) {
        error_log("Get student error: " . $e->getMessage());
        return false;
    }
}

function getAllStudents() {
    global $DBcon;
    
    try {
        $sql = "SELECT * FROM students_info ORDER BY sn DESC";
        $stmt = $DBcon->prepare($sql);
        $stmt->execute();
        return $stmt->fetchAll(PDO::FETCH_ASSOC);
    } catch (PDOException $e) {
        error_log("Get all students error: " . $e->getMessage());
        return [];
    }
}

// Generate CSRF token
$csrf_token = generate_csrf_token();
?>

<!-- HTML CODE REMAINS THE SAME AS BEFORE -->
<!DOCTYPE html>
<html lang="en">
<head>
  <!-- Required meta tags -->
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no">
  <title>Student Management - School Admin</title>
  <!-- plugins:css -->
  <link rel="stylesheet" href="vendors/iconfonts/font-awesome/css/all.min.css">
  <link rel="stylesheet" href="vendors/css/vendor.bundle.base.css">
  <link rel="stylesheet" href="vendors/css/vendor.bundle.addons.css">
  <!-- endinject -->
  <!-- plugin css for this page -->
  <!-- End plugin css for this page -->
  <!-- inject:css -->
  <link rel="stylesheet" href="css/style.css">
  <!-- endinject -->
  <style>
    .action-buttons .btn {
        margin: 2px;
    }
    .table-responsive {
        overflow-x: auto;
    }
    .student-image {
        width: 50px;
        height: 50px;
        object-fit: cover;
        border-radius: 50%;
    }
    .alert {
        padding: 12px 20px;
        border-radius: 4px;
        margin-bottom: 20px;
    }
    .alert-success {
        background-color: #d4edda;
        color: #155724;
        border: 1px solid #c3e6cb;
    }
    .alert-error {
        background-color: #f8d7da;
        color: #721c24;
        border: 1px solid #f5c6cb;
    }
    .form-group {
        margin-bottom: 1.5rem;
    }
    .card-title {
        display: flex;
        align-items: center;
    }
    .card-title i {
        margin-right: 10px;
    }
    .image-upload-options {
        border: 1px solid #dee2e6;
        border-radius: 4px;
        padding: 15px;
        margin-bottom: 15px;
    }
    .webcam-container {
        margin-bottom: 15px;
        text-align: center;
    }
    #webcamVideo {
        width: 100%;
        max-width: 300px;
        border: 2px solid #007bff;
        border-radius: 4px;
    }
    #webcamCanvas {
        display: none;
        max-width: 300px;
        border: 2px solid #28a745;
        border-radius: 4px;
    }
    .image-preview {
        text-align: center;
        margin-top: 15px;
    }
    .preview-image {
        max-width: 200px;
        max-height: 200px;
        border-radius: 4px;
        border: 2px solid #dee2e6;
    }
    .upload-tabs {
        margin-bottom: 15px;
        display: flex;
        gap: 5px;
    }
    .upload-tab {
        padding: 10px 15px;
        background: #f8f9fa;
        border: 1px solid #dee2e6;
        cursor: pointer;
        border-radius: 4px;
        flex: 1;
        text-align: center;
    }
    .upload-tab.active {
        background: #007bff;
        color: white;
        border-color: #007bff;
    }
    .upload-content {
        display: none;
    }
    .upload-content.active {
        display: block;
    }
    .webcam-controls {
        margin-top: 10px;
    }
  </style>
</head>
<body>
  <div class="container-scroller">
  <?php include("header.php"); ?>
    <div class="container-fluid page-body-wrapper">
      <!-- partial:partials/_settings-panel.html -->
      <?php include("sidebar.php"); ?>
      <div class="main-panel">
        <div class="content-wrapper">
          <div class="page-header">
            <h3 class="page-title">
              Student Management
            </h3>
            <nav aria-label="breadcrumb">
              <ol class="breadcrumb">
                <li class="breadcrumb-item"><a href="#">Dashboard</a></li>
                <li class="breadcrumb-item active" aria-current="page">Students</li>
              </ol>
            </nav>
          </div>
          
          <!-- Display Messages -->
          <?php if ($message): ?>
          <div class="alert alert-<?php echo $message_type === 'success' ? 'success' : 'error'; ?>">
            <?php echo $message; ?>
          </div>
          <?php endif; ?>
          
          <div class="row">
            <div class="col-12 grid-margin">
              <div class="card">
                <div class="card-body">
                  <div class="d-flex justify-content-between align-items-center mb-4">
                    <h4 class="card-title">
                      <i class="fas fa-table"></i>
                      <?php 
                        switch($action) {
                            case 'create': echo 'Add New Student'; break;
                            case 'edit': echo 'Edit Student'; break;
                            default: echo 'Student List'; break;
                        }
                      ?>
                    </h4>
                    <?php if ($action === 'list'): ?>
                    <div>
                      <a href="studentbatch.php" class="btn btn-success btn-sm mr-2">
                        <i class="fas fa-file-import"></i> Import Excel
                      </a>
                      <a href="?action=create" class="btn btn-primary btn-sm">
                        <i class="fas fa-plus"></i> Add New Student
                      </a>
                    </div>
                    <?php endif; ?>
                  </div>
                  
                  <?php if ($action === 'list'): ?>
                  <!-- Student List -->
                  <div class="table-responsive">
                    <table class="table table-striped">
                      <thead>
                        <tr>
                          <th>#</th>
                          <th>Image</th>
                          <th>Full Name</th>
                          <th>Registration No</th>
                          <th>Class</th>
                          <th>Admission Year</th>
                          <th>Actions</th>
                        </tr>
                      </thead>
                      <tbody>
                        <?php 
                        $students = getAllStudents();
                        if (count($students) > 0):
                          foreach ($students as $student): 
                        ?>
                        <tr>
                          <td><?php echo $student['sn']; ?></td>
                          <td>
                            <?php if (!empty($student['image']) && file_exists('../' . $student['image'])): ?>
                            <img src="../<?php echo htmlspecialchars($student['image']); ?>" alt="Student Image" class="student-image">
                            <?php else: ?>
                            <div class="student-image bg-light d-flex align-items-center justify-content-center">
                              <i class="fas fa-user text-muted"></i>
                            </div>
                            <?php endif; ?>
                          </td>
                          <td><?php echo htmlspecialchars($student['fullname']); ?></td>
                          <td><?php echo htmlspecialchars($student['regno']); ?></td>
                          <td><?php echo htmlspecialchars($student['class_id']); ?></td>
                          <td><?php echo htmlspecialchars($student['admin_year']); ?></td>
                          <td class="action-buttons">
                            <a href="?action=edit&id=<?php echo $student['sn']; ?>" class="btn btn-info btn-sm">
                              <i class="fas fa-edit"></i>
                            </a>
                            <form method="POST" style="display: inline-block;" onsubmit="return confirm('Are you sure you want to delete this student?');">
                              <input type="hidden" name="csrf_token" value="<?php echo $csrf_token; ?>">
                              <input type="hidden" name="action" value="delete">
                              <input type="hidden" name="id" value="<?php echo $student['sn']; ?>">
                              <button type="submit" class="btn btn-danger btn-sm">
                                <i class="fas fa-trash"></i>
                              </button>
                            </form>
                          </td>
                        </tr>
                        <?php 
                          endforeach;
                        else:
                        ?>
                        <tr>
                          <td colspan="7" class="text-center">No students found. <a href="?action=create">Add the first student</a>.</td>
                        </tr>
                        <?php endif; ?>
                      </tbody>
                    </table>
                  </div>
                  <?php elseif ($action === 'create' || ($action === 'edit' && $student)): ?>
                  <!-- Student Form -->
                  <form method="POST" enctype="multipart/form-data" id="studentForm">
                    <input type="hidden" name="csrf_token" value="<?php echo $csrf_token; ?>">
                    <input type="hidden" name="action" value="<?php echo $action; ?>">
                    <input type="hidden" name="webcam_image" id="webcamImageData" value="">
                    
                    <?php if ($action === 'edit' && $student): ?>
                    <input type="hidden" name="id" value="<?php echo $student['sn']; ?>">
                    <?php endif; ?>
                    
                    <div class="row">
                      <div class="col-md-6">
                        <div class="form-group">
                          <label for="fullname">Full Name *</label>
                          <input type="text" class="form-control" id="fullname" name="fullname" 
                                 value="<?php echo isset($student) ? htmlspecialchars($student['fullname']) : ''; ?>" 
                                 required>
                        </div>
                      </div>
                      <div class="col-md-6">
                        <div class="form-group">
                          <label for="regno">Registration Number *</label>
                          <input type="text" class="form-control" id="regno" name="regno" 
                                 value="<?php echo isset($student) ? htmlspecialchars($student['regno']) : ''; ?>" 
                                 required>
                        </div>
                      </div>
                    </div>
                    
                    <div class="row">
                      <div class="col-md-6">
                        <div class="form-group">
                          <label for="class_id">Class *</label>
                          <select class="form-control" id="class_id" name="class_id" required>
                            <option value="">Select Class</option>
                            <?php foreach ($classes as $class): ?>
                            <option value="<?php echo htmlspecialchars($class['classid']); ?>" 
                                <?php echo (isset($student) && $student['class_id'] === $class['classid']) ? 'selected' : ''; ?>>
                                <?php echo htmlspecialchars($class['classid']); ?>
                            </option>
                            <?php endforeach; ?>
                          </select>
                        </div>
                      </div>
                      <div class="col-md-6">
                        <div class="form-group">
                          <label for="admin_year">Admission Year</label>
                          <select class="form-control" id="admin_year" name="admin_year">
                            <option value="">Select Academic Year</option>
                            <?php foreach ($academic_years as $year): ?>
                            <option value="<?php echo htmlspecialchars($year['academic_year']); ?>"
                                <?php echo (isset($student) && $student['admin_year'] === $year['academic_year']) ? 'selected' : ''; ?>>
                                <?php echo htmlspecialchars($year['academic_year']); ?>
                            </option>
                            <?php endforeach; ?>
                          </select>
                        </div>
                      </div>
                    </div>
                    
                    <div class="form-group">
                      <label>Student Image</label>
                      <div class="image-upload-options">
                        <div class="upload-tabs">
                          <span class="upload-tab active" data-tab="file">Upload File</span>
                          <span class="upload-tab" data-tab="webcam">Take Photo</span>
                          <?php if ($action === 'edit' && !empty($student['image'])): ?>
                          <span class="upload-tab" data-tab="current">Current Image</span>
                          <?php endif; ?>
                        </div>
                        
                        <!-- File Upload -->
                        <div class="upload-content active" id="fileTab">
                          <input type="file" class="form-control-file" id="image_upload" name="image_upload" accept="image/*">
                          <small class="form-text text-muted">Max file size: 2MB. Allowed types: JPG, JPEG, PNG, GIF</small>
                        </div>
                        
                        <!-- Webcam -->
                        <div class="upload-content" id="webcamTab">
                          <div class="webcam-container">
                            <video id="webcamVideo" autoplay playsinline></video>
                            <canvas id="webcamCanvas"></canvas>
                          </div>
                          <div class="webcam-controls text-center">
                            <button type="button" id="captureBtn" class="btn btn-primary btn-sm">
                              <i class="fas fa-camera"></i> Capture Photo
                            </button>
                            <button type="button" id="retakeBtn" class="btn btn-secondary btn-sm" style="display: none;">
                              <i class="fas fa-redo"></i> Retake
                            </button>
                          </div>
                        </div>
                        
                        <!-- Current Image -->
                        <?php if ($action === 'edit' && !empty($student['image'])): ?>
                        <div class="upload-content" id="currentTab">
                          <div class="image-preview">
                            <img src="../<?php echo htmlspecialchars($student['image']); ?>" alt="Current Image" class="preview-image">
                            <p class="text-muted mt-2">Current student image</p>
                          </div>
                        </div>
                        <?php endif; ?>
                        
                        <!-- Image Preview -->
                        <div class="image-preview" id="imagePreview" style="display: none;">
                          <img id="previewImage" class="preview-image">
                          <p class="text-muted mt-2">New Image Preview</p>
                        </div>
                      </div>
                    </div>
                    
                    <div class="form-group">
                      <button type="submit" class="btn btn-primary mr-2">
                        <i class="fas fa-save"></i> 
                        <?php echo $action === 'create' ? 'Create Student' : 'Update Student'; ?>
                      </button>
                      <a href="?" class="btn btn-light">Cancel</a>
                    </div>
                  </form>
                  <?php endif; ?>
                </div>
              </div>
            </div>
          </div>
        </div>
        <!-- partial:partials/_footer.html -->
        <footer class="footer">
          <div class="d-sm-flex justify-content-center justify-content-sm-between">
            <span class="text-muted text-center text-sm-left d-block d-sm-inline-block">Copyright © 2018. All rights reserved.</span>
            <span class="float-none float-sm-right d-block mt-1 mt-sm-0 text-center">Hand-crafted & made with <i class="far fa-heart text-danger"></i></span>
          </div>
        </footer>
        <!-- partial -->
      </div>
    </div>
  </div>
  
  <!-- plugins:js -->
  <script src="vendors/js/vendor.bundle.base.js"></script>
  <script src="vendors/js/vendor.bundle.addons.js"></script>
  <!-- endinject -->

  <!-- Plugin js for this page-->
  <!-- End plugin js for this page-->
  <!-- inject:js -->
  <script src="js/off-canvas.js"></script>
  <script src="js/hoverable-collapse.js"></script>
  <script src="js/misc.js"></script>
  <script src="js/settings.js"></script>
  <script src="js/todolist.js"></script>
  <!-- endinject -->
  <!-- Custom js for this page-->
  <script src="js/dashboard.js"></script>
  
  <script>
    document.addEventListener('DOMContentLoaded', function() {
      // Tab switching
      const tabs = document.querySelectorAll('.upload-tab');
      const contents = document.querySelectorAll('.upload-content');
      
      tabs.forEach(tab => {
        tab.addEventListener('click', function() {
          const tabName = this.getAttribute('data-tab');
          
          // Update tabs
          tabs.forEach(t => t.classList.remove('active'));
          this.classList.add('active');
          
          // Update contents
          contents.forEach(content => content.classList.remove('active'));
          document.getElementById(tabName + 'Tab').classList.add('active');
          
          // Stop webcam when switching away from webcam tab
          if (tabName !== 'webcam') {
            stopWebcam();
          } else {
            startWebcam();
          }
        });
      });
      
      // Webcam functionality
      const video = document.getElementById('webcamVideo');
      const canvas = document.getElementById('webcamCanvas');
      const captureBtn = document.getElementById('captureBtn');
      const retakeBtn = document.getElementById('retakeBtn');
      const webcamImageData = document.getElementById('webcamImageData');
      const previewImage = document.getElementById('previewImage');
      const imagePreview = document.getElementById('imagePreview');
      let stream = null;
      
      function startWebcam() {
        if (navigator.mediaDevices && navigator.mediaDevices.getUserMedia) {
          navigator.mediaDevices.getUserMedia({ 
            video: { 
              width: { ideal: 640 }, 
              height: { ideal: 480 } 
            } 
          })
            .then(function(mediaStream) {
              stream = mediaStream;
              video.srcObject = mediaStream;
              video.style.display = 'block';
              canvas.style.display = 'none';
              captureBtn.style.display = 'inline-block';
              retakeBtn.style.display = 'none';
              webcamImageData.value = ''; // Clear any previous webcam data
            })
            .catch(function(error) {
              console.error('Error accessing webcam:', error);
              alert('Unable to access webcam. Please check permissions and make sure no other application is using the camera.');
            });
        } else {
          alert('Webcam not supported in this browser.');
        }
      }
      
      function stopWebcam() {
        if (stream) {
          stream.getTracks().forEach(track => track.stop());
          stream = null;
        }
      }
      
      captureBtn.addEventListener('click', function() {
        const context = canvas.getContext('2d');
        canvas.width = video.videoWidth;
        canvas.height = video.videoHeight;
        context.drawImage(video, 0, 0, canvas.width, canvas.height);
        
        // Convert to base64
        const imageData = canvas.toDataURL('image/jpeg', 0.8);
        webcamImageData.value = imageData;
        
        // Show preview
        previewImage.src = imageData;
        imagePreview.style.display = 'block';
        
        // Switch UI
        video.style.display = 'none';
        canvas.style.display = 'block';
        captureBtn.style.display = 'none';
        retakeBtn.style.display = 'inline-block';
        
        // Stop webcam
        stopWebcam();
      });
      
      retakeBtn.addEventListener('click', function() {
        webcamImageData.value = '';
        imagePreview.style.display = 'none';
        startWebcam();
      });
      
      // File upload preview
      const fileUpload = document.getElementById('image_upload');
      fileUpload.addEventListener('change', function() {
        if (this.files && this.files[0]) {
          const reader = new FileReader();
          reader.onload = function(e) {
            previewImage.src = e.target.result;
            imagePreview.style.display = 'block';
          }
          reader.readAsDataURL(this.files[0]);
          
          // Clear webcam data when file is selected
          webcamImageData.value = '';
        }
      });
      
      // Start webcam if webcam tab is active on page load
      if (document.getElementById('webcamTab').classList.contains('active')) {
        startWebcam();
      }
      
      // Clean up webcam on page unload
      window.addEventListener('beforeunload', function() {
        stopWebcam();
      });

      // Form submission validation
      document.getElementById('studentForm').addEventListener('submit', function(e) {
        // Basic validation - you can add more specific validations here
        const fullname = document.getElementById('fullname').value.trim();
        const regno = document.getElementById('regno').value.trim();
        const class_id = document.getElementById('class_id').value;
        
        if (!fullname || !regno || !class_id) {
          e.preventDefault();
          alert('Please fill in all required fields (marked with *).');
          return false;
        }
      });
    });
  </script>
</body>
</html>