<?php
// students_crud.php - FIXED VERSION
require_once '../includes/dbcon.php';

// Simple helper functions (assume is_logged_in(), redirect() are defined in includes)
if (!is_logged_in()) {
    redirect('login.php');
}

// Get classes and academic years
$classes = [];
$academic_years = [];
try {
    $stmt = $DBcon->query("SELECT classid FROM class ORDER BY classid");
    $classes = $stmt->fetchAll(PDO::FETCH_ASSOC);

    $stmt = $DBcon->query("SELECT academic_year FROM calender ORDER BY academic_year DESC");
    $academic_years = $stmt->fetchAll(PDO::FETCH_ASSOC);
} catch (PDOException $e) {
    error_log("Database error: " . $e->getMessage());
}

// Initialize variables
$action = isset($_GET['action']) ? $_GET['action'] : 'list';
$id = isset($_GET['id']) ? intval($_GET['id']) : 0;
$message = '';
$message_type = '';
$student = null;
$students = [];
$current_page = isset($_GET['page']) ? max(1, intval($_GET['page'])) : 1;
$per_page = 25;
$total_records = 0;
$total_pages = 0;

// CSRF token generation (if session not started)
if (session_status() !== PHP_SESSION_ACTIVE) {
    session_start();
}
if (empty($_SESSION['csrf_token'])) {
    $_SESSION['csrf_token'] = bin2hex(random_bytes(32));
}
$csrf_token = $_SESSION['csrf_token'];

// Helper: validate CSRF on POST
function check_csrf() {
    if (session_status() !== PHP_SESSION_ACTIVE) {
        session_start();
    }
    $posted = $_POST['csrf_token'] ?? '';
    if (empty($posted) || !hash_equals($_SESSION['csrf_token'] ?? '', $posted)) {
        return false;
    }
    return true;
}

// Image handling functions
function saveWebcamImage($base64_image) {
    if (empty($base64_image) || $base64_image === 'data:,') {
        return '';
    }

    $upload_dir = __DIR__ . '/../uploads/students/';
    if (!file_exists($upload_dir)) {
        mkdir($upload_dir, 0755, true);
    }

    if (preg_match('/^data:image\/(\w+);base64,/', $base64_image, $type)) {
        $image_data = substr($base64_image, strpos($base64_image, ',') + 1);
        $type = strtolower($type[1]);

        if (!in_array($type, ['jpg', 'jpeg', 'png', 'gif'])) {
            return '';
        }

        $image_data = base64_decode($image_data);
        if ($image_data === false) {
            return '';
        }

        $filename = 'student_' . uniqid() . '.' . $type;
        $filepath = $upload_dir . $filename;

        if (file_put_contents($filepath, $image_data)) {
            return 'uploads/students/' . $filename;
        }
    }

    return '';
}

function saveUploadedImage($file) {
    if (!isset($file) || $file['error'] !== UPLOAD_ERR_OK) {
        return '';
    }

    $allowed_types = ['image/jpeg', 'image/jpg', 'image/png', 'image/gif'];
    $max_size = 2 * 1024 * 1024;

    if (!in_array($file['type'], $allowed_types) || $file['size'] > $max_size) {
        return '';
    }

    $upload_dir = __DIR__ . '/../uploads/students/';
    if (!file_exists($upload_dir)) {
        mkdir($upload_dir, 0755, true);
    }

    $extension = pathinfo($file['name'], PATHINFO_EXTENSION);
    $filename = 'student_' . uniqid() . '.' . $extension;
    $filepath = $upload_dir . $filename;

    if (move_uploaded_file($file['tmp_name'], $filepath)) {
        return 'uploads/students/' . $filename;
    }

    return '';
}

// Handle POST requests (Create, Update, Delete)
if ($_SERVER['REQUEST_METHOD'] === 'POST') {
    // CSRF check
    if (!check_csrf()) {
        $message = 'Invalid CSRF token.';
        $message_type = 'error';
    } else {
        $post_action = $_POST['action'] ?? '';

        if ($post_action === 'create' || $post_action === 'update') {
            // Basic validation
            $fullname = trim($_POST['fullname'] ?? '');
            $regno = trim($_POST['regno'] ?? '');
            $class_id = $_POST['class_id'] ?? '';
            $admin_year = $_POST['admin_year'] ?? '';

            if (empty($fullname) || empty($regno) || empty($class_id)) {
                $message = 'Please fill all required fields.';
                $message_type = 'error';
            } else {
                try {
                    // Handle image upload
                    $image_path = '';

                    // Check for webcam image
                    if (!empty($_POST['webcam_image']) && $_POST['webcam_image'] !== 'data:,') {
                        $image_path = saveWebcamImage($_POST['webcam_image']);
                    }
                    // Check for file upload
                    elseif (isset($_FILES['image_upload']) && $_FILES['image_upload']['error'] === UPLOAD_ERR_OK) {
                        $image_path = saveUploadedImage($_FILES['image_upload']);
                    }

                    if ($post_action === 'create') {
                        // CREATE STUDENT
                        $sql = "INSERT INTO students_info (fullname, regno, class_id, admin_year, image) 
                                VALUES (:fullname, :regno, :class_id, :admin_year, :image)";

                        $stmt = $DBcon->prepare($sql);
                        $stmt->bindParam(':fullname', $fullname);
                        $stmt->bindParam(':regno', $regno);
                        $stmt->bindParam(':class_id', $class_id);
                        $stmt->bindParam(':admin_year', $admin_year);
                        $stmt->bindParam(':image', $image_path);

                        if ($stmt->execute()) {
                            $message = 'Student created successfully.';
                            $message_type = 'success';
                            $action = 'list';

                            // Also insert into promoted table
                            $promoted_sql = "INSERT INTO promoted (regno, accademic_year, class_id) 
                                            VALUES (:regno, :year, :class)";
                            $promoted_stmt = $DBcon->prepare($promoted_sql);
                            $promoted_stmt->execute([
                                ':regno' => $regno,
                                ':year' => $admin_year,
                                ':class' => $class_id
                            ]);
                        } else {
                            $message = 'Failed to create student.';
                            $message_type = 'error';
                        }
                    } elseif ($post_action === 'update') {
                        // UPDATE STUDENT
                        $student_id = intval($_POST['id'] ?? 0);

                        if ($student_id > 0) {
                            // Get current student data
                            $current_stmt = $DBcon->prepare("SELECT * FROM students_info WHERE sn = :id");
                            $current_stmt->execute([':id' => $student_id]);
                            $current_student = $current_stmt->fetch(PDO::FETCH_ASSOC);

                            if ($current_student) {
                                // If no new image, keep the old one
                                if (empty($image_path)) {
                                    $image_path = $current_student['image'];
                                } else {
                                    // Delete old image if exists
                                    if (!empty($current_student['image']) && file_exists(__DIR__ . '/../' . $current_student['image'])) {
                                        @unlink(__DIR__ . '/../' . $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);
                                $stmt->bindParam(':fullname', $fullname);
                                $stmt->bindParam(':regno', $regno);
                                $stmt->bindParam(':class_id', $class_id);
                                $stmt->bindParam(':admin_year', $admin_year);
                                $stmt->bindParam(':image', $image_path);
                                $stmt->bindParam(':id', $student_id, PDO::PARAM_INT);

                                if ($stmt->execute()) {
                                    $message = 'Student updated successfully.';
                                    $message_type = 'success';
                                    $action = 'list';

                                    // Update promoted table
                                    $promoted_sql = "UPDATE promoted 
                                                   SET regno = :new_regno, 
                                                       accademic_year = :year, 
                                                       class_id = :class 
                                                   WHERE regno = :old_regno";
                                    $promoted_stmt = $DBcon->prepare($promoted_sql);
                                    $promoted_stmt->execute([
                                        ':new_regno' => $regno,
                                        ':year' => $admin_year,
                                        ':class' => $class_id,
                                        ':old_regno' => $current_student['regno']
                                    ]);
                                } else {
                                    $message = 'Failed to update student.';
                                    $message_type = 'error';
                                }
                            } else {
                                $message = 'Student not found.';
                                $message_type = 'error';
                                $action = 'list';
                            }
                        } else {
                            $message = 'Invalid student ID.';
                            $message_type = 'error';
                        }
                    }
                } catch (PDOException $e) {
                    error_log("Database error: " . $e->getMessage());
                    $message = 'Database error occurred.';
                    $message_type = 'error';
                }
            }
        } elseif ($post_action === 'delete') {
            // DELETE SINGLE STUDENT
            $student_id = intval($_POST['id'] ?? 0);

            if ($student_id > 0) {
                try {
                    // Get student info first
                    $stmt = $DBcon->prepare("SELECT regno, image FROM students_info WHERE sn = :id");
                    $stmt->execute([':id' => $student_id]);
                    $student_data = $stmt->fetch(PDO::FETCH_ASSOC);

                    if ($student_data) {
                        // Delete from promoted table
                        $promoted_stmt = $DBcon->prepare("DELETE FROM promoted WHERE regno = :regno");
                        $promoted_stmt->execute([':regno' => $student_data['regno']]);

                        // Delete image if exists
                        if (!empty($student_data['image']) && file_exists(__DIR__ . '/../' . $student_data['image'])) {
                            @unlink(__DIR__ . '/../' . $student_data['image']);
                        }

                        // Delete student
                        $delete_stmt = $DBcon->prepare("DELETE FROM students_info WHERE sn = :id");
                        if ($delete_stmt->execute([':id' => $student_id])) {
                            $message = 'Student deleted successfully.';
                            $message_type = 'success';
                        }
                    }
                } catch (PDOException $e) {
                    error_log("Delete error: " . $e->getMessage());
                    $message = 'Failed to delete student.';
                    $message_type = 'error';
                }
            }
        } elseif ($post_action === 'bulk_delete') {
            // BULK DELETE
            if (isset($_POST['selected_students']) && is_array($_POST['selected_students'])) {
                $success_count = 0;

                foreach ($_POST['selected_students'] as $student_id_raw) {
                    $student_id = intval($student_id_raw);
                    if ($student_id > 0) {
                        try {
                            // Similar to single delete logic
                            $stmt = $DBcon->prepare("SELECT regno, image FROM students_info WHERE sn = :id");
                            $stmt->execute([':id' => $student_id]);
                            $student_data = $stmt->fetch(PDO::FETCH_ASSOC);

                            if ($student_data) {
                                // Delete from promoted table
                                $promoted_stmt = $DBcon->prepare("DELETE FROM promoted WHERE regno = :regno");
                                $promoted_stmt->execute([':regno' => $student_data['regno']]);

                                // Delete image
                                if (!empty($student_data['image']) && file_exists(__DIR__ . '/../' . $student_data['image'])) {
                                    @unlink(__DIR__ . '/../' . $student_data['image']);
                                }

                                // Delete student
                                $delete_stmt = $DBcon->prepare("DELETE FROM students_info WHERE sn = :id");
                                if ($delete_stmt->execute([':id' => $student_id])) {
                                    $success_count++;
                                }
                            }
                        } catch (PDOException $e) {
                            error_log("Bulk delete error: " . $e->getMessage());
                        }
                    }
                }

                if ($success_count > 0) {
                    $message = "Successfully deleted $success_count student(s).";
                    $message_type = 'success';
                } else {
                    $message = 'No students were deleted.';
                    $message_type = 'error';
                }
            }
        }
    }
}

// Handle Excel Export (CSV) - MODIFIED TO SORT ALPHABETICALLY
if (isset($_GET['export']) && $_GET['export'] === 'excel') {
    try {
        $filter_class = $_GET['filter_class'] ?? '';
        $filter_year = $_GET['filter_year'] ?? '';

        $sql = "SELECT * FROM students_info WHERE 1=1";
        $params = [];

        if (!empty($filter_class)) {
            $sql .= " AND class_id = :class_id";
            $params[':class_id'] = $filter_class;
        }

        if (!empty($filter_year)) {
            $sql .= " AND admin_year = :admin_year";
            $params[':admin_year'] = $filter_year;
        }

        // MODIFIED: Order by fullname alphabetically (A-Z) instead of sn DESC
        $sql .= " ORDER BY fullname ASC";

        $stmt = $DBcon->prepare($sql);
        $stmt->execute($params);
        $students = $stmt->fetchAll(PDO::FETCH_ASSOC);

        // Generate CSV
        header('Content-Type: text/csv');
        header('Content-Disposition: attachment;filename="students_export_' . date('Y-m-d_H-i-s') . '.csv"');

        $output = fopen('php://output', 'w');
        
        // CSV header row
        fputcsv($output, ['SN', 'Full Name', 'Registration Number', 'Class', 'Admission Year', 'Image Path']);

        foreach ($students as $student) {
            fputcsv($output, [
                $student['sn'],
                $student['fullname'],
                $student['regno'],
                $student['class_id'],
                $student['admin_year'],
                $student['image']
            ]);
        }

        fclose($output);
        exit;
    } catch (PDOException $e) {
        error_log("Export error: " . $e->getMessage());
    }
}

// Get student for editing
if ($action === 'edit' && $id > 0) {
    try {
        $stmt = $DBcon->prepare("SELECT * FROM students_info WHERE sn = :id");
        $stmt->execute([':id' => $id]);
        $student = $stmt->fetch(PDO::FETCH_ASSOC);

        if (!$student) {
            $message = 'Student not found.';
            $message_type = 'error';
            $action = 'list';
        }
    } catch (PDOException $e) {
        error_log("Get student error: " . $e->getMessage());
        $action = 'list';
    }
}

// Get students for listing (with filters and pagination)
if ($action === 'list') {
    try {
        $filter_class = $_GET['filter_class'] ?? '';
        $filter_year = $_GET['filter_year'] ?? '';

        // Build query with filters
        $sql = "SELECT * FROM students_info WHERE 1=1";
        $count_sql = "SELECT COUNT(*) as total FROM students_info WHERE 1=1";
        $params = [];
        $count_params = [];

        if (!empty($filter_class)) {
            $sql .= " AND class_id = :class_id";
            $count_sql .= " AND class_id = :class_id";
            $params[':class_id'] = $filter_class;
            $count_params[':class_id'] = $filter_class;
        }

        if (!empty($filter_year)) {
            $sql .= " AND admin_year = :admin_year";
            $count_sql .= " AND admin_year = :admin_year";
            $params[':admin_year'] = $filter_year;
            $count_params[':admin_year'] = $filter_year;
        }

        $sql .= " ORDER BY sn DESC LIMIT :offset, :per_page";

        // Get total count
        $count_stmt = $DBcon->prepare($count_sql);
        $count_stmt->execute($count_params);
        $total_result = $count_stmt->fetch(PDO::FETCH_ASSOC);
        $total_records = $total_result['total'] ?? 0;
        $total_pages = ceil($total_records / $per_page);

        // Get paginated results
        $offset = ($current_page - 1) * $per_page;
        $stmt = $DBcon->prepare($sql);

        foreach ($params as $key => $value) {
            $stmt->bindValue($key, $value);
        }
        $stmt->bindValue(':offset', $offset, PDO::PARAM_INT);
        $stmt->bindValue(':per_page', $per_page, PDO::PARAM_INT);

        $stmt->execute();
        $students = $stmt->fetchAll(PDO::FETCH_ASSOC);

    } catch (PDOException $e) {
        error_log("List students error: " . $e->getMessage());
        $students = [];
    }
}
?>
<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no">
  <title>Student Management - School Admin</title>
  <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">
  <link rel="stylesheet" href="css/style.css">
  <style>
    .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; }
    .bulk-actions { background: #f8f9fa; padding: 10px; border-radius: 4px; margin-bottom: 15px; }
    .upload-tab { padding: 8px 15px; background: #e9ecef; border: 1px solid #dee2e6; cursor: pointer; margin-right: 5px; border-radius: 4px; display:inline-block;}
    .upload-tab.active { background: #007bff; color: white; border-color: #007bff; }
    .upload-content { display: none; }
    .upload-content.active { display: block; }
    #webcamVideo { max-width: 300px; border: 2px solid #007bff; border-radius: 4px; }
    .preview-image { max-width: 200px; max-height: 200px; border-radius: 4px; }
  </style>
</head>
<body>
  <div class="container-scroller">
    <?php include("header.php"); ?>
    <div class="container-fluid page-body-wrapper">
      <?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">Students</li>
              </ol>
            </nav>
          </div>

          <?php if ($message): ?>
          <div class="alert alert-<?php echo $message_type === 'success' ? 'success' : 'error'; ?>">
            <?php echo htmlspecialchars($message); ?>
          </div>
          <?php endif; ?>

          <div class="row">
            <div class="col-12 grid-margin">
              <div class="card">
                <div class="card-body">
                  <h4 class="card-title mb-4">
                    <i class="fas fa-table"></i>
                    <?php
                      echo $action === 'create' ? 'Add New Student' :
                           ($action === 'edit' ? 'Edit Student' : 'Student List');
                    ?>
                  </h4>

                  <?php if ($action === 'list'): ?>
                  <!-- List View -->
                  <div class="mb-4">
                    <a href="?action=create" class="btn btn-primary btn-sm">
                      <i class="fas fa-plus"></i> Add New Student
                    </a>
                    <?php
                      $export_url = '?export=excel';
                      if (!empty($filter_class)) $export_url .= '&filter_class=' . urlencode($filter_class);
                      if (!empty($filter_year)) $export_url .= '&filter_year=' . urlencode($filter_year);
                    ?>
                    <a href="<?php echo $export_url; ?>" class="btn btn-success btn-sm" title="Export in Alphabetical Order (A-Z)">
                      <i class="fas fa-file-excel"></i> Export (A-Z)
                    </a>
                  </div>

                  <!-- Filters -->
                  <form method="GET" class="mb-4">
                    <input type="hidden" name="action" value="list">
                    <div class="row">
                      <div class="col-md-4">
                        <select name="filter_class" class="form-control">
                          <option value="">All Classes</option>
                          <?php foreach ($classes as $class): ?>
                          <option value="<?php echo htmlspecialchars($class['classid']); ?>" <?php echo (isset($filter_class) && $filter_class === $class['classid']) ? 'selected' : ''; ?>>
                            <?php echo htmlspecialchars($class['classid']); ?>
                          </option>
                          <?php endforeach; ?>
                        </select>
                      </div>
                      <div class="col-md-4">
                        <select name="filter_year" class="form-control">
                          <option value="">All Years</option>
                          <?php foreach ($academic_years as $year): ?>
                          <option value="<?php echo htmlspecialchars($year['academic_year']); ?>" <?php echo (isset($filter_year) && $filter_year === $year['academic_year']) ? 'selected' : ''; ?>>
                            <?php echo htmlspecialchars($year['academic_year']); ?>
                          </option>
                          <?php endforeach; ?>
                        </select>
                      </div>
                      <div class="col-md-4">
                        <button type="submit" class="btn btn-primary">Filter</button>
                        <a href="?" class="btn btn-light">Clear</a>
                      </div>
                    </div>
                  </form>

                  <!-- Bulk Actions -->
                  <form method="POST" id="bulkForm" class="mb-4">
                    <input type="hidden" name="csrf_token" value="<?php echo $csrf_token; ?>">
                    <input type="hidden" name="action" value="bulk_delete">
                    <div class="bulk-actions">
                      <button type="button" class="btn btn-danger btn-sm" id="bulkDeleteBtn" disabled>
                        Delete Selected (<span id="selectedCount">0</span>)
                      </button>
                      <span class="ml-3">Total: <?php echo htmlspecialchars($total_records); ?> records</span>
                    </div>

                    <!-- Students Table -->
                    <div class="table-responsive">
                      <table class="table table-striped">
                        <thead>
                          <tr>
                            <th><input type="checkbox" id="selectAll"></th>
                            <th>ID</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 if (count($students) > 0): ?>
                            <?php foreach ($students as $s): ?>
                            <tr>
                              <td><input type="checkbox" class="student-check" name="selected_students[]" value="<?php echo intval($s['sn']); ?>"></td>
                              <td><?php echo intval($s['sn']); ?></td>
                              <td>
                                <?php if (!empty($s['image']) && file_exists(__DIR__ . '/../' . $s['image'])): ?>
                                <img src="../<?php echo htmlspecialchars($s['image']); ?>" class="student-image">
                                <?php else: ?>
                                <div class="student-image bg-light text-center">
                                  <i class="fas fa-user text-muted"></i>
                                </div>
                                <?php endif; ?>
                              </td>
                              <td><?php echo htmlspecialchars($s['fullname']); ?></td>
                              <td><?php echo htmlspecialchars($s['regno']); ?></td>
                              <td><?php echo htmlspecialchars($s['class_id']); ?></td>
                              <td><?php echo htmlspecialchars($s['admin_year']); ?></td>
                              <td>
                                <a href="?action=edit&id=<?php echo intval($s['sn']); ?>" class="btn btn-info btn-sm">
                                  <i class="fas fa-edit"></i>
                                </a>
                                <form method="POST" style="display:inline;" onsubmit="return confirm('Delete this student?');">
                                  <input type="hidden" name="csrf_token" value="<?php echo $csrf_token; ?>">
                                  <input type="hidden" name="action" value="delete">
                                  <input type="hidden" name="id" value="<?php echo intval($s['sn']); ?>">
                                  <button type="submit" class="btn btn-danger btn-sm">
                                    <i class="fas fa-trash"></i>
                                  </button>
                                </form>
                              </td>
                            </tr>
                            <?php endforeach; ?>
                          <?php else: ?>
                            <tr>
                              <td colspan="8" class="text-center py-4">No students found.</td>
                            </tr>
                          <?php endif; ?>
                        </tbody>
                      </table>
                    </div>
                  </form>

                  <!-- Pagination -->
                  <?php if ($total_pages > 1): ?>
                  <nav>
                    <ul class="pagination justify-content-center">
                      <?php for ($i = 1; $i <= $total_pages; $i++): ?>
                      <li class="page-item <?php echo $i == $current_page ? 'active' : ''; ?>">
                        <a class="page-link" href="?page=<?php echo $i; ?>&filter_class=<?php echo urlencode($filter_class ?? ''); ?>&filter_year=<?php echo urlencode($filter_year ?? ''); ?>">
                          <?php echo $i; ?>
                        </a>
                      </li>
                      <?php endfor; ?>
                    </ul>
                  </nav>
                  <?php endif; ?>

                  <?php elseif ($action === 'create' || $action === 'edit'): ?>
                  <!-- Create/Edit Form -->
                  <form method="POST" enctype="multipart/form-data">
                    <input type="hidden" name="csrf_token" value="<?php echo $csrf_token; ?>">
                    <?php
                      // Ensure the form posts the expected action values for create/update
                      $form_action_value = $action === 'edit' ? 'update' : 'create';
                    ?>
                    <input type="hidden" name="action" value="<?php echo $form_action_value; ?>">
                    <input type="hidden" name="webcam_image" id="webcamImageData" value="">

                    <?php if ($action === 'edit' && $student): ?>
                    <input type="hidden" name="id" value="<?php echo intval($student['sn']); ?>">
                    <?php endif; ?>

                    <div class="row">
                      <div class="col-md-6">
                        <div class="form-group">
                          <label>Full Name *</label>
                          <input type="text" name="fullname" class="form-control"
                                 value="<?php echo htmlspecialchars($student['fullname'] ?? ''); ?>" required>
                        </div>
                      </div>
                      <div class="col-md-6">
                        <div class="form-group">
                          <label>Registration Number *</label>
                          <input type="text" name="regno" class="form-control"
                                 value="<?php echo htmlspecialchars($student['regno'] ?? ''); ?>" required>
                        </div>
                      </div>
                    </div>

                    <div class="row">
                      <div class="col-md-6">
                        <div class="form-group">
                          <label>Class *</label>
                          <select name="class_id" class="form-control" required>
                            <option value="">Select Class</option>
                            <?php foreach ($classes as $class): ?>
                            <option value="<?php echo htmlspecialchars($class['classid']); ?>"
                              <?php echo (isset($student['class_id']) && $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>Admission Year</label>
                          <select name="admin_year" class="form-control">
                            <option value="">Select Year</option>
                            <?php foreach ($academic_years as $year): ?>
                            <option value="<?php echo htmlspecialchars($year['academic_year']); ?>"
                              <?php echo (isset($student['admin_year']) && $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="mb-3">
                        <span class="upload-tab active" onclick="showTab('file', this)">Upload File</span>
                        <span class="upload-tab" onclick="showTab('webcam', this)">Take Photo</span>
                        <?php if ($action === 'edit' && !empty($student['image'])): ?>
                        <span class="upload-tab" onclick="showTab('current', this)">Current Image</span>
                        <?php endif; ?>
                      </div>

                      <div id="fileTab" class="upload-content active">
                        <input type="file" name="image_upload" class="form-control" accept="image/*">
                        <small class="text-muted">Max 2MB, JPG/PNG/GIF</small>
                      </div>

                      <div id="webcamTab" class="upload-content">
                        <div class="text-center">
                          <video id="webcamVideo" autoplay playsinline></video>
                          <canvas id="webcamCanvas" style="display:none;"></canvas>
                          <div class="mt-2">
                            <button type="button" class="btn btn-primary btn-sm" id="captureBtn" onclick="capturePhoto()">
                              <i class="fas fa-camera"></i> Capture
                            </button>
                            <button type="button" class="btn btn-secondary btn-sm" id="retakeBtn" onclick="retakePhoto()" style="display:none;">
                              Retake
                            </button>
                          </div>
                        </div>
                      </div>

                      <?php if ($action === 'edit' && !empty($student['image'])): ?>
                      <div id="currentTab" class="upload-content">
                        <img src="../<?php echo htmlspecialchars($student['image']); ?>" class="preview-image">
                      </div>
                      <?php endif; ?>

                      <div id="imagePreview" class="mt-3" style="display:none;">
                        <img id="previewImage" class="preview-image">
                      </div>
                    </div>

                    <div class="form-group">
                      <button type="submit" class="btn btn-primary">
                        <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>

        <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>
          </div>
        </footer>
      </div>
    </div>
  </div>

  <script src="vendors/js/vendor.bundle.base.js"></script>
  <script src="vendors/js/vendor.bundle.addons.js"></script>

  <script>
  // Bulk selection
  document.addEventListener('DOMContentLoaded', function() {
      const selectAll = document.getElementById('selectAll');
      const studentChecks = document.querySelectorAll('.student-check');
      const bulkDeleteBtn = document.getElementById('bulkDeleteBtn');
      const selectedCount = document.getElementById('selectedCount');
      const bulkForm = document.getElementById('bulkForm');

      function updateSelection() {
          const checked = document.querySelectorAll('.student-check:checked');
          const count = checked.length;
          selectedCount.textContent = count;
          bulkDeleteBtn.disabled = count === 0;
      }

      if (selectAll) {
          selectAll.addEventListener('change', function() {
              document.querySelectorAll('.student-check').forEach(check => {
                  check.checked = this.checked;
              });
              updateSelection();
          });
      }

      document.querySelectorAll('.student-check').forEach(check => {
          check.addEventListener('change', updateSelection);
      });

      bulkDeleteBtn.addEventListener('click', function() {
          const count = parseInt(selectedCount.textContent, 10);
          if (count > 0 && confirm(`Delete ${count} selected student(s)?`)) {
              bulkForm.submit();
          }
      });
  });

  // Image upload tabs - pass the clicked element to avoid using global 'event'
  function showTab(tabName, el) {
      // Hide all tabs
      document.querySelectorAll('.upload-content').forEach(tab => {
          tab.style.display = 'none';
          tab.classList.remove('active');
      });
      document.querySelectorAll('.upload-tab').forEach(tab => {
          tab.classList.remove('active');
      });

      // Show selected tab
      const target = document.getElementById(tabName + 'Tab');
      if (target) {
          target.style.display = 'block';
          target.classList.add('active');
      }
      if (el) {
          el.classList.add('active');
      }

      // Stop webcam if switching away from webcam tab
      if (tabName !== 'webcam') {
          if (window.stream) {
              window.stream.getTracks().forEach(track => track.stop());
          }
      } else {
          startWebcam();
      }
  }

  // Webcam functionality
  let stream = null;

  function startWebcam() {
      if (navigator.mediaDevices && navigator.mediaDevices.getUserMedia) {
          navigator.mediaDevices.getUserMedia({ video: true })
              .then(function(mediaStream) {
                  stream = mediaStream;
                  const video = document.getElementById('webcamVideo');
                  video.srcObject = mediaStream;
              })
              .catch(function(error) {
                  console.error('Webcam error:', error);
                  alert('Cannot access webcam. Please check permissions.');
              });
      }
  }

  function capturePhoto() {
      const video = document.getElementById('webcamVideo');
      const canvas = document.getElementById('webcamCanvas');
      const context = canvas.getContext('2d');

      canvas.width = video.videoWidth || 640;
      canvas.height = video.videoHeight || 480;
      context.drawImage(video, 0, 0, canvas.width, canvas.height);

      // Convert to base64
      const imageData = canvas.toDataURL('image/jpeg');
      document.getElementById('webcamImageData').value = imageData;

      // Show preview
      document.getElementById('previewImage').src = imageData;
      document.getElementById('imagePreview').style.display = 'block';

      // Hide video, show canvas
      video.style.display = 'none';
      canvas.style.display = 'block';

      // Stop webcam
      if (stream) {
          stream.getTracks().forEach(track => track.stop());
      }

      // Toggle capture/retake buttons
      const captureBtn = document.getElementById('captureBtn');
      const retakeBtn = document.getElementById('retakeBtn');
      if (captureBtn) captureBtn.style.display = 'none';
      if (retakeBtn) retakeBtn.style.display = 'inline-block';
  }

  function retakePhoto() {
      document.getElementById('webcamImageData').value = '';
      document.getElementById('imagePreview').style.display = 'none';

      const video = document.getElementById('webcamVideo');
      const canvas = document.getElementById('webcamCanvas');

      video.style.display = 'block';
      canvas.style.display = 'none';

      startWebcam();

      const captureBtn = document.getElementById('captureBtn');
      const retakeBtn = document.getElementById('retakeBtn');
      if (captureBtn) captureBtn.style.display = 'inline-block';
      if (retakeBtn) retakeBtn.style.display = 'none';
  }

  // File upload preview
  document.addEventListener('DOMContentLoaded', function() {
      const fileInput = document.querySelector('input[name="image_upload"]');
      if (fileInput) {
          fileInput.addEventListener('change', function() {
              if (this.files && this.files[0]) {
                  const reader = new FileReader();
                  reader.onload = function(e) {
                      document.getElementById('previewImage').src = e.target.result;
                      document.getElementById('imagePreview').style.display = 'block';
                      document.getElementById('webcamImageData').value = '';
                  };
                  reader.readAsDataURL(this.files[0]);
              }
          });
      }

      // Start webcam if webcam tab is active
      if (document.getElementById('webcamTab') && document.getElementById('webcamTab').classList.contains('active')) {
          startWebcam();
      }
  });
  </script>
</body>
</html>