<?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 [];
    }
}

// NEW FUNCTION: Insert record into promoted table
function insertIntoPromotedTable($regno, $academic_year, $class_id) {
    global $DBcon;
    
    try {
        $sql = "INSERT INTO promoted (regno, accademic_year, class_id) 
                VALUES (:regno, :accademic_year, :class_id)";
        $stmt = $DBcon->prepare($sql);
        
        $result = $stmt->execute([
            ':regno' => sanitize_input($regno),
            ':accademic_year' => sanitize_input($academic_year),
            ':class_id' => sanitize_input($class_id)
        ]);
        
        return $result;
        
    } catch (PDOException $e) {
        error_log("Insert into promoted table error: " . $e->getMessage());
        return false;
    }
}

// NEW FUNCTION: Update record in promoted table
function updatePromotedTable($old_regno, $new_regno, $academic_year, $class_id) {
    global $DBcon;
    
    try {
        // First check if record exists in promoted table
        $check_sql = "SELECT sn FROM promoted WHERE regno = :old_regno";
        $check_stmt = $DBcon->prepare($check_sql);
        $check_stmt->execute([':old_regno' => sanitize_input($old_regno)]);
        $existing_record = $check_stmt->fetch(PDO::FETCH_ASSOC);
        
        if ($existing_record) {
            // Update existing record
            $sql = "UPDATE promoted 
                    SET regno = :new_regno, 
                        accademic_year = :accademic_year, 
                        class_id = :class_id 
                    WHERE regno = :old_regno";
            $stmt = $DBcon->prepare($sql);
            
            $result = $stmt->execute([
                ':new_regno' => sanitize_input($new_regno),
                ':accademic_year' => sanitize_input($academic_year),
                ':class_id' => sanitize_input($class_id),
                ':old_regno' => sanitize_input($old_regno)
            ]);
        } else {
            // Insert new record if not exists
            $result = insertIntoPromotedTable($new_regno, $academic_year, $class_id);
        }
        
        return $result;
        
    } catch (PDOException $e) {
        error_log("Update promoted table error: " . $e->getMessage());
        return false;
    }
}

// NEW FUNCTION: Delete record from promoted table
function deleteFromPromotedTable($regno) {
    global $DBcon;
    
    try {
        $sql = "DELETE FROM promoted WHERE regno = :regno";
        $stmt = $DBcon->prepare($sql);
        return $stmt->execute([':regno' => sanitize_input($regno)]);
    } catch (PDOException $e) {
        error_log("Delete from promoted table error: " . $e->getMessage());
        return false;
    }
}

// CRUD Functions
function getAllStudents($filters = [], $page = 1, $per_page = 25) {
    global $DBcon;
    
    try {
        // Build WHERE clause based on filters
        $where_clause = "";
        $params = [];
        
        if (!empty($filters['class_id'])) {
            $where_clause .= " WHERE class_id = :class_id";
            $params[':class_id'] = $filters['class_id'];
        }
        
        if (!empty($filters['admin_year'])) {
            $where_clause .= empty($where_clause) ? " WHERE" : " AND";
            $where_clause .= " admin_year = :admin_year";
            $params[':admin_year'] = $filters['admin_year'];
        }
        
        // Get total count for pagination
        $count_sql = "SELECT COUNT(*) as total FROM students_info" . $where_clause;
        $count_stmt = $DBcon->prepare($count_sql);
        $count_stmt->execute($params);
        $total_result = $count_stmt->fetch(PDO::FETCH_ASSOC);
        $total_records = $total_result['total'];
        $total_pages = ceil($total_records / $per_page);
        
        // Calculate offset
        $offset = ($page - 1) * $per_page;
        
        // Get students with pagination
        $sql = "SELECT * FROM students_info" . $where_clause . " ORDER BY sn DESC LIMIT :offset, :per_page";
        $stmt = $DBcon->prepare($sql);
        
        // Bind parameters
        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);
        
        return [
            'students' => $students,
            'total_records' => $total_records,
            'total_pages' => $total_pages,
            'current_page' => $page
        ];
        
    } catch (PDOException $e) {
        error_log("Get all students error: " . $e->getMessage());
        return [
            'students' => [],
            'total_records' => 0,
            'total_pages' => 0,
            'current_page' => 1
        ];
    }
}

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);
        return $result;
    } catch (PDOException $e) {
        error_log("Get student error: " . $e->getMessage());
        return false;
    }
}

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
        ]);
        
        // INSERT INTO PROMOTED TABLE - NEW CODE ADDED
        if ($result) {
            $promoted_result = insertIntoPromotedTable($data['regno'], $data['admin_year'], $data['class_id']);
            if (!$promoted_result) {
                error_log("Failed to insert into promoted table for student: " . $data['regno']);
                // Don't return false here as student creation was successful
                // Just log the error for the promoted table insertion
            }
        }
        
        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) {
            return false;
        }
        
        // Handle image upload
        $image_path = handleImageUpload($files, $data);
        
        // If no new image was uploaded, keep the current image
        if ($image_path === '') {
            $image_path = $current_student['image'];
        } else if ($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']);
            }
        } else {
            // Image upload failed
            $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'])
        ];
        
        $result = $stmt->execute($params);
        
        // UPDATE PROMOTED TABLE - NEW CODE ADDED
        if ($result) {
            $update_promoted = updatePromotedTable($current_student['regno'], $data['regno'], $data['admin_year'], $data['class_id']);
            if (!$update_promoted) {
                error_log("Failed to update promoted table for student: " . $data['regno']);
                // Don't return false here as student update was successful
                // Just log the error for the promoted table update
            }
        }
        
        return $result;
        
    } catch (PDOException $e) {
        error_log("Update student error: " . $e->getMessage());
        return false;
    }
}

function handleImageUpload($files, $data) {
    // Check for webcam image first
    if (!empty($data['webcam_image']) && $data['webcam_image'] !== 'data:,') {
        return saveWebcamImage($data['webcam_image']);
    }
    
    // Check for file upload
    if (isset($files['image_upload']) && $files['image_upload']['error'] === UPLOAD_ERR_OK) {
        return saveUploadedImage($files['image_upload']);
    }
    
    // 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'])) {
            return false;
        }
        
        $image_data = base64_decode($image_data);
        
        if ($image_data === false) {
            return false;
        }
    } else {
        return false;
    }
    
    $filename = 'student_' . uniqid() . '.' . $type;
    $filepath = $upload_dir . $filename;
    
    if (file_put_contents($filepath, $image_data)) {
        return 'uploads/students/' . $filename;
    }
    
    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)) {
        return false;
    }
    
    if ($file['size'] > $max_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)) {
        return 'uploads/students/' . $filename;
    }
    
    return false;
}

function deleteStudent($id) {
    global $DBcon;
    
    try {
        // Get student data first to delete from promoted table
        $student = getStudent($id);
        if (!$student) {
            return false;
        }
        
        // DELETE FROM PROMOTED TABLE - NEW CODE ADDED
        if ($student && !empty($student['regno'])) {
            $delete_promoted = deleteFromPromotedTable($student['regno']);
            if (!$delete_promoted) {
                error_log("Failed to delete from promoted table for student: " . $student['regno']);
                // Continue with student deletion even if promoted table deletion fails
            }
        }
        
        // Delete student image if it exists
        if (!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;
    }
}

// Generate CSRF token
$csrf_token = generate_csrf_token();

// Get classes and academic years
$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.';
        $message_type = 'error';
    } else {
        // Process different actions
        switch ($_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;
                
            case 'bulk_delete':
                if (isset($_POST['selected_students']) && is_array($_POST['selected_students'])) {
                    $success_count = 0;
                    $error_count = 0;
                    foreach ($_POST['selected_students'] as $student_id) {
                        if (deleteStudent($student_id)) {
                            $success_count++;
                        } else {
                            $error_count++;
                        }
                    }
                    if ($success_count > 0) {
                        $message = "Successfully deleted $success_count student(s).";
                        $message_type = 'success';
                        if ($error_count > 0) {
                            $message .= " Failed to delete $error_count student(s).";
                        }
                    } else {
                        $message = 'Failed to delete selected students.';
                        $message_type = 'error';
                    }
                } else {
                    $message = 'No students selected for deletion.';
                    $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';
    }
}

// Get filter parameters
$filter_class = isset($_GET['filter_class']) ? sanitize_input($_GET['filter_class']) : '';
$filter_year = isset($_GET['filter_year']) ? sanitize_input($_GET['filter_year']) : '';
$current_page = isset($_GET['page']) ? max(1, intval($_GET['page'])) : 1;

// Build filters array
$filters = [];
if (!empty($filter_class)) {
    $filters['class_id'] = $filter_class;
}
if (!empty($filter_year)) {
    $filters['admin_year'] = $filter_year;
}

// Get students with filters and pagination
$students_data = getAllStudents($filters, $current_page, 25);
$students = $students_data['students'];
$total_records = $students_data['total_records'];
$total_pages = $students_data['total_pages'];
?>

<!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>
    .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; }
    .filter-section { background-color: #f8f9fa; border-radius: 4px; padding: 15px; margin-bottom: 20px; }
    .pagination { justify-content: center; margin-top: 20px; }
    .bulk-actions { margin-bottom: 15px; display: flex; align-items: center; gap: 10px; flex-wrap: wrap; padding: 10px; background: #f8f9fa; border-radius: 4px; }
    .records-info { color: #6c757d; font-size: 0.9rem; margin-left: auto; }
    .no-records { text-align: center; padding: 30px; color: #6c757d; }
    .bulk-delete-btn:disabled { opacity: 0.5; cursor: not-allowed; }
    .bulk-delete-btn:not(:disabled):hover { background-color: #c82333; border-color: #bd2130; }
    .checkbox-cell { width: 40px; text-align: center; vertical-align: middle; }
    .table th { vertical-align: middle; }
    @media (max-width: 768px) {
        .bulk-actions { flex-direction: column; align-items: flex-start; }
        .records-info { margin-left: 0; margin-top: 10px; }
        .filter-section .row > div { margin-bottom: 10px; }
        .upload-tabs { flex-direction: column; }
    }
  </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" aria-current="page">Students</li>
              </ol>
            </nav>
          </div>
          
          <?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 ($action === 'list'): ?>
                  <!-- Filters Section -->
                  <div class="filter-section">
                    <form method="GET" id="filterForm">
                      <div class="row">
                        <div class="col-md-4">
                          <div class="form-group">
                            <label for="filter_class">Filter by Class</label>
                            <select class="form-control" id="filter_class" name="filter_class">
                              <option value="">All Classes</option>
                              <?php foreach ($classes as $class): ?>
                              <option value="<?php echo htmlspecialchars($class['classid']); ?>" 
                                  <?php echo $filter_class === $class['classid'] ? 'selected' : ''; ?>>
                                  <?php echo htmlspecialchars($class['classid']); ?>
                              </option>
                              <?php endforeach; ?>
                            </select>
                          </div>
                        </div>
                        <div class="col-md-4">
                          <div class="form-group">
                            <label for="filter_year">Filter by Admission Year</label>
                            <select class="form-control" id="filter_year" name="filter_year">
                              <option value="">All Years</option>
                              <?php foreach ($academic_years as $year): ?>
                              <option value="<?php echo htmlspecialchars($year['academic_year']); ?>"
                                  <?php echo $filter_year === $year['academic_year'] ? 'selected' : ''; ?>>
                                  <?php echo htmlspecialchars($year['academic_year']); ?>
                              </option>
                              <?php endforeach; ?>
                            </select>
                          </div>
                        </div>
                        <div class="col-md-4 d-flex align-items-end">
                          <div class="form-group w-100">
                            <button type="submit" class="btn btn-primary mr-2">
                              <i class="fas fa-filter"></i> Apply Filters
                            </button>
                            <a href="?" class="btn btn-light">Clear</a>
                          </div>
                        </div>
                      </div>
                    </form>
                  </div>
                  
                  <!-- Bulk Actions -->
                  <div class="bulk-actions">
                    <div class="form-check">
                      <input type="checkbox" class="form-check-input" id="selectAll">
                      <label class="form-check-label" for="selectAll">Select All</label>
                    </div>
                    <button type="button" class="btn btn-danger btn-sm bulk-delete-btn" id="bulkDeleteBtn" disabled>
                      <i class="fas fa-trash"></i> Delete Selected (<span id="selectedCount">0</span>)
                    </button>
                    <div class="records-info">
                      Showing <?php echo count($students); ?> of <?php echo $total_records; ?> records
                    </div>
                  </div>
                  
                  <!-- Student List -->
                  <div class="table-responsive">
                    <table class="table table-striped">
                      <thead>
                        <tr>
                          <th class="checkbox-cell">
                            <input type="checkbox" class="form-check-input" id="selectAllHeader">
                          </th>
                          <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 if (count($students) > 0): ?>
                          <?php foreach ($students as $student): ?>
                          <tr>
                            <td class="checkbox-cell">
                              <input type="checkbox" class="form-check-input student-checkbox" value="<?php echo $student['sn']; ?>">
                            </td>
                            <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 $student['sn']; ?>">
                                <button type="submit" class="btn btn-danger btn-sm">
                                  <i class="fas fa-trash"></i>
                                </button>
                              </form>
                            </td>
                          </tr>
                          <?php endforeach; ?>
                        <?php else: ?>
                        <tr>
                          <td colspan="8" class="no-records">
                            <i class="fas fa-user-slash fa-2x mb-2"></i>
                            <p>No students found. 
                              <?php if (!empty($filter_class) || !empty($filter_year)): ?>
                              Try changing your filters or <a href="?">clear all filters</a>.
                              <?php else: ?>
                              <a href="?action=create">Add the first student</a>.
                              <?php endif; ?>
                            </p>
                          </td>
                        </tr>
                        <?php endif; ?>
                      </tbody>
                    </table>
                  </div>
                  
                  <!-- Pagination -->
                  <?php if ($total_pages > 1): ?>
                  <nav aria-label="Page navigation">
                    <ul class="pagination">
                      <li class="page-item <?php echo $current_page <= 1 ? 'disabled' : ''; ?>">
                        <a class="page-link" href="?<?php echo http_build_query(array_merge($_GET, ['page' => $current_page - 1])); ?>" aria-label="Previous">
                          <span aria-hidden="true">&laquo;</span>
                        </a>
                      </li>
                      
                      <?php for ($i = 1; $i <= $total_pages; $i++): ?>
                        <li class="page-item <?php echo $i == $current_page ? 'active' : ''; ?>">
                          <a class="page-link" href="?<?php echo http_build_query(array_merge($_GET, ['page' => $i])); ?>"><?php echo $i; ?></a>
                        </li>
                      <?php endfor; ?>
                      
                      <li class="page-item <?php echo $current_page >= $total_pages ? 'disabled' : ''; ?>">
                        <a class="page-link" href="?<?php echo http_build_query(array_merge($_GET, ['page' => $current_page + 1])); ?>" aria-label="Next">
                          <span aria-hidden="true">&raquo;</span>
                        </a>
                      </li>
                    </ul>
                  </nav>
                  <?php endif; ?>
                  
                  <?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>
                        
                        <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>
                        
                        <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>
                        
                        <?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; ?>
                        
                        <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>
        
        <!-- Hidden Bulk Delete Form -->
        <form method="POST" id="bulkDeleteForm" style="display: none;">
          <input type="hidden" name="csrf_token" value="<?php echo $csrf_token; ?>">
          <input type="hidden" name="action" value="bulk_delete">
          <div id="selectedStudentsContainer"></div>
        </form>
        
        <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>
      </div>
    </div>
  </div>
  
  <script src="vendors/js/vendor.bundle.base.js"></script>
  <script src="vendors/js/vendor.bundle.addons.js"></script>
  <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>
  <script src="js/dashboard.js"></script>
  
  <script>
    // Bulk Selection System
    document.addEventListener('DOMContentLoaded', function() {
        const selectAllCheckbox = document.getElementById('selectAll');
        const selectAllHeader = document.getElementById('selectAllHeader');
        const studentCheckboxes = document.querySelectorAll('.student-checkbox');
        const bulkDeleteBtn = document.getElementById('bulkDeleteBtn');
        const selectedCountSpan = document.getElementById('selectedCount');
        const bulkDeleteForm = document.getElementById('bulkDeleteForm');
        const selectedStudentsContainer = document.getElementById('selectedStudentsContainer');
        
        function updateSelection() {
            const selectedCheckboxes = document.querySelectorAll('.student-checkbox:checked');
            const selectedCount = selectedCheckboxes.length;
            
            selectedCountSpan.textContent = selectedCount;
            bulkDeleteBtn.disabled = selectedCount === 0;
            
            const totalCheckboxes = studentCheckboxes.length;
            const allSelected = totalCheckboxes > 0 && selectedCount === totalCheckboxes;
            const someSelected = selectedCount > 0 && selectedCount < totalCheckboxes;
            
            if (selectAllCheckbox) {
                selectAllCheckbox.checked = allSelected;
                selectAllCheckbox.indeterminate = someSelected;
            }
            
            if (selectAllHeader) {
                selectAllHeader.checked = allSelected;
                selectAllHeader.indeterminate = someSelected;
            }
        }
        
        function setupSelectAll(checkbox, targetCheckboxes) {
            if (checkbox) {
                checkbox.addEventListener('change', function() {
                    const isChecked = this.checked;
                    targetCheckboxes.forEach(cb => {
                        cb.checked = isChecked;
                    });
                    updateSelection();
                });
            }
        }
        
        setupSelectAll(selectAllCheckbox, studentCheckboxes);
        setupSelectAll(selectAllHeader, studentCheckboxes);
        
        studentCheckboxes.forEach(checkbox => {
            checkbox.addEventListener('change', updateSelection);
        });
        
        bulkDeleteBtn.addEventListener('click', function() {
            if (this.disabled) return;
            
            const selectedCheckboxes = document.querySelectorAll('.student-checkbox:checked');
            const selectedCount = selectedCheckboxes.length;
            
            if (selectedCount === 0) return;
            
            if (!confirm(`Are you sure you want to delete ${selectedCount} selected student(s)? This action cannot be undone.`)) {
                return;
            }
            
            selectedStudentsContainer.innerHTML = '';
            
            selectedCheckboxes.forEach(checkbox => {
                const input = document.createElement('input');
                input.type = 'hidden';
                input.name = 'selected_students[]';
                input.value = checkbox.value;
                selectedStudentsContainer.appendChild(input);
            });
            
            bulkDeleteForm.submit();
        });
        
        updateSelection();
    });

    // Webcam and Form Functionality
    document.addEventListener('DOMContentLoaded', function() {
        const tabs = document.querySelectorAll('.upload-tab');
        const contents = document.querySelectorAll('.upload-content');
        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;
        
        tabs.forEach(tab => {
            tab.addEventListener('click', function() {
                const tabName = this.getAttribute('data-tab');
                
                tabs.forEach(t => t.classList.remove('active'));
                this.classList.add('active');
                
                contents.forEach(content => content.classList.remove('active'));
                document.getElementById(tabName + 'Tab').classList.add('active');
                
                if (tabName !== 'webcam') {
                    stopWebcam();
                } else {
                    startWebcam();
                }
            });
        });
        
        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 = '';
                }).catch(function(error) {
                    console.error('Error accessing webcam:', error);
                    alert('Unable to access webcam. Please check permissions.');
                });
            } 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);
            
            const imageData = canvas.toDataURL('image/jpeg', 0.8);
            webcamImageData.value = imageData;
            
            previewImage.src = imageData;
            imagePreview.style.display = 'block';
            
            video.style.display = 'none';
            canvas.style.display = 'block';
            captureBtn.style.display = 'none';
            retakeBtn.style.display = 'inline-block';
            
            stopWebcam();
        });
        
        retakeBtn.addEventListener('click', function() {
            webcamImageData.value = '';
            imagePreview.style.display = 'none';
            startWebcam();
        });
        
        const fileUpload = document.getElementById('image_upload');
        if (fileUpload) {
            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]);
                    webcamImageData.value = '';
                }
            });
        }
        
        if (document.getElementById('webcamTab') && document.getElementById('webcamTab').classList.contains('active')) {
            startWebcam();
        }
        
        window.addEventListener('beforeunload', function() {
            stopWebcam();
        });

        const studentForm = document.getElementById('studentForm');
        if (studentForm) {
            studentForm.addEventListener('submit', function(e) {
                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>