admin.php

<?php
// Include database connection and authentication check
require_once 'includes/db_connect.php';
require_once 'includes/auth_check.php';

// This page is for faculty only
requireFaculty();

$error = '';
$success = '';

// Get all users
$users = [];
$query = "SELECT * FROM users ORDER BY created_at DESC";
$result = $conn->query($query);

if ($result && $result->num_rows > 0) {
    while ($row = $result->fetch_assoc()) {
        $users[] = $row;
    }
}

// Handle user activation/deactivation
if (isset($_GET['action']) && isset($_GET['id'])) {
    $action = $_GET['action'];
    $user_id = (int)$_GET['id'];
    
    // Can't modify yourself
    if ($user_id === (int)$_SESSION['user_id']) {
        $error = "You cannot modify your own account status.";
    } else {
        if ($action === 'activate') {
            $status = 'active';
            $success_msg = "User activated successfully.";
        } elseif ($action === 'deactivate') {
            $status = 'inactive';
            $success_msg = "User deactivated successfully.";
        } else {
            $error = "Invalid action.";
        }
        
        if (empty($error)) {
            $update_query = "UPDATE users SET status = ? WHERE id = ?";
            $update_stmt = $conn->prepare($update_query);
            $update_stmt->bind_param("si", $status, $user_id);
            
            if ($update_stmt->execute()) {
                $success = $success_msg;
                
                // Refresh user list
                $result = $conn->query($query);
                $users = [];
                if ($result && $result->num_rows > 0) {
                    while ($row = $result->fetch_assoc()) {
                        $users[] = $row;
                    }
                }
            } else {
                $error = "Failed to update user status: " . $conn->error;
            }
        }
    }
}

// Count stats
$totalUsers = count($users);
$activeUsers = 0;
$inactiveUsers = 0;
$studentUsers = 0;
$facultyUsers = 0;

foreach ($users as $user) {
    if ($user['status'] === 'active') $activeUsers++;
    if ($user['status'] === 'inactive') $inactiveUsers++;
    if ($user['user_type'] === 'student') $studentUsers++;
    if ($user['user_type'] === 'faculty') $facultyUsers++;
}

// Include header
include 'includes/header.php';
?>

<div class="row mb-4">
    <div class="col-md-12">
        <nav aria-label="breadcrumb">
            <ol class="breadcrumb">
                <li class="breadcrumb-item"><a href="index.php">Home</a></li>
                <li class="breadcrumb-item active">Admin Panel</li>
            </ol>
        </nav>
        <h2><i class="fas fa-cogs me-2"></i> Admin Panel</h2>
        <p class="lead">Manage users and system settings</p>
    </div>
</div>

<?php if (!empty($error)): ?>
    <div class="alert alert-danger alert-dismissible fade show" role="alert">
        <i class="fas fa-exclamation-circle me-2"></i> <?php echo $error; ?>
        <button type="button" class="btn-close" data-bs-dismiss="alert" aria-label="Close"></button>
    </div>
<?php endif; ?>

<?php if (!empty($success)): ?>
    <div class="alert alert-success alert-dismissible fade show" role="alert">
        <i class="fas fa-check-circle me-2"></i> <?php echo $success; ?>
        <button type="button" class="btn-close" data-bs-dismiss="alert" aria-label="Close"></button>
    </div>
<?php endif; ?>

<div class="row mb-4">
    <div class="col-md-3">
        <div class="card text-center mb-3 shadow-sm">
            <div class="card-body">
                <i class="fas fa-users fa-3x mb-3 text-primary"></i>
                <h5 class="card-title">Total Users</h5>
                <p class="card-text display-4"><?php echo $totalUsers; ?></p>
            </div>
        </div>
    </div>
    <div class="col-md-3">
        <div class="card text-center mb-3 shadow-sm">
            <div class="card-body">
                <i class="fas fa-user-graduate fa-3x mb-3 text-success"></i>
                <h5 class="card-title">Students</h5>
                <p class="card-text display-4"><?php echo $studentUsers; ?></p>
            </div>
        </div>
    </div>
    <div class="col-md-3">
        <div class="card text-center mb-3 shadow-sm">
            <div class="card-body">
                <i class="fas fa-chalkboard-teacher fa-3x mb-3 text-danger"></i>
                <h5 class="card-title">Faculty</h5>
                <p class="card-text display-4"><?php echo $facultyUsers; ?></p>
            </div>
        </div>
    </div>
    <div class="col-md-3">
        <div class="card text-center mb-3 shadow-sm">
            <div class="card-body">
                <i class="fas fa-toggle-on fa-3x mb-3 text-warning"></i>
                <h5 class="card-title">Active/Inactive</h5>
                <p class="card-text display-4"><?php echo $activeUsers; ?> / <?php echo $inactiveUsers; ?></p>
            </div>
        </div>
    </div>
</div>

<div class="row">
    <div class="col-md-12">
        <div class="card shadow-sm">
            <div class="card-header bg-primary text-white">
                <h5 class="mb-0"><i class="fas fa-users me-2"></i> User Management</h5>
            </div>
            <div class="card-body">
                <?php if (count($users) > 0): ?>
                    <div class="table-responsive">
                        <table class="table table-striped table-hover">
                            <thead class="table-light">
                                <tr>
                                    <th>ID</th>
                                    <th>Username</th>
                                    <th>Email</th>
                                    <th>Type</th>
                                    <th>Status</th>
                                    <th>Created</th>
                                    <th>Last Login</th>
                                    <th>Actions</th>
                                </tr>
                            </thead>
                            <tbody>
                                <?php foreach ($users as $user): ?>
                                    <tr>
                                        <td><?php echo $user['id']; ?></td>
                                        <td><?php echo htmlspecialchars($user['username']); ?></td>
                                        <td><?php echo htmlspecialchars($user['email']); ?></td>
                                        <td>
                                            <span class="badge <?php echo $user['user_type'] === 'faculty' ? 'bg-danger' : 'bg-success'; ?>">
                                                <?php echo ucfirst($user['user_type']); ?>
                                            </span>
                                        </td>
                                        <td>
                                            <span class="badge <?php echo $user['status'] === 'active' ? 'bg-success' : 'bg-secondary'; ?>">
                                                <?php echo ucfirst($user['status']); ?>
                                            </span>
                                        </td>
                                        <td><?php echo date('M d, Y', strtotime($user['created_at'])); ?></td>
                                        <td><?php echo $user['last_login'] ? date('M d, Y H:i', strtotime($user['last_login'])) : 'Never'; ?></td>
                                        <td>
                                            <?php if ((int)$user['id'] !== (int)$_SESSION['user_id']): ?>
                                                <?php if ($user['status'] === 'active'): ?>
                                                    <a href="admin.php?action=deactivate&id=<?php echo $user['id']; ?>" class="btn btn-sm btn-warning">
                                                        <i class="fas fa-toggle-off"></i> Deactivate
                                                    </a>
                                                <?php else: ?>
                                                    <a href="admin.php?action=activate&id=<?php echo $user['id']; ?>" class="btn btn-sm btn-success">
                                                        <i class="fas fa-toggle-on"></i> Activate
                                                    </a>
                                                <?php endif; ?>
                                            <?php else: ?>
                                                <span class="text-muted">Current User</span>
                                            <?php endif; ?>
                                        </td>
                                    </tr>
                                <?php endforeach; ?>
                            </tbody>
                        </table>
                    </div>
                <?php else: ?>
                    <div class="alert alert-info">
                        <i class="fas fa-info-circle me-2"></i> No users found in the database.
                    </div>
                <?php endif; ?>
            </div>
        </div>
    </div>
</div>

<?php
// Include footer
include 'includes/footer.php';

// Close connection
$conn->close();
?>