<?php
// Start session
session_start();

// Include database configuration
require_once 'database/db_config.php';

// Check if user is logged in and is an admin
if (!isset($_SESSION['user_id']) || ($_SESSION['role'] !== 'admin' && $_SESSION['role'] !== 'director')) {
    header('Location: login.php');
    exit;
}

// Add instructor-specific columns if they don't exist
$columns_to_add = [
    'designation' => "ALTER TABLE users ADD COLUMN IF NOT EXISTS designation VARCHAR(255) DEFAULT NULL",
    'expertise' => "ALTER TABLE users ADD COLUMN IF NOT EXISTS expertise TEXT DEFAULT NULL",
    'social_links' => "ALTER TABLE users ADD COLUMN IF NOT EXISTS social_links TEXT DEFAULT NULL"
];

$success = true;
$messages = [];

foreach ($columns_to_add as $column => $sql) {
    try {
        $result = $conn->query($sql);
        if ($result) {
            $messages[] = "Column '$column' added successfully or already exists.";
        } else {
            $success = false;
            $messages[] = "Failed to add column '$column': " . $conn->error;
        }
    } catch (Exception $e) {
        $success = false;
        $messages[] = "Error adding column '$column': " . $e->getMessage();
    }
}

// Store messages in session
$_SESSION['update_messages'] = $messages;
$_SESSION['update_success'] = $success;

// Redirect back to instructors page
header('Location: instructors.php');
exit;
?>