<?php
// Start session
session_start();

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

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

// Check if the question_banks table exists
$table_check = $conn->query("SHOW TABLES LIKE 'question_banks'");
$table_exists = $table_check->num_rows > 0;

if (!$table_exists) {
    // Create the question_banks table
    $create_table_query = "
    CREATE TABLE IF NOT EXISTS `question_banks` (
      `id` int(11) NOT NULL AUTO_INCREMENT,
      `title` varchar(255) NOT NULL,
      `description` text DEFAULT NULL,
      `course_id` int(11) DEFAULT NULL,
      `created_at` timestamp NOT NULL DEFAULT current_timestamp(),
      `updated_at` timestamp NULL DEFAULT current_timestamp() ON UPDATE current_timestamp(),
      PRIMARY KEY (`id`),
      KEY `course_id` (`course_id`),
      CONSTRAINT `question_banks_course_id_fk` FOREIGN KEY (`course_id`) REFERENCES `courses` (`id`) ON DELETE SET NULL
    ) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_general_ci;
    ";
    
    if ($conn->query($create_table_query)) {
        $success_message = "Question banks table created successfully.";
    } else {
        $error_message = "Error creating question banks table: " . $conn->error;
    }
} else {
    // Check if course_id field exists
    $field_check = $conn->query("SHOW COLUMNS FROM `question_banks` LIKE 'course_id'");
    $field_exists = $field_check->num_rows > 0;
    
    if (!$field_exists) {
        // Add course_id field
        $add_field_query = "
        ALTER TABLE `question_banks` 
        ADD COLUMN `course_id` int(11) DEFAULT NULL AFTER `description`,
        ADD KEY `course_id` (`course_id`),
        ADD CONSTRAINT `question_banks_course_id_fk` FOREIGN KEY (`course_id`) REFERENCES `courses` (`id`) ON DELETE SET NULL
        ";
        
        if ($conn->query($add_field_query)) {
            $success_message = "Course ID field added to question banks table successfully.";
        } else {
            $error_message = "Error adding course ID field: " . $conn->error;
        }
    } else {
        $success_message = "Question banks table already exists with course_id field.";
    }
}

// Redirect back to banks page
$_SESSION['success_message'] = $success_message ?? null;
$_SESSION['error_message'] = $error_message ?? null;
header("Location: ../banks.php");
exit();
?>