<?php
/**
 * Get Subcategories by Category ID
 * AJAX endpoint for dynamic subcategory loading
 */

header('Content-Type: application/json');

require_once __DIR__ . '/config/database.php';
require_once __DIR__ . '/config/settings.php';
require_once __DIR__ . '/includes/functions.php';

// Start session and check authentication
startSession();

// Check if user is logged in
if (!isLoggedIn()) {
    echo json_encode([
        'success' => false,
        'message' => 'Not authenticated'
    ]);
    exit();
}

// Get category ID from request
$category_id = isset($_GET['category_id']) ? intval($_GET['category_id']) : 0;

if (empty($category_id)) {
    echo json_encode([
        'success' => false,
        'message' => 'Category ID is required',
        'subcategories' => []
    ]);
    exit();
}

// Fetch subcategories for this category
$query = "SELECT subcategory_id, subcategory_name, description 
          FROM expense_subcategories 
          WHERE category_id = ? AND status = 'active'
          ORDER BY subcategory_name";

$subcategories = fetchAll($query, "i", [$category_id]);

// Return JSON response
echo json_encode([
    'success' => true,
    'category_id' => $category_id,
    'subcategories' => $subcategories,
    'count' => count($subcategories)
]);
?>