<?php
require_once 'db_connection.php';

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

if (isset($_GET['category_id'])) {
    $categoryId = intval($_GET['category_id']);
    
    $query = "SELECT id, name FROM expense_heads WHERE category_id = ? ORDER BY name";
    $stmt = $conn->prepare($query);
    $stmt->bind_param("i", $categoryId);
    $stmt->execute();
    $result = $stmt->get_result();
    $heads = $result->fetch_all(MYSQLI_ASSOC);
    
    echo json_encode($heads);
} else {
    echo json_encode(['error' => 'Category ID is required']);
}
?>