<?php
session_start();
header('Content-Type: application/json');

if ($_SERVER['REQUEST_METHOD'] === 'POST') {
    $captcha_input = $_POST['captcha'] ?? '';
    
    if (isset($_SESSION['captcha'])) {
        if (strtoupper($captcha_input) === $_SESSION['captcha']) {
            echo json_encode(['status' => 'valid']);
        } else {
            echo json_encode(['status' => 'invalid']);
        }
    } else {
        echo json_encode(['status' => 'invalid', 'error' => 'session_missing']);
    }
} else {
    echo json_encode(['status' => 'error', 'message' => 'Invalid request method']);
}