<?php
/**
 * gmaps-key.php — Google Maps API key proxy
 * Serves the key only to same-origin requests.
 * Key is read from environment — never hardcoded in source.
 */
declare(strict_types=1);

$host      = $_SERVER['HTTP_HOST']             ?? '';
$origin    = $_SERVER['HTTP_ORIGIN']           ?? '';
$referer   = $_SERVER['HTTP_REFERER']          ?? '';
$forwarded = $_SERVER['HTTP_X_FORWARDED_HOST'] ?? '';

$allowed = ['tasplanning.report', 'localhost', '127.0.0.1'];

// Check all available headers — HTTP_HOST is always present via Apache
$candidates = array_filter([
    parse_url('https://' . $host,      PHP_URL_HOST),
    parse_url($origin,                 PHP_URL_HOST),
    parse_url($referer,                PHP_URL_HOST),
    parse_url('https://' . $forwarded, PHP_URL_HOST),
]);

$matched = false;
foreach ($candidates as $c) {
    if (in_array(preg_replace('/:\d+$/', '', $c ?? ''), $allowed, true)) {
        $matched = true;
        break;
    }
}

if (!$matched) {
    http_response_code(403);
    header('Content-Type: application/json');
    echo json_encode(['error' => 'Forbidden', 'host' => $host, 'referer' => $referer]);
    exit;
}

// $_SERVER is more reliable than getenv() under Apache/mod_php
$key = $_SERVER['GMAPS_API_KEY']
    ?? $_ENV['GMAPS_API_KEY']
    ?? getenv('GMAPS_API_KEY')
    ?: '';

if (!$key) {
    http_response_code(503);
    header('Content-Type: application/json');
    echo json_encode(['error' => 'Key not configured']);
    exit;
}

header('Content-Type: application/json');
header('Cache-Control: no-store, no-cache, must-revalidate');
echo json_encode(['key' => $key]);