DramaboxApp.php

<?php
final class DramaboxApp {
    private static $privateKey = null;

    private static function initPrivateKey(): void {
    if (self::$privateKey !== null) return;
        try {
            $pemFile = __DIR__ . '/private_key.pem';
            
            if (!file_exists($pemFile)) {
                throw new RuntimeException("Private key file not found: {$pemFile}");
            }
            
            $pem = file_get_contents($pemFile);
            if ($pem === false) {
                throw new RuntimeException("Failed to read private key file");
            }

            self::$privateKey = openssl_pkey_get_private($pem);
            if (!self::$privateKey) {
                throw new RuntimeException("Failed to load private key");
            }
        } catch (Throwable $e) {
            error_log("[dramaboxapp] Failed to initialize private key: " . $e->getMessage());
            self::$privateKey = null;
        }
    }

    public static function sign(string $str): ?string {
        if (self::$privateKey === null) self::initPrivateKey();
        if (!self::$privateKey) return null;

        $signature = '';
        $ok = openssl_sign($str, $signature, self::$privateKey, OPENSSL_ALGO_SHA256);
        if (!$ok) return null;
        return base64_encode($signature);
    }

    public static function dramabox(string $str): ?string {
        return self::sign($str);
    }
}
?>