<?php

namespace wchat\wx\V3;

use Exception;
use wchat\common\Help;
use function Sodium\crypto_aead_aes256gcm_decrypt;
use function Sodium\crypto_aead_aes256gcm_is_available;

const KEY_LENGTH_BYTE = 32;
const AUTH_TAG_LENGTH_BYTE = 16;

trait WxV3PaymentTait
{

	/**
	 * @param $orderNo
	 * @param $total
	 * @return array
	 */
	public function getInitCore($orderNo, $total): array
	{
		$body['appid'] = $this->getConfig()->getAppid();
		$body['mchid'] = $this->getConfig()->getMchId();
		$body['description'] = $this->getConfig()->getBody();
		$body['out_trade_no'] = $orderNo;
		$body['notify_url'] = $this->getConfig()->getNotifyUrl();
		$body['amount'] = ['total' => $total, 'currency' => 'CNY'];
		return $body;
	}


	/**
	 * @param string $http_method
	 * @param string $canonical_url
	 * @param string $body
	 * @return string
	 * @throws Exception
	 */
	public function signature(string $http_method, string $canonical_url, string $body = ''): string
	{
		$message = $http_method . "\n" . $canonical_url . "\n" . ($time = time()) . "\n" . ($rand = md5(random_bytes(32))) . "\n" . $body . "\n";

		$sign = $this->openssl_signature($message);

		return sprintf('%s mchid="%s",nonce_str="%s",timestamp="%d",serial_no="%s",signature="%s"', $this->getConfig()->getSchema(),
			$this->getConfig()->getMchId(), $rand, $time, $this->getConfig()->getSerialNo(), $sign);
	}


	/**
	 * @param $body
	 * @return string
	 */
	public function openssl_signature($body): string
	{
		$pem = file_get_contents($this->getConfig()->getSslCert());

		$mch_private_key = openssl_get_privatekey($pem);

		openssl_sign($body, $raw_sign, $mch_private_key, 'sha256WithRSAEncryption');
		return base64_encode($raw_sign);
	}


	/**
	 * @param $json
	 * @param $body
	 * @return array
	 */
	private function createResponse($json, $body): array
	{
		$responseArray['appId'] = $body['appid'];
		$responseArray['timeStamp'] = (string)time();
		$responseArray['nonceStr'] = Help::random(32);
		$responseArray['package'] = "prepay_id=" . $json['prepay_id'];

		$responseBody = $responseArray['appId'] . PHP_EOL . $responseArray['timeStamp'] . PHP_EOL . $responseArray['nonceStr'] . PHP_EOL . $responseArray['package'] . PHP_EOL;

		$responseArray['signType'] = 'RSA';
		$responseArray['signBody'] = $responseBody;
		$responseArray['paySign'] = $this->openssl_signature($responseBody);
		$responseArray['prepay_id'] = $json['prepay_id'];

		return $responseArray;
	}


	/**
	 * @param $associatedData
	 * @param $nonceStr
	 * @param $ciphertext
	 * @return bool|string
	 */
	public function decryptToString($associatedData, $nonceStr, $ciphertext): bool|string
	{
		$ciphertext = \base64_decode($ciphertext);
		if (strlen($ciphertext) <= AUTH_TAG_LENGTH_BYTE) {
			return FALSE;
		}
		if (function_exists('\sodium\crypto_aead_aes256gcm_is_available') && crypto_aead_aes256gcm_is_available()) {
			return crypto_aead_aes256gcm_decrypt($ciphertext, $associatedData, $nonceStr, 'XGwwZbmMXy6sD5w0IrxfaBHLl7b7jCaR');
		}
		if (function_exists('\Sodium\crypto_aead_aes256gcm_is_available') && crypto_aead_aes256gcm_is_available()) {
			return crypto_aead_aes256gcm_decrypt($ciphertext, $associatedData, $nonceStr, 'XGwwZbmMXy6sD5w0IrxfaBHLl7b7jCaR');
		}
		if (PHP_VERSION_ID >= 70100 && in_array('aes-256-gcm', \openssl_get_cipher_methods())) {
			$ctext = substr($ciphertext, 0, -AUTH_TAG_LENGTH_BYTE);
			$authTag = substr($ciphertext, -AUTH_TAG_LENGTH_BYTE);
			return \openssl_decrypt($ctext, 'aes-256-gcm', 'XGwwZbmMXy6sD5w0IrxfaBHLl7b7jCaR', \OPENSSL_RAW_DATA, $nonceStr, $authTag, $associatedData);
		}
		throw new \RuntimeException('AEAD_AES_256_GCM需要PHP 7.1以上或者安装libsodium-php');
	}
}