<?php

/*
 * This file is part of the overtrue/wechat.
 *
 * (c) overtrue <i@overtrue.me>
 *
 * This source file is subject to the MIT license that is bundled
 * with this source code in the file LICENSE.
 */

namespace EasyWeChat\Kernel;

use EasyWeChat\Kernel\Contracts\MessageInterface;
use EasyWeChat\Kernel\Exceptions\BadRequestException;
use EasyWeChat\Kernel\Exceptions\InvalidArgumentException;
use EasyWeChat\Kernel\Messages\Message;
use EasyWeChat\Kernel\Messages\News;
use EasyWeChat\Kernel\Messages\NewsItem;
use EasyWeChat\Kernel\Messages\Raw as RawMessage;
use EasyWeChat\Kernel\Messages\Text;
use EasyWeChat\Kernel\Support\XML;
use EasyWeChat\Kernel\Traits\Observable;
use EasyWeChat\Kernel\Traits\ResponseCastable;
use Symfony\Component\HttpFoundation\Response;

/**
 * Class ServerGuard.
 *
 * 1. url 里的 signature 只是将 token+nonce+timestamp 得到的签名,只是用于验证当前请求的,在公众号环境下一直有
 * 2. 企业号消息发送时是没有的,因为固定为完全模式,所以 url 里不会存在 signature, 只有 msg_signature 用于解密消息的
 *
 * @author overtrue <i@overtrue.me>
 */
class ServerGuard
{
 use Observable;
 use ResponseCastable;

 /**
 * @var bool
 */
 protected $alwaysValidate = false;

 /**
 * Empty string.
 */
 const SUCCESS_EMPTY_RESPONSE = 'success';

 /**
 * @var array
 */
 const MESSAGE_TYPE_MAPPING = [
 'text' => Message::TEXT,
 'image' => Message::IMAGE,
 'voice' => Message::VOICE,
 'video' => Message::VIDEO,
 'shortvideo' => Message::SHORT_VIDEO,
 'location' => Message::LOCATION,
 'link' => Message::LINK,
 'device_event' => Message::DEVICE_EVENT,
 'device_text' => Message::DEVICE_TEXT,
 'event' => Message::EVENT,
 'file' => Message::FILE,
 'miniprogrampage' => Message::MINIPROGRAM_PAGE,
 ];

 /**
 * @var \EasyWeChat\Kernel\ServiceContainer
 */
 protected $app;

 /**
 * Constructor.
 *
 * @codeCoverageIgnore
 *
 * @param \EasyWeChat\Kernel\ServiceContainer $app
 */
 public function __construct(ServiceContainer $app)
 {
 $this->app = $app;

 foreach ($this->app->extension->observers() as $observer) {
 call_user_func_array([$this, 'push'], $observer);
 }
 }

 /**
 * Handle and return response.
 *
 * @return Response
 *
 * @throws BadRequestException
 * @throws \EasyWeChat\Kernel\Exceptions\InvalidArgumentException
 * @throws \EasyWeChat\Kernel\Exceptions\InvalidConfigException
 */
 public function serve(): Response
 {
 $this->app['logger']->debug('Request received:', [
 'method' => $this->app['request']->getMethod(),
 'uri' => $this->app['request']->getUri(),
 'content-type' => $this->app['request']->getContentType(),
 'content' => $this->app['request']->getContent(),
 ]);

 $response = $this->validate()->resolve();

 $this->app['logger']->debug('Server response created:', ['content' => $response->getContent()]);

 return $response;
 }

 /**
 * @return $this
 *
 * @throws \EasyWeChat\Kernel\Exceptions\BadRequestException
 */
 public function validate()
 {
 if (!$this->alwaysValidate && !$this->isSafeMode()) {
 return $this;
 }

 if ($this->app['request']->get('signature') !== $this->signature([
 $this->getToken(),
 $this->app['request']->get('timestamp'),
 $this->app['request']->get('nonce'),
 ])) {
 throw new BadRequestException('Invalid request signature.', 400);
 }

 return $this;
 }

 /**
 * Force validate request.
 *
 * @return $this
 */
 public function forceValidate()
 {
 $this->alwaysValidate = true;

 return $this;
 }

 /**
 * Get request message.
 *
 * @return array|\EasyWeChat\Kernel\Support\Collection|object|string
 *
 * @throws BadRequestException
 * @throws \EasyWeChat\Kernel\Exceptions\InvalidArgumentException
 * @throws \EasyWeChat\Kernel\Exceptions\InvalidConfigException
 */
 public function getMessage()
 {
 $message = $this->parseMessage($this->app['request']->getContent(false));

 if (!is_array($message) || empty($message)) {
 throw new BadRequestException('No message received.');
 }

 if ($this->isSafeMode() && !empty($message['Encrypt'])) {
 $message = $this->decryptMessage($message);

 // Handle JSON format.
 $dataSet = json_decode($message, true);

 if ($dataSet && (JSON_ERROR_NONE === json_last_error())) {
 return $dataSet;
 }

 $message = XML::parse($message);
 }

 return $this->detectAndCastResponseToType($message, $this->app->config->get('response_type'));
 }

 /**
 * Resolve server request and return the response.
 *
 * @return \Symfony\Component\HttpFoundation\Response
 *
 * @throws \EasyWeChat\Kernel\Exceptions\BadRequestException
 * @throws \EasyWeChat\Kernel\Exceptions\InvalidArgumentException
 * @throws \EasyWeChat\Kernel\Exceptions\InvalidConfigException
 */
 protected function resolve(): Response
 {
 $result = $this->handleRequest();

 if ($this->shouldReturnRawResponse()) {
 $response = new Response($result['response']);
 } else {
 $response = new Response(
 $this->buildResponse($result['to'], $result['from'], $result['response']),
 200,
 ['Content-Type' => 'application/xml']
 );
 }

 $this->app->events->dispatch(new Events\ServerGuardResponseCreated($response));

 return $response;
 }

 /**
 * @return string|null
 */
 protected function getToken()
 {
 return $this->app['config']['token'];
 }

 /**
 * @param string $to
 * @param string $from
 * @param \EasyWeChat\Kernel\Contracts\MessageInterface|string|int $message
 *
 * @return string
 *
 * @throws \EasyWeChat\Kernel\Exceptions\InvalidArgumentException
 */
 public function buildResponse(string $to, string $from, $message)
 {
 if (empty($message) || self::SUCCESS_EMPTY_RESPONSE === $message) {
 return self::SUCCESS_EMPTY_RESPONSE;
 }

 if ($message instanceof RawMessage) {
 return $message->get('content', self::SUCCESS_EMPTY_RESPONSE);
 }

 if (is_string($message) || is_numeric($message)) {
 $message = new Text((string) $message);
 }

 if (is_array($message) && reset($message) instanceof NewsItem) {
 $message = new News($message);
 }

 if (!($message instanceof Message)) {
 throw new InvalidArgumentException(sprintf('Invalid Messages type "%s".', gettype($message)));
 }

 return $this->buildReply($to, $from, $message);
 }

 /**
 * Handle request.
 *
 * @return array
 *
 * @throws \EasyWeChat\Kernel\Exceptions\BadRequestException
 * @throws \EasyWeChat\Kernel\Exceptions\InvalidArgumentException
 * @throws \EasyWeChat\Kernel\Exceptions\InvalidConfigException
 */
 protected function handleRequest(): array
 {
 $castedMessage = $this->getMessage();

 $messageArray = $this->detectAndCastResponseToType($castedMessage, 'array');

 $response = $this->dispatch(self::MESSAGE_TYPE_MAPPING[$messageArray['MsgType'] ?? $messageArray['msg_type'] ?? 'text'], $castedMessage);

 return [
 'to' => $messageArray['FromUserName'] ?? '',
 'from' => $messageArray['ToUserName'] ?? '',
 'response' => $response,
 ];
 }

 /**
 * Build reply XML.
 *
 * @param string $to
 * @param string $from
 * @param \EasyWeChat\Kernel\Contracts\MessageInterface $message
 *
 * @return string
 */
 protected function buildReply(string $to, string $from, MessageInterface $message): string
 {
 $prepends = [
 'ToUserName' => $to,
 'FromUserName' => $from,
 'CreateTime' => time(),
 'MsgType' => $message->getType(),
 ];

 $response = $message->transformToXml($prepends);

 if ($this->isSafeMode()) {
 $this->app['logger']->debug('Messages safe mode is enabled.');
 $response = $this->app['encryptor']->encrypt($response);
 }

 return $response;
 }

 /**
 * @param array $params
 *
 * @return string
 */
 protected function signature(array $params)
 {
 sort($params, SORT_STRING);

 return sha1(implode($params));
 }

 /**
 * Parse message array from raw php input.
 *
 * @param string $content
 *
 * @return array
 *
 * @throws \EasyWeChat\Kernel\Exceptions\BadRequestException
 */
 protected function parseMessage($content)
 {
 try {
 if (0 === stripos($content, '<')) {
 $content = XML::parse($content);
 } else {
 // Handle JSON format.
 $dataSet = json_decode($content, true);
 if ($dataSet && (JSON_ERROR_NONE === json_last_error())) {
 $content = $dataSet;
 }
 }

 return (array) $content;
 } catch (\Exception $e) {
 throw new BadRequestException(sprintf('Invalid message content:(%s) %s', $e->getCode(), $e->getMessage()), $e->getCode());
 }
 }

 /**
 * Check the request message safe mode.
 *
 * @return bool
 */
 protected function isSafeMode(): bool
 {
 return $this->app['request']->get('signature') && 'aes' === $this->app['request']->get('encrypt_type');
 }

 /**
 * @return bool
 */
 protected function shouldReturnRawResponse(): bool
 {
 return false;
 }

 /**
 * @param array $message
 *
 * @return mixed
 */
 protected function decryptMessage(array $message)
 {
 return $message = $this->app['encryptor']->decrypt(
 $message['Encrypt'],
 $this->app['request']->get('msg_signature'),
 $this->app['request']->get('nonce'),
 $this->app['request']->get('timestamp')
 );
 }
}