<?php

use RingCentral\Psr7\Response;

/*

To enable the initializer feature (https://help.aliyun.com/document_detail/89029.html)

please implement the initializer function as below：

function initializer($context) {

    echo 'initializing' . PHP_EOL;

}

*/

function handler($request, $context): Response

{

    /*

    $body       = $request->getBody()->getContents();

    $queries    = $request->getQueryParams();

    $method     = $request->getMethod();

    $headers    = $request->getHeaders();

    $path       = $request->getAttribute('path');

    $requestURI = $request->getAttribute('requestURI');

    $clientIP   = $request->getAttribute('clientIP');

    */

    /* Config */

    $upstream_pc_url = 'https://api.bilibili.com/pgc/player/web/playurl';

    $upstream_app_url = 'https://api.bilibili.com/pgc/player/api/playurl';

    $upstream_pc_search_url = 'https://api.bilibili.com/x/web-interface/search/type';

    $timeout = 5; // seconds

    /* Read incoming request */

    $request_method = $request->getMethod();

    $request_query = stristr($request->getAttribute("requestURI"), '?');

    $req_referer = $request->getHeaderLine('referer');;

    $request_headers = $request->getHeaders();

    $request_body = $request->getBody()->getContents();

    $request_uri = $request->getAttribute('requestURI');

    /* Forward request */

    $ch = curl_init();

    // 处理请求相关 header

    $request_headers = array_remove_by_key($request_headers,'Host');

    $request_headers = array_remove_by_key($request_headers,'X-Forwarded-For');

    // 配置 body 压缩方式

    $request_headers = array_remove_by_key($request_headers,'Accept-Encoding');

    curl_setopt($ch, CURLOPT_ENCODING, "identity");// 好像 b 站只有 br 压缩

    $headers = array();

    foreach ($request_headers as $key => $value) {

        $headers[] = $key . ": " .implode($value);

    }

    // 判断请求接口

    if(substr_count($request_uri,'/search/type')!=0){

        $url = $upstream_pc_search_url . '?' .$request_query;

        curl_setopt($ch, CURLOPT_REFERER, $req_referer);

    }elseif (substr_count($request_uri,'playurl')!=0){

        // 判断使用的那个 pc 还是 app 接口

        if(substr_count($request_query,'platform=android')!=0){

            $url = $upstream_app_url . '?' .$request_query;

            curl_setopt($ch, CURLOPT_USERAGENT, 'Bilibili Freedoooooom/MarkII');

        }else{

            $url = $upstream_pc_url . '?' .$request_query;

            curl_setopt($ch, CURLOPT_REFERER, $req_referer);

        }

    }else{

        $header['Content-Type'] = 'text/plain';

        return new Response(

            502,

            $header,

            'Failed to match interface.'

        );

    }

    //curl 配置

    curl_setopt($ch, CURLOPT_TIMEOUT, $timeout);

    curl_setopt($ch, CURLOPT_CUSTOMREQUEST, $request_method);

    curl_setopt($ch, CURLOPT_URL, $url);

    curl_setopt($ch, CURLOPT_HTTPHEADER, $headers);

    curl_setopt($ch, CURLOPT_POSTFIELDS, $request_body);

    curl_setopt($ch, CURLOPT_HEADER, true);

    curl_setopt($ch, CURLOPT_FOLLOWLOCATION, false);

    curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);

    $response = curl_exec($ch);

    $header = array();

    if ($response === false) {

        $header['Content-Type'] = 'text/plain';

        return new Response(

            502,

            $header,

            'Upstream host did not respond.'

        );

    } else {

        $header_length = curl_getinfo($ch, CURLINFO_HEADER_SIZE);

        $response_headers = explode("\n", substr($response, 0, $header_length));

        $response_body = substr($response, $header_length);

        // 处理返回相关 header

        foreach ($response_headers as $n => $response_header) {

            // 配置返回的 body 压缩方式

            if (strpos($response_header, "Content-Encoding") !== false) {

                $response_headers[$n] = "Content-Encoding: identity\n";

            }

            // 删除 B 站返回的 Content-Length, 防止浏览器只读取 Content-Length 长度的数据，造成 json 不完整

            if (strpos($response_header, "Content-Length") !== false) {

                unset($response_headers[$n]);

            }

            // 阿里云函数好像会自己添加 Access-Control-Allow-Credentials 头，删除 b 站返回的

            if (strpos($response_header, "Access-Control-Allow-Credentials") !== false) {

                unset($response_headers[$n]);

            }

        }

        unset($response_header); 

        //response_headers 数组转成 key=>value 形式

        foreach ($response_headers as $header_string) {

            $header_tmp = explode(': ', $header_string, 2);

            if (count($header_tmp) == 2) {

                $header[$header_tmp[0]] = trim($header_tmp[1]);

            }

        }

        curl_close($ch);

        // 这行用于调试请求信息

        // return new Response(200, array(), json_encode(array('header' => $header, 'body' => $response_body, 'url' => $url, 'response'=>$response, 'curl_headers'=>$curl_response_headers)));

        return new Response(

            200,

            $header,

            $response_body

        );

    }

}

/*tool*/

// 某个字符串在另一个字符串第 N 此出现的下标

function str_n_pos($str, $find, $n)

{

    $pos_val = 0;

    for ($i = 1; $i <= $n; $i++) {

        $pos = strpos($str, $find);

        $str = substr($str, $pos + 1);

        $pos_val = $pos + $pos_val + 1;

    }

    $count = $pos_val - 1;

    return $count;

}

function array_remove_by_key($arr, $key)

{

	if(!array_key_exists($key, $arr)){

		return $arr;

	}

	$keys = array_keys($arr);

	$index = array_search($key, $keys);

	if($index !== FALSE){

		array_splice($arr, $index, 1);

	}

	return $arr;

}