next

// 反代目標網站.
const upstream = 'github.com';

// 反代目標網站的移動版.
const upstream_mobile = 'github.com';

// 訪問區域黑名單（按需設置）.
const blocked_region = [''];

// IP地址黑名單（按需設置）.
const blocked_ip_address = ['0.0.0.0', '127.0.0.1'];

// 路徑替換.
const replace_dict = {
  '$upstream': '$custom_domain', // 將"$upstream"替換為"$custom_domain"
  '//github.com': '' // 移除路徑中的"//github.com"
};

addEventListener('fetch', event => {
  event.respondWith(fetchAndApply(event.request));
});

async function fetchAndApply(request) {
  const region = request.headers.get('cf-ipcountry').toUpperCase(); // 獲取訪問者所在的地區
  const ip_address = request.headers.get('cf-connecting-ip'); // 獲取訪問者的IP地址
  const user_agent = request.headers.get('user-agent'); // 獲取訪問者的User-Agent頭部信息

  let response = null;
  let url = new URL(request.url);
  let url_host = url.host;

  if (url.protocol == 'http:') { // 如果請求協議是HTTP，則重定向到HTTPS
	url.protocol = 'https:';
	response = Response.redirect(url.href);
	return response;
  }

  if (await device_status(user_agent)) { // 判斷是否為移動設備
	var upstream_domain = upstream;
  } else {
	var upstream_domain = upstream_mobile;
  }

  url.host = upstream_domain;

  if (blocked_region.includes(region)) { // 檢查訪問區域是否在黑名單中
	response = new Response('Access denied: WorkersProxy is not available in your region yet.', {
	  status: 403
	});
  } else if (blocked_ip_address.includes(ip_address)){ // 檢查IP地址是否在黑名單中
	response = new Response('Access denied: Your IP address is blocked by WorkersProxy.', {
	  status: 403
	});
  } else {
	let method = request.method;
	let request_headers = request.headers;
	let new_request_headers = new Headers(request_headers);

	new_request_headers.set('Host', upstream_domain); // 設置請求頭的Host字段為反代目標網站的域名
	new_request_headers.set('Referer', url.href); // 設置請求頭的Referer字段為當前請求的URL

	let original_response = await fetch(url.href, {
	  method: method,
	  headers: new_request_headers
	});

	let original_response_clone = original_response.clone();
	let original_text = null;
	let response_headers = original_response.headers;
	let new_response_headers = new Headers(response_headers);
	let status = original_response.status;

	// 修改響應頭的設置
	new_response_headers.set('cache-control', 'public, max-age=14400');
	new_response_headers.set('access-control-allow-origin', '*');
	new_response_headers.set('access-control-allow-credentials', true);
	new_response_headers.delete('content-security-policy');
	new_response_headers.delete('content-security-policy-report-only');
	new_response_headers.delete('clear-site-data');

	const content_type = new_response_headers.get('content-type');
	if (content_type && content_type.includes('text/html') && content_type.includes('UTF-8')) {
	  original_text = await replace_response_text(original_response_clone, upstream_domain, url_host); // 替換響應中的文本內容
	} else {
	  original_text = original_response_clone.body;
	}

	response = new Response(original_text, {
	  status,
	  headers: new_response_headers
	});
  }
  return response;
}

async function replace_response_text(response, upstream_domain, host_name) {
  let text = await response.text();

  for (let i in replace_dict) {
	let j = replace_dict[i];
	if (i == '$upstream') {
	  i = upstream_domain;
	} else if (i == '$custom_domain') {
	  i = host_name;
	}

	if (j == '$upstream') {
	  j = upstream_domain;
	} else if (j == '$custom_domain') {
	  j = host_name;
	}

	let re = new RegExp(i, 'g');
	text = text.replace(re, j); // 使用正則表達式替換文本內容
  }

  return text;
}

async function device_status(user_agent_info) {
  var agents = ["Android", "iPhone", "SymbianOS", "Windows Phone", "iPad", "iPod"];
  var flag = true;
  for (var v = 0; v < agents.length; v++) {
	if (user_agent_info.indexOf(agents[v]) > 0) {
	  flag = false;
	  break;
	}
  }
  return flag;
}