/*经测试可选择的网站

谷歌 www.google.com

Duckduckgo duckduckgo.com

Github github.com

英文维基百科 en.wikipedia.org 移动端那里填en.m.wikipedia.org

中文维基百科 zh.wikipedia.org 移动端那里填zh.m.wikipedia.org

*/

// 你想镜像的站点

const upstream = 'en.wikipedia.org'

// 针对移动端适配站点，没有就和保持和上面一致

const upstream_mobile = 'en.m.wikipedia.org'

// 只允许某些地区直接访问（有防火墙的五位杰出代表），其他地区跳转回原网站

const not_blocked_region = ['CN', 'KP', 'SY', 'PK', 'CU']

// 禁止自访问 and ip黑名单

const blocked_ip_address = ['0.0.0.0', '127.0.0.1']

// 你想镜像的站点

const replace_dict = {

    '$upstream': '$custom_domain',

    '// en.wikipedia.org': ''

}

// 剩下的就不用管了

addEventListener('fetch', event => {

    event.respondWith(fetchAndApply(event.request));

});

async function fetchAndApply(request) {

    const region = request.headers.get('cf-ipcountry').toUpperCase();

    const ip_address = request.headers.get('cf-connecting-ip');

    const user_agent = request.headers.get('user-agent');

    let response = null;

    url = new URL(request.url);

    let url_host = url.host;

    const { pathname, search } = url

    //强制使用https

    url.protocol = 'https:'

    if (await device_status(user_agent)) {

        upstream_domain = upstream

    } else {

        upstream_domain = upstream_mobile

    }

    const statusCode = 301

    destinationURL = 'https://' + upstream_domain + pathname + search

    url.host = upstream_domain;

    if (!not_blocked_region.includes(region)) {

        response = Response.redirect(destinationURL, statusCode);

    } else if(blocked_ip_address.includes(ip_address)){

        response = Response.redirect(destinationURL, statusCode);

    } 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);

        new_request_headers.set('Referer', url.href);

        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;

        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.includes('text/html') && content_type.includes('UTF-8')) {

            original_text = await replace_response_text(original_response_clone, upstream_domain, url_host);

        } 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()

    var i, j;

    for (i in replace_dict) {

        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);

    }

    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;

}