import * as url from 'url';

export function getProxyUrl(reqUrl: url.Url): url.Url | undefined {
    let usingSsl = reqUrl.protocol === 'https:';

    let proxyUrl: url.Url;
    if (checkBypass(reqUrl)) {
        return proxyUrl;
    }

    let proxyVar: string;
    if (usingSsl) {
        proxyVar = process.env["https_proxy"] ||
                    process.env["HTTPS_PROXY"];
        
    } else {
        proxyVar = process.env["http_proxy"] ||
                    process.env["HTTP_PROXY"];
    }

    if (proxyVar) {
        proxyUrl = url.parse(proxyVar);
    }

    return proxyUrl;
}


export function checkBypass(reqUrl: url.Url): boolean {
    if (!reqUrl.hostname) {
        return false
    }

    let noProxy = process.env["no_proxy"] || process.env["NO_PROXY"] || '';
    if (!noProxy) {
        return false
    }

    // Determine the request port
    let reqPort: number
    if (reqUrl.port) {
        reqPort = Number(reqUrl.port)
    }
    else if (reqUrl.protocol === 'http:') {
        reqPort = 80
    }
    else if (reqUrl.protocol === 'https:') {
        reqPort = 443
    }

    // Format the request hostname and hostname with port
    let upperReqHosts = [reqUrl.hostname.toUpperCase()]
    if (typeof reqPort === 'number') {
        upperReqHosts.push(`${upperReqHosts[0]}:${reqPort}`)
    }

    // Compare request host against noproxy
    for (let upperNoProxyItem of noProxy.split(',').map(x => x.trim().toUpperCase()).filter(x => x)) {
        if (upperReqHosts.some(x => x === upperNoProxyItem)) {
            return true
        }
    }

    return false
}