const qs    = require('querystring');
const https = require('https');
const url   = require('url');

const googleLink = function (text) {
    const query = encodeURIComponent(text).replace(/%20/g,'+');
    return "<https://www.google.com/search?q=" + query + "|google.com/search?q=" + query + ">";
}

const qrCode = function (url) {
    return {
        "response_type": "ephemeral",
        "attachments": [{
            "fallback": "https://chart.googleapis.com/chart?chs=512x512&cht=qr&chl=" + url,
            "text": "QR code linking to " + url,
            "image_url": "https://chart.googleapis.com/chart?chs=512x512&cht=qr&chl=" + url,
            "thumb_url": "https://chart.googleapis.com/chart?chs=256x256&cht=qr&chl=" + url
        }]
    }
}

const in_channel = function (text) {
    return {
        "response_type": "in_channel",
        "text": text,
        "unfurl_links": true
    }
}

const not_in_channel = function (text) {
    return {
        "response_type": "ephemeral",
        "text": text,
        "unfurl_links": true
    }
}

const post_message = function (url, message) {
    const body = JSON.stringify(message);
    var options = {
        hostname: url.hostname,
        port: url.port,
        path: url.path,
        method: 'POST',
        headers: {
            'Content-Type': 'application/json',
            'Content-Length': body.length
        }
    };
    var req = https.request(options);
    req.write(body);
    req.end();
    return;
}

exports.handler = function (event, context, callback) {
    const params = qs.parse(event.body);
    const command = params.command;
    const text = params.text;
    const response_url = url.parse(params.response_url);
    const token = params.token;
    
    if (text === "debug") {
        post_message(response_url, in_channel("Message Recieved"));
        callback(null, not_in_channel(response_url.path));
    } else switch(command) {
    case "/google":
        callback(null, not_in_channel("Let me Google that for you..."));
        post_message(response_url, in_channel(googleLink(text)));
        break;
    case "/qr":
        callback(null, qrCode(text));
        break;
    default:
        callback(null, not_in_channel("I have no idea what you are asking of me"));
    }
};