server.mjs

// Cheese Finder server by Rob Miles October 2022
// Version 1.1
// If you move the server to a different location you will
// have to update the base path string to reflect the new location

// Rob Miles www.robmiles.com

import http from 'http';
import fs from 'fs';
import path from 'path';
import url from 'url';
import { setupGame, grid, noOfCheeses } from './game.mjs';

const basePath = "./";

var gridWidth = 10;
var gridHeight = 10;
let absoluteHour = 0;

function getAbsoluteHour(date) {
    let result = (date.getUTCFullYear() * 372 * 24) +
        (date.getUTCMonth() * 31 * 24) +
        (date.getUTCDate() * 24) +
        date.getUTCHours();
    return result;
}

function handlePageRequest(request, response) {

    if(request.url == '/'){
        request.url = '/index.html';
    }

    console.log("Page request for:" + request.url);

    let filePath = basePath + request.url;

    let fileTypeDecode = {
        html: "text/HTML",
        css: "text/css",
        ico: "image/x-icon",
        mjs: "text/javascript",
        js: "text/javascript",
        jpg: "image/jpeg",
        jpeg: "image/jpeg",
        png: "image/png",
        tiff: "image/tiff"
    }

    if (fs.existsSync(filePath)) {
        // If it is a file - return it 
        console.log("     found file OK");
        response.statusCode = 200;
        let extension = path.extname(filePath);
        extension = extension.slice(1);
        extension = extension.toLowerCase();
        let contentType = fileTypeDecode[extension];
        if (contentType == undefined) {
            console.log("     invalid content type")
            response.statusCode = 415;
            response.setHeader('Content-Type', 'text/plain');
            response.write("Unspported media type: " + extension);
            response.end();
        }
        else {
            response.setHeader('Content-Type', contentType);
            let readStream = fs.createReadStream(filePath);
            readStream.pipe(response);
        }
    }
    else {
        // If it is not a file it might be a command

        // get the date
        let date = new Date();

        // get the absolute hour for this date
        let newAbsoluteHour = getAbsoluteHour(date);

        if (newAbsoluteHour != absoluteHour) {

            // Set up the game grid

            // this is what we want
            let gameRequest = {
                width: gridWidth,
                height: gridHeight,
                colorStyles: ["white", "red", "orange", "yellow", "yellowGreen", "lightGreen", "cyan",
                    "lightBlue", "blue", "purple", "magenta", "darkGray"],
                minCheeses: 1,
                maxCheeses: 6,
                startValue: newAbsoluteHour,
                randMult: 8121,
                randAdd: 28413,
                randModulus: 134456789
            }

            // set up the game
            setupGame(gameRequest);

            // update the absoluteHour value
            absoluteHour = newAbsoluteHour;
        }

        var parsedUrl = url.parse(request.url, true);
        let json;
        console.log("    local path:" + parsedUrl.pathname);
        switch (parsedUrl.pathname) {
            case '/getstart.json':
                response.statusCode = 200;
                response.setHeader('Content-Type', 'text/json');
                let answer = { width: gridWidth, height: gridHeight, noOfCheeses: noOfCheeses, hour: absoluteHour };
                json = JSON.stringify(answer);
                response.write(json);
                response.end();
                break;

            case '/getstyle.json':
                let x = Number(parsedUrl.query.x);
                let y = Number(parsedUrl.query.y);
                response.statusCode = 200;
                response.setHeader('Content-Type', 'text/json');
                console.log("Got: (" + x + "," + y + ")");
                let styleText = grid[x][y].style;
                let styleObject = { style: styleText, hour: absoluteHour };
                let styleJSON = JSON.stringify(styleObject);
                response.write(styleJSON);
                response.end();
                break;
            default:
                console.log("     file not found")
                response.statusCode = 404;
                response.setHeader('Content-Type', 'text/plain');
                response.write("Cant find file at: " + filePath);
                response.end();
        }
    }
}

let server = http.createServer(handlePageRequest);

console.log("Server running");

const port = process.env.PORT || 8080

server.listen(port);