Save&Load System for CopperLicht Game Engine

//Important Advice:
//For this example, I use simple numbers because I want you to be able to learn how to use this,
//but you shouldn't actually use simple numbers in your Save File, because people can open it
//and edit it by writing "500" and already have 500 coins without earning them.
//So, even though I use simple numbers for this example, you should create a way to encrypt them
//in your own head. For example, if the number of the first line of the text file equals the
//highest level unlocked by your customer, you should think of your own symbols to hide the number.
//Instead of the number "50" meaning all levels have been unlocked, I would put "zxpx2a" instead.
//You should keep a notebook that will allow you to know what the symbols mean.
//And if you think you need real encryption, you actually don't, because for professional games,
//One person could finish the whole game fairly and unlock all items fairly, but he might
//share that Save File on the internet, so all people could copy it and have all items unlocked.
//That's why you don't need to use real encryption to hide the progress. Just use your own symbols
//that will deter most people from just writing "100" on every line of the Save File and having
//all items unlocked.
//You should obviously use real encryption for multi-player online games, but I only enjoy
//single-player games, so I don't have advice for that. And if you're attempting to create a fair
//and balanced multi-player online game, you probably have already decided to NOT use the
//WebGL & JavaScript platform, because the source code can be viewed by everyone.



//This script works well in Firefox, Chrome, and the Edge browser.
//It doesn't work in Internet Explorer, but wise people won't use that one.



//Usage instructions:
//Put this script in a text editor and save it as a file called "SaveAndLoadData.js".
//Put it in your source directory with the other ".js" files, and attach the line below to your main script
//by putting it in the HTML section at the top (don't include the two forward slashes at the beginning
//of the line, of course):
//<script type="text/javascript" src="src/SaveAndLoadData.js"></script>
//
//
//(I don't know how to add this to the "compiled" version of CopperLicht, which combines the separate source
// files as one huge ".js" file, so I can't help you do that.)
//
//
//When you want to Save the game, use this:
//SaveFileDialog();
//
//
//When you want to load the game, use this:
//LoadFileDialog();
//
//
//You will definitely need to modify this script to attach all of the variables that you want to be included in
//the Saves of your game. Please read all of the comments in this file for more information.





//The information in the variable below will be added to the Save File. I used this for testing.
var DataToPlaceInFile = null;

var textFile = null;

//I will show you how to use the two lines below, so you can check the current progress of a player.
ThePlayerHasReachedThisLevelSoFar = 5;
NumberOfCoinsAcquiredByPlayerSoFar = 40;

makeTextFile = function (text) {

    var data = new Blob([text], {type: 'text/plain'});

// If we are replacing a previously generated file we need to
// manually revoke the object URL to avoid memory leaks.
    if (textFile !== null) {
        window.URL.revokeObjectURL(textFile);
    }

    textFile = window.URL.createObjectURL(data);

    return textFile;
};


var fileReader = new FileReader();


var create = document.getElementById('create'),
textbox = document.getElementById('textbox');

SaveFileDialog = function () {
    var SaveDataToATextFile = document.createElement('a');
    SaveDataToATextFile.setAttribute('download', 'savefile.txt');

    //Imagine this: While playing the game, the player has reached level 2, and he has 40 coins.
    //During part of your game's script, you will have a variable that stores the highest level
    //reached, and the number of coins acquired. So, imagine that your variables for those parts
    //are called "ThePlayerHasReachedThisLevelSoFar" and "NumberOfCoinsAcquiredByPlayerSoFar".
    //To combine them into one text file, I decided to first combine them into one large variable,
    //called "DataToPlaceInFile". I'll add a backslash and a lowercase "n" after each line,
    //like this: "\n". That will allow each part of the code to be written on a separate line.
    //So, imagine that the previous status of the Save File showed that the highest level reached
    //by the player is Level 2, and the number of coins acquired is 30. Now, imagine that the
    //player reached Level 5, and he has 40 coins now. Those variables should be done by your
    //own script, but when you modify this "SaveAndLoadData" file so it can capture those variables,
    //it would work like this example:
    DataToPlaceInFile = ThePlayerHasReachedThisLevelSoFar + "\n" + NumberOfCoinsAcquiredByPlayerSoFar;

    //Now, we will start the process of creating the Save File.
    SaveDataToATextFile.href = makeTextFile(DataToPlaceInFile);
    document.body.appendChild(SaveDataToATextFile);

    // wait for the link to be added to the document
    window.requestAnimationFrame(function ()
    {
        var SimulateAMouseClick = new MouseEvent('click');
        SaveDataToATextFile.dispatchEvent(SimulateAMouseClick);
        document.body.removeChild(SaveDataToATextFile);
    });

}, false;


var LoadDataFromSaveFile = document.createElement("input");
LoadDataFromSaveFile.setAttribute("id", "SelectFileToImport");
LoadDataFromSaveFile.setAttribute("type", "file");


LoadFileDialog = function()
{
    var SimulateAMouseClick = new MouseEvent('click');
    LoadDataFromSaveFile.dispatchEvent(SimulateAMouseClick);
}


LoadDataFromSaveFile.onchange = function(e) {

    file = LoadDataFromSaveFile.files[0];

    fileReader.onload = function(){

        // Show contents of entire file as one string, for testing.
        //console.log(this.result);

        // Separate contents of file into separate lines, so you can manipulate them later.
        var lines = this.result.split(/[\r\n]+/g); // tolerate Windows linebreaks and Unix linebreaks.
        for(var line = 0; line < lines.length; line++){
            //I used the line below to make the lines appear in the console, just to test the code.
            console.log(lines[line]);
        }


        //Line 1 of the text file contains the highest level that has been reached by the player.
        //During the loading process, I will store it in a separate variable, so the game will start
        //with these accomplishments already unlocked and available.
        //Note: For Computers, the first item in lists is always zero instead of one.
        //That's why the code says "if (line = 0)" instead of "if (line = 1)".
        ThePlayerHasReachedThisLevelSoFar = lines[0];

        //Now, I will put the value of Line 2 into a separate variable.
        //Line 2 stores the number of coins acquired by the player when he last saved the game.
        NumberOfCoinsAcquiredByPlayerSoFar = lines[1];


    };
    fileReader.readAsText(file);
    e.target.value = null;
};