// date: 2015-11-25, author: shining ying
// Function: It will auto change the most top text layer
// it also can read from CSV type Excel file for the codeList
// if you want random code, then use this website to help for CSV file of code list
//   http://www.generaterandomcodes.com/free-generate-random-codes-tool

// ref: http://stackoverflow.com/questions/14571008/photoshop-scripting-changing-text-of-a-text-layer

//#####################################
// core functions
//#####################################

function getTextLayer(target) {
// this basically loops all the layers to find the
// upmost text layer with the content #nn... and returns it
    if (target == null) return false;
    var layers      = target.layers;
        layerLen    = layers.length;
    for (var i = 0; i < layerLen; i++) {
        var layer       = layers[i];
            isLayerSet  = layer.typename == 'LayerSet';
            isValid     = layer.kind == LayerKind.TEXT;
            //&& /^\s*#\d+\s*$/.test(layer.textItem.contents);
            // we're allowing spaces around the text just in case
        if (!isLayerSet && !isValid) continue;
        if (isLayerSet) {
            var found = getTextLayer(layer);
            if (found) return found;
        } else return layer;
    }
    return false;
}
// ref: http://stackoverflow.com/questions/10073699/pad-a-number-with-leading-zeros-in-javascript
function pad(n, width, z) {
  z = z || '0';
  n = n + '';
  return n.length >= width ? n : new Array(width - n.length + 1).join(z) + n;
}

function range(start, stop, step) {
    if (typeof stop == 'undefined') {
        // one param defined
        stop = start;
        start = 0;
    }
    if (typeof step == 'undefined') step = 1;
    if ((step > 0 && start >= stop) || (step < 0 && start <= stop)) return [];
    var result = [];
    for (var i = start; step > 0 ? i < stop : i > stop; i += step) result.push(i);
    return result;
}

//#####################################
// generate png code file
//#####################################
function codeGeneratePNG( doc, txtLayer, theData ){
    // prepare dir to save the pictures
    var ext = '.png';
    dir = decodeURI(doc.path) + '/png_code';
    if (!Folder(dir).exists) Folder(dir).create();
    
    // Now we have the text layer, the very top one.
    var codeList = theData; //["000001","00002","00003"];
    var total = codeList.length;
    var padAmount = total.toString().length;

    for (i = 0; i < codeList.length; i++) { 
        code = codeList[i];
        // Step 1: update content
        txtLayer.textItem.contents = code;
        
        // Step 2: save the file
        
        fileName = dir + '/' + pad(i,padAmount) + ext;
        
        if (!File(fileName).exists){
            var file = new File(fileName);
            opts = new ExportOptionsSaveForWeb();
            with (opts) {
                format = SaveDocumentType.PNG;
                PNG8 = false;
            }
            doc.exportDocument(file, ExportType.SAVEFORWEB, opts);
            // save for web
        }
    }
    
    // done
    alert("Done, say 'Thank You.'\n       ^_^");
}

//#####################################
// Start the Generating Process
//#####################################

var doc;
try {
    doc = app.activeDocument;
    // the front document
} catch(e) {}
var txtLayer = getTextLayer(doc);
// obviously, the text layer if found

// User Menu now
if (txtLayer) {
    var msg = "     Welcome to Photoshop Coupon or Code Generator!\n";
    msg+="                 ---------Written by Ying, the Great Programmer\n\n";
    msg+="Purpose of This Tool:\n";
    msg+="  Sometimes making Coupon design is easy, but save 700 coupons with different coupon code is tough; Then this tool is born to save your life.\n\n"
    msg+="How to Use this Tool:\n\n";
    msg+="1. Make sure\n  * you have the Code Text layer on the very top of all other text layers (as long as above all other text layer, it is fine),\n  * and You have set your Text Layer alignment and font and size already, then choose the way you want to generate code;\n\n"
    msg+="   1.1 if you choose to Generate Code by enter number range in next prompt dialog,\n      make sure the number is write as format as '1-200', or '10001-10005',\n      Dont write like '0001-0005', write as '1-5,4',\n      I will auto make them into 0001 to 0005 as with 4 paddings;\n\n";
    msg+="   1.2 if you choose to Generate Code by using a CSV file,\n      use excel to make the list of codes in first colume, and save as CSV file,\n      named as 'code.csv' and put next to your current Photoshop file inside the folder, by using a CSV file, it make your life easy if you are so special about the fancy code,\n      this tool can read it automatically, save your trouble on math and save my trouble on more auto code.\n\n";
    msg+="2. Once you are ready, click the 'Generate by Number' or 'Generate by CSV' button, if you are not sure yet, click 'Cancel';\n\n";
    msg+="3. While Generating, it will save all the generated files as PNG in a folder called 'png_code' next to your current PSD file. BE Patient, Generating can take time.\n\n\n         Cheers - Ying\n\n\n         Are you Ready?";
    //alert(msg);
    var ready = confirm(msg);
    if(ready){
        var byCSV = confirm(" * Click Yes to 'Generate by CSV file'.\n * Click No for 'Generate by Number Range' or 'Cancel'.");
        if(byCSV) {
            // alert("Doing CSV");
            //#####################################
            // get data from CSV file
            //#####################################
            var data = [];
            var dataFile = new File(decodeURI(doc.path) + '/code.csv');
            if (File(dataFile).exists){
                dataFile.open('r');
                //dataFile.readln(); // Skip first line
                while (!dataFile.eof) {
                  var dataFileLine = dataFile.readln();
                  var dataFilePieces = dataFileLine.split(',');
                  if (dataFilePieces[0] != "") data.push(dataFilePieces[0]);
                }
                dataFile.close();
                codeGeneratePNG(doc, txtLayer, data);
            }
            else alert("'code.csv' file doesn't exist next to the PSD file.")
        }
        else{
            var byNum = confirm(" * Click Yes to Generate by Number Range method.\n * Click No to Cancel.");
            if(byNum){
                var rangeTxt = prompt(" * Write as format as '1-200', or '10001-10005';\n * Dont write like '0001-0005', write as '1-5,4', it will auto make them into 0001 to 0005 as with 4 paddings;", "");
                //alert("Doing Number Range.")
                //#####################################
                // generate data from number range
                //#####################################
                inputs = rangeTxt.replace(/ /g,'').split(",");
                if (inputs.length >=1){
                    var inputRange = inputs[0].split("-");
                    var numData = range( parseInt(inputRange[0]), parseInt(inputRange[1])+1 );
                    
                    if(inputs.length >= 2){
                        inputPad = parseInt(inputs[1]);
                        var numFormatData = [];
                        for (i = 0; i < numData.length; i++) numFormatData.push( pad(numData[i],inputPad) );
                        codeGeneratePNG(doc, txtLayer, numFormatData);
                    }
                    else codeGeneratePNG(doc, txtLayer, numData);
                }
                else alert("Make sure enter correct format of number range.");
            }
        }
    }
}


/*
if (doc) {
    doc.close(SaveOptions.DONOTSAVECHANGES);
    // close the original layered document without saving
}
*/
doc = null;
// remove reference