#target photoshop
// ------------------------------------------------------- ZMIENNE GLOBALNE ----------------------------------------------------
var opcje = new PDFOpenOptions;
opcje.bitsPerChannel = BitsPerChannelType.EIGHT;
opcje.cropPage = CropToType.MEDIABOX;
opcje.mode = OpenDocumentMode.CMYK;
opcje.usePageNumber = true;
opcje.resolution = 300;
opcje.supressWarnings = true;

var saveOpts = new PDFSaveOptions;
saveOpts.layers = false;

var presOpts = new PresentationOptions;
presOpts.presentation = false;
presOpts.PDFFileOptions = saveOpts;


var strona = 1;

var listPages, listRanges = [];
// -------------------------------------------------- KLASY ---------------------------------------------------------
function Range (start, end, singleSided) {
    this.singleSided = singleSided;
    this.start = start;
    this.end = end;
    }   

function Page (isPrevEmpty, isEmpty, isNextEmpty){
    this.isPrevEmpty = isPrevEmpty;
    this.isEmpty = isEmpty;
    this.isNextEmpty = isNextEmpty;
    }

// ------------------------------------------------------- FUNKCJE --------------------------------------------------------------------

function isEven(value){
    if (value%2 == 0)
        return true;
    else
        return false;
}//koniec

function openFiles (file, openOpts, startPage){
    
    var docName = file.name;
    var docPath = file.path;
    var condition = true;
    
    var docFolder = new Folder(docPath + "/" + docName);
    try {
        docFolder.create();
        }
    catch (e){
        alert(e);
        }
    
            while (condition == true){
            try{
                openOpts.page = startPage;
                app.open(File(file) , openOpts);
                startPage++;
                }
            catch (e){
                condition = false;
                startPage = startPage -1;
                //console.log(startPage);
                break;
                }
        }
    return docFolder;
}//koniec

function checkEmpty (pageNum, docFolder){
    
    var isEmpty, currentPage;
    
    var folderUtils = new Folder(docFolder + "/robocze");
    folderUtils.create();
    
   currentPage = new Page();
    var tValPrev, tValCurr, tValNext = [];
    
try{
    tValCurr[0] = app.documents[pageNum].channels[0].histogram[0];
    tValCurr[1] = app.documents[pageNum].channels[0].histogram[128];
    tValCurr[2] = app.documents[pageNum].channels[0].histogram[255];
    tValNext[0] = app.documents[(pageNum+1)].channels[0].histogram[0];
    tValNext[1] = app.documents[(pageNum+1)].channels[0].histogram[128];
    tValNext[2] = app.documents[(pageNum+1)].channels[0].histogram[255];
    
    if( tValCurr[0] > 0 && tValCurr[1] > 0 && tValCurr[2] > 0){
        currentPage.isEmpty = false;
        }
    else {
        currentPage.isEmpty = true;
        }
    
     if( tValNext[0] > 0 && tValNext[1] > 0 && tValNext[2] > 0){
        currentPage.isNextEmpty = false;
        }
    else {
        currentPage.isNextEmpty = true;
        }
    
    if (typeof listPages[(pageNum-1)] === 'undefined'){
        currentPage.isPrevEmpty = true;
        }
    else {
        currentPage.isPrevEmpty = listPages[(pageNum-1)].isNextEmpty;
        
    listPages.push(currentPage);
    app.documents[pageNum].saveAs( File( folderUtils + "/" + pageNum ), saveOpts, true, Extension.LOWERCASE);
   // console.log("strona " + pageNum + " - " );
   }
}

catch (e){ 
    if (typeof e === RangeError){
    currentPage.isNextEmpty = "END";
    }
    else {
        throw e;
        }
    
    return 0;
 }//koniec   

function checkRanges (){
    
        
    var testedPage, currentEnd, currentStart;
    var currentRange = new Range();
    
    for (var b = 0; b < listPages.length; b++){
        testedPage = listPages[b];
        var bIsEven = isEven(b+1);
        //currentStart = currentRange.start;
        //currentEnd = currentRange.end;
        
        //początek tablicy listPages
        if (b == 0 && testedPage.isEmpty == false && testedPage.isNextEmpty == true){
            currentRange.singleSided = true;
            currentRange.start = b;
            currentRange.end = b;
            continue;
            }
        else if (b == 0 && testedPage.isEmpty == false && testedPage.isNextEmpty == false){
            currentRange.singleSided = false;
            currentRange.start = b;
            currentRange.end = b+1;
            continue;
            }
        else {
            continue;
            }
        
        // puste
        if (testedPage.isEmpty == true){
            continue;
            }
        
        //jednostronne
        if (bIsEven == true && testedPage.isEmpty == false && testedPage.isNextEmpty == true){
            if (currentRange.singleSided == false){
                listRanges.push(currentRange);
                currentRange = new Range();
                currentRange.singleSided = true;
                currentRange.start = b;
                currentRange.end = b;
                }
            currentRange.end = b;
            continue;
            }
        // dwustronne
         if (testedPage.isEmpty == false && testedPage.isNextEmpty == false){
            if (currentRange.singleSided == true && testedPage.isPrevEmpty == true){
                listRanges.push(currentRange);
                currentRange = new Range();
                currentRange.singleSided = false;
                currentRange.start = b;
                currentRange.end = b;
                }
            currentRange.end = b;
            continue;
            }
        if (testedPage.isNextEmpty == "END"){
            listRanges.push(currentRange);
            }
    }
}
    }//koniec

function saveRanges (docFolder, listRanges){
    
   
    var folderSingleSided = new Folder(docFolder + "/jednostronne");
    folderSingleSided.create();
    var folderDoubleSided = new Folder (docFolder + "/dwustronne");
    folderDoubleSided.create();
    var utilFolder = docFolder + "/robocze";
    
    
    
    for (var s = 0; s < listRanges.length; s++){
        var saveStart = listRanges[s].start;
        var saveEnd = listRanges[s].end;
        var saveSingleSided = listRanges[s].singleSided;
        var inputFiles = [];
        
        for (var d = 0; d <= (saveEnd - saveStart); d++){
            var pg = saveStart+d;
            inputFiles[d] = utilFolder + "/" + pg + ".pdf";
           }
        if (saveSingleSided == true){    
         app.makePDFPresentation (inputFiles, File (folderSingleSided + s), presOpts);
         }
        else {
         app.makePDFPresentation (inputFiles, File (folderDoubleSided + s), presOpts);
         }
        inputFiles = [];
        }
    
    }//koniec

//-------------------------------------------------------------- SKRYPT ------------------------------------------------------------
var filesList = openDialog();
alert(filesList);
openFiles (filesList, opcje, strona);
var folder = filesList.path;
for (var q = 0; q < app.documents.length; q++){
    checkEmpty (q, folder);
    }
checkRanges ();
saveRanges (folder, listRanges);