// Author: Mattias @ Randomuse.org
// License: http://creativecommons.org/licenses/by/2.5/

//create and assign variables for default preferences
startRulerUnits = app.preferences.rulerUnits
startTypeUnits = app.preferences.typeUnits
startDisplayDialogs = app.displayDialogs

//change settings
app.preferences.rulerUnits = Units.PIXELS
app.preferences.typeUnits = TypeUnits.PIXELS

if (app.documents.length != 0) {
   // Use first document as base for the target document.
   newdocWidthpx = documents[0].width
   newdocHeight = documents[0].height
   newdocRes = documents[0].resolution
   // How many documents open?
   docsToMerge = documents.length

   // Add the target document
   app.documents.add(newdocWidthpx, newdocHeight, newdocRes)
   // Get a ref to the target document
   trgtDocRef = app.activeDocument

   // Keep track of how many documents added
   addedDocs = 0
   
   // Loop the documents to merge as items
   for (i=0;i<docsToMerge;i++){
     
     // Set an item as active document
     this.activeDocument = documents[i]
     // Get name to use as layername later
     srcDocName = documents[i].name
     
     // Add to target only if there are no layers and the item match the target document's height and width
     if ( (documents[i].layerSets.length == 0) && (documents[i].layers.length == 1) && (documents[i].layers[0].visible) && (documents[i].width == newdocWidthpx) && (documents[i].height == newdocHeight) ) {
     
	   // Select all and copy
	   documents[i].selection.selectAll();
	   documents[i].selection.copy(false);
	   documents[i].selection.deselect();
 
       // Set target document as active
       this.activeDocument = trgtDocRef
	 
	   // Paste above copy as a layer
	   var theNewlayer = trgtDocRef.paste(false);
	   // Name layer = original documents name
	   theNewlayer.name = srcDocName;
	   // Add 1 to added documents
	   addedDocs = addedDocs + 1
	   // Set opacity
	   theNewlayer.opacity = 100/addedDocs
     }
   }
}


//restore beginning preferences
app.preferences.rulerunits = startRulerUnits
app.preferences.typeunits = startTypeUnits
app.displayDialogs = startDisplayDialogs