//  jdSmartBaker.jsx
	//  Creatogether Smart Baker
	//  
	//  Created by Dan Borufka and Jake Rathmanner on 2011-04-24.
	//  Copyright (c) 2010 Creatogether. All rights reserved.
	//  
	//  Bake properties with detection of gaps and linear interpolation
	//  in Adobe(R) After Effects(R) CS4 or later. Use at your 
	//  own risk. Brought to you by Jake and Dan of 
	//  creatogether.com
	//  
	//  Notes:
	//  This script allows you to bake properties of layers
	//  with consideration of gaps and linear interpolation.
    //  The Detection threshold defines how generous 
    //  the detection of gaps and interpolation operates.
	//  
	//  For any further info 
	//  visit us at http://www.creatogether.com/jd-smart-baker
	//  
	//  You can use this script as a dockable panel by 
	//  placing it in a ScriptUI Panels subfolder of the 
	//  Scripts folder, and then choosing the jdSmartBaker.jsx 
	//  from the Window menu.

    var scriptName = "JD Smart Baker";

    // *** function to round a number to "digits" numbers - e.g. round(5.4257, 2) returns 5.42 ***
    
    function round(nr, digits)
    {
        digits = Math.pow(10, digits);
        return Math.round(nr*digits)/digits;
    }

    // *** simple function to calculate linear interpolation ***
    
    function linear(delta, min, max)
    {
        return min + (max - min) * delta;
    }

    // *** main bake-repair engine ***
    
    function smartBake(pal)
    {
        var actItem = app.project.activeItem;
        var selection = actItem.selectedLayers[0];
        var thresh = 10-parseInt(pal.grp.threshold.sldr.value);
        var expr = "";

        var props = selection.selectedProperties;
        var A, B, C, delta, same;
    
        if(props.length  == 0 || app.project == null || actItem == null || !(actItem instanceof CompItem) || actItem.selectedLayers.length == 0) 
            alert("You first must select the properties of a layer to be baked inside a comp.");
        else
        {
            app.beginUndoGroup("JD Smart Baker");
            for(var j in props)
            {
                var prop = props[j];
                if(!prop.expressionEnabled)
                {
                    if(prop.expression != "") expr = prop.expression;
                    prop.expression = "value;";
                    prop.expressionEnabled = true;
                }
                app.executeCommand(app.findMenuCommandId("Convert Expression to Keyframes"));   // run built-in baking-engine
                
                for(var i=prop.numKeys; i>0; i--)
                {
                    same = true;                                        	// are the two adjacent keyframes (current key-1 and current key+1) the same?
                    
                    A = prop.keyValue(i);                              		// current keyframe
                    B = (i > 1 ? prop.keyValue(i-1) : false);				// previous keyframe
                    C = (i < prop.numKeys ? prop.keyValue(i+1) : false);	// next keyframe - replace false by B 
                                                                        	// to automatically remove the last key as well if necessary
                    
                    if(i>1 && i<prop.numKeys)               			 	// if the current keyframe is neither first nor last
                        delta = (prop.keyTime(i) - prop.keyTime(i-1)) / (prop.keyTime(i+1) - prop.keyTime(i-1));    // relative position between both adjacent keyframes

                    if(typeof A == "object")
                    {
                        for(var j in A)                         	       	// walk thru all sub properties,
                            if(A[j] != B[j] ||  A[j] != C[j])     			// check if their keyframes are different from each other
                                if(round(A[j], thresh) != round(linear(delta, B[j], C[j]) ,thresh))		// and if the current keyframe corresponds to a
                                    same = false;														// linear interpolated value of the two surrounding keyframes
                    }
                    else if(A != B || A != C) 
                        if(round(A,thresh) != round(linear(delta, B, C), thresh))
                            same = false;
                
                    if(same)                                          		 // if the surrounding keys are the same, remove the current keyframe
                        prop.removeKey(i);
                    else
                    {
                        prop.setInterpolationTypeAtKey(i, KeyframeInterpolationType.LINEAR); // otherwise set the interpolation mode to linear
                        prop.setSpatialAutoBezierAtKey(i, false);							 // turn auto-bezier off
                    }
                }
                prop.expressionEnabled = false;              				// turn expression off
                if(expr != "") prop.expression = expr;
            }
            app.endUndoGroup();
            gui.close(1);                                               	// close the option panel
        }
    }

    // **** create UI... ****
	
	function createUI(thisObj)
	{
		var pal = ( thisObj instanceof Panel) ? thisObj : new Window("palette", scriptName, undefined, {});
		if(pal != null)
		{
             var res = "group { \
                                orientation:'column', alignment:['fill','top'], alignChildren:['fill','top'], spacing:4, margins:[0,0,0,0], \
                                threshold: Group { \
                                    alignment:['fill','top'], \
                                    lbl1: StaticText { text:'Detection threshold:', preferredSize:[100,10]}, \
                                    sldr: Slider { minvalue:0, maxvalue:15, value:8, preferredSize: [138,20], helpTip:'Slide to change value' }, \
                                    val: StaticText {text:'8', preferredSize:[14,10]},\
                                },\
                                btns: Group {\
                                    btn: Button { text:'Smart Bake', preferredSize:[270,30]},\
                                }\
                            }";
                
                pal.margins = [6,6,6,!(pal instanceof Window) ? 0 : 6];
                pal.grp = pal.add(res);        
                if(pal instanceof Window)
                {
                	pal.center();
                	pal.show();
                }
                	
                pal.grp.threshold.sldr.onChanging = function()
                {
                    this.value = Math.round(this.value);
                    this.parent.val.text = (this.value);
                };
                pal.grp.btns.btn.onClick = function() { smartBake(pal); };
		}
		pal.layout.layout(true);
	    pal.layout.resize();
		pal.onResizing = pal.onResize = function () {this.layout.resize();}
	};

    // *** start ***
    
	var smartBakePanel = createUI(this);