g_KVals = new Array();
var g_counter = 0;

function preMain() {
     
    setDefaultBarFgColor(Color.yellow , 0); // %K
    setDefaultBarFgColor(Color.cyan , 1); // %D
    
}

function main(inputLength, inputSmoothingK, inputSmoothingD) {
    if(inputLength == null)
        inputLength = 15;
    if(inputSmoothingK == null)
        inputSmoothingK = 3;
    if(inputSmoothingD == null)
        inputSmoothingD = 5;
  
    var nLength = inputLength;
    var nSmoothingK = inputSmoothingK;
    var nSmoothingD = inputSmoothingD;
    var d_wma_k = 0.0;
    var d_wma_d = 0.0;
    
    var nBarState = getBarState();

    d_wma_k = GetK(nLength , nSmoothingK );
    g_KVals[g_counter] = d_wma_k; 
    
     
    d_wma_d = GetD(nSmoothingD);
    
    g_counter++;
    
    return new Array(d_wma_k , d_wma_d);

    
}

function GetK(nLength , nSmoothingK){
    var raw_K = new StochStudy(nLength, 1 , 1);
    var i;
    var sum_K = 0.0;
    var KVals;
        
    // Returns an array of raw K's 
    KVals = raw_K.getValue(StochStudy.FAST , 0 , -nSmoothingK);   
    
    if (KVals == null)
        return null;
       
    for(i=0;i < nSmoothingK; i++){
        sum_K += KVals[i] * (nSmoothingK - i);
    }
    
    sum_K /= (nSmoothingK * (nSmoothingK + 1) /2);
      
	
    return sum_K;
}

function GetD(nSmoothingD){
    var i;
    var KVal;
    var sum_D = 0.0;
    var nWeight = nSmoothingD;
    var counter = g_counter;
    
    for(i= counter; i > counter - nSmoothingD; i--){
        KVal = g_KVals[i];
        
        if(KVal == null)
            return null;
        
        sum_D += KVal * (nWeight) ;
        
        nWeight--;
    }   
    
    sum_D /= (nSmoothingD * (nSmoothingD + 1) / 2 );
    
    return sum_D;
}