-- Id: 20557
-- More information about this indicator can be found at:
-- http://fxcodebase.com/code/viewtopic.php?f=17&t=65729

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-- Indicator profile initialization routine

function Init()
    indicator:name("Volume Price Change");
    indicator:description("");
    indicator:requiredSource(core.Bar);
    indicator:type(core.Oscillator);
	
	indicator.parameters:addGroup("Calculation"); 
    indicator.parameters:addInteger("length", "Period", "", 15, 2, 2000);
	indicator.parameters:addInteger("price_smoothing", "Price Smoothing", "", 15 );
	indicator.parameters:addInteger("signal_smoothing", "Signal Smoothing", "", 15 );
  
	indicator.parameters:addGroup("Style"); 	
    indicator.parameters:addColor("color1", "Line Color Down", "", core.rgb(0,255,0 ));
	 indicator.parameters:addColor("color2", "Line Color Up", "", core.rgb(255,0, 0));
	indicator.parameters:addInteger("style1", "Line Style", "", core.LINE_SOLID);
    indicator.parameters:setFlag("style1", core.FLAG_LEVEL_STYLE);	
	indicator.parameters:addInteger("width1", "Line Width", "", 3, 1, 5);
	
	

	 indicator.parameters:addColor("color3", "Signal Line Color", "", core.rgb(0,0, 255));
	indicator.parameters:addInteger("style2", "Line Style", "", core.LINE_SOLID);
    indicator.parameters:setFlag("style2", core.FLAG_LEVEL_STYLE);	
	indicator.parameters:addInteger("width2", "Line Width", "", 3, 1, 5);
	
end

-- Indicator instance initialization routine
-- Processes indicator parameters and creates output streams
-- Parameters block

local length,price_smoothing,signal_smoothing; 
local first;
local source = nil;
local MVA,EMA1,EMA2,EMA3;
local vpc,signal;

-- Routine
 function Prepare(nameOnly) 

     length = instance.parameters.length; 
	 price_smoothing = instance.parameters.price_smoothing;
	 signal_smoothing= instance.parameters.signal_smoothing;
 
    local name = profile:id() .. "(" ..  instance.source:name().. ", " ..  length .. ", " ..  signal_smoothing  .. ")";
    instance:name(name); 


    if   (nameOnly) then
        return;
    end

   
			
    source = instance.source;
    
    
   
	if price_smoothing> 1 then
    EMA1 = core.indicators:create("EMA", source.close, price_smoothing); 
	EMA2= core.indicators:create("EMA", source.volume, price_smoothing); 
	
	MVA= core.indicators:create("MVA", EMA2.DATA, length); 
    first=MVA.DATA:first();
	else
	MVA= core.indicators:create("MVA", source.volume, length); 
    first=MVA.DATA:first();
	end
 
	vpc = instance:addStream("vpc" , core.Line, "vpc","vpc",instance.parameters.color1, first);
	vpc:setWidth(instance.parameters.width1);
    vpc:setStyle(instance.parameters.style1);
	
	
    
    if signal_smoothing > 1 then
	
	EMA3= core.indicators:create("EMA", vpc, signal_smoothing); 
	signal = instance:addStream("signal" , core.Line, "signal","signal",instance.parameters.color3, first);
	signal:setWidth(instance.parameters.width2);
    signal:setStyle(instance.parameters.style2);
	
	signal:setPrecision(math.max(2, instance.source:getPrecision()));
	vpc:setPrecision(math.max(2, instance.source:getPrecision()));
	end
	
end

-- Indicator calculation routine
function Update(period, mode)
 
	if price_smoothing >  1 then
	EMA1:update(mode); 
	EMA2:update(mode);
	MVA:update(mode); 
	
	if period < MVA.DATA:first() then
	return;
	end
	
	vpc[period] = (EMA1.DATA[period]- EMA1.DATA[period-length+1]) * MVA.DATA[period];	
	else
	MVA:update(mode);
	
	if period < MVA.DATA:first() then
	return;
	end
	
	vpc[period] = (source.close[period]- source.close[period-length+1]) * MVA.DATA[period];
	end
	
    if signal_smoothing > 1 then
	EMA3:update(mode);
	
	if period < EMA3.DATA:first() then
	return
	end
	
	signal[period]=EMA3.DATA[period];
	
	if vpc[period]> signal[period] then
	vpc:setColor(period, instance.parameters.color1);
	else
	vpc:setColor(period, instance.parameters.color2);
	end
	
	end
	
	 
end