-- More information about this indicator can be found at:
-- http://fxcodebase.com/code/viewtopic.php?f=17&t=62412

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-- Indicator profile initialization routine
-- Defines indicator profile properties and indicator parameters
-- TODO: Add minimal and maximal value of numeric parameters and default color of the streams
function Init()
    indicator:name("Elastic Volume Weighted Moving Average with Real volume/Transactions");
    indicator:description("Elastic Volume Weighted Moving Average with Real volume/Transactions");
    indicator:requiredSource(core.Bar);
    indicator:type(core.Indicator);
    indicator.parameters:addGroup("Calculation");
    indicator.parameters:addString("Ind", "Type of indicator", "", "Volume");
    indicator.parameters:addStringAlternative("Ind", "Volume", "", "Volume");
    indicator.parameters:addStringAlternative("Ind", "Transactions", "", "Transactions");
    indicator.parameters:addInteger("Period", "Period", "Period", 14);
	indicator.parameters:addGroup("Style");
    indicator.parameters:addColor("EVWMA_color", "Color of EVWMA", "Color of EVWMA", core.rgb(255, 0, 0));
	indicator.parameters:addInteger("width", "Line width", "", 1, 1, 5);
    indicator.parameters:addInteger("style", "Line style", "", core.LINE_SOLID);
    indicator.parameters:setFlag("style", core.FLAG_LINE_STYLE);
end

-- Indicator instance initialization routine
-- Processes indicator parameters and creates output streams
-- TODO: Refine the first period calculation for each of the output streams.
-- TODO: Calculate all constants, create instances all subsequent indicators and load all required libraries
-- Parameters block
local Period;

local first;
local source = nil;
local Ind;

local FirstStart;
local LastTime;

-- Streams block
local EVWMA = nil;

-- Routine
function Prepare(nameOnly)
    Period = instance.parameters.Period;
    source = instance.source;
    first = source:first()+Period;

    local name = profile:id() .. "(" .. source:name() .. ", " .. tostring(Period) .. ")";
    instance:name(name);
	
	if   (nameOnly) then
        return;
    end
	
	
     if instance.parameters.Ind=="Volume" then
      Ind=core.indicators:create("REAL VOLUME", source);
     else
      Ind=core.indicators:create("TRANSACTIONS", source);
     end

    if (not (nameOnly)) then
        EVWMA = instance:addStream("EVWMA", core.Line, name, "EVWMA", instance.parameters.EVWMA_color, first);
		EVWMA:setWidth(instance.parameters.width);
        EVWMA:setStyle(instance.parameters.style);
    end
    FirstStart=true;
    LastTime=0;

end

-- Indicator calculation routine
-- TODO: Add your code for calculation output values
function Update(period, mode)
    if period < first then
	return;
	end
        Ind:update(mode);
        EVWMA[period]=EVWMA[period-1];
        if not(Ind.DATA:hasData(period)) then
            if period==first then
                FirstStart=true;
            end    
            return;
        elseif FirstStart then
            FirstStart=false;
            instance:updateFrom(first);    
        elseif LastTime~=source:date(period) and period==source:size()-1 then
            LastTime=source:date(period);
            instance:updateFrom(period-10);
        end
	
	local Total = mathex.sum(Ind.DATA, period-Period+1, period);	
	
        EVWMA[period] = ((Total-Ind.DATA[period])*EVWMA[period-1]+Ind.DATA[period]*source.close[period])/Total;
    
end

function AsyncOperationFinished(cookie, success, message)

end