-- Id: 13896
-- More information about this indicator can be found at:
-- http://fxcodebase.com/code/viewtopic.php?f=17&t=62066

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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("Market Direction Indicator");
    indicator:description("Market Direction Indicator");
    indicator:requiredSource(core.Tick);
    indicator:type(core.Oscillator);
    indicator.parameters:addGroup("Calculation");
    indicator.parameters:addInteger("lenMA1", "Short Length", "Short Length", 13);
    indicator.parameters:addInteger("lenMA2", "Long Length", "Long Length", 55);
    indicator.parameters:addInteger("cutoff", "No-trend cutoff", "No-trend cutoff", 2);
	 indicator.parameters:addBoolean("sbz", "Show Below Zero", "Show Below Zero", false);
    indicator.parameters:addGroup("Style");
    indicator.parameters:addColor("Neutral_color", "Color of Neutral", "Color of Neutral", core.rgb(128, 128, 128));
	indicator.parameters:addColor("UpUp_color", "Color of Up in Up Trend", "Color of Up Trend", core.rgb(0, 255, 0));
	indicator.parameters:addColor("DownUp_color", "Color of Down in Up Trend", "Color of Up Trend", core.rgb(50,205,50));
	indicator.parameters:addColor("UpDown_color", "Color of Up in Down Trend", "Color of Down Trend", core.rgb(255, 0, 0));
	indicator.parameters:addColor("DownDown_color", "Color of Down in Down Trend", "Color of Down Trend", core.rgb(255, 153, 0));
	
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 lenMA1;
local lenMA2;
local cutoff;
local sbz;
local first;
local source = nil;
 
-- Streams block
local mdi = nil;
local cp;
-- Routine
function Prepare(nameOnly) 
    lenMA1 = instance.parameters.lenMA1;
    lenMA2 = instance.parameters.lenMA2;
    cutoff = instance.parameters.cutoff;
	sbz = instance.parameters.sbz;
    source = instance.source;
	first = source:first()+math.max(lenMA1, lenMA2);

	
	cp = instance:addInternalStream(0, 0);
	 
    local name = profile:id() .. "(" .. source:name() .. ", " .. tostring(lenMA1) .. ", " .. tostring(lenMA2) .. ", " .. tostring(cutoff) .. ")";
    instance:name(name);
	
	if   (nameOnly) then
        return;
    end

   
        mdi = instance:addStream("mdi", core.Bar, name, "mdi", instance.parameters.Neutral_color, first);
    mdi:setPrecision(math.max(2, instance.source:getPrecision()));
    
end

-- Indicator calculation routine
-- TODO: Add your code for calculation output values
function Update(period)
    if period < first or not  source:hasData(period) then
	return;
	end
	
	cp[period]=Calculate(period);
    
	if sbz then
	mdi[period] =math.abs(100*( cp[period-1] - cp[period])/((source[period]+source[period-1])/2));
	else
	mdi[period] =100*( cp[period-1] - cp[period])/((source[period]+source[period-1])/2);
	end
	
	local Color;
	
	if mdi[period]<-cutoff then
		 if  mdi[period]>mdi[period-1] then
		 Color=instance.parameters.UpDown_color;
		 else
		 Color=instance.parameters.DownDown_color;
		 end
	elseif mdi[period]>cutoff then
		 if  mdi[period]>mdi[period-1] then
		 Color=instance.parameters.UpUp_color;
		 else
		 Color=instance.parameters.DownUp_color;
		 end
	else
	Color=instance.parameters.Neutral_color;
	end
    mdi:setColor(period, Color);
end


function Calculate(period)
return lenMA1*(mathex.sum(source, period-lenMA2+1, period)) - lenMA2*(mathex.sum(source, period-lenMA1+1, period)) / (lenMA2-lenMA1);
end