-- More information about this indicator can be found at:
-- http://fxcodebase.com/code/viewtopic.php?f=17&t=61209


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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("Custom Smoothing Function");
    indicator:description("Custom Smoothing Function");
    indicator:requiredSource(core.Tick);
    indicator:type(core.Indicator);
    indicator.parameters:addGroup("Calculation");	
    indicator.parameters:addInteger("Period", "Period", "Period", 14);
	indicator.parameters:addGroup("Style");	
    indicator.parameters:addColor("CSF_color", "Color of CSF", "Color of CSF", 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 SmoothingMultiplier;
-- Streams block
local CSF = nil;

-- Routine
function Prepare(nameOnly)
    Period = instance.parameters.Period;
    source = instance.source;
    first = source:first();
    SmoothingMultiplier  = (2 / Period);
    local name = profile:id() .. "(" .. source:name() .. ", " .. tostring(Period) .. ")";
    instance:name(name);
 
    if   (nameOnly) then
        return;
    end
	
        CSF = instance:addStream("CSF", core.Line, name, "CSF", instance.parameters.CSF_color, first);
		CSF:setWidth(instance.parameters.width);
        CSF:setStyle(instance.parameters.style);
    
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
        CSF[period] = (source[period] - CSF[period-1]) * SmoothingMultiplier +  CSF[period-1];
    
end