-- Id: 17118
-- More information about this indicator can be found at:
-- http://fxcodebase.com/code/viewtopic.php?f=17&t=64155

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function Init()
    indicator:name("Wilder ATR");
    indicator:description("");
    indicator:requiredSource(core.Bar);
    indicator:type(core.Oscillator);
 

    indicator.parameters:addGroup("Calculation");
    indicator.parameters:addInteger("N", "Period","", 14, 2, 1000);
	
	indicator.parameters:addString("Method", "MA Method", "Method" , "WMA");
    indicator.parameters:addStringAlternative("Method", "MVA", "MVA" , "MVA");
    indicator.parameters:addStringAlternative("Method", "EMA", "EMA" , "EMA");
    indicator.parameters:addStringAlternative("Method", "LWMA", "LWMA" , "LWMA");
    indicator.parameters:addStringAlternative("Method", "TMA", "TMA" , "TMA");
    indicator.parameters:addStringAlternative("Method", "SMMA", "SMMA" , "SMMA");
    indicator.parameters:addStringAlternative("Method", "KAMA", "KAMA" , "KAMA");
    indicator.parameters:addStringAlternative("Method", "VIDYA", "VIDYA" , "VIDYA");
    indicator.parameters:addStringAlternative("Method", "WMA", "WMA" , "WMA");
	
	
	
    indicator.parameters:addGroup("Style");
    indicator.parameters:addColor("clrATR", "Line Color","", core.rgb(0, 255, 0));
    indicator.parameters:addInteger("widthATR", "Line Width","", 1, 1, 5);
    indicator.parameters:addInteger("styleATR", "Line Style","", core.LINE_SOLID);
    indicator.parameters:setFlag("styleATR", core.FLAG_LEVEL_STYLE);
end

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

local first;
local source = nil;
local tr = nil;
local trFirst = nil;
local tAbs = math.abs;
local MA;
local Method;
-- Streams block
local ATR = nil;

-- Routine
function Prepare(nameOnly)
    n = instance.parameters.N;
    source = instance.source;
	Method= instance.parameters.Method;

    local name = profile:id() .. "(" .. source:name() .. ", " .. n .. ", " .. Method .. ")";
    instance:name(name);
    if nameOnly then
        return;
    end
    tr = instance:addInternalStream(source:first() + 1, 0);
   
	
    assert(core.indicators:findIndicator(Method) ~= nil, Method .. " indicator must be installed");
	MA= core.indicators:create(Method, tr, n);	
	first = MA.DATA:first();
	 
    ATR = instance:addStream("ATR", core.Line, name, "ATR", instance.parameters.clrATR, first)
    ATR:setWidth(instance.parameters.widthATR);
    ATR:setStyle(instance.parameters.styleATR);
    local precision = math.max(2, source:getPrecision());
    ATR:setPrecision(precision);
    trFirst = tr:first();

   
 
end

function getTrueRange(period)
    local hl = tAbs(source.high[period] - source.low[period]);
    local hc = tAbs(source.high[period] - source.close[period - 1]);
    local lc = tAbs(source.low[period] - source.close[period - 1]);

    local tr = hl;
    if (tr < hc) then
        tr = hc;
    end
    if (tr < lc) then
        tr = lc;
    end
    return tr;
end
 
function Update(period,mode)
    if period >= trFirst then
        tr[period] = getTrueRange(period);
    end
	
	MA:update(mode);
    if period < first then
	return;
	end
	
        ATR[period] = MA.DATA[period];
    
end