-- More information about this indicator can be found at:
-- http://fxcodebase.com/code/viewtopic.php?f=17&t=34062
-- Id: 8878

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function Init()
    indicator:name("Trend Strength oscillator");
    indicator:description("Trend Strength oscillator");
    indicator:requiredSource(core.Tick);
    indicator:type(core.Oscillator);
    
    indicator.parameters:addGroup("Calculation");
    indicator.parameters:addString("Method", "Method", "", "MVA");
    indicator.parameters:addStringAlternative("Method", "MVA", "", "MVA");
    indicator.parameters:addStringAlternative("Method", "EMA", "", "EMA");
    indicator.parameters:addStringAlternative("Method", "KAMA", "", "KAMA");
    indicator.parameters:addStringAlternative("Method", "Wilder", "", "Wilder");
    indicator.parameters:addStringAlternative("Method", "LWMA", "", "LWMA");
    indicator.parameters:addStringAlternative("Method", "SineWMA", "", "SineWMA");
    indicator.parameters:addStringAlternative("Method", "TriMA", "", "TriMA");
    indicator.parameters:addStringAlternative("Method", "LSMA", "", "LSMA");
    indicator.parameters:addStringAlternative("Method", "SMMA", "", "SMMA");
    indicator.parameters:addStringAlternative("Method", "HMA", "", "HMA");
    indicator.parameters:addStringAlternative("Method", "ZeroLagEMA", "", "ZeroLagEMA");
    indicator.parameters:addStringAlternative("Method", "DEMA", "", "DEMA");
    indicator.parameters:addStringAlternative("Method", "T3", "", "T3");
    indicator.parameters:addStringAlternative("Method", "ITrend", "", "ITrend");
    indicator.parameters:addStringAlternative("Method", "Median", "", "Median");
    indicator.parameters:addStringAlternative("Method", "GeoMean", "", "GeoMean");
    indicator.parameters:addStringAlternative("Method", "REMA", "", "REMA");
    indicator.parameters:addStringAlternative("Method", "ILRS", "", "ILRS");
    indicator.parameters:addStringAlternative("Method", "IE/2", "", "IE/2");
    indicator.parameters:addStringAlternative("Method", "TriMAgen", "", "TriMAgen");
    indicator.parameters:addStringAlternative("Method", "JSmooth", "", "JSmooth");
    indicator.parameters:addInteger("Period", "Start period", "", 10);
    indicator.parameters:addInteger("Step", "Step", "", 10);
    indicator.parameters:addInteger("MaxSteps", "Max. steps", "", 11);

    indicator.parameters:addGroup("Style");
    indicator.parameters:addColor("clr", "Color", "Color", core.rgb(255, 255, 0));
    indicator.parameters:addInteger("widthLinReg", "Line width", "Line width", 1, 1, 5);
    indicator.parameters:addInteger("styleLinReg", "Line style", "Line style", core.LINE_SOLID);
    indicator.parameters:setFlag("styleLinReg", core.FLAG_LINE_STYLE);
end

local first;
local source = nil;
local Method;
local Period;
local Step;
local MaxSteps;
local MAs={};
local TS=nil;

function Prepare(nameOnly)
    source = instance.source;
    Method=instance.parameters.Method;
    Period=instance.parameters.Period;
    Step=instance.parameters.Step;
    MaxSteps=instance.parameters.MaxSteps;
    
    local name = profile:id() .. "(" .. source:name() .. ", " .. instance.parameters.Method .. ", " .. instance.parameters.Period .. ", " .. instance.parameters.Step .. ", " .. instance.parameters.MaxSteps .. ")";
    instance:name(name);
    if nameOnly then
        return;
    end
    local i;
	assert(core.indicators:findIndicator("AVERAGES") ~= nil, "Please, download and install AVERAGES.LUA indicator"); 
    for i=0, MaxSteps, 1 do
        MAs[i]=core.indicators:create("AVERAGES", source, Method, Period+i*Step, false);
        first = MAs[i].DATA:first();
    end
    TS = instance:addStream("TS", core.Line, name .. ".TS", "TS", instance.parameters.clr, first);
    TS:setPrecision(math.max(2, instance.source:getPrecision()));
    TS:setWidth(instance.parameters.widthLinReg);
    TS:setStyle(instance.parameters.styleLinReg);
end

function Update(period, mode)


   if period<first then
   return;
   end
   
    local i;
    local res=0;
    for i=0, MaxSteps, 1 do
     MAs[i]:update(mode);
     res=res+MAs[i].DATA[period];
    end
    res=MaxSteps*MAs[0].DATA[period]-res;
    TS[period]=res;
 
end