-- Id: 19305
-- More information about this indicator can be found at:
-- http://fxcodebase.com/code/viewtopic.php?f=17&t=3102

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-- Indicator profile initialization routine
-- Defines indicator profile properties and indicator parameters
function Init()
    indicator:name("SuperTrend Indicator");
    indicator:description("The indicator displays the buying and selling with the colors. The indicator is initially developed by Jason Robinson for MT4");
    indicator:requiredSource(core.Bar);
    indicator:type(core.Oscillator);

	indicator.parameters:addGroup("Calculation");
    indicator.parameters:addInteger("N", "Number of periods", "No description", 10);
    indicator.parameters:addDouble("M", "Multiplier", "No description", 1.5);
	indicator.parameters:addGroup("Style");
    indicator.parameters:addColor("UP_color", "Color of UP", "Color of UP", core.rgb(0, 255, 0));
    indicator.parameters:addColor("DN_color", "Color of DN", "Color of DN", core.rgb(255, 0, 0));
 
end

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

local first;
local source = nil;
local ATR = nil;

-- Streams block
local OUT = nil;
local UP = nil;
local DN = nil;
local TR = nil;

-- Routine
function Prepare(nameOnly) 
    N = instance.parameters.N;
    M = instance.parameters.M;
    source = instance.source;
   
    local name = profile:id() .. "(" .. source:name() .. ", " .. N .. ", " .. M .. ")";
    instance:name(name);
	
	if   (nameOnly) then
        return;
    end
	
	 ATR = core.indicators:create("ATR", source, N);
    first = ATR.DATA:first();
	
    UP = instance:addInternalStream(first, 0);
    DN = instance:addInternalStream(first, 0);
    TR = instance:addInternalStream(first, 0);
    OUT = instance:addStream("ST", core.Bar, name .. ".Super Trend", "Super Trend", instance.parameters.UP_color, first);    
	OUT:addLevel(0);
	OUT:setPrecision(math.max(2, instance.source:getPrecision()));
end

-- Indicator calculation routine
function Update(period, mode)
    ATR:update(mode);
    TR[period] = 1;
	OUT[period] = 1; 
    if period <first then
	return;
	end
        local  change;        
       
        UP[period] = source.median[period] + ATR.DATA[period] * M;
        DN[period] = source.median[period] - ATR.DATA[period] * M;

        if period >= first + 1 then
            change = false;
            if source.close[period] > UP[period - 1] then
                TR[period] = 1;
                if TR[period - 1] == -1 then
                    change = true;
                end
            elseif source.close[period] < DN[period - 1] then
                TR[period] = -1;
                if TR[period - 1] == 1 then
                    change = true;
                end
            else
                TR[period] = TR[period - 1];
            end

            local flag, flagh;

            if TR[period] < 0 and TR[period - 1] > 0 then
               flag = 1;
            else
               flag = 0;
            end

            if TR[period] > 0 and TR[period - 1] < 0 then
               flagh = 1;
            else
               flagh = 0;
            end

            if TR[period] > 0 and DN[period] < DN[period - 1] then
                DN[period] = DN[period - 1];
            end

            if TR[period] < 0 and UP[period] > UP[period - 1] then
                UP[period] = UP[period - 1];
            end

            if flag == 1 then
                UP[period] = source.median[period] + ATR.DATA[period] * M;
            end

            if flagh == 1 then
                DN[period] = source.median[period] - ATR.DATA[period] * M;
            end

            if TR[period] == 1 then 
                 OUT:setColor(period, instance.parameters.UP_color); 				
            end

            if TR[period] == -1 then                
                OUT:setColor(period, instance.parameters.DN_color);				
            end
        end
    
end