-- More information about this indicator can be found at:
-- http://fxcodebase.com/code/viewtopic.php?f=17&t=1256
-- Id:
--+------------------------------------------------------------------+
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--+------------------------------------------------------------------+
--|                                      Developed by : Mario Jemic  |                    
--|                                          mario.jemic@gmail.com   |
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--+------------------------------------------------------------------+
-- I have simplified this indicator a bit
--Indicator does not calculate the value of HA for each period alone.
--Values are calculated by External function
--Standard Heiken Ashi Indicator

function Init()
	indicator:name("Price Trend Line")
	indicator:description("Price Trend Line")
	--Sets the type of the required source of the indicator Bar or Tick
	indicator:requiredSource(core.Bar)
	--Sets the type - Indicator or Oscillator.
	indicator:type(core.Indicator)

	indicator.parameters:addString("Type", "Mode", "", "highlow1");
	indicator.parameters:addStringAlternative("Type", "High/low", "", "highlow1");
	indicator.parameters:addStringAlternative("Type", "Close", "", "close1");	
	indicator.parameters:addStringAlternative("Type", "HA High/low", "", "highlow2");
	indicator.parameters:addStringAlternative("Type", "HA Close", "", "close2");
	
	indicator.parameters:addColor("Up", "Up Color", "Color", core.rgb(0, 255, 0))
	indicator.parameters:addColor("Dn", "Down Color", "Color", 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

--definition of variables
local source = nil
local LINE = nil

local Up, Dn
local first = 0
local Type
local Indicator;
-- Routine
function Prepare(nameOnly)
	source = instance.source

	Up = instance.parameters.Up
	Dn = instance.parameters.Dn
	Type = instance.parameters.Type;

	local name = "Heiken Ashi Trend Line" .. "(" .. source:name() .. ")"
	instance:name(name)
	if nameOnly then
		return
	end

	--Creates an instance of the indicator
	--Calls Heiken Ashi indicator
	--Heiken Ashi indicator return indicator stream.
	
      if (Type == "highlow2" or Type == "close2") then
	Indicator= core.indicators:create("HA", source );
	first = Indicator.DATA:first() + 1
	else
     
	first = source:first() + 1
	end
	 
	
	--Adds a stream to the indicator output
	LINE = instance:addStream("Line", core.Line, name, "close", Up, first)
	LINE:setWidth(instance.parameters.width)
	LINE:setStyle(instance.parameters.style)
end

-- Indicator calculation routine
function Update(period, mode)
	if period < source:first()   then
		return
	end
	
 
    

     if (Type == "highlow2" or Type == "close2") then
	
	
	        Indicator:update(mode);
	
	       if Indicator.open[period] < Indicator.close[period] then
				if Type == "highlow2" then
					LINE[period] = Indicator.high[period]
				else
					LINE[period] = Indicator.close[period];
				end
				LINE:setColor(period, Dn)
			else
				if Type == "highlow2" then
					LINE[period] = Indicator.low[period]
				else
					LINE[period] = Indicator.close[period];
				end
				LINE:setColor(period, Up)
			end
			
	end	 
	
	if (Type == "highlow1" or Type== "close1") then
	
	
			if source.open[period] < source.close[period] then
				if Type == "highlow1" then
					LINE[period] = source.high[period]
				else
					LINE[period] = source.close[period];
				end
				LINE:setColor(period, Dn)
			else
				if Type == "highlow1" then
					LINE[period] = source.low[period]
				else
					LINE[period] = source.close[period];
				end
				LINE:setColor(period, Up)
			end
	end	
end