-- More information about this indicator can be found at:
-- http://fxcodebase.com/code/viewtopic.php?f=17&t=2483
-- Available @ http://fxcodebase.com/code/viewtopic.php?f=17&t=2483&hilit=TD_Lines&start=50


--+------------------------------------------------------------------+
--|                               Copyright © 2018, Gehtsoft USA LLC | 
--|                                            http://fxcodebase.com |
--+------------------------------------------------------------------+
--|                                      Developed by : Mario Jemic  |                    
--|                                          mario.jemic@gmail.com   |
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--+------------------------------------------------------------------+


function Init()
    indicator:name("TD Lines indicator");
    indicator:description("TD Lines indicator");
    indicator:requiredSource(core.Bar);
    indicator:type(core.Indicator);

    indicator.parameters:addGroup("Calculation");
    indicator.parameters:addBoolean("FractalAsTD", "FractalAsTD", "", false);
    indicator.parameters:addBoolean("output_streams", "Output streams", "", false);

    indicator.parameters:addGroup("Style");
    indicator.parameters:addColor("clrUP", "Color UP", "Color UP", core.rgb(0, 255, 0));
    indicator.parameters:addColor("clrDN", "Color DN", "Color DN", core.rgb(255, 0, 0));
    indicator.parameters:addColor("clrL1", "Color L1", "Color L1", core.rgb(0, 255, 0));
    indicator.parameters:addColor("clrL2", "Color L2", "Color L2", core.rgb(255, 0, 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);
	
	indicator.parameters:addGroup("Extension");
	indicator.parameters:addInteger("Number", "Extension Period", "Extension Period", 10, 0 , 1000);
	indicator.parameters:addInteger("Extension", "Extension Line style", "Extension Line style", core.LINE_DOT);
    indicator.parameters:setFlag("Extension", core.FLAG_LINE_STYLE);
end

local first;
local source = nil;
local FractalAsTD;
local buffUp;
local buffDn;
local up=nil;
local down=nil;
local TOP;
local BOTTOM;
local TARGET;
local SIZE;
local Number;

function Prepare(nameOnly)
    Number=instance.parameters.Number; 
    source = instance.source;
    FractalAsTD=instance.parameters.FractalAsTD;
    first = source:first()+6;
    up = instance:addInternalStream(first, 0);
    down = instance:addInternalStream(first, 0);
    local name = profile:id() .. "(" .. source:name() .. ")";
    instance:name(name);
	
	if   (nameOnly) then
        return;
    end
	
	
    buffUp = instance:createTextOutput ("Up", "Up", "Wingdings", 10, core.H_Center, core.V_Center, instance.parameters.clrUP, first);
    buffDn = instance:createTextOutput ("Dn", "Dn", "Wingdings", 10, core.H_Center, core.V_Center, instance.parameters.clrDN, first);
    if instance.parameters.output_streams then
        TOP = instance:addStream("Top", core.Line, name, "Top", instance.parameters.clrUP, first);
        BOTTOM = instance:addStream("Bottom", core.Line, name, "Bottom", instance.parameters.clrDN, first);
        TARGET = instance:addStream("Target", core.Line, name, "Target", instance.parameters.clrDN, first);
    else
        TOP = instance:addInternalStream(0, 0);
        BOTTOM = instance:addInternalStream(0, 0);
    end
	
	local s, e = core.getcandle(source:barSize(), core.now(), 0, 0);
    SIZE = e-s;
end

function Update(period, mode)
    if (period>first) then
        if FractalAsTD==false then
            if source.high[period-3]<source.high[period-2] and source.high[period-1]<source.high[period-2] then
                up[period-2]=source.high[period-2];
                buffUp:set(period-2, source.high[period-2], "\159", "");
            end
            if source.high[period-4]<source.high[period-2] and source.high[period-3]==source.high[period-2] and source.high[period-1]<source.high[period-2] then
                up[period-2]=source.high[period-2];
                buffUp:set(period-2, source.high[period-2], "\159", "");
            end
            if source.high[period-5]<source.high[period-2] and source.high[period-4]==source.high[period-2] and source.high[period-3]==source.high[period-2] and source.high[period-1]<source.high[period-2] then
                up[period-2]=source.high[period-2];
                buffUp:set(period-2, source.high[period-2], "\159", "");
            end
            if source.high[period-6]<source.high[period-2] and source.high[period-5]==source.high[period-2] and source.high[period-4]==source.high[period-2] and source.high[period-3]==source.high[period-2] and source.high[period-1]<source.high[period-2] then
                up[period-2]=source.high[period-2];
                buffUp:set(period-2, source.high[period-2], "\159", "");
            end
            if source.low[period-3]>source.low[period-2] and source.low[period-1]>source.low[period-2] then
                down[period-2]=source.low[period-2];
                buffDn:set(period-2, source.low[period-2], "\159", "");
            end
            if source.low[period-4]>source.low[period-2] and source.low[period-3]==source.low[period-2] and source.low[period-1]>source.low[period-2] then
                down[period-2]=source.low[period-2];
                buffDn:set(period-2, source.low[period-2], "\159", "");
            end
            if source.low[period-5]>source.low[period-2] and source.low[period-4]==source.low[period-2] and source.low[period-3]==source.low[period-2] and source.low[period-1]>source.low[period-2] then
                down[period-2]=source.low[period-2];
                buffDn:set(period-2, source.low[period-2], "\159", "");
            end
            if source.low[period-6]>source.low[period-2] and source.low[period-5]==source.low[period-2] and source.low[period-4]==source.low[period-2] and source.low[period-3]==source.low[period-2] and source.low[period-1]>source.low[period-2] then
                down[period-2]=source.low[period-2];
                buffDn:set(period-2, source.low[period-2], "\159", "");
            end
        else
            if source.high[period-3]>source.high[period-2] and source.high[period-3]>source.high[period-1] and source.high[period-3]>source.high[period-4] and source.high[period-3]>source.high[period-5] then
                up[period-3]=source.high[period-3];
                buffUp:set(period-3, source.high[period-3], "\159", "");
            end
            if source.low[period-3]<source.low[period-2] and source.low[period-3]<source.low[period-1] and source.low[period-3]<source.low[period-4] and source.low[period-3]<source.low[period-5] then
                down[period-3]=source.low[period-3];
                buffDn:set(period-3, source.low[period-3], "\159", "");
            end
        end
        if period==source:size()-1 then
            local H1=nil;
            local H2=nil;
            local L1=nil;
            local L2=nil;
            local i=period;
            while (H2==nil or L2==nil) and i>first do
                if up[i]==source.high[i] then
                    if H1==nil then
                        H1=i;
                    elseif up[i]>up[H1] and H2==nil then 
                        H2=i;
                    end
                end
                if down[i]==source.low[i] then
                    if L1==nil then
                        L1=i;
                    elseif down[i]<down[L1] and L2==nil then 
                        L2=i;
                    end
                end
                i=i-1;
            end
            if (H1~=nil and H2~=nil) or (L1~=nil and L2~=nil) then
                core.host:execute("removeAll");
            end
        	local MIN, MAX;
	        local One,Two;
            if H1~=nil and H2~=nil then
                local value1 = up[H2]-0.5*(up[H1]-up[H2])/(H1-H2);
                local value2 = up[H2]+(period-H2-0.5)*(up[H1]-up[H2])/(H1-H2);
                local period_date = source:date(period);
                if not instance.parameters.output_streams then
                    core.host:execute("drawLine", 1, source:date(H2), value1, period_date, value2, instance.parameters.clrUP,instance.parameters.styleLinReg,instance.parameters.widthLinReg);
                end
                core.drawLine(TOP, core.range(H2, period), value1, H2, value2, period);
                One, Two= getline(H1, up[H1], H2, up[H2]);
                if not instance.parameters.output_streams then
	 	            core.host:execute("drawLine", 5, period_date, TOP[period], period_date+SIZE * Number, One * (period+Number) + Two, instance.parameters.clrUP,instance.parameters.Extension,instance.parameters.widthLinReg);
                end
			    for i= H2, period, 1 do
				    if i== H2 then
				        MAX= TOP[i] -source.low[i];
				    end
				    if MAX <  TOP[i] -source.low[i] then
				        MAX =  TOP[i] -source.low[i]
				    end
			    end
	            BOTTOM[H2-1]= 666;		
	        end
            if L1~=nil and L2~=nil then
                local value1 = down[L2]-0.5*(down[L1]-down[L2])/(L1-L2);
                local value2 = down[L2]+(period-L2-0.5)*(down[L1]-down[L2])/(L1-L2);
                local period_date = source:date(period);
                if not instance.parameters.output_streams then
                    core.host:execute("drawLine", 2, source:date(L2), value1, period_date, value2, instance.parameters.clrDN,instance.parameters.styleLinReg,instance.parameters.widthLinReg);
                end
                core.drawLine(BOTTOM, core.range(L2, period), value1, L2,  value2, period);
                One, Two= getline(L1, down[L1], L2, down[L2]);
                if not instance.parameters.output_streams then
    	            core.host:execute("drawLine", 6, period_date, BOTTOM[period], period_date + SIZE * Number, One * (period+Number) + Two, instance.parameters.clrDN,instance.parameters.Extension,instance.parameters.widthLinReg);
                end
                for i= L2, period, 1 do
				    if i== L2 then
				        MIN= source.high[i]-BOTTOM[i];
				    end
				    if MIN <  source.high[i]-BOTTOM[i] then
				        MIN =  source.high[i]-BOTTOM[i]
				    end
			    end
	            BOTTOM[L2-1]= 666;		
            end
	        if MAX ~= nil then 
                for i = period-1 , first , -1 do
                    if TOP[i]== 666 then               			  
				        break;
				    end
				    if TOP:hasData(i - 1) and core.crossesOver(source.close, TOP, i) then
                        if instance.parameters.output_streams then
                            core.drawLine(TARGET, core.range(i, period), TOP[i] + MAX, i, TOP[i] + MAX, period);
                        else
                            core.host:execute("drawLine", 3, source:date(i), TOP[i] +MAX, source:date(period), TOP[i] +MAX ,instance.parameters.clrUP,instance.parameters.styleLinReg,instance.parameters.widthLinReg);	
                            core.host:execute("drawLine", 7, source:date(period), TOP[i] +MAX, source:date(period)+SIZE * Number, TOP[i] +MAX ,instance.parameters.clrUP,instance.parameters.Extension,instance.parameters.widthLinReg);
                        end
				        break;
				    end  
		        end 
	        end
	        if MIN ~= nil then 
				for i = period-1 , first , -1 do 
                    if BOTTOM[i]== 666 then					
					    break;
					end
				    if BOTTOM:hasData(i - 1) and core.crossesUnder(source.close, BOTTOM, i) then
                        if instance.parameters.output_streams then
                            core.drawLine(TARGET, core.range(i, period), BOTTOM[i]-MIN, i, BOTTOM[i]-MIN, period);
                        else
                            core.host:execute("drawLine", 4, source:date(i), BOTTOM[i]-MIN, source:date(period), BOTTOM[i]-MIN  ,instance.parameters.clrUP,instance.parameters.styleLinReg,instance.parameters.widthLinReg);
                            core.host:execute("drawLine", 8, source:date(period), BOTTOM[i]-MIN, source:date(period)+SIZE * Number, BOTTOM[i]-MIN  ,instance.parameters.clrUP,instance.parameters.Extension,instance.parameters.widthLinReg);		    					   
                        end
					    break;
					end    
			    end 
	        end
        end
    end 
end

function getline(x1, y1, x2, y2)
    local a = ((y2 - y1) / (x2 - x1));
    local b = (y1 - a * x1);
    return a, b;
end