-- More information about this indicator can be found at:
-- http://fxcodebase.com/code/viewtopic.php?f=17&t=69779
 
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-- Indicator profile initialization routine
-- Defines indicator profile properties and indicator parameters
-- TODO: Add minimal and maximal value of numeric parameters and default color of the streams
function Init()
    indicator:name("Moving Average Envelope (New Version)");
    indicator:description("");
    indicator:requiredSource(core.Tick);
    indicator:type(core.Indicator);
	
	
	indicator.parameters:addGroup("Shift Calculation");
	indicator.parameters:addBoolean("Shift", "Half Period shift", "", true);
    indicator.parameters:addInteger("SX", "Shift in periods", "Postive is future, negative is past", 0);
    indicator.parameters:addInteger("SY", "Shift in points", "", 0);
	
	
    indicator.parameters:addGroup("Calculation");

    indicator.parameters:addInteger("N", "Number of periods for Moving Average", "", 14);
    indicator.parameters:addString("MET", "Moving Average Method", "The methods marked by an asterisk (*) require the appropriate indicators to be loaded.", "MVA");
    indicator.parameters:addStringAlternative("MET", "MVA", "", "MVA");
    indicator.parameters:addStringAlternative("MET", "EMA", "", "EMA");
    indicator.parameters:addStringAlternative("MET", "LWMA", "", "LWMA");
    indicator.parameters:addStringAlternative("MET", "SMMA*", "", "SMMA");
    indicator.parameters:addStringAlternative("MET", "Vidya (1995)*", "", "VIDYA");
    indicator.parameters:addStringAlternative("MET", "Vidya (1992)*", "", "VIDYA92");
    indicator.parameters:addStringAlternative("MET", "Wilders*", "", "WMA");

    indicator.parameters:addDouble("B", "Band Width", "", 25);
    indicator.parameters:addString("BWU", "Band Width Units", "", "%%");
    indicator.parameters:addStringAlternative("BWU", "In 1/100 of percent", "", "%%");
    indicator.parameters:addStringAlternative("BWU", "In pips", "", "pip(s)");



    indicator.parameters:addGroup("Style");
    indicator.parameters:addBoolean("SM", "Show MA line", "", true);
    indicator.parameters:addColor("MVA_color", "Color of MA line", "", core.rgb(255, 0, 0));
	
	indicator.parameters:addInteger("style1", "Line Style", "", core.LINE_SOLID);
    indicator.parameters:setFlag("style1", core.FLAG_LEVEL_STYLE);	
	indicator.parameters:addInteger("width1", "Line Width", "", 3, 1, 5);
	
    indicator.parameters:addColor("B_color", "Color of Band", "", core.rgb(0, 0, 255));
	
	indicator.parameters:addInteger("style2", "Line Style", "", core.LINE_SOLID);
    indicator.parameters:setFlag("style2", core.FLAG_LEVEL_STYLE);	
	indicator.parameters:addInteger("width2", "Line Width", "", 3, 1, 5);
end

-- Indicator instance initialization routine
-- Processes indicator parameters and creates output streams
-- TODO: Refine the first period calculation for each of the output streams.
-- TODO: Calculate all constants, create instances all subsequent indicators and load all required libraries
-- Parameters block
local N;
local B;
local BWU;
local MET;
local SM;
local Shift;
local first;
local source = nil;
local IND;

-- Streams block
local MVA = nil;
local UB = nil;
local LB = nil;
local SX, SY;

-- Routine
 function Prepare(nameOnly) 
    N = instance.parameters.N;
    B = instance.parameters.B;
    BWU = instance.parameters.BWU;
    MET = instance.parameters.MET;
    SM = instance.parameters.SM;
	Shift= instance.parameters.Shift;
	
    source = instance.source;
    assert(core.indicators:findIndicator(MET) ~= nil, MET .. " indicator must be installed");
    IND = core.indicators:create(MET, source, N);
    first = IND.DATA:first()+1;
    SX = instance.parameters.SX;
    SY = instance.parameters.SY;

    local name = profile:id() .. "(" .. source:name() .. "," .. MET .. "(" .. N .. ")," .. B .. BWU .. ")";
    instance:name(name);
	
	if   (nameOnly) then
        return;
    end

    if BWU == "%%" then
        BWU = 1;
    else
        BWU = 2;
        B = B * source:pipSize();
    end

    if SM then
        MVA = instance:addStream("MVA", core.Line, name .. ".MVA", "MVA", instance.parameters.MVA_color, first, SX);
		MVA:setPrecision(math.max(10, source:getPrecision()));
		MVA:setWidth(instance.parameters.width1);
        MVA:setStyle(instance.parameters.style1);
    end
    UB = instance:addStream("UB", core.Line, name .. ".UB", "UB", instance.parameters.B_color, first, SX);	
    LB = instance:addStream("LB", core.Line, name .. ".LB", "LB", instance.parameters.B_color, first, SX);
	
	UB:setPrecision(math.max(10, source:getPrecision()));
	LB:setPrecision(math.max(10, source:getPrecision()));
	
	UB:setWidth(instance.parameters.width2);
    UB:setStyle(instance.parameters.style2);
	LB:setWidth(instance.parameters.width2);
    LB:setStyle(instance.parameters.style2);
end

-- Indicator calculation routine
-- TODO: Add your code for calculation output values
function Update(period, mode)

    IND:update(mode);
	 
    if period < first then
	return;
	end
	

        local d;
		
		
		if	Shift then
		d= (IND.DATA[period-1] +IND.DATA[period])/2;
		else
		d= IND.DATA[period];
		end
		
		
		
        local s;
        if BWU == 1 then
            s = d * B / 10000;
        else
            s = B;
        end

        if SM then
            MVA[period + SX] = d + SY;
        end
        UB[period + SX] = d + s + SY;
        LB[period + SX] = d - s + SY;
    
end