-- Id: 3543
-- More information about this indicator can be found at:
-- http://fxcodebase.com/code/viewtopic.php?f=17&t=3847

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function Init()
    indicator:name("Projection Oscillator");
    indicator:description("Projection Oscillator");
    indicator:requiredSource(core.Bar);
    indicator:type(core.Oscillator);

    indicator.parameters:addGroup("Calculation");
    indicator.parameters:addInteger("Period", "Period", "", 14);

    indicator.parameters:addGroup("Style");
    indicator.parameters:addColor("clr", "Color", "Color", core.rgb(0, 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 Period;
local Buff=nil;

function Prepare(nameOnly)
    source = instance.source;
    Period=instance.parameters.Period;
    first =  source:first()+Period;
    local name = profile:id() .. "(" .. source:name() .. ", " .. instance.parameters.Period .. ")";
    instance:name(name);
    if nameOnly then
        return;
    end
    Buff = instance:addStream("Buff", core.Line, name .. ".Buff", "Buff", instance.parameters.clr, first);
    Buff:setPrecision(math.max(2, instance.source:getPrecision()));
    Buff:setWidth(instance.parameters.widthLinReg);
    Buff:setStyle(instance.parameters.styleLinReg);
    Buff:addLevel(20);
    Buff:addLevel(50);
    Buff:addLevel(80);
end

function Update(period, mode)
   if (period<first) then
   return;
   end
   
    local SlopeHigh=mathex.lregSlope(source.high,period-Period+1,period);
    local SlopeLow=mathex.lregSlope(source.low,period-Period+1,period);
    local i;
    local UpProjBand=source.high[period];
    local DnProjBand=source.low[period];
    for i=1,Period,1 do
     UpProjBand=math.max(UpProjBand,source.high[period-i]+i*SlopeHigh);
     DnProjBand=math.min(DnProjBand,source.low[period-i]-i*SlopeLow);
    end
    Buff[period]=100*(source.close[period]-DnProjBand)/(UpProjBand-DnProjBand);
 
end