-- More information about this indicator can be found at:
-- http://fxcodebase.com/code/viewtopic.php?f=17&t=33488
-- Id: 8755

--+------------------------------------------------------------------+
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--+------------------------------------------------------------------+

function Init()
    indicator:name("Percent Difference Oscillator");
    indicator:description("Percent Difference Oscillator");
    indicator:requiredSource(core.Tick);
    indicator:type(core.Oscillator);
    indicator.parameters:addGroup("Calculation");
    indicator.parameters:addInteger("Period", "Period", "Period", 14);
	indicator.parameters:addString("Method", "MA Method", "Method" , "MVA");
    indicator.parameters:addStringAlternative("Method", "MVA", "MVA" , "MVA");
    indicator.parameters:addStringAlternative("Method", "EMA", "EMA" , "EMA");
 indicator.parameters:addStringAlternative("Method", "LWMA", "LWMA" , "LWMA");
    indicator.parameters:addStringAlternative("Method", "TMA", "TMA" , "TMA");
    indicator.parameters:addStringAlternative("Method", "SMMA", "SMMA" , "SMMA");
    indicator.parameters:addStringAlternative("Method", "KAMA", "KAMA" , "KAMA");
    indicator.parameters:addStringAlternative("Method", "VIDYA", "VIDYA" , "VIDYA");
    indicator.parameters:addStringAlternative("Method", "WMA", "WMA" , "WMA");
	indicator.parameters:addGroup("Style");
    indicator.parameters:addColor("PDO_color", "Color of PDO", "Color of PDO", 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

-- 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 Period;
local Method;
local first;
local source = nil;
local MA;
-- Streams block
local PDO = nil;

-- Routine
function Prepare(nameOnly)
    Period = instance.parameters.Period;
	Method = instance.parameters.Method;
    source = instance.source;

    local name = profile:id() .. "(" .. source:name() .. ", " .. tostring(Period) .. ", " .. tostring(Method).. ")";
    instance:name(name);

    if (not (nameOnly)) then
    assert(core.indicators:findIndicator(Method) ~= nil, Method .. " indicator must be installed");
        MA = core.indicators:create(Method, source, Period);
        first = MA.DATA:first();
        PDO = instance:addStream("PDO", core.Line, name, "PDO", instance.parameters.PDO_color, first);
    PDO:setPrecision(math.max(2, instance.source:getPrecision()));
		PDO:setWidth(instance.parameters.width);
        PDO:setStyle(instance.parameters.style);
    end
end

-- Indicator calculation routine
-- TODO: Add your code for calculation output values
function Update(period, mode)  
    MA:update(mode);
    if period < first  then
	return;
	end
    PDO[period] = 100*(source[period]-MA.DATA[period])/MA.DATA[period];
    
end