-- Id: 
-- More information about this indicator can be found at:
-- http://fxcodebase.com/code/viewtopic.php?f=17&t=1968

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-- Indicator profile initialization routine
-- Defines indicator profile properties and indicator parameters
function Init()
    indicator:name("Market Facilitation Index")
    indicator:description("Bill Williams' Market facilitation index")
    indicator:requiredSource(core.Bar)
    indicator:type(core.Oscillator)
    indicator:setTag("group", "Volume Indicators")

    indicator.parameters:addGroup("Calculation")
    indicator.parameters:addDouble(
        "RANGE",
        "Range",
        "Multiplication factor, which brings the difference in points down to whole",
        1,
        0.00001,
        100
    )
    indicator.parameters:addDouble("volume_inc", "% volume for squat", "", 50);

    indicator.parameters:addGroup("Style")
    local colors = core.colors()
    indicator.parameters:addColor("MUVU_Color", "MFI Up/Volume Up Color", "", colors.Lime)
    indicator.parameters:addColor("MDVD_Color", "MFI Down/Volume Down Color", "", colors.SaddleBrown)
    indicator.parameters:addColor("MUVD_Color", "MFI Up/Volume Down Color", "", colors.Blue)
    indicator.parameters:addColor("MDVU_Color", "MFI Down/Volume Up Color", "", colors.Pink)

    indicator.parameters:addColor("Squat_Color", "Squat Market Color", "", colors.Red)
end

local source
local RANGE
local first
local first1
local MFI
local point
local MUVU
local MDVD
local MUVD
local MDVU
local MU
local VU
local volume_inc;
local squat;

function Prepare(nameOnly)
    source = instance.source
    first = source:first() + 1
    first1 = source:first()
    RANGE = instance.parameters.RANGE
    point = source:pipSize()
    volume_inc = 1 + instance.parameters.volume_inc / 100;

    local name
    name = profile:id() .. "(" .. source:name() .. "," .. RANGE .. ")"
    instance:name(name)

    if (nameOnly) then
        return
    end

    assert(source:supportsVolume(), "The source must have volume")

    MFI = instance:addStream("MUVU", core.Bar, name .. ".MFI", "MFI", instance.parameters.MUVU_Color, first)
    MFI:setPrecision(5)
    MU = instance:addInternalStream(0, 0)
    VU = instance:addInternalStream(0, 0)
    squat = instance:createTextOutput("Squat", "Squat", "Wingdings", 12, core.H_Center, core.V_Top, instance.parameters.Squat_Color, 0);
    core.host:execute("attachTextToChart", "Squat");
end

function Update(period, mode)
    MU[period] = 0
    VU[period] = 0

    if period >= first1 then
        MFI[period] = RANGE * (source.high[period] - source.low[period]) / (source.volume[period] * point)
        if source.volume[period] / source.volume[period - 1] >= volume_inc
            and MFI[period] < MFI[period - 1]
        then
            squat:set(period, source.high[period], "\225", "Squat");
        end
    end

    if period >= first then
        local mu, vu

        mu = MU[period - 1]
        vu = VU[period - 1]

        if MFI[period] > MFI[period - 1] then
            mu = 1
        elseif MFI[period] < MFI[period - 1] then
            mu = -1
        end

        if source.volume[period] > source.volume[period - 1] then
            vu = 1
        elseif source.volume[period] < source.volume[period - 1] then
            vu = -1
        end

        MU[period] = mu
        VU[period] = vu

        if mu > 0 and vu > 0 then
            MFI:setColor(period, instance.parameters.MUVU_Color)
        elseif mu < 0 and vu < 0 then
            MFI:setColor(period, instance.parameters.MDVD_Color)
        elseif mu > 0 and vu < 0 then
            MFI:setColor(period, instance.parameters.MUVD_Color)
        elseif mu < 0 and vu > 0 then
            MFI:setColor(period, instance.parameters.MDVU_Color)
        end
    end
end