--+------------------------------------------------------------------+
--|                               Copyright © 2020, Gehtsoft USA LLC |
--|                                            http://fxcodebase.com |
--+------------------------------------------------------------------+
--|                                      Developed by : Mario Jemic  |
--|                                           mario.jemic@gmail.com  |
--|                          https://AppliedMachineLearning.systems  |
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--|                                 Support our efforts by donating  |
--|                                   Paypal: https://goo.gl/9Rj74e  |
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--+------------------------------------------------------------------+

function Init()
    indicator:name("Simple ZigZag indicator with counter")
    indicator:description("Simple ZigZag indicator with counter")
    indicator:requiredSource(core.Tick)
    indicator:type(core.Indicator)

    indicator.parameters:addGroup("Calculation")
    indicator.parameters:addString("Method", "Method", "", "Pips")
    indicator.parameters:addStringAlternative("Method", "Pips", "", "Pips")
    indicator.parameters:addStringAlternative("Method", "Percent", "", "Percent")
    indicator.parameters:addDouble("Step", "Step (pips or percent)", "", 30)

    indicator.parameters:addGroup("Style")
    indicator.parameters:addColor("UPclr", "Up Color", "Up Color", core.rgb(0, 255, 0))
    indicator.parameters:addColor("DNclr", "Dn Color", "Dn Color", 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:addColor("UP_Text_color", "UP Text color", "UP Text color", core.rgb(0, 255, 255))
    indicator.parameters:addColor("DN_Text_color", "DN Text color", "DN Text color", core.rgb(255, 255, 0))
    indicator.parameters:addInteger("TextSize", "Text size", "Text size", 10)
end

local first
local source = nil
local Step, StepPoint
local Method
local Direction
local MinBar, MaxBar
local MaxPrice, MinPrice
local UpTextBuff = nil
local DnTextBuff = nil
local pipSize

function Prepare()
    source = instance.source
    Step = instance.parameters.Step
    Method = instance.parameters.Method
    first = source:first() + 2
    Direction = instance:addInternalStream(first, 0)
    MinBar = instance:addInternalStream(first, 0)
    MaxBar = instance:addInternalStream(first, 0)
    MinPrice = instance:addInternalStream(first, 0)
    MaxPrice = instance:addInternalStream(first, 0)
    local name = profile:id() .. "(" .. source:name() .. ", " .. instance.parameters.Step .. ")"
    instance:name(name)
    StepPoint = Step * source:pipSize()
    UpTextBuff =
        instance:createTextOutput(
        "UpText",
        "UpText",
        "Arial",
        instance.parameters.TextSize,
        core.H_Center,
        core.V_Center,
        instance.parameters.UP_Text_color,
        first
    )
    DnTextBuff =
        instance:createTextOutput(
        "DnText",
        "DnText",
        "Arial",
        instance.parameters.TextSize,
        core.H_Center,
        core.V_Center,
        instance.parameters.DN_Text_color,
        first
    )
    pipSize = source:pipSize()
end

function Draw(price1, period1, price2, period2)
    if price2 >= price1 then
        core.host:execute(
            "drawLine",
            2 * period1,
            source:date(period1),
            price1,
            source:date(period2),
            price2,
            instance.parameters.UPclr,
            instance.parameters.styleLinReg,
            instance.parameters.widthLinReg
        )
        if MaxPrice[period1] == source[period1] then
            DeleteLabels(period1 + 1, period2, UpTextBuff)
        else
            DeleteLabels(period1, period2, UpTextBuff)
        end
        UpTextBuff:set(period2, price2, TextFormat(period2 - period1, price2 - price1))
    else
        core.host:execute(
            "drawLine",
            2 * period1 + 1,
            source:date(period1),
            price1,
            source:date(period2),
            price2,
            instance.parameters.DNclr,
            instance.parameters.styleLinReg,
            instance.parameters.widthLinReg
        )
        if MinPrice[period1] == source[period1] then
            DeleteLabels(period1 + 1, period2, DnTextBuff)
        else
            DeleteLabels(period1, period2, DnTextBuff)
        end
        DnTextBuff:set(period2, price2, TextFormat(period2 - period1, price2 - price1))
    end
    return
end

function DeleteLabels(startBar, endBar, Buff)
    local i
    for i = startBar, endBar, 1 do
        Buff:setNoData(i)
    end
    return
end

function TextFormat(bars, pips)
    return "" .. math.abs(bars) + 1 .. " bars, " .. math.floor(math.abs(pips) / pipSize * 10 + 0.5) / 10 .. " pips"
end

function CalculateUp(period, price)
    local LastBar = MaxBar[period]
    if MaxPrice[LastBar] == nil or MaxPrice[LastBar] == 0 then
        MaxPrice[LastBar] = source[LastBar]
    end
    if price > MaxPrice[LastBar] then
        MaxPrice[LastBar] = nil
        MaxPrice[period] = price
        MaxBar[period] = period
        LastBar = period
        if MinBar[period] ~= nil then
            Draw(MinPrice[MinBar[period]], MinBar[period], price, period)
        end
    end
    if
        (price + StepPoint < MaxPrice[LastBar] and Method == "Pips") or
            (price * (1 + Step / 100) < MaxPrice[LastBar] and Method == "Percent")
     then
        Direction[period] = -1
        MinPrice[period] = price
        MinBar[period] = period
        if MaxBar[period] ~= nil then
            Draw(MaxPrice[MaxBar[period]], MaxBar[period], price, period)
        end
    end
    return
end

function CalculateDn(period, price)
    local LastBar = MinBar[period]
    if MinPrice[LastBar] == nil or MinPrice[LastBar] == 0 then
        MinPrice[LastBar] = source[LastBar]
    end
    if price < MinPrice[LastBar] then
        MinPrice[LastBar] = nil
        MinPrice[period] = price
        MinBar[period] = period
        LastBar = period
        if MaxBar[period] ~= nil then
            Draw(MaxPrice[MaxBar[period]], MaxBar[period], price, period)
        end
    end
    if
        (price - StepPoint > MinPrice[LastBar] and Method == "Pips") or
            (price * (1 - Step / 100) > MinPrice[LastBar] and Method == "Percent")
     then
        Direction[period] = 1
        MaxPrice[period] = price
        MaxBar[period] = period
        if MinBar[period] ~= nil then
            Draw(MinPrice[MinBar[period]], MinBar[period], price, period)
        end
    end
    return
end

function Calculate(period, price)
    if Direction[period] == 1 then
        CalculateUp(period, price)
    else
        CalculateDn(period, price)
    end
    return
end

function Update(period, mode)
    if period > first and period <= source:size() - 1 then
        MinBar[period] = MinBar[period - 1]
        MaxBar[period] = MaxBar[period - 1]
        Direction[period] = Direction[period - 1]
        MinPrice[period] = nil
        MaxPrice[period] = nil
        if source[period] < source[period] then
            Calculate(period, source[period])
            Calculate(period, source[period])
        else
            Calculate(period, source[period])
            Calculate(period, source[period])
        end
    elseif period == first then
        Direction[period] = 1
        MinBar[period] = period
        MaxBar[period] = period
        if source[period] > source[period] then
            MinPrice[period] = source[period]
            MaxPrice[period] = source[period]
        else
            MinPrice[period] = source[period]
            MaxPrice[period] = source[period]
        end
    end
end