HA Candles

// This Pine Script® code is subject to the terms of the Mozilla Public License 2.0 at https://mozilla.org/MPL/2.0/
// © teshmi9z

//@version=6
indicator("HA", overlay=true)
customBuyColor = color.new(#00FFFF, 0)
customSellColor = color.new(#FF0000, 0)
var string candleGroup = 'Candlestick Settings'
candleType = input.string('Linear Regression', 'Candle Type', options = ['Candlesticks', 'Heikin Ashi', 'Linear Regression'], group = candleGroup, tooltip = 'Choose the type of candles to display. This does not impact signal calculations.')
lrcLength = input.int(6, 'Linear Regression Length', minval = 1, group = candleGroup, tooltip = 'Length for Linear Regression calculations. Lower values are more responsive but noisier.')

// Heikin Ashi
calculateHA() =>
    var haOpen = 0.0
    var haHigh = 0.0
    var haLow = 0.0
    var haClose = 0.0

    newHaClose = (open + high + low + close) / 4
    newHaOpen = na(haOpen[1]) ? (open + close) / 2 : (haOpen[1] + haClose[1]) / 2
    newHaHigh = math.max(high, math.max(newHaOpen, newHaClose))
    newHaLow = math.min(low, math.min(newHaOpen, newHaClose))

    haClose := newHaClose
    haOpen := newHaOpen
    haHigh := newHaHigh
    haLow := newHaLow

    [newHaOpen, newHaHigh, newHaLow, newHaClose]

[oHA, hHA, lHA, cHA] = calculateHA()

var float displayOpen = na
var float displayHigh = na
var float displayLow = na
var float displayClose = na

if candleType == 'Candlesticks'
    displayOpen := open
    displayHigh := high
    displayLow := low
    displayClose := close
else if candleType == 'Heikin Ashi'
    displayOpen := oHA
    displayHigh := hHA
    displayLow := lHA
    displayClose := cHA
else if candleType == 'Linear Regression'
    displayOpen := ta.linreg(open, lrcLength, 0)
    displayHigh := ta.linreg(high, lrcLength, 0)
    displayLow := ta.linreg(low, lrcLength, 0)
    displayClose := ta.linreg(close, lrcLength, 0)

// Determine coloring
isBullishCandle = displayClose > displayOpen
isBearishCandle = displayClose < displayOpen
// ===========================================================================================================
// CANDLE PLOTTING
// ===========================================================================================================

candleColor = isBullishCandle ? customBuyColor : customSellColor

plotcandle(candleType != 'Candlesticks' ? displayOpen : na,
           candleType != 'Candlesticks' ? displayHigh : na,
           candleType != 'Candlesticks' ? displayLow : na,
           candleType != 'Candlesticks' ? displayClose : na,
           title = 'Alternative Candles',
           color = candleType != 'Candlesticks' ? candleColor : na,
           wickcolor = candleType != 'Candlesticks' ? candleColor : na,
           bordercolor = candleType != 'Candlesticks' ? candleColor : na)