Terminal Velocity Stop

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

//@version=6
indicator("Terminal Velocity Stop | Lyro RS", "TVS | Lyro RS", overlay = true)

//---------------------------------------------------------------------------------------------------------------------{
//Settings
//---------------------------------------------------------------------------------------------------------------------{
atrLen = input.int(14, 'ATR Length', minval = 1, group = 'Settings')

mult   = input.float(3.0, '+ Multiplier', minval = 0.5, step = 0.25
  , tooltip = 'Distance of the stop target from price'
  , group = 'Settings')

multm  = input.float(3.0, '- Multiplier', minval = 0.5, step = 0.25
  , tooltip = 'Distance of the stop target from price in downtrends'
  , group = 'Settings')

vmax   = input.float(0.3, 'Terminal Velocity', minval = 0.05, maxval = 2, step = 0.05
  , tooltip = 'Maximum speed of the stop in ATR per bar. However violent the move, the stop can never travel faster than this — parabolic candles cannot yank it into the noise'
  , group = 'Settings')

//---------------------------------------------------------------------------------------------------------------------{
//Color
//---------------------------------------------------------------------------------------------------------------------{
ColMode = input.string('Mystic', 'Custom Color Palette', inline = 'drop', options = ['Classic', 'Mystic', 'Accented', 'Royal'], display = display.none, group = 'Color', tooltip = 'Choose a predefined color scheme for indicator visualization.')
cpyn    = input.bool(false, 'Use Custom Palette', group = 'Color', display = display.none)
cp_UpC  = input.color(#00ff00, 'Custom Up', inline = 'Custom Palette', group = 'Color', display = display.none)
cp_DnC  = input.color(#ff0000, 'Custom Down', inline = 'Custom Palette', group = 'Color', display = display.none)

color UpC = na
color DnC = na

switch ColMode
    "Classic" =>
        UpC := #00E676
        DnC := #880E4F
    "Mystic" =>
        UpC := #30FDCF
        DnC := #E117B7
    "Accented" =>
        UpC := #9618F7
        DnC := #FF0078
    "Royal" =>
        UpC := #FFC107
        DnC := #673AB7

if cpyn
    UpC := cp_UpC
    DnC := cp_DnC

//---------------------------------------------------------------------------------------------------------------------{
//Terminal Velocity Stop
//---------------------------------------------------------------------------------------------------------------------{
//A falling object stops accelerating at terminal velocity. This stop
//chases its ATR target but its per-bar travel is hard-capped: after
//a vertical candle a normal stop teleports right under price and the
//first pause knocks the position out — this one keeps its distance
//and closes it at a controlled speed.
atr = ta.atr(atrLen)

var float stop = na
var int   dir  = 1

target = dir == 1 ? close - mult * atr : close + multm * atr

if na(stop)
    stop := target
else
    step = math.max(math.min(target - stop, vmax * atr), -vmax * atr)

    if dir == 1
        stop := math.max(stop, stop + step)

        if close < stop
            dir  := -1
            stop := close + multm * atr
    else
        stop := math.min(stop, stop + step)

        if close > stop
            dir  := 1
            stop := close - mult * atr

flipUp   = dir == 1 and dir[1] == -1
flipDown = dir == -1 and dir[1] == 1

css = dir == 1 ? UpC : DnC

//---------------------------------------------------------------------------------------------------------------------{
//Visuals
//---------------------------------------------------------------------------------------------------------------------{
plot(dir == 1 and not flipUp ? stop : na, 'Bull Stop [Glow]', color.new(UpC, 80), 6, plot.style_linebr, editable = false)
plot(dir == 1 and not flipUp ? stop : na, 'Bull Stop', UpC, 2, plot.style_linebr)
plot(dir == -1 and not flipDown ? stop : na, 'Bear Stop [Glow]', color.new(DnC, 80), 6, plot.style_linebr, editable = false)
plot(dir == -1 and not flipDown ? stop : na, 'Bear Stop', DnC, 2, plot.style_linebr)

pStop  = plot(stop, 'Stop Anchor', na, editable = false)
pPrice = plot(close, 'Price Anchor', na, editable = false)
fill(pStop, pPrice,
     dir == 1 ? stop : close, dir == 1 ? close : stop,
     dir == 1 ? color.new(UpC, 90) : color.new(DnC, 50),
     dir == 1 ? color.new(UpC, 50) : color.new(DnC, 90),
     'Trend Cloud')

plot(flipUp or flipDown ? stop : na, 'Flip Dot', color.new(css, 0), 4, plot.style_circles, join = false)
plotcandle(open, high, low, close, color= css, wickcolor= css, bordercolor= css, force_overlay= true)

//---------------------------------------------------------------------------------------------------------------------{
//Alerts
//---------------------------------------------------------------------------------------------------------------------{
alertcondition(flipUp, 'Bullish Flip', 'TVS | Lyro RS: Bullish stop flip on {{ticker}} ({{interval}})')
alertcondition(flipDown, 'Bearish Flip', 'TVS | Lyro RS: Bearish stop flip on {{ticker}} ({{interval}})')

//---------------------------------------------------------------------------------------------------------------------}