Taught to Trade - Swing Ratio Grid

//@version=6
// Taught to Trade - Swing Ratio Grid
//
// A retracement grid that makes its two hidden parameters visible.
//
// Every retracement rule depends on two things it usually refuses to state:
//   (1) WHICH SWING you measured, and
//   (2) WHICH RATIO SET you used.
// This tool puts both on the chart. The swing comes from a pivot lookback you set
// yourself, and the pivot is only used once it is CONFIRMED - that many bars after
// it formed - so nothing here is drawn from information that did not exist at the time.
//
// The ratio set is switchable, including an arbitrary 0.4 / 0.5 / 0.6 control grid that
// has no connection to the golden ratio. Switching between sets and watching how little
// the levels move is the entire point of the tool.
//
// Marking where price traded is a fact. Nothing here predicts, ranks or scores anything,
// and no buy/sell signal is sent. Alerts are conditions you arm yourself.
//
// All series reads happen at top level; conditional blocks touch only var scalars.
indicator("Taught to Trade - Swing Ratio Grid", shorttitle = "TT SWING GRID",
     overlay = true, max_bars_back = 5000)

// ─────────────────────────────── Inputs ───────────────────────────────
grpS = "Swing"
pivLen = input.int(20, "Swing pivot lookback (bars each side)", minval = 2, maxval = 200, group = grpS,
     tooltip = "The parameter most retracement rules leave unstated. A pivot is only confirmed this many bars AFTER it forms, so every level drawn here uses confirmed structure only. Raise it for fewer, larger swings.")

grpR = "Ratio set"
setName = input.string("Fibonacci", "Grid", group = grpR,
     options = ["Fibonacci", "Arbitrary control (0.4/0.5/0.6)", "Thirds"],
     tooltip = "Switch between the sets and watch how little the levels move. On most instruments the difference is smaller than one bar's range. That comparison is the reason this input exists.")

grpD = "Draw"
showGrid  = input.bool(true, "Grid levels",        group = grpD)
showSwing = input.bool(true, "Swing high / low",   group = grpD)
showTbl   = input.bool(true, "Readout table",      group = grpD)
tblPosIn  = input.string("Bottom left", "Table position", group = grpD,
     options = ["Bottom left", "Bottom right", "Top left", "Top right", "Middle right"],
     tooltip = "Bottom left sits over the oldest bars, away from the price scale and the badges TradingView draws in the bottom-right corner.")

colGrid  = input.color(color.new(#2F6FED, 0), "Grid",  group = grpD, inline = "c1")
colSwing = input.color(color.new(#8A94A6, 0), "Swing", group = grpD, inline = "c1")

// ──────────────────────── Pivots (top level only) ────────────────────────
ph = ta.pivothigh(pivLen, pivLen)
pl = ta.pivotlow(pivLen, pivLen)

var float swHi    = na
var int   swHiBar = na
var float swLo    = na
var int   swLoBar = na

if not na(ph)
    swHi    := ph
    swHiBar := bar_index - pivLen
if not na(pl)
    swLo    := pl
    swLoBar := bar_index - pivLen

// ─────────────────────────── Ratio selection ───────────────────────────
isFib   = setName == "Fibonacci"
isThird = setName == "Thirds"

r1 = isFib ? 0.236 : isThird ? 0.333 : 0.4
r2 = isFib ? 0.382 : isThird ? 0.500 : 0.5
r3 = isFib ? 0.500 : isThird ? 0.667 : 0.6
r4 = isFib ? 0.618 : na
r5 = isFib ? 0.786 : na

bool  ok  = not na(swHi) and not na(swLo) and swHi > swLo
float rng = ok ? swHi - swLo : na

f_lvl(float r) => ok and not na(r) and rng > 0 ? swLo + rng * r : na

l1 = f_lvl(r1)
l2 = f_lvl(r2)
l3 = f_lvl(r3)
l4 = f_lvl(r4)
l5 = f_lvl(r5)

// ─────────────────────────────── Draw ───────────────────────────────
plot(showGrid  ? l1 : na, "Grid level 1", color = colGrid,  linewidth = 1, style = plot.style_linebr)
plot(showGrid  ? l2 : na, "Grid level 2", color = colGrid,  linewidth = 1, style = plot.style_linebr)
plot(showGrid  ? l3 : na, "Grid level 3", color = colGrid,  linewidth = 2, style = plot.style_linebr)
plot(showGrid  ? l4 : na, "Grid level 4", color = colGrid,  linewidth = 1, style = plot.style_linebr)
plot(showGrid  ? l5 : na, "Grid level 5", color = colGrid,  linewidth = 1, style = plot.style_linebr)

plot(showSwing and ok ? swHi : na, "Swing high", color = colSwing, linewidth = 1, style = plot.style_linebr)
plot(showSwing and ok ? swLo : na, "Swing low",  color = colSwing, linewidth = 1, style = plot.style_linebr)

// ─────────────────────────────── Table ───────────────────────────────
bgCol  = color.new(#0E1526, 10)
txtCol = color.new(#E6EAF2, 0)
hdrCol = color.new(#2F6FED, 0)

tblPos = tblPosIn == "Bottom right" ? position.bottom_right : tblPosIn == "Top left" ? position.top_left :
     tblPosIn == "Top right" ? position.top_right : tblPosIn == "Middle right" ? position.middle_right : position.bottom_left

var table t = table.new(tblPos, 2, 7, border_width = 1,
     border_color = color.new(#2F6FED, 70))

f_num(float v) => na(v) ? "-" : str.tostring(v, format.mintick)

f_row(int r, string k, string v) =>
    table.cell(t, 0, r, k, text_color = txtCol, text_size = size.small,
         text_halign = text.align_left,  bgcolor = bgCol)
    table.cell(t, 1, r, v, text_color = txtCol, text_size = size.small,
         text_halign = text.align_right, bgcolor = bgCol)

// retracement position of the current close inside the swing
retrPct = ok and rng > 0 ? (close - swLo) / rng * 100.0 : na

// short label for the active set
setShort = isFib ? "Fibonacci" : isThird ? "Thirds" : "Control 0.4/0.5/0.6"

if barstate.islast and showTbl
    table.cell(t, 0, 0, "SWING GRID", text_color = color.white, text_size = size.small, bgcolor = hdrCol)
    table.cell(t, 1, 0, setShort,     text_color = color.white, text_size = size.small, bgcolor = hdrCol)
    f_row(1, "Swing high",        f_num(swHi))
    f_row(2, "Swing low",         f_num(swLo))
    f_row(3, "Swing range",       f_num(rng))
    f_row(4, "Pivot lookback",    str.tostring(pivLen) + " bars each side")
    f_row(5, "Confirmed after",   str.tostring(pivLen) + " bars")
    f_row(6, "Close in swing",    na(retrPct) ? "-" : str.tostring(retrPct, "#.#") + "%")

// ─────────────── Alerts (conditions you arm yourself) ───────────────
// Every ta.* call is evaluated at top level on every bar so its history stays
// consistent. Calling them inside the alertcondition expression would let the
// short-circuit skip bars and corrupt the crossover state.
xL1 = ta.cross(close, l1)
xL2 = ta.cross(close, l2)
xL3 = ta.cross(close, l3)
xL4 = ta.cross(close, l4)
xL5 = ta.cross(close, l5)
xHi = ta.crossover(close, swHi)
xLo = ta.crossunder(close, swLo)

alertcondition(not na(l1) and xL1, title = "Close crossed grid level 1",
     message = "Swing Ratio Grid: close crossed the first grid level.")
alertcondition(not na(l2) and xL2, title = "Close crossed grid level 2",
     message = "Swing Ratio Grid: close crossed the second grid level.")
alertcondition(not na(l3) and xL3, title = "Close crossed the midpoint level",
     message = "Swing Ratio Grid: close crossed the midpoint grid level.")
alertcondition(not na(l4) and xL4, title = "Close crossed grid level 4",
     message = "Swing Ratio Grid: close crossed the fourth grid level.")
alertcondition(not na(l5) and xL5, title = "Close crossed grid level 5",
     message = "Swing Ratio Grid: close crossed the fifth grid level.")
alertcondition(not na(swHi) and xHi, title = "Close crossed above the swing high",
     message = "Swing Ratio Grid: close crossed above the confirmed swing high.")
alertcondition(not na(swLo) and xLo, title = "Close crossed below the swing low",
     message = "Swing Ratio Grid: close crossed below the confirmed swing low.")