//@version=6
indicator("Manual harmonic ratio audit", overlay = false)
x = input.float(100, "X")
a = input.float(120, "A")
b = input.float(107.64, "B")
c = input.float(116.50, "C")
d = input.float(104.28, "D")
family = input.string("Gartley", "Family",
  options = ["Gartley", "Bat", "Butterfly", "Crab"])
tolerance = input.float(0.005, "Ratio tolerance",
  minval = 0)
xa = math.abs(a - x)
ab = math.abs(b - a)
bc = math.abs(c - b)
cd = math.abs(d - c)
valid = xa > 0 and ab > 0 and bc > 0
rb = valid ? ab / xa : na
rc = valid ? bc / ab : na
rd = valid ? math.abs(d - a) / xa : na
projection = valid ? cd / bc : na
bMin = family == "Gartley" ? 0.618 :
  family == "Bat" ? 0.382 :
  family == "Butterfly" ? 0.786 : 0.382
bMax = family == "Bat" or family == "Crab" ? 0.618 : bMin
dRatio = family == "Gartley" ? 0.786 :
  family == "Bat" ? 0.886 :
  family == "Butterfly" ? 1.27 : 1.618
pMin = family == "Gartley" ? 1.27 :
  family == "Crab" ? 2.618 : 1.618
pMax = family == "Gartley" ? 1.618 :
  family == "Crab" ? 3.618 : 2.618
shape = (a > x and b < a and b > x and c > b and c < a
  and d < c) or (a < x and b > a and b < x and c < b
  and c > a and d > c)
bPass = rb >= bMin - tolerance and rb <= bMax + tolerance
if family == "Bat"
    bPass := rb >= 0.382 - tolerance and
      rb <= 0.50 + tolerance
passed = valid and shape and bPass and
  rc >= 0.382 - tolerance and rc <= 0.886 + tolerance and
  math.abs(rd - dRatio) <= tolerance and
  projection >= pMin - tolerance and
  projection <= pMax + tolerance
plot(rb, "B / XA", color.blue)
plot(rc, "C / AB", color.gray)
plot(rd, "AD / XA", color.red)
plot(projection, "CD / BC", color.orange)
bgcolor(passed ? color.new(color.green, 85) : na)