// HA: Heikin-Ashi
// Smoothed candle transformation with recursive open
// HA_Close = (O + H + L + C) / 4
// HA_Open  = (prev_HA_Open + prev_HA_Close) / 2
// HA_High  = max(H, HA_Open, HA_Close)
// HA_Low   = min(L, HA_Open, HA_Close)

//@version=6
indicator("HA: Heikin-Ashi", overlay=true)

var float haOpen  = na
var float haClose = na

haClose := (open + high + low + close) * 0.25
haOpen  := na(haOpen) ? (open + close) * 0.5 : (haOpen + haClose[1]) * 0.5
haHigh   = math.max(high, haOpen, haClose)
haLow    = math.min(low,  haOpen, haClose)

plotcandle(haOpen, haHigh, haLow, haClose, "HA", color=haClose >= haOpen ? color.green : color.red)