MACD histogram

// overlay = false
const fastLen = input.int("Fast length",   12, { min: 1, group: "MACD" });
const slowLen = input.int("Slow length",   26, { min: 1, group: "MACD" });
const sigLen  = input.int("Signal length",  9, { min: 1, group: "MACD" });
const src     = input.source("Source", "close");

plot("MACD",     null, { color: "#22c55eFF", linewidth: 2 });
plot("Signal",   null, { color: "#f59e0bFF", linewidth: 2 });
plot("Histogram", null, {
  style: "histogram",
  colorUp:   "#22c55eCC",
  colorDown: "#ef4444CC",
});

hline(0, { color: "#6b728060" });

onBar(() => {
  const m = ta.macd(src, fastLen, slowLen, sigLen);
  if (na(m.macd)) return;

  plot("MACD",      m.macd);
  plot("Signal",    m.signal);
  plot("Histogram", m.hist);
});

// overlay = false
const src = input.source("Source", "close");

plot("MACD",     null, { linewidth: 2 });
plot("Signal",   null, { color: "#f59e0bFF" });
plot("Histogram", null, { style: "histogram" });

hline(0, { color: "#6b728060" });

const macdSeries = Series("macd-val");

onBar(() => {
  const m = ta.macd(src, 12, 26, 9);
  if (na(m.macd)) return;

  // Color MACD line based on trend
  const macdColor = m.macd > m.signal ? "#22c55eFF" : "#ef4444FF";
  // Note: per-bar color changes on 'plot' require re-registering with null each time
  // For simplicity, use a fixed color and rely on the histogram for the trend signal:

  plot("MACD",      m.macd);
  plot("Signal",    m.signal);
  plot("Histogram", m.hist);

  macdSeries.set(m.macd);
});

plot("Histogram", null, {
  style: "histogram",
  colorUp:   "#22c55eCC",  // green bars when MACD > signal
  colorDown: "#ef4444CC",  // red bars when MACD < signal
});