From ca9e44a41a4a996de702b8479c31f4e1bf3844fa Mon Sep 17 00:00:00 2001
From: u1 <u1@rv32i.pl>
Date: Sat, 10 Jan 2026 23:02:30 +0000
Subject: [PATCH] feat(visualizer): add DLOB depth bands panel

---
 .../features/market/DlobDepthBandsPanel.tsx   | 75 +++++++++++++++++++
 1 file changed, 75 insertions(+)
 create mode 100644 apps/visualizer/src/features/market/DlobDepthBandsPanel.tsx

diff --git a/apps/visualizer/src/features/market/DlobDepthBandsPanel.tsx b/apps/visualizer/src/features/market/DlobDepthBandsPanel.tsx
new file mode 100644
index 0000000..6b0d27b
--- /dev/null
+++ b/apps/visualizer/src/features/market/DlobDepthBandsPanel.tsx
@@ -0,0 +1,75 @@
+import type { CSSProperties } from 'react';
+import { useMemo } from 'react';
+import type { DlobDepthBandRow } from './useDlobDepthBands';
+
+function formatUsd(v: number | null | undefined): string {
+  if (v == null || !Number.isFinite(v)) return '—';
+  if (v >= 1_000_000) return `$${(v / 1_000_000).toFixed(2)}M`;
+  if (v >= 1000) return `$${(v / 1000).toFixed(0)}K`;
+  if (v >= 1) return `$${v.toFixed(2)}`;
+  return `$${v.toPrecision(4)}`;
+}
+
+function formatPct(v: number | null | undefined): string {
+  if (v == null || !Number.isFinite(v)) return '—';
+  return `${v.toFixed(0)}%`;
+}
+
+function bandRowStyle(askScale: number, bidScale: number): CSSProperties {
+  const a = Number.isFinite(askScale) && askScale > 0 ? Math.min(1, askScale) : 0;
+  const b = Number.isFinite(bidScale) && bidScale > 0 ? Math.min(1, bidScale) : 0;
+  return { ['--ask-scale' as any]: a, ['--bid-scale' as any]: b } as CSSProperties;
+}
+
+export default function DlobDepthBandsPanel({ rows }: { rows: DlobDepthBandRow[] }) {
+  const sorted = useMemo(() => rows.slice().sort((a, b) => a.bandBps - b.bandBps), [rows]);
+
+  const maxUsd = useMemo(() => {
+    let max = 0;
+    for (const r of sorted) {
+      if (r.askUsd != null && Number.isFinite(r.askUsd)) max = Math.max(max, r.askUsd);
+      if (r.bidUsd != null && Number.isFinite(r.bidUsd)) max = Math.max(max, r.bidUsd);
+    }
+    return max;
+  }, [sorted]);
+
+  return (
+    <div className="dlobDepth">
+      <div className="dlobDepth__head">
+        <div className="dlobDepth__title">Depth (bands)</div>
+        <div className="dlobDepth__meta">±bps around mid</div>
+      </div>
+
+      <div className="dlobDepth__table">
+        <div className="dlobDepthRow dlobDepthRow--head">
+          <span>Band</span>
+          <span className="dlobDepthRow__num">Ask USD</span>
+          <span className="dlobDepthRow__num">Bid USD</span>
+          <span className="dlobDepthRow__num">Bid %</span>
+        </div>
+
+        {sorted.length ? (
+          sorted.map((r) => (
+            <div
+              key={r.bandBps}
+              className="dlobDepthRow"
+              style={bandRowStyle(maxUsd > 0 ? (r.askUsd || 0) / maxUsd : 0, maxUsd > 0 ? (r.bidUsd || 0) / maxUsd : 0)}
+              title={`band=${r.bandBps}bps bid=${r.bidUsd ?? '—'} ask=${r.askUsd ?? '—'} imbalance=${r.imbalance ?? '—'}`}
+            >
+              <span className="dlobDepthRow__band">{r.bandBps} bps</span>
+              <span className="dlobDepthRow__num neg">{formatUsd(r.askUsd)}</span>
+              <span className="dlobDepthRow__num pos">{formatUsd(r.bidUsd)}</span>
+              <span className="dlobDepthRow__num muted">
+                {r.imbalance == null || !Number.isFinite(r.imbalance)
+                  ? '—'
+                  : formatPct(((r.imbalance + 1) / 2) * 100)}
+              </span>
+            </div>
+          ))
+        ) : (
+          <div className="dlobDepth__empty muted">No depth band rows yet.</div>
+        )}
+      </div>
+    </div>
+  );
+}