feat(supply-chain): detect AIS dark-transit anomalies in war zones (koala73#1595)

* feat(supply-chain): detect AIS dark-transit anomalies in war zones

When PortWatch history shows >50% traffic drop in war_zone or critical
chokepoints, surface it as intelligence: "Traffic down X% vs 30-day
baseline — vessels may be transiting dark (AIS off)".

The absence of AIS signals in conflict zones like Hormuz is itself a
signal (vessels disabling transponders to avoid targeting).

Changes:
- Add detectTrafficAnomaly() comparing 7-day vs 30-day baseline
- Boost disruption score by 10 when traffic anomaly detected
- Show WoW% from PortWatch even when real-time AIS counts are 0
- 6 new tests for anomaly detection edge cases

* fix(supply-chain): clamp disruptionScore to 100 and dedupe anomaly function

P1: disruptionScore could exceed 100 when anomalyBonus was added on top
of a max-score base, rendering "110/100" in the UI. Now clamped before
assignment, not just for status.

P2: detectTrafficAnomaly was duplicated in test file, so regressions in
the real code path would go undetected. Moved function into _scoring.mjs
(pure, no server deps). Both handler and tests import the same function.

* fix(supply-chain): require 37 days for traffic anomaly detection

detectTrafficAnomaly needs 7 recent + 30 baseline days. The threshold
was 30, which would use a partial baseline (23 days). Now correctly
requires 37 rows before signaling.

Author: koala73

server/worldmonitor/supply-chain/v1/_scoring.mjs

@@ -72,6 +72,20 @@ export function riskRating(hhi) {
   return 'low';
 }
 
+export function detectTrafficAnomaly(history, threatLevel) {
+  if (!history || history.length < 37) return { dropPct: 0, signal: false };
+  const sorted = [...history].sort((a, b) => b.date.localeCompare(a.date));
+  let recent7 = 0;
+  let baseline30 = 0;
+  for (let i = 0; i < 7 && i < sorted.length; i++) recent7 += sorted[i].total;
+  for (let i = 7; i < 37 && i < sorted.length; i++) baseline30 += sorted[i].total;
+  const baselineAvg7 = (baseline30 / Math.min(30, sorted.length - 7)) * 7;
+  if (baselineAvg7 < 14) return { dropPct: 0, signal: false };
+  const dropPct = Math.round(((baselineAvg7 - recent7) / baselineAvg7) * 100);
+  const isHighThreat = threatLevel === 'war_zone' || threatLevel === 'critical';
+  return { dropPct, signal: dropPct >= 50 && isHighThreat };
+}
+
 export function detectSpike(history) {
   if (!history || history.length < 3) return false;
   const values = history.map(h => typeof h === 'number' ? h : h.value).filter(v => Number.isFinite(v));

server/worldmonitor/supply-chain/v1/get-chokepoint-status.ts

@@ -19,7 +19,7 @@ import type { PortWatchData } from './_portwatch-upstream';
 import type { CorridorRiskData } from './_corridorrisk-upstream';
 import { CANONICAL_CHOKEPOINTS } from './_chokepoint-ids';
 // @ts-expect-error — .mjs module, no declaration file
-import { computeDisruptionScore, scoreToStatus, SEVERITY_SCORE, THREAT_LEVEL } from './_scoring.mjs';
+import { computeDisruptionScore, scoreToStatus, SEVERITY_SCORE, THREAT_LEVEL, detectTrafficAnomaly } from './_scoring.mjs';
 
 const REDIS_CACHE_KEY = 'supply_chain:chokepoints:v4';
 const PORTWATCH_REDIS_KEY = 'supply_chain:portwatch:v1';
@@ -295,7 +295,10 @@ async function fetchChokepointData(): Promise<ChokepointFetchResult> {
     }, 0);
 
     const threatScore = (THREAT_LEVEL as Record<string, number>)[cp.threatLevel] ?? 0;
-    const disruptionScore = computeDisruptionScore(threatScore, matchedWarnings.length, maxSeverity);
+    const pw = portwatchData?.[cp.id];
+    const anomaly = detectTrafficAnomaly(pw?.history ?? [], cp.threatLevel);
+    const anomalyBonus = anomaly.signal ? 10 : 0;
+    const disruptionScore = Math.min(100, computeDisruptionScore(threatScore, matchedWarnings.length, maxSeverity) + anomalyBonus);
     const status = scoreToStatus(disruptionScore);
 
     const congestionLevel = maxSeverity >= 3 ? 'high' : maxSeverity >= 2 ? 'elevated' : maxSeverity >= 1 ? 'low' : 'normal';
@@ -304,13 +307,16 @@ async function fetchChokepointData(): Promise<ChokepointFetchResult> {
     if (cp.threatDescription) {
       descriptions.push(cp.threatDescription);
     }
+    if (anomaly.signal) {
+      descriptions.push(`Traffic down ${anomaly.dropPct}% vs 30-day baseline — vessels may be transiting dark (AIS off)`);
+    }
     if (!threatConfigFresh) {
       descriptions.push(THREAT_CONFIG_STALE_NOTE);
     }
     if (matchedWarnings.length > 0 || matchedDisruptions.length > 0) {
       descriptions.push(`Navigational warnings: ${matchedWarnings.length}`);
       descriptions.push(`AIS vessel disruptions: ${matchedDisruptions.length}`);
-    } else if (!cp.threatDescription) {
+    } else if (!cp.threatDescription && !anomaly.signal) {
       descriptions.push('No active disruptions');
     }
 

src/components/SupplyChainPanel.ts

@@ -132,9 +132,15 @@ export class SupplyChainPanel extends Panel {
         const statusDot = cp.status === 'red' ? 'sc-dot-red' : cp.status === 'yellow' ? 'sc-dot-yellow' : 'sc-dot-green';
         const aisDisruptions = cp.aisDisruptions ?? (cp.congestionLevel === 'normal' ? 0 : 1);
         const ts = cp.transitSummary;
-        const transitRow = ts && ts.todayTotal > 0
-          ? `<div class="trade-sector">${t('components.supplyChain.transit24h')}: ${ts.todayTotal} vessels (${ts.todayTanker} ${t('components.supplyChain.tankers')}, ${ts.todayCargo} ${t('components.supplyChain.cargo')}, ${ts.todayOther} other) | ${t('components.supplyChain.wowChange')}: <span class="trade-flow-change ${ts.wowChangePct >= 0 ? 'change-positive' : 'change-negative'}">${ts.wowChangePct >= 0 ? '\u25B2' : '\u25BC'}${Math.abs(ts.wowChangePct).toFixed(1)}%</span></div>`
-          : '';
+        const hasRealtimeCounts = ts && ts.todayTotal > 0;
+        const hasWow = ts && ts.wowChangePct !== 0;
+        const wowPct = ts?.wowChangePct ?? 0;
+        const wowSpan = hasWow ? `<span class="trade-flow-change ${wowPct >= 0 ? 'change-positive' : 'change-negative'}">${wowPct >= 0 ? '\u25B2' : '\u25BC'}${Math.abs(wowPct).toFixed(1)}%</span>` : '';
+        const transitRow = hasRealtimeCounts
+          ? `<div class="trade-sector">${t('components.supplyChain.transit24h')}: ${ts.todayTotal} vessels (${ts.todayTanker} ${t('components.supplyChain.tankers')}, ${ts.todayCargo} ${t('components.supplyChain.cargo')}, ${ts.todayOther} other)${hasWow ? ` | ${t('components.supplyChain.wowChange')}: ${wowSpan}` : ''}</div>`
+          : hasWow
+            ? `<div class="trade-sector">${t('components.supplyChain.wowChange')}: ${wowSpan}</div>`
+            : '';
         const riskRow = ts?.riskLevel
           ? `<div class="trade-sector">${t('components.supplyChain.riskLevel')}: ${escapeHtml(ts.riskLevel)} | ${ts.incidentCount7d} incidents (7d)</div>`
           : '';

tests/portwatch-upstream.test.mjs

@@ -133,3 +133,45 @@ describe('computeWowChangePct', () => {
     assert.equal(computeWowChangePct(makeDays(10, 50, 0)), 0);
   });
 });
+
+import { detectTrafficAnomaly } from '../server/worldmonitor/supply-chain/v1/_scoring.mjs';
+
+describe('detectTrafficAnomaly', () => {
+  it('flags >50% drop in war_zone as signal', () => {
+    // 7 recent days at 5/day, 30 baseline days at 100/day
+    const history = [...makeDays(7, 5, 0), ...makeDays(30, 100, 7)];
+    const result = detectTrafficAnomaly(history, 'war_zone');
+    assert.ok(result.signal, 'should flag as signal');
+    assert.ok(result.dropPct >= 90, `expected >90% drop, got ${result.dropPct}%`);
+  });
+
+  it('does NOT flag >50% drop in normal threat chokepoint', () => {
+    const history = [...makeDays(7, 5, 0), ...makeDays(30, 100, 7)];
+    const result = detectTrafficAnomaly(history, 'normal');
+    assert.equal(result.signal, false);
+  });
+
+  it('does NOT flag when drop is <50%', () => {
+    // 7 days at 60/day, 30 baseline at 100/day = 40% drop
+    const history = [...makeDays(7, 60, 0), ...makeDays(30, 100, 7)];
+    const result = detectTrafficAnomaly(history, 'war_zone');
+    assert.equal(result.signal, false);
+  });
+
+  it('returns no signal with <37 days of history (needs 7 recent + 30 baseline)', () => {
+    const result = detectTrafficAnomaly(makeDays(36, 100, 0), 'war_zone');
+    assert.equal(result.signal, false);
+    assert.equal(result.dropPct, 0);
+  });
+
+  it('flags critical threat level same as war_zone', () => {
+    const history = [...makeDays(7, 5, 0), ...makeDays(30, 100, 7)];
+    assert.ok(detectTrafficAnomaly(history, 'critical').signal);
+  });
+
+  it('ignores low-baseline chokepoints (< 2 vessels/day avg)', () => {
+    const history = [...makeDays(7, 0, 0), ...makeDays(30, 1, 7)];
+    const result = detectTrafficAnomaly(history, 'war_zone');
+    assert.equal(result.signal, false);
+  });
+});