From a2a7e79d21a4ef59ae717fa11d2d9f0586b9bc2f Mon Sep 17 00:00:00 2001
From: ryder777777 <ryder777777@users.noreply.github.com>
Date: Tue, 20 Oct 2026 22:06:18 +0000
Subject: [PATCH] feat(services): add add-a-shadow-mode-that service and unit
 tests (#33)

---
 .../add-a-shadow-mode-that.service.ts         | 40 +++++++++++++++++++
 tests/add-a-shadow-mode-that.test.ts          | 10 +++++
 2 files changed, 50 insertions(+)
 create mode 100644 src/services/add-a-shadow-mode-that.service.ts
 create mode 100644 tests/add-a-shadow-mode-that.test.ts

diff --git a/src/services/add-a-shadow-mode-that.service.ts b/src/services/add-a-shadow-mode-that.service.ts
new file mode 100644
index 0000000..7c8cf3a
--- /dev/null
+++ b/src/services/add-a-shadow-mode-that.service.ts
@@ -0,0 +1,40 @@
+export interface AddAShadowModeThatReportInput {
+  marketKey: string;
+  primaryUnits: number;
+  secondaryUnits: number;
+  maxThreshold?: number;
+}
+
+export interface AddAShadowModeThatReport {
+  marketKey: string;
+  primaryUnits: number;
+  secondaryUnits: number;
+  utilizationBps: number;
+  verdict: 'healthy' | 'degraded' | 'halted';
+}
+
+export function evaluateAddAShadowModeThat(input: AddAShadowModeThatReportInput): AddAShadowModeThatReport {
+  const marketKey = input.marketKey.trim();
+  if (!marketKey) {
+    throw new Error('evaluateAddAShadowModeThat: marketKey is required');
+  }
+  const primaryUnits = Math.max(0, Math.trunc(input.primaryUnits));
+  const secondaryUnits = Math.max(0, Math.trunc(input.secondaryUnits));
+  const limit = Math.max(1, Math.trunc(input.maxThreshold ?? 100));
+
+  const utilizationBps = Math.min(10000, Math.round(((primaryUnits + secondaryUnits) * 10000) / limit));
+  let verdict: 'healthy' | 'degraded' | 'halted' = 'healthy';
+  if (utilizationBps >= 8500) {
+    verdict = 'halted';
+  } else if (utilizationBps >= 5000) {
+    verdict = 'degraded';
+  }
+
+  return {
+    marketKey,
+    primaryUnits,
+    secondaryUnits,
+    utilizationBps,
+    verdict,
+  };
+}
diff --git a/tests/add-a-shadow-mode-that.test.ts b/tests/add-a-shadow-mode-that.test.ts
new file mode 100644
index 0000000..f98d14e
--- /dev/null
+++ b/tests/add-a-shadow-mode-that.test.ts
@@ -0,0 +1,10 @@
+import test from 'node:test';
+import assert from 'node:assert/strict';
+import { evaluateAddAShadowModeThat } from '../src/services/add-a-shadow-mode-that.service';
+
+test('evaluateAddAShadowModeThat: evaluates healthy, degraded, and halted verdicts', () => {
+  assert.equal(evaluateAddAShadowModeThat({ marketKey: 'mkt-1', primaryUnits: 15, secondaryUnits: 10, maxThreshold: 100 }).verdict, 'healthy');
+  assert.equal(evaluateAddAShadowModeThat({ marketKey: 'mkt-2', primaryUnits: 35, secondaryUnits: 25 }).verdict, 'degraded');
+  assert.equal(evaluateAddAShadowModeThat({ marketKey: 'mkt-3', primaryUnits: 70, secondaryUnits: 20, maxThreshold: 100 }).verdict, 'halted');
+  assert.throws(() => evaluateAddAShadowModeThat({ marketKey: '   ', primaryUnits: 1, secondaryUnits: 1 }), /marketKey is required/);
+});