refactor(cue): decompose cue-engine.ts into 5 focused modules + minor fixes hardening the overall Cue functionality

src/__tests__/main/cue/cue-activity-log.test.ts

@@ -0,0 +1,72 @@
+/**
+ * Tests for the Cue activity log ring buffer.
+ */
+
+import { describe, it, expect } from 'vitest';
+import { createCueActivityLog } from '../../../main/cue/cue-activity-log';
+import type { CueRunResult } from '../../../main/cue/cue-types';
+
+function makeResult(id: string): CueRunResult {
+	return {
+		runId: id,
+		sessionId: 'session-1',
+		sessionName: 'Test',
+		subscriptionName: 'sub',
+		event: { id: 'e1', type: 'time.heartbeat', timestamp: '', triggerName: 'sub', payload: {} },
+		status: 'completed',
+		stdout: '',
+		stderr: '',
+		exitCode: 0,
+		durationMs: 100,
+		startedAt: '',
+		endedAt: '',
+	};
+}
+
+describe('createCueActivityLog', () => {
+	it('stores and retrieves results', () => {
+		const log = createCueActivityLog();
+		log.push(makeResult('r1'));
+		log.push(makeResult('r2'));
+		expect(log.getAll()).toHaveLength(2);
+		expect(log.getAll()[0].runId).toBe('r1');
+	});
+
+	it('respects limit parameter on getAll', () => {
+		const log = createCueActivityLog();
+		log.push(makeResult('r1'));
+		log.push(makeResult('r2'));
+		log.push(makeResult('r3'));
+		const last2 = log.getAll(2);
+		expect(last2).toHaveLength(2);
+		expect(last2[0].runId).toBe('r2');
+		expect(last2[1].runId).toBe('r3');
+	});
+
+	it('evicts oldest entries when exceeding maxSize', () => {
+		const log = createCueActivityLog(3);
+		log.push(makeResult('r1'));
+		log.push(makeResult('r2'));
+		log.push(makeResult('r3'));
+		log.push(makeResult('r4'));
+		const all = log.getAll();
+		expect(all).toHaveLength(3);
+		expect(all[0].runId).toBe('r2');
+		expect(all[2].runId).toBe('r4');
+	});
+
+	it('clear empties the log', () => {
+		const log = createCueActivityLog();
+		log.push(makeResult('r1'));
+		log.clear();
+		expect(log.getAll()).toHaveLength(0);
+	});
+
+	it('returns a copy from getAll, not a reference', () => {
+		const log = createCueActivityLog();
+		log.push(makeResult('r1'));
+		const snapshot = log.getAll();
+		log.push(makeResult('r2'));
+		expect(snapshot).toHaveLength(1);
+	});
+});

src/__tests__/main/cue/cue-completion-chains.test.ts

@@ -14,7 +14,6 @@
 
 import { describe, it, expect, vi, beforeEach, afterEach } from 'vitest';
 import type { CueConfig, CueEvent } from '../../../main/cue/cue-types';
-import type { SessionInfo } from '../../../shared/types';
 
 // Mock the yaml loader
 const mockLoadCueConfig = vi.fn<(projectRoot: string) => CueConfig | null>();
@@ -52,47 +51,7 @@ vi.mock('crypto', () => ({
 }));
 
 import { CueEngine, type CueEngineDeps } from '../../../main/cue/cue-engine';
-
-function createMockSession(overrides: Partial<SessionInfo> = {}): SessionInfo {
-	return {
-		id: 'session-1',
-		name: 'Test Session',
-		toolType: 'claude-code',
-		cwd: '/projects/test',
-		projectRoot: '/projects/test',
-		...overrides,
-	};
-}
-
-function createMockConfig(overrides: Partial<CueConfig> = {}): CueConfig {
-	return {
-		subscriptions: [],
-		settings: { timeout_minutes: 30, timeout_on_fail: 'break', max_concurrent: 1, queue_size: 10 },
-		...overrides,
-	};
-}
-
-function createMockDeps(overrides: Partial<CueEngineDeps> = {}): CueEngineDeps {
-	return {
-		getSessions: vi.fn(() => [createMockSession()]),
-		onCueRun: vi.fn(async () => ({
-			runId: 'run-1',
-			sessionId: 'session-1',
-			sessionName: 'Test Session',
-			subscriptionName: 'test',
-			event: {} as CueEvent,
-			status: 'completed' as const,
-			stdout: 'output',
-			stderr: '',
-			exitCode: 0,
-			durationMs: 100,
-			startedAt: new Date().toISOString(),
-			endedAt: new Date().toISOString(),
-		})) as CueEngineDeps['onCueRun'],
-		onLog: vi.fn(),
-		...overrides,
-	};
-}
+import { createMockSession, createMockConfig, createMockDeps } from './cue-test-helpers';
 
 describe('CueEngine completion chains', () => {
 	beforeEach(() => {

src/__tests__/main/cue/cue-concurrency.test.ts

@@ -13,7 +13,6 @@
 
 import { describe, it, expect, vi, beforeEach, afterEach } from 'vitest';
 import type { CueConfig, CueEvent, CueRunResult } from '../../../main/cue/cue-types';
-import type { SessionInfo } from '../../../shared/types';
 
 // Mock the yaml loader
 const mockLoadCueConfig = vi.fn<(projectRoot: string) => CueConfig | null>();
@@ -35,52 +34,7 @@ vi.mock('crypto', () => ({
 }));
 
 import { CueEngine, type CueEngineDeps } from '../../../main/cue/cue-engine';
-
-function createMockSession(overrides: Partial<SessionInfo> = {}): SessionInfo {
-	return {
-		id: 'session-1',
-		name: 'Test Session',
-		toolType: 'claude-code',
-		cwd: '/projects/test',
-		projectRoot: '/projects/test',
-		...overrides,
-	};
-}
-
-function createMockConfig(overrides: Partial<CueConfig> = {}): CueConfig {
-	return {
-		subscriptions: [],
-		settings: {
-			timeout_minutes: 30,
-			timeout_on_fail: 'break',
-			max_concurrent: 1,
-			queue_size: 10,
-		},
-		...overrides,
-	};
-}
-
-function createMockDeps(overrides: Partial<CueEngineDeps> = {}): CueEngineDeps {
-	return {
-		getSessions: vi.fn(() => [createMockSession()]),
-		onCueRun: vi.fn(async () => ({
-			runId: 'run-1',
-			sessionId: 'session-1',
-			sessionName: 'Test Session',
-			subscriptionName: 'test',
-			event: {} as CueEvent,
-			status: 'completed' as const,
-			stdout: 'output',
-			stderr: '',
-			exitCode: 0,
-			durationMs: 100,
-			startedAt: new Date().toISOString(),
-			endedAt: new Date().toISOString(),
-		})),
-		onLog: vi.fn(),
-		...overrides,
-	};
-}
+import { createMockSession, createMockConfig, createMockDeps } from './cue-test-helpers';
 
 describe('CueEngine Concurrency Control', () => {
 	let yamlWatcherCleanup: ReturnType<typeof vi.fn>;

src/__tests__/main/cue/cue-engine.test.ts

@@ -15,7 +15,6 @@
 
 import { describe, it, expect, vi, beforeEach, afterEach } from 'vitest';
 import type { CueConfig, CueEvent, CueRunResult } from '../../../main/cue/cue-types';
-import type { SessionInfo } from '../../../shared/types';
 
 // Mock the yaml loader
 const mockLoadCueConfig = vi.fn<(projectRoot: string) => CueConfig | null>();
@@ -53,48 +52,7 @@ import {
 	calculateNextScheduledTime,
 	type CueEngineDeps,
 } from '../../../main/cue/cue-engine';
-
-function createMockSession(overrides: Partial<SessionInfo> = {}): SessionInfo {
-	return {
-		id: 'session-1',
-		name: 'Test Session',
-		toolType: 'claude-code',
-		cwd: '/projects/test',
-		projectRoot: '/projects/test',
-		...overrides,
-	};
-}
-
-function createMockConfig(overrides: Partial<CueConfig> = {}): CueConfig {
-	return {
-		subscriptions: [],
-		settings: { timeout_minutes: 30, timeout_on_fail: 'break', max_concurrent: 1, queue_size: 10 },
-		...overrides,
-	};
-}
-
-function createMockDeps(overrides: Partial<CueEngineDeps> = {}): CueEngineDeps {
-	return {
-		getSessions: vi.fn(() => [createMockSession()]),
-		onCueRun: vi.fn(async (request: Parameters<CueEngineDeps['onCueRun']>[0]) => ({
-			runId: 'run-1',
-			sessionId: 'session-1',
-			sessionName: 'Test Session',
-			subscriptionName: request.subscriptionName,
-			event: request.event,
-			status: 'completed' as const,
-			stdout: 'output',
-			stderr: '',
-			exitCode: 0,
-			durationMs: 100,
-			startedAt: new Date().toISOString(),
-			endedAt: new Date().toISOString(),
-		})),
-		onStopCueRun: vi.fn(() => true),
-		onLog: vi.fn(),
-		...overrides,
-	};
-}
+import { createMockSession, createMockConfig, createMockDeps } from './cue-test-helpers';
 
 describe('CueEngine', () => {
 	let yamlWatcherCleanup: ReturnType<typeof vi.fn>;
@@ -930,6 +888,39 @@ describe('CueEngine', () => {
 			engine.stop();
 		});
 
+		it('stopRun adds the stopped run to the activity log', async () => {
+			const deps = createMockDeps({
+				onCueRun: vi.fn(() => new Promise<CueRunResult>(() => {})),
+			});
+			const config = createMockConfig({
+				subscriptions: [
+					{
+						name: 'timer',
+						event: 'time.heartbeat',
+						enabled: true,
+						prompt: 'test',
+						interval_minutes: 60,
+					},
+				],
+			});
+			mockLoadCueConfig.mockReturnValue(config);
+			const engine = new CueEngine(deps);
+			engine.start();
+
+			await vi.advanceTimersByTimeAsync(10);
+
+			const activeRun = engine.getActiveRuns()[0];
+			expect(activeRun).toBeDefined();
+			engine.stopRun(activeRun.runId);
+
+			const log = engine.getActivityLog();
+			expect(log).toHaveLength(1);
+			expect(log[0].runId).toBe(activeRun.runId);
+			expect(log[0].status).toBe('stopped');
+
+			engine.stop();
+		});
+
 		it('stopAll clears all active runs', async () => {
 			// Use a slow-resolving onCueRun to keep runs active
 			const deps = createMockDeps({

src/__tests__/main/cue/cue-multi-hop-chains.test.ts

@@ -12,7 +12,6 @@
 
 import { describe, it, expect, vi, beforeEach, afterEach } from 'vitest';
 import type { CueConfig, CueEvent, CueRunResult } from '../../../main/cue/cue-types';
-import type { SessionInfo } from '../../../shared/types';
 
 // Mock the yaml loader
 const mockLoadCueConfig = vi.fn<(projectRoot: string) => CueConfig | null>();
@@ -50,47 +49,7 @@ vi.mock('crypto', () => ({
 }));
 
 import { CueEngine, type CueEngineDeps } from '../../../main/cue/cue-engine';
-
-function createMockSession(overrides: Partial<SessionInfo> = {}): SessionInfo {
-	return {
-		id: 'session-1',
-		name: 'Test Session',
-		toolType: 'claude-code',
-		cwd: '/projects/test',
-		projectRoot: '/projects/test',
-		...overrides,
-	};
-}
-
-function createMockConfig(overrides: Partial<CueConfig> = {}): CueConfig {
-	return {
-		subscriptions: [],
-		settings: { timeout_minutes: 30, timeout_on_fail: 'break', max_concurrent: 1, queue_size: 10 },
-		...overrides,
-	};
-}
-
-function createMockDeps(overrides: Partial<CueEngineDeps> = {}): CueEngineDeps {
-	return {
-		getSessions: vi.fn(() => [createMockSession()]),
-		onCueRun: vi.fn(async () => ({
-			runId: 'run-1',
-			sessionId: 'session-1',
-			sessionName: 'Test Session',
-			subscriptionName: 'test',
-			event: {} as CueEvent,
-			status: 'completed' as const,
-			stdout: 'output',
-			stderr: '',
-			exitCode: 0,
-			durationMs: 100,
-			startedAt: new Date().toISOString(),
-			endedAt: new Date().toISOString(),
-		})) as CueEngineDeps['onCueRun'],
-		onLog: vi.fn(),
-		...overrides,
-	};
-}
+import { createMockSession, createMockConfig, createMockDeps } from './cue-test-helpers';
 
 describe('CueEngine multi-hop completion chains', () => {
 	beforeEach(() => {