refactor: consolidate backend services

Replace per-source services (LocationService, WeatherService,
TflService, FeedEngineService) with a single UserSessionManager
that owns all per-user state. Source creation is delegated to
thin FeedSourceProvider implementations per source type.

Co-authored-by: Ona <no-reply@ona.com>

apps/aris-backend/src/session/feed-source-provider.ts

@@ -0,0 +1,9 @@
+import type { FeedSource } from "@aris/core"
+
+export interface FeedSourceProvider {
+	feedSourceForUser(userId: string): FeedSource
+}
+
+export type FeedSourceProviderFn = (userId: string) => FeedSource
+
+export type FeedSourceProviderInput = FeedSourceProvider | FeedSourceProviderFn

apps/aris-backend/src/session/index.ts

@@ -0,0 +1,7 @@
+export type {
+	FeedSourceProvider,
+	FeedSourceProviderFn,
+	FeedSourceProviderInput,
+} from "./feed-source-provider.ts"
+export { UserSession } from "./user-session.ts"
+export { UserSessionManager } from "./user-session-manager.ts"

apps/aris-backend/src/session/user-session-manager.test.ts

@@ -0,0 +1,166 @@
+import { LocationSource } from "@aris/source-location"
+import { describe, expect, mock, test } from "bun:test"
+
+import { WeatherSourceProvider } from "../weather/provider.ts"
+import { UserSessionManager } from "./user-session-manager.ts"
+
+import type { WeatherKitClient, WeatherKitResponse } from "@aris/source-weatherkit"
+
+const mockWeatherClient: WeatherKitClient = {
+	fetch: async () => ({}) as WeatherKitResponse,
+}
+
+describe("UserSessionManager", () => {
+	test("getOrCreate creates session on first call", () => {
+		const manager = new UserSessionManager([() => new LocationSource()])
+
+		const session = manager.getOrCreate("user-1")
+
+		expect(session).toBeDefined()
+		expect(session.engine).toBeDefined()
+	})
+
+	test("getOrCreate returns same session for same user", () => {
+		const manager = new UserSessionManager([() => new LocationSource()])
+
+		const session1 = manager.getOrCreate("user-1")
+		const session2 = manager.getOrCreate("user-1")
+
+		expect(session1).toBe(session2)
+	})
+
+	test("getOrCreate returns different sessions for different users", () => {
+		const manager = new UserSessionManager([() => new LocationSource()])
+
+		const session1 = manager.getOrCreate("user-1")
+		const session2 = manager.getOrCreate("user-2")
+
+		expect(session1).not.toBe(session2)
+	})
+
+	test("each user gets independent source instances", () => {
+		const manager = new UserSessionManager([() => new LocationSource()])
+
+		const session1 = manager.getOrCreate("user-1")
+		const session2 = manager.getOrCreate("user-2")
+
+		const source1 = session1.getSource<LocationSource>("aris.location")
+		const source2 = session2.getSource<LocationSource>("aris.location")
+
+		expect(source1).not.toBe(source2)
+	})
+
+	test("remove destroys session and allows re-creation", () => {
+		const manager = new UserSessionManager([() => new LocationSource()])
+
+		const session1 = manager.getOrCreate("user-1")
+		manager.remove("user-1")
+		const session2 = manager.getOrCreate("user-1")
+
+		expect(session1).not.toBe(session2)
+	})
+
+	test("remove is no-op for unknown user", () => {
+		const manager = new UserSessionManager([() => new LocationSource()])
+
+		expect(() => manager.remove("unknown")).not.toThrow()
+	})
+
+	test("accepts function providers", async () => {
+		const manager = new UserSessionManager([() => new LocationSource()])
+
+		const session = manager.getOrCreate("user-1")
+		const result = await session.engine.refresh()
+
+		expect(result.errors).toHaveLength(0)
+	})
+
+	test("accepts object providers", () => {
+		const provider = new WeatherSourceProvider({ client: mockWeatherClient })
+		const manager = new UserSessionManager([() => new LocationSource(), provider])
+
+		const session = manager.getOrCreate("user-1")
+
+		expect(session.getSource("aris.weather")).toBeDefined()
+	})
+
+	test("accepts mixed providers", () => {
+		const provider = new WeatherSourceProvider({ client: mockWeatherClient })
+		const manager = new UserSessionManager([() => new LocationSource(), provider])
+
+		const session = manager.getOrCreate("user-1")
+
+		expect(session.getSource("aris.location")).toBeDefined()
+		expect(session.getSource("aris.weather")).toBeDefined()
+	})
+
+	test("refresh returns feed result through session", async () => {
+		const manager = new UserSessionManager([() => new LocationSource()])
+
+		const session = manager.getOrCreate("user-1")
+		const result = await session.engine.refresh()
+
+		expect(result).toHaveProperty("context")
+		expect(result).toHaveProperty("items")
+		expect(result).toHaveProperty("errors")
+		expect(result.context.time).toBeInstanceOf(Date)
+	})
+
+	test("location update via executeAction works", async () => {
+		const manager = new UserSessionManager([() => new LocationSource()])
+
+		const session = manager.getOrCreate("user-1")
+		await session.engine.executeAction("aris.location", "update-location", {
+			lat: 51.5074,
+			lng: -0.1278,
+			accuracy: 10,
+			timestamp: new Date(),
+		})
+
+		const source = session.getSource<LocationSource>("aris.location")
+		expect(source?.lastLocation?.lat).toBe(51.5074)
+	})
+
+	test("subscribe receives updates after location push", async () => {
+		const manager = new UserSessionManager([() => new LocationSource()])
+		const callback = mock()
+
+		const session = manager.getOrCreate("user-1")
+		session.engine.subscribe(callback)
+
+		await session.engine.executeAction("aris.location", "update-location", {
+			lat: 51.5074,
+			lng: -0.1278,
+			accuracy: 10,
+			timestamp: new Date(),
+		})
+
+		// Wait for async update propagation
+		await new Promise((resolve) => setTimeout(resolve, 10))
+
+		expect(callback).toHaveBeenCalled()
+	})
+
+	test("remove stops reactive updates", async () => {
+		const manager = new UserSessionManager([() => new LocationSource()])
+		const callback = mock()
+
+		const session = manager.getOrCreate("user-1")
+		session.engine.subscribe(callback)
+
+		manager.remove("user-1")
+
+		// Create new session and push location — old callback should not fire
+		const session2 = manager.getOrCreate("user-1")
+		await session2.engine.executeAction("aris.location", "update-location", {
+			lat: 51.5074,
+			lng: -0.1278,
+			accuracy: 10,
+			timestamp: new Date(),
+		})
+
+		await new Promise((resolve) => setTimeout(resolve, 10))
+
+		expect(callback).not.toHaveBeenCalled()
+	})
+})

apps/aris-backend/src/session/user-session-manager.ts

@@ -0,0 +1,31 @@
+import type { FeedSourceProviderInput } from "./feed-source-provider.ts"
+import { UserSession } from "./user-session.ts"
+
+export class UserSessionManager {
+	private sessions = new Map<string, UserSession>()
+	private readonly providers: FeedSourceProviderInput[]
+
+	constructor(providers: FeedSourceProviderInput[]) {
+		this.providers = providers
+	}
+
+	getOrCreate(userId: string): UserSession {
+		let session = this.sessions.get(userId)
+		if (!session) {
+			const sources = this.providers.map((p) =>
+				typeof p === "function" ? p(userId) : p.feedSourceForUser(userId),
+			)
+			session = new UserSession(sources)
+			this.sessions.set(userId, session)
+		}
+		return session
+	}
+
+	remove(userId: string): void {
+		const session = this.sessions.get(userId)
+		if (session) {
+			session.destroy()
+			this.sessions.delete(userId)
+		}
+	}
+}

apps/aris-backend/src/session/user-session.test.ts

@@ -0,0 +1,72 @@
+import type { ActionDefinition, Context, FeedSource } from "@aris/core"
+
+import { LocationSource } from "@aris/source-location"
+import { describe, expect, test } from "bun:test"
+
+import { UserSession } from "./user-session.ts"
+
+function createStubSource(id: string): FeedSource {
+	return {
+		id,
+		async listActions(): Promise<Record<string, ActionDefinition>> {
+			return {}
+		},
+		async executeAction(): Promise<unknown> {
+			return undefined
+		},
+		async fetchContext(): Promise<Partial<Context> | null> {
+			return null
+		},
+		async fetchItems() {
+			return []
+		},
+	}
+}
+
+describe("UserSession", () => {
+	test("registers sources and starts engine", async () => {
+		const session = new UserSession([createStubSource("test-a"), createStubSource("test-b")])
+
+		const result = await session.engine.refresh()
+
+		expect(result.errors).toHaveLength(0)
+	})
+
+	test("getSource returns registered source", () => {
+		const location = new LocationSource()
+		const session = new UserSession([location])
+
+		const result = session.getSource<LocationSource>("aris.location")
+
+		expect(result).toBe(location)
+	})
+
+	test("getSource returns undefined for unknown source", () => {
+		const session = new UserSession([createStubSource("test")])
+
+		expect(session.getSource("unknown")).toBeUndefined()
+	})
+
+	test("destroy stops engine and clears sources", () => {
+		const session = new UserSession([createStubSource("test")])
+
+		session.destroy()
+
+		expect(session.getSource("test")).toBeUndefined()
+	})
+
+	test("engine.executeAction routes to correct source", async () => {
+		const location = new LocationSource()
+		const session = new UserSession([location])
+
+		await session.engine.executeAction("aris.location", "update-location", {
+			lat: 51.5,
+			lng: -0.1,
+			accuracy: 10,
+			timestamp: new Date(),
+		})
+
+		expect(location.lastLocation).toBeDefined()
+		expect(location.lastLocation!.lat).toBe(51.5)
+	})
+})

apps/aris-backend/src/session/user-session.ts

@@ -0,0 +1,24 @@
+import { FeedEngine, type FeedSource } from "@aris/core"
+
+export class UserSession {
+	readonly engine: FeedEngine
+	private sources = new Map<string, FeedSource>()
+
+	constructor(sources: FeedSource[]) {
+		this.engine = new FeedEngine()
+		for (const source of sources) {
+			this.sources.set(source.id, source)
+			this.engine.register(source)
+		}
+		this.engine.start()
+	}
+
+	getSource<T extends FeedSource>(sourceId: string): T | undefined {
+		return this.sources.get(sourceId) as T | undefined
+	}
+
+	destroy(): void {
+		this.engine.stop()
+		this.sources.clear()
+	}
+}