import { describe, expect, it, vi } from "vitest";
import { DomainEvent } from "@tff/core";
import { SimpleEventBus } from "../../../../../src/infrastructure/adapters/event-bus/simple-event-bus.js";

describe("SimpleEventBus", () => {
	it("delivers event to subscriber", () => {
		const bus = new SimpleEventBus();
		const handler = vi.fn();
		bus.subscribe("SLICE_STATUS_CHANGED", handler);
		const event = DomainEvent.create("SLICE_STATUS_CHANGED", {
			sliceId: "M01-S04",
			from: "planning",
			to: "executing",
		});
		bus.publish(event);
		expect(handler).toHaveBeenCalledOnce();
		expect(handler).toHaveBeenCalledWith(event);
	});

	it("delivers to multiple subscribers for same event", () => {
		const bus = new SimpleEventBus();
		const h1 = vi.fn();
		const h2 = vi.fn();
		bus.subscribe("TASK_COMPLETED", h1);
		bus.subscribe("TASK_COMPLETED", h2);
		const event = DomainEvent.create("TASK_COMPLETED", {
			taskId: "T01",
			sliceId: "M01-S04",
			executor: "opus",
		});
		bus.publish(event);
		expect(h1).toHaveBeenCalledOnce();
		expect(h2).toHaveBeenCalledOnce();
	});

	it("does not deliver to unsubscribed event types", () => {
		const bus = new SimpleEventBus();
		const handler = vi.fn();
		bus.subscribe("TASK_COMPLETED", handler);
		const event = DomainEvent.create("SLICE_STATUS_CHANGED", {
			sliceId: "M01-S04",
			from: "a",
			to: "b",
		});
		bus.publish(event);
		expect(handler).not.toHaveBeenCalled();
	});

	it("does not throw when publishing with no subscribers", () => {
		const bus = new SimpleEventBus();
		const event = DomainEvent.create("SLICE_PLANNED", { sliceId: "x" });
		expect(() => bus.publish(event)).not.toThrow();
	});
});