import { afterEach, describe, expect, it, vi } from "vitest";

import { createWebWorkspaceSyncBus } from "./webWorkspaceSync";

class FakeBroadcastChannel {
  static channels = new Map<string, Set<FakeBroadcastChannel>>();
  onmessage: ((event: MessageEvent) => void) | null = null;

  constructor(private readonly name: string) {
    const peers = FakeBroadcastChannel.channels.get(name) ?? new Set();
    peers.add(this);
    FakeBroadcastChannel.channels.set(name, peers);
  }

  postMessage(data: unknown): void {
    for (const peer of FakeBroadcastChannel.channels.get(this.name) ?? []) {
      if (peer !== this) {
        peer.onmessage?.({ data } as MessageEvent);
      }
    }
  }

  close(): void {
    FakeBroadcastChannel.channels.get(this.name)?.delete(this);
  }
}

afterEach(() => {
  vi.unstubAllGlobals();
  FakeBroadcastChannel.channels.clear();
});

describe("web workspace sync bus (#205)", () => {
  it("broadcasts focus changes to other browser hosts, not itself", () => {
    vi.stubGlobal("BroadcastChannel", FakeBroadcastChannel);
    const first = createWebWorkspaceSyncBus();
    const second = createWebWorkspaceSyncBus();
    const firstHandler = vi.fn();
    const secondHandler = vi.fn();
    first.subscribe(firstHandler);
    second.subscribe(secondHandler);

    first.publish({
      type: "focus",
      project: { id: "p-1", name: "Demo", root: "/srv/demo" },
      activePanel: "tickets",
    });

    expect(firstHandler).not.toHaveBeenCalled();
    expect(secondHandler).toHaveBeenCalledWith(
      expect.objectContaining({
        type: "focus",
        sourceId: first.sourceId,
        project: { id: "p-1", name: "Demo", root: "/srv/demo" },
        activePanel: "tickets",
      }),
    );

    first.close();
    second.close();
  });
});