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

// The pure set logic lives in a vscode-free helper the class wraps, so unit-test the class
// with a Memento stub (vitest runs vscode-free; the module imports vscode only for types +
// EventEmitter — mock it).
vi.mock("vscode", () => ({
  EventEmitter: class {
    private handlers: Array<(e: unknown) => void> = [];
    event = (h: (e: unknown) => void) => { this.handlers.push(h); return { dispose() {} }; };
    fire(e: unknown) { for (const h of this.handlers) h(e); }
    dispose() {}
  },
  Uri: { parse: (s: string) => ({ toString: () => s }) },
  commands: { executeCommand: vi.fn() },
  window: { activeTextEditor: undefined },
}));
import { CoeditingRegistry } from "../src/coeditingRegistry";

function memento(): { store: Map<string, unknown> } & { get: any; update: any } {
  const store = new Map<string, unknown>();
  return {
    store,
    get: (k: string, dflt?: unknown) => (store.has(k) ? store.get(k) : dflt),
    update: (k: string, v: unknown) => { store.set(k, v); return Promise.resolve(); },
  } as any;
}

describe("CoeditingRegistry", () => {
  it("enter/exit flips membership and fires onDidChange", () => {
    const reg = new CoeditingRegistry(memento() as any);
    const events: Array<{ uri: string; coediting: boolean }> = [];
    reg.onDidChange((e) => events.push(e as any));
    const uri = { toString: () => "file:///a.md" } as any;
    expect(reg.isCoediting(uri)).toBe(false);
    reg.enter(uri);
    expect(reg.isCoediting(uri)).toBe(true);
    reg.exit(uri);
    expect(reg.isCoediting(uri)).toBe(false);
    expect(events).toEqual([
      { uri: "file:///a.md", coediting: true },
      { uri: "file:///a.md", coediting: false },
    ]);
  });

  it("persists the set across construction (reload survival)", () => {
    const m = memento();
    const reg1 = new CoeditingRegistry(m as any);
    reg1.enter({ toString: () => "file:///a.md" } as any);
    const reg2 = new CoeditingRegistry(m as any);
    expect(reg2.isCoediting({ toString: () => "file:///a.md" } as any)).toBe(true);
    expect(reg2.list()).toEqual(["file:///a.md"]);
  });

  it("enter is idempotent (no duplicate events)", () => {
    const reg = new CoeditingRegistry(memento() as any);
    const events: unknown[] = [];
    reg.onDidChange((e) => events.push(e));
    const uri = { toString: () => "file:///a.md" } as any;
    reg.enter(uri);
    reg.enter(uri);
    expect(events).toHaveLength(1);
  });
});