import { fromEventEmitter, fromEventTarget } from './transport.js';

// Two socket shapes exist in the wild and the adapters are what let this package
// ignore the difference: browsers/Deno/Workers use `addEventListener`, `ws` on
// Node uses `.on()`.

class EventTargetSocket {
  readonly sent: string[] = [];
  closed = false;
  private readonly listeners = new Map<string, Set<(event: any) => void>>();

  send(data: string) {
    this.sent.push(data);
  }
  close() {
    this.closed = true;
  }
  addEventListener(type: string, listener: (event: any) => void) {
    if (!this.listeners.has(type)) this.listeners.set(type, new Set());
    this.listeners.get(type)!.add(listener);
  }
  removeEventListener(type: string, listener: (event: any) => void) {
    this.listeners.get(type)?.delete(listener);
  }
  count(type: string) {
    return this.listeners.get(type)?.size ?? 0;
  }
  emit(type: string, event: any) {
    for (const l of Array.from(this.listeners.get(type) ?? [])) l(event);
  }
}

class EventEmitterSocket {
  readonly sent: string[] = [];
  closed = false;
  private readonly listeners = new Map<string, Set<(...args: any[]) => void>>();

  send(data: string) {
    this.sent.push(data);
  }
  close() {
    this.closed = true;
  }
  on(type: string, listener: (...args: any[]) => void) {
    if (!this.listeners.has(type)) this.listeners.set(type, new Set());
    this.listeners.get(type)!.add(listener);
  }
  off(type: string, listener: (...args: any[]) => void) {
    this.listeners.get(type)?.delete(listener);
  }
  count(type: string) {
    return this.listeners.get(type)?.size ?? 0;
  }
  emit(type: string, ...args: any[]) {
    for (const l of Array.from(this.listeners.get(type) ?? [])) l(...args);
  }
}

describe('fromEventTarget', () => {
  it('forwards send and close', () => {
    const socket = new EventTargetSocket();
    const sut = fromEventTarget(socket);

    sut.send('hello');
    sut.close();

    expect(socket.sent).toEqual(['hello']);
    expect(socket.closed).toBe(true);
  });

  it('unwraps the MessageEvent', () => {
    const socket = new EventTargetSocket();
    const onMessage = vi.fn();
    fromEventTarget(socket).onMessage(onMessage);

    socket.emit('message', { data: 'payload' });

    expect(onMessage).toHaveBeenCalledWith('payload');
  });

  it('reports close', () => {
    const socket = new EventTargetSocket();
    const onClose = vi.fn();
    fromEventTarget(socket).onClose(onClose);

    socket.emit('close', {});

    expect(onClose).toHaveBeenCalledTimes(1);
  });

  it('returns an unsubscribe that really unsubscribes', () => {
    const socket = new EventTargetSocket();
    const onMessage = vi.fn();
    const unsubscribe = fromEventTarget(socket).onMessage(onMessage);

    expect(socket.count('message')).toBe(1);
    unsubscribe();
    expect(socket.count('message')).toBe(0);

    socket.emit('message', { data: 'ignored' });
    expect(onMessage).not.toHaveBeenCalled();
  });
});

describe('fromEventEmitter', () => {
  it('forwards send and close', () => {
    const socket = new EventEmitterSocket();
    const sut = fromEventEmitter(socket);

    sut.send('hello');
    sut.close();

    expect(socket.sent).toEqual(['hello']);
    expect(socket.closed).toBe(true);
  });

  it('takes the payload as the first argument, not an event', () => {
    const socket = new EventEmitterSocket();
    const onMessage = vi.fn();
    fromEventEmitter(socket).onMessage(onMessage);

    socket.emit('message', 'payload', false);

    expect(onMessage).toHaveBeenCalledWith('payload');
  });

  // ws v8 hands text frames over as a Buffer.
  it('stringifies a Buffer payload', () => {
    const socket = new EventEmitterSocket();
    const onMessage = vi.fn();
    fromEventEmitter(socket).onMessage(onMessage);

    socket.emit('message', Buffer.from('{"a":1}'), false);

    expect(onMessage).toHaveBeenCalledWith('{"a":1}');
  });

  it('reports close', () => {
    const socket = new EventEmitterSocket();
    const onClose = vi.fn();
    fromEventEmitter(socket).onClose(onClose);

    socket.emit('close', 1000, Buffer.from(''));

    expect(onClose).toHaveBeenCalledTimes(1);
  });

  it('returns an unsubscribe that really unsubscribes', () => {
    const socket = new EventEmitterSocket();
    const onMessage = vi.fn();
    const unsubscribe = fromEventEmitter(socket).onMessage(onMessage);

    expect(socket.count('message')).toBe(1);
    unsubscribe();
    expect(socket.count('message')).toBe(0);
  });
});