export enum EventType {
  INITIAL_STATE = "INITIAL_STATE",
  SET_CONTROLLABLE = "SET_CONTROLLABLE",
  ENTITY_BORN = "ENTITY_BORN",
  ENTITY_DEATH = "ENTITY_DEATH",
  ENTITY_POSITION_UPDATE = "ENTITY_POSITION_UPDATE",
}

export interface Event {
  event_type: EventType;
  data: any;
}

export interface EntityPositionUpdateEvent extends Event {
  event_type: EventType.ENTITY_POSITION_UPDATE;
  data: {
    id: string;
    position: {
      x: number;
      y: number;
    };
  };
}

export interface InitialStateEvent extends Event {
  event_type: EventType.INITIAL_STATE;
  data: {
    world: { width: number; height: number };
    entities: any[];
  };
}

export interface SetControllableEvent extends Event {
  event_type: EventType.SET_CONTROLLABLE;
  data: {
    id: string;
    client_id: string;
  };
}

export interface EventQueue {
  peek(): Event[];
  clear(): void;
}

export interface EventPublisher {
  add(event: Event): void;
  publish(): void;
}

export class WebSocketEventQueue implements EventQueue {
  private queue: Event[];

  constructor(websocket: WebSocket) {
    this.queue = [];
    this.listen_to(websocket);
  }

  public peek() {
    return this.queue;
  }

  public clear() {
    this.queue = [];
  }

  private listen_to(websocket: WebSocket) {
    websocket.onmessage = ({ data }) => {
      const [event_type, event_data] = JSON.parse(data);
      this.queue.push({ event_type, data: event_data } as Event);
    };
  }
}

export class WebsocketEventPublisher implements EventPublisher {
  private queue: Event[];

  constructor(private readonly websocket: WebSocket) {
    this.queue = [];
  }

  public add(event: Event) {
    this.queue.push(event);
  }

  public publish() {
    this.websocket.send(JSON.stringify(this.queue));
    this.queue = [];
  }
}