class KeyDownManager {
  handlerList = [];

  // return id;
  register(handler, name) {
    this.handlerList.push([name, handler]);
    console.log("register keydown", name);
  }

  deregister(name) {
    console.log("deregister keydown", name);
    this.handlerList = this.handlerList.filter((v) => v[0] !== name);
  }

  constructor() {
    document.addEventListener("keydown", (event) => {
      for (let i = this.handlerList.length - 1; i >= 0; i--) {
        let ret = this.handlerList[i][1](event);

        if (!ret) {
          break;
        }
      }
    });
  }
}

var globalKeyDownManager = new KeyDownManager();

export { globalKeyDownManager };