import { Injectable, NgZone } from '@angular/core';
import { ShortcutHandler, register, unregister } from '@tauri-apps/api/globalShortcut';
import { Observable, Subscriber } from 'rxjs';

@Injectable({
  providedIn: 'root'
})
export class ShortcutService {
  private internalHandlers: Map<string, [ShortcutHandler, Subscriber<string>, () => void]> = new Map<string, [ShortcutHandler, Subscriber<string>, () => void]>();

  constructor(private zone: NgZone) {}

  register(shortcut: string) {
    return new Observable<string>((subscriber) => {

      let originalHandler: ShortcutHandler = (s) => this.zone.run(() => subscriber.next(s));

      const teardown = () => {
        unregister(shortcut);
        this.internalHandlers.delete(shortcut);
      };

      this.internalHandlers.set(shortcut, [originalHandler, subscriber, teardown]);

      register(shortcut, originalHandler)

      return teardown;
    });
  }

  rebind_from_to(previousShortcut: string, nextShortcut: string) {
    let [oldHandler, subscriber, teardown] = this.internalHandlers.get(previousShortcut)!;

    subscriber.remove(teardown);
    teardown();

    teardown = () => {
      unregister(nextShortcut);
      this.internalHandlers.delete(nextShortcut);
    };

    register(nextShortcut, oldHandler);

    this.internalHandlers.set(nextShortcut, [oldHandler, subscriber, teardown]);
  }
}