/**
 * viewMode — App-Ansicht: 'compact' (klassischer Vollbild-Chat wie vor 0.2.2.0)
 * oder 'cockpit' (zoombarer Kachel-Desktop).
 *
 * Default 'compact' → fuer normale Nutzung aendert sich nichts (Mama-tauglich).
 * Umschaltbar ueber den Header-Button; persistiert in AsyncStorage. Muster wie
 * services/rvs.ts (Singleton mit Listener-Liste).
 */

import AsyncStorage from '@react-native-async-storage/async-storage';

export type ViewModeValue = 'compact' | 'cockpit';

const KEY = 'aria_view_mode';
type Sub = (mode: ViewModeValue) => void;

class ViewMode {
  private mode: ViewModeValue = 'compact';
  private subs: Sub[] = [];
  private loaded = false;

  constructor() {
    AsyncStorage.getItem(KEY).then((v) => {
      if (v === 'cockpit' || v === 'compact') this.mode = v;
      this.loaded = true;
      this.emit();
    }).catch(() => { this.loaded = true; });
  }

  get(): ViewModeValue { return this.mode; }
  isLoaded(): boolean { return this.loaded; }

  set(mode: ViewModeValue): void {
    if (this.mode === mode) return;
    this.mode = mode;
    AsyncStorage.setItem(KEY, mode).catch(() => {});
    this.emit();
  }

  toggle(): void {
    this.set(this.mode === 'compact' ? 'cockpit' : 'compact');
  }

  subscribe(cb: Sub): () => void {
    this.subs.push(cb);
    cb(this.mode);
    return () => { this.subs = this.subs.filter((s) => s !== cb); };
  }

  private emit(): void {
    const m = this.mode;
    this.subs.forEach((cb) => cb(m));
  }
}

const viewMode = new ViewMode();
export default viewMode;