/**
 * Author: Simon-Pierre Boucher
 * Contact: contact@spboucher.ai
 * Project: Groupe Ka / Ka Maps
 *
 * Tiny typed event hub. All MapLibre listeners are centralized in KaMap
 * and re-emitted here so app components never attach raw map listeners
 * (and cleanup happens in exactly one place).
 */

export type KaEventMap = {
  /** Camera settled after user interaction or animation.
   *  `byUser` distingue le geste (drag, molette, pincement, boutons de
   *  navigation) d'un mouvement programmé (fitBounds, easeTo interne) —
   *  c'est ce qui permet de « respecter l'intention de l'utilisateur ». */
  moveend: { center: { lat: number; lng: number }; zoom: number; byUser: boolean };
  /** Viewport diverged from the last searched area. */
  searchAreaDirty: { dirty: boolean };
  /** A property was selected (click) or deselected (null). */
  select: { propertyId: string | null; origin: "map" | "app" };
  /** Hover changed (desktop only). */
  hover: { propertyId: string | null };
  /** A cluster was clicked; the map is easing to expansion zoom. */
  clusterExpand: { count: number };
  /** Data finished loading into the property source. */
  data: { count: number; totalCount?: number };
  /** Loading state of the bounds query pipeline. */
  loading: { loading: boolean };
  /** Non-fatal error (tiles, query…) the app may surface. */
  error: { scope: "tiles" | "query" | "style"; error: unknown };
  /** Le spotlight bâtiment (focusBuilding) a trouvé son empreinte 3D. */
  buildingFocus: { found: boolean };
  /** Outil de dessin : état courant (en cours de tracé et/ou polygone posé).
   *  `polygon` est un anneau [lng, lat][] fermé implicitement (≥ 3 sommets). */
  draw: { polygon: [number, number][] | null; drawing: boolean };
  /** Survol d'une bulle de cluster — fourchette de prix + position écran. */
  clusterHover: {
    info: { count: number; min: number | null; max: number | null; x: number; y: number } | null;
  };
};

type Handler<T> = (payload: T) => void;

export class KaEventHub {
  private handlers = new Map<keyof KaEventMap, Set<Handler<never>>>();

  on<K extends keyof KaEventMap>(
    event: K,
    handler: Handler<KaEventMap[K]>,
  ): () => void {
    let set = this.handlers.get(event);
    if (!set) {
      set = new Set();
      this.handlers.set(event, set);
    }
    set.add(handler as Handler<never>);
    return () => set?.delete(handler as Handler<never>);
  }

  emit<K extends keyof KaEventMap>(event: K, payload: KaEventMap[K]): void {
    const set = this.handlers.get(event);
    if (!set) return;
    for (const handler of set) (handler as Handler<KaEventMap[K]>)(payload);
  }

  clear(): void {
    this.handlers.clear();
  }
}