/**
 * Author: Simon-Pierre Boucher
 * Contact: contact@spboucher.ai
 * Project: Groupe Ka / Ka Maps
 *
 * URL state serialization: /map?lat=46.8139&lng=-71.2080&zoom=13
 * Each app decides which extra parameters it exposes; Ka Maps only owns
 * the camera portion so URLs stay short and stable.
 */

export interface CameraUrlState {
  lat: number;
  lng: number;
  zoom: number;
}

/** Serialize camera state into URLSearchParams (mutates a copy, returns it). */
export function cameraToParams(
  state: CameraUrlState,
  base?: URLSearchParams,
): URLSearchParams {
  const params = new URLSearchParams(base);
  params.set("lat", state.lat.toFixed(5));
  params.set("lng", state.lng.toFixed(5));
  params.set("zoom", trimZoom(state.zoom));
  return params;
}

/** Parse camera state from URLSearchParams; null when absent or malformed. */
export function cameraFromParams(params: URLSearchParams): CameraUrlState | null {
  const rawLat = params.get("lat");
  const rawLng = params.get("lng");
  const rawZoom = params.get("zoom");
  if (rawLat === null || rawLng === null || rawZoom === null) return null;
  const lat = Number(rawLat);
  const lng = Number(rawLng);
  const zoom = Number(rawZoom);
  if (!Number.isFinite(lat) || !Number.isFinite(lng) || !Number.isFinite(zoom)) return null;
  if (lat < -90 || lat > 90 || lng < -180 || lng > 180) return null;
  return { lat, lng, zoom: Math.min(22, Math.max(0, zoom)) };
}

function trimZoom(zoom: number): string {
  return (Math.round(zoom * 100) / 100).toString();
}