export type WaterbodyVisual = {
  shore: number;
  waves: number;
  markerX: number;
  markerY: number;
  code: string;
};

export function stableVisualHash(identity: string): number {
  return [...identity.trim().toLocaleLowerCase("ru")]
    .reduce((hash, char) => Math.imul(hash ^ (char.codePointAt(0) ?? 0), 16777619) >>> 0, 2166136261);
}

export function waterbodyVisual(identity: string): WaterbodyVisual {
  const hash = stableVisualHash(identity || "waterbody");
  return {
    shore: hash % 8,
    waves: 1 + ((hash >>> 4) % 3),
    markerX: 32 + ((hash >>> 8) % 59),
    markerY: 18 + ((hash >>> 15) % 23),
    code: hash.toString(36).toUpperCase().padStart(2, "0").slice(-2),
  };
}