/** Stable positive 32-bit id for EmulatorJS EJS_gameID. */
export function hashGameId(profileId: string, gameKey: string): number {
  const input = `${profileId}::${gameKey}`;
  let h = 2166136261;
  for (let i = 0; i < input.length; i++) {
    h ^= input.charCodeAt(i);
    h = Math.imul(h, 16777619);
  }
  // Keep in signed 32-bit positive range EmulatorJS expects
  return (h >>> 0) % 2_147_483_647 || 1;
}

export function newId(prefix = ""): string {
  const rand =
    typeof crypto !== "undefined" && "randomUUID" in crypto
      ? crypto.randomUUID()
      : `${Date.now()}-${Math.random().toString(36).slice(2)}`;
  return prefix ? `${prefix}_${rand}` : rand;
}

export async function hashPassword(password: string, salt: string): Promise<string> {
  const data = new TextEncoder().encode(`${salt}:${password}`);
  const digest = await crypto.subtle.digest("SHA-256", data);
  return Array.from(new Uint8Array(digest))
    .map((b) => b.toString(16).padStart(2, "0"))
    .join("");
}

export function randomSalt(): string {
  const bytes = new Uint8Array(16);
  crypto.getRandomValues(bytes);
  return Array.from(bytes)
    .map((b) => b.toString(16).padStart(2, "0"))
    .join("");
}