// Copyright 2019-2026 @pezkuwi/extension-inject authors & contributors
// SPDX-License-Identifier: Apache-2.0

// cyrb53 (c) 2018 bryc (github.com/bryc)
// A fast and simple hash function with decent collision resistance.
// Largely inspired by MurmurHash2/3, but with a focus on speed/simplicity.
// Public domain. Attribution appreciated.
//
// From https://github.com/bryc/code/blob/fed42df9db547493452e32375c93d7854383e480/jshash/experimental/cyrb53.js
// As shared in https://stackoverflow.com/a/52171480
//
// Small changes made to the code as linked above:
//   - Seed value is required (set as Date.now() in usage, could change)
//   - Return value is a hex string (as per comment in SO answer)
//   - TS typings added
//   - Non-intrusive coding-style variable declaration changes
export function cyrb53 (input: string, seed = Date.now()): string {
  let h1 = 0xdeadbeef ^ seed;
  let h2 = 0x41c6ce57 ^ seed;

  for (let i = 0, count = input.length; i < count; i++) {
    const ch = input.charCodeAt(i);

    h1 = Math.imul(h1 ^ ch, 2654435761);
    h2 = Math.imul(h2 ^ ch, 1597334677);
  }

  h1 = Math.imul(h1 ^ (h1 >>> 16), 2246822507) ^ Math.imul(h2 ^ (h2 >>> 13), 3266489909);
  h2 = Math.imul(h2 ^ (h2 >>> 16), 2246822507) ^ Math.imul(h1 ^ (h1 >>> 13), 3266489909);

  // https://stackoverflow.com/a/52171480
  return (h2 >>> 0).toString(16).padStart(8, '0') + (h1 >>> 0).toString(16).padStart(8, '0');
}
