import type { keccak256 as Keccak256 } from "ethereum-cryptography/keccak";
import type { sha256 as Sha256 } from "ethereum-cryptography/sha256";

// We don't load ethereum-cryptography on startup because it's slow to
// initialize and this module is transitively imported from many places.
let keccak256Impl: typeof Keccak256 | undefined;
let sha256Impl: typeof Sha256 | undefined;

/**
 * Computes the Keccak-256 hash of the input bytes.
 *
 * @param bytes The input bytes to hash.
 * @returns The Keccak-256 hash of the input bytes.
 */
export async function keccak256(bytes: Uint8Array): Promise<Uint8Array> {
  if (keccak256Impl === undefined) {
    ({ keccak256: keccak256Impl } = await import(
      "ethereum-cryptography/keccak"
    ));
  }
  return keccak256Impl(bytes);
}

/**
 * Computes the SHA-256 hash of the input bytes.
 *
 * @param bytes The input bytes to hash.
 * @returns The SHA-256 hash of the input bytes.
 */
export async function sha256(bytes: Uint8Array): Promise<Uint8Array> {
  if (sha256Impl === undefined) {
    ({ sha256: sha256Impl } = await import("ethereum-cryptography/sha256"));
  }
  return sha256Impl(bytes);
}

/**
 * Creates a non-cryptographic hash-based identifier for the given input.
 *
 * This function is primarily intended for generating unique identifiers from
 * a given input string.
 * It uses the SHA-1 hash algorithm, which is not cryptographically secure, but
 * is sufficient for this use case as long as the input is not generated by an
 * attacker.
 *
 * Note: The exact algorithm used (SHA-1) is not crucial for the function's
 * purpose of generating unique identifiers, and could be replaced if needed.
 *
 * @param data The input string to be hashed.
 * @returns The SHA-1 hash of the input string, represented as a
 * hexadecimal string.
 */
export async function createNonCryptographicHashId(
  data: string,
): Promise<string> {
  const message = new TextEncoder().encode(data);
  const buffer = await crypto.subtle.digest("SHA-1", message);
  return Buffer.from(buffer).toString("hex");
}