import { crc32c } from '@node-dlc/checksum';

/**
 * CRC32C checksum for the provided value
 */
export class Checksum {
  public static fromBuffer(buf: Buffer): Checksum {
    return new Checksum(crc32c(buf));
  }

  public static empty(): Checksum {
    return new Checksum(0);
  }

  private _checksum: number;

  private constructor(checksum: number) {
    this._checksum = checksum;
  }

  public equals(other: Checksum): boolean {
    return this._checksum === other._checksum;
  }

  public toNumber(): number {
    return this._checksum;
  }

  public toBuffer(): Buffer {
    const buf = Buffer.alloc(4);
    buf.writeUInt32BE(this._checksum, 0);
    return buf;
  }

  public toString(): string {
    return this._checksum.toString(16);
  }
}