export class Amount {
  @inline
  constructor(public bytes: ByteArray) {
    if ((bytes.length != 8) && (bytes.length != 48))
      rollback("", pack_error_code(bytes.length));
  }

  @inline
  get length(): i32 {
    return this.bytes.length;
  }

  @inline
  isXrp(): bool {
    return this.length == 8;
  }

  @inline
  get drops(): i64 {
    if (!this.isXrp())
      rollback("", pack_error_code(0));
    if (<u64>(this.bytes[0]) >> 7)
      rollback("", pack_error_code(this.bytes[0]));

    return ((<u64>(this.bytes[0]) & 0xb00111111) << 56) +
      (<u64>(this.bytes[1]) << 48) +
      (<u64>(this.bytes[2]) << 40) +
      (<u64>(this.bytes[3]) << 32) +
      (<u64>(this.bytes[4]) << 24) +
      (<u64>(this.bytes[5]) << 16) +
      (<u64>(this.bytes[6]) << 8) +
      <u64>(this.bytes[7]);
  }

  @inline
  get tokenAmount(): i64 {
    if (this.isXrp())
      rollback("", pack_error_code(0));

    let r = $float_sto_set(changetype<u32>(this.bytes), 8);
    if (r < 0)
      rollback("", pack_error_code(r));

    return r;
  }

  @inline
  get currencyCode(): ByteView {
    if (this.isXrp())
      rollback("", pack_error_code(0));

    return new ByteView(this.bytes, 8, 20);
  }

  @inline
  static fromDrops(drops: u64): Amount {
    let buf = new ByteArray(8);
    buf[0] = <u8>((drops >> 56) & 0x3F);
    buf[1] = <u8>((drops >> 48) & 0xFF);
    buf[2] = <u8>((drops >> 40) & 0xFF);
    buf[3] = <u8>((drops >> 32) & 0xFF);
    buf[4] = <u8>((drops >> 24) & 0xFF);
    buf[5] = <u8>((drops >> 16) & 0xFF);
    buf[6] = <u8>((drops >> 8) & 0xFF);
    buf[7] = <u8>(drops & 0xFF);

    return new Amount(buf);
  }
};