import { Cbor, CborByte, CborEncoded, CborUnsigned } from ".";
import { CardanoTransaction } from "../transactions";
import { CardanoUTXO } from "../utxos";
import { CborArray } from "./array";
import { CborInteger } from "./integer";
import { CborUtxo } from "./utxo";

const TRANSACTION_START = 4;

const encodeTransactionBody = (
  encodedInputs: string,
  encodedOutputs: string,
  fee?: number,
  requiredSigners?: string,
  scriptHash?: string,
  collateral?: CardanoUTXO[],
  auxiliaryDataHash?: string
) => {
  const mapSize =
    2 +
    (fee ? 1 : 0) +
    (requiredSigners ? 1 : 0) +
    (scriptHash ? 1 : 0) +
    (collateral ? 1 : 0) +
    (auxiliaryDataHash ? 1 : 0);

  const mapValues = [
    fee ? `02${CborUnsigned.encode(fee)}` : "",
    auxiliaryDataHash ? `07${CborByte.encode(auxiliaryDataHash)}` : "",
    scriptHash ? `0B${CborByte.encode(scriptHash)}` : "",
    collateral
      ? `0D81${
          CborTransaction.encodeTransaction(collateral[0].transaction).encoded
        }`
      : "",
    requiredSigners ? `0E81${CborByte.encode(requiredSigners)}` : "",
  ];

  const value = `a${mapSize}00${encodedInputs}01${encodedOutputs}${mapValues.join(
    ""
  )}`;

  return {
    encoded: value,
    length: value.length,
  };
};

const encodeTransaction = (
  tx: CardanoTransaction
): CborEncoded<CardanoTransaction> => {
  return {
    data: tx,
    encoded: `82${CborByte.encode(tx.hash)}${CborUnsigned.encode(tx.index)}`,
  };
};

const readTransaction = (
  value: string
): CardanoTransaction & { headerLength: number } => {
  const hash = CborByte.read(value.substring(TRANSACTION_START));
  const indexStart = TRANSACTION_START + 4 + hash.length;
  const index = CborInteger.read(value.substring(indexStart));

  const indexLength = Cbor.readNextItemStringLength(
    value.substring(indexStart)
  );

  return {
    hash,
    index,
    headerLength: indexStart + indexLength + 2,
  };
};

const decode = (value: string) => {
  const transaction = readTransaction(value);
  const utxo = CborUtxo.decode(value, transaction.headerLength);

  return {
    transaction: {
      hash: transaction.hash,
      index: transaction.index,
    },
    utxo,
  };
};

export const CborTransaction = {
  encodeTransactionBody,
  encodeTransaction,
  decode,
};