// Copyright (c) 2011-2016 The Cryptonote developers
// Distributed under the MIT/X11 software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.

#include "TransactionExtra.h"

#include "Common/MemoryInputStream.h"
#include "Common/StreamTools.h"
#include "Common/StringTools.h"
#include "CryptoNoteTools.h"
#include "Serialization/BinaryOutputStreamSerializer.h"
#include "Serialization/BinaryInputStreamSerializer.h"

using namespace Crypto;
using namespace Common;

namespace CryptoNote {

bool parseTransactionExtra(const std::vector<uint8_t> &transactionExtra, std::vector<TransactionExtraField> &transactionExtraFields) {
  transactionExtraFields.clear();

  if (transactionExtra.empty())
    return true;

  try {
    MemoryInputStream iss(transactionExtra.data(), transactionExtra.size());
    BinaryInputStreamSerializer ar(iss);

    int c = 0;

    while (!iss.endOfStream()) {
      c = read<uint8_t>(iss);
      switch (c) {
      case TX_EXTRA_TAG_PADDING: {
        size_t size = 1;
        for (; !iss.endOfStream() && size <= TX_EXTRA_PADDING_MAX_COUNT; ++size) {
          if (read<uint8_t>(iss) != 0) {
            return false; // all bytes should be zero
          }
        }

        if (size > TX_EXTRA_PADDING_MAX_COUNT) {
          return false;
        }

        transactionExtraFields.push_back(TransactionExtraPadding{ size });
        break;
      }

      case TX_EXTRA_TAG_PUBKEY: {
        TransactionExtraPublicKey extraPk;
        ar(extraPk.publicKey, "public_key");
        transactionExtraFields.push_back(extraPk);
        break;
      }

      case TX_EXTRA_NONCE: {
        TransactionExtraNonce extraNonce;
        uint8_t size = read<uint8_t>(iss);
        if (size > 0) {
          extraNonce.nonce.resize(size);
          read(iss, extraNonce.nonce.data(), extraNonce.nonce.size());
        }

        transactionExtraFields.push_back(extraNonce);
        break;
      }
      }
    }
  } catch (std::exception &) {
    return false;
  }

  return true;
}

struct ExtraSerializerVisitor : public boost::static_visitor<bool> {
  std::vector<uint8_t>& extra;

  ExtraSerializerVisitor(std::vector<uint8_t>& tx_extra)
    : extra(tx_extra) {}

  bool operator()(const TransactionExtraPadding& t) {
    if (t.size > TX_EXTRA_PADDING_MAX_COUNT) {
      return false;
    }
    extra.insert(extra.end(), t.size, 0);
    return true;
  }

  bool operator()(const TransactionExtraPublicKey& t) {
    return addTransactionPublicKeyToExtra(extra, t.publicKey);
  }

  bool operator()(const TransactionExtraNonce& t) {
    return addExtraNonceToTransactionExtra(extra, t.nonce);
  }
};

bool writeTransactionExtra(std::vector<uint8_t>& tx_extra, const std::vector<TransactionExtraField>& tx_extra_fields) {
  ExtraSerializerVisitor visitor(tx_extra);

  for (const auto& tag : tx_extra_fields) {
    if (!boost::apply_visitor(visitor, tag)) {
      return false;
    }
  }

  return true;
}

PublicKey getTransactionPublicKeyFromExtra(const std::vector<uint8_t>& tx_extra) {
  std::vector<TransactionExtraField> tx_extra_fields;
  parseTransactionExtra(tx_extra, tx_extra_fields);

  TransactionExtraPublicKey pub_key_field;
  if (!findTransactionExtraFieldByType(tx_extra_fields, pub_key_field))
    return boost::value_initialized<PublicKey>();

  return pub_key_field.publicKey;
}

bool addTransactionPublicKeyToExtra(std::vector<uint8_t>& tx_extra, const PublicKey& tx_pub_key) {
  tx_extra.resize(tx_extra.size() + 1 + sizeof(PublicKey));
  tx_extra[tx_extra.size() - 1 - sizeof(PublicKey)] = TX_EXTRA_TAG_PUBKEY;
  *reinterpret_cast<PublicKey*>(&tx_extra[tx_extra.size() - sizeof(PublicKey)]) = tx_pub_key;
  return true;
}


bool addExtraNonceToTransactionExtra(std::vector<uint8_t>& tx_extra, const BinaryArray& extra_nonce) {
  if (extra_nonce.size() > TX_EXTRA_NONCE_MAX_COUNT) {
    return false;
  }

  size_t start_pos = tx_extra.size();
  tx_extra.resize(tx_extra.size() + 2 + extra_nonce.size());
  //write tag
  tx_extra[start_pos] = TX_EXTRA_NONCE;
  //write len
  ++start_pos;
  tx_extra[start_pos] = static_cast<uint8_t>(extra_nonce.size());
  //write data
  ++start_pos;
  memcpy(&tx_extra[start_pos], extra_nonce.data(), extra_nonce.size());
  return true;
}

void setPaymentIdToTransactionExtraNonce(std::vector<uint8_t>& extra_nonce, const Hash& payment_id) {
  extra_nonce.clear();
  extra_nonce.push_back(TX_EXTRA_NONCE_PAYMENT_ID);
  const uint8_t* payment_id_ptr = reinterpret_cast<const uint8_t*>(&payment_id);
  std::copy(payment_id_ptr, payment_id_ptr + sizeof(payment_id), std::back_inserter(extra_nonce));
}

bool getPaymentIdFromTransactionExtraNonce(const std::vector<uint8_t>& extra_nonce, Hash& payment_id) {
  if (sizeof(Hash) + 1 != extra_nonce.size())
    return false;
  if (TX_EXTRA_NONCE_PAYMENT_ID != extra_nonce[0])
    return false;
  payment_id = *reinterpret_cast<const Hash*>(extra_nonce.data() + 1);
  return true;
}

bool parsePaymentId(const std::string& paymentIdString, Hash& paymentId) {
  return Common::podFromHex(paymentIdString, paymentId);
}

bool createTxExtraWithPaymentId(const std::string& paymentIdString, std::vector<uint8_t>& extra) {
  Hash paymentIdBin;

  if (!parsePaymentId(paymentIdString, paymentIdBin)) {
    return false;
  }

  std::vector<uint8_t> extraNonce;
  CryptoNote::setPaymentIdToTransactionExtraNonce(extraNonce, paymentIdBin);

  if (!CryptoNote::addExtraNonceToTransactionExtra(extra, extraNonce)) {
    return false;
  }

  return true;
}

bool getPaymentIdFromTxExtra(const std::vector<uint8_t>& extra, Hash& paymentId) {
  std::vector<TransactionExtraField> tx_extra_fields;
  if (!parseTransactionExtra(extra, tx_extra_fields)) {
    return false;
  }

  TransactionExtraNonce extra_nonce;
  if (findTransactionExtraFieldByType(tx_extra_fields, extra_nonce)) {
    if (!getPaymentIdFromTransactionExtraNonce(extra_nonce.nonce, paymentId)) {
      return false;
    }
  } else {
    return false;
  }

  return true;
}


}