#define LOG_MODULE PacketLogModuleDhcpLayer

#include "DhcpLayer.h"

#include "Logger.h"

namespace pcpp

{

  constexpr uint32_t DhcpMagicNumber = 0x63538263;

  DhcpOption DhcpOptionBuilder::build() const

  {

    size_t recSize = 2 * sizeof(uint8_t) + m_RecValueLen;

    uint8_t recType = static_cast<uint8_t>(m_RecType);

    if ((recType == DHCPOPT_END || recType == DHCPOPT_PAD))

    {

      if (m_RecValueLen != 0)

      {

        PCPP_LOG_ERROR(

            "Can't set DHCP END option or DHCP PAD option with size different than 0, tried to set size "

            << (int)m_RecValueLen);

        return DhcpOption(nullptr);

      }

      recSize = sizeof(uint8_t);

    }

    uint8_t* recordBuffer = new uint8_t[recSize];

    memset(recordBuffer, 0, recSize);

    recordBuffer[0] = recType;

    if (recSize > 1)

    {

      recordBuffer[1] = static_cast<uint8_t>(m_RecValueLen);

      if (m_RecValue != nullptr)

        memcpy(recordBuffer + 2, m_RecValue, m_RecValueLen);

      else

        memset(recordBuffer + 2, 0, m_RecValueLen);

    }

    return DhcpOption(recordBuffer);

  }

  DhcpLayer::DhcpLayer(uint8_t* data, size_t dataLen, Layer* prevLayer, Packet* packet)

      : Layer(data, dataLen, prevLayer, packet, DHCP)

  {}

  void DhcpLayer::initDhcpLayer(size_t numOfBytesToAllocate)

  {

    allocData(numOfBytesToAllocate);

    m_Protocol = DHCP;

  }

  DhcpLayer::DhcpLayer() : Layer()

  {

    initDhcpLayer(sizeof(dhcp_header));

  }

  DhcpLayer::DhcpLayer(DhcpMessageType msgType, const MacAddress& clientMacAddr) : Layer()

  {

    initDhcpLayer(sizeof(dhcp_header) + 4 * sizeof(uint8_t));

    setClientHardwareAddress(clientMacAddr);

    uint8_t* msgTypeOptionPtr = m_Data + sizeof(dhcp_header);

    msgTypeOptionPtr[0] = (uint8_t)DHCPOPT_DHCP_MESSAGE_TYPE;  // option code

    msgTypeOptionPtr[1] = 1;                                   // option len

    msgTypeOptionPtr[2] = (uint8_t)msgType;                    // option data - message type

    msgTypeOptionPtr[3] = (uint8_t)DHCPOPT_END;

  }

  MacAddress DhcpLayer::getClientHardwareAddress() const

  {

    dhcp_header* hdr = getDhcpHeader();

    if (hdr != nullptr && hdr->hardwareType == 1 && hdr->hardwareAddressLength == 6)

      return MacAddress(hdr->clientHardwareAddress);

    PCPP_LOG_DEBUG("Hardware type isn't Ethernet or hardware addr len != 6, returning MacAddress:Zero");

    return MacAddress::Zero;

  }

  void DhcpLayer::setClientHardwareAddress(const MacAddress& addr)

  {

    dhcp_header* hdr = getDhcpHeader();

    hdr->hardwareType = 1;           // Ethernet

    hdr->hardwareAddressLength = 6;  // MAC address length

    addr.copyTo(hdr->clientHardwareAddress);

  }

  void DhcpLayer::computeCalculateFields()

  {

    dhcp_header* hdr = getDhcpHeader();

    hdr->magicNumber = DhcpMagicNumber;

    DhcpMessageType msgType = getMessageType();

    switch (msgType)

    {

    case DHCP_DISCOVER:

    case DHCP_REQUEST:

    case DHCP_DECLINE:

    case DHCP_RELEASE:

    case DHCP_INFORM:

    case DHCP_UNKNOWN_MSG_TYPE:

      hdr->opCode = DHCP_BOOTREQUEST;

      break;

    case DHCP_OFFER:

    case DHCP_ACK:

    case DHCP_NAK:

      hdr->opCode = DHCP_BOOTREPLY;

      break;

    default:

      break;

    }

    hdr->hardwareType = 1;           // Ethernet

    hdr->hardwareAddressLength = 6;  // MAC address length

  }

  std::string DhcpLayer::toString() const

  {

    std::string msgType = "Unknown";

    switch (getMessageType())

    {

    case DHCP_DISCOVER:

    {

      msgType = "Discover";

      break;

    }

    case DHCP_OFFER:

    {

      msgType = "Offer";

      break;

    }

    case DHCP_REQUEST:

    {

      msgType = "Request";

      break;

    }

    case DHCP_DECLINE:

    {

      msgType = "Decline";

      break;

    }

    case DHCP_ACK:

    {

      msgType = "Acknowledge";

      break;

    }

    case DHCP_NAK:

    {

      msgType = "Negative Acknowledge";

      break;

    }

    case DHCP_RELEASE:

    {

      msgType = "Release";

      break;

    }

    case DHCP_INFORM:

    {

      msgType = "Inform";

      break;

    }

    default:

      break;

    }

    return "DHCP layer (" + msgType + ")";

  }

  DhcpMessageType DhcpLayer::getMessageType() const

  {

    DhcpOption opt = getOptionData(DHCPOPT_DHCP_MESSAGE_TYPE);

    if (opt.isNull())

      return DHCP_UNKNOWN_MSG_TYPE;

    return (DhcpMessageType)opt.getValueAs<uint8_t>();

  }

  bool DhcpLayer::setMessageType(DhcpMessageType msgType)

  {

    if (msgType == DHCP_UNKNOWN_MSG_TYPE)

      return false;

    DhcpOption opt = getOptionData(DHCPOPT_DHCP_MESSAGE_TYPE);

    if (opt.isNull())

    {

      opt = addOptionAfter(DhcpOptionBuilder(DHCPOPT_DHCP_MESSAGE_TYPE, (uint8_t)msgType), DHCPOPT_UNKNOWN);

      if (opt.isNull())

        return false;

    }

    opt.setValue<uint8_t>((uint8_t)msgType);

    return true;

  }

  DhcpOption DhcpLayer::getOptionData(DhcpOptionTypes option) const

  {

    return m_OptionReader.getTLVRecord((uint8_t)option, getOptionsBasePtr(), getHeaderLen() - sizeof(dhcp_header));

  }

  DhcpOption DhcpLayer::getFirstOptionData() const

  {

    return m_OptionReader.getFirstTLVRecord(getOptionsBasePtr(), getHeaderLen() - sizeof(dhcp_header));

  }

  DhcpOption DhcpLayer::getNextOptionData(DhcpOption dhcpOption) const

  {

    return m_OptionReader.getNextTLVRecord(dhcpOption, getOptionsBasePtr(), getHeaderLen() - sizeof(dhcp_header));

  }

  size_t DhcpLayer::getOptionsCount() const

  {

    return m_OptionReader.getTLVRecordCount(getOptionsBasePtr(), getHeaderLen() - sizeof(dhcp_header));

  }

  DhcpOption DhcpLayer::addOptionAt(const DhcpOptionBuilder& optionBuilder, int offset)

  {

    DhcpOption newOpt = optionBuilder.build();

    if (newOpt.isNull())

    {

      PCPP_LOG_ERROR("Cannot build new option of type " << (int)newOpt.getType());

      return DhcpOption(nullptr);

    }

    size_t sizeToExtend = newOpt.getTotalSize();

    if (!extendLayer(offset, sizeToExtend))

    {

      PCPP_LOG_ERROR("Could not extend DhcpLayer in [" << newOpt.getTotalSize() << "] bytes");

      newOpt.purgeRecordData();

      return DhcpOption(nullptr);

    }

    memcpy(m_Data + offset, newOpt.getRecordBasePtr(), newOpt.getTotalSize());

    uint8_t* newOptPtr = m_Data + offset;

    m_OptionReader.changeTLVRecordCount(1);

    newOpt.purgeRecordData();

    return DhcpOption(newOptPtr);

  }

  DhcpOption DhcpLayer::addOption(const DhcpOptionBuilder& optionBuilder)

  {

    int offset = 0;

    DhcpOption endOpt = getOptionData(DHCPOPT_END);

    if (!endOpt.isNull())

      offset = endOpt.getRecordBasePtr() - m_Data;

    else

      offset = getHeaderLen();

    return addOptionAt(optionBuilder, offset);

  }

  DhcpOption DhcpLayer::addOptionAfter(const DhcpOptionBuilder& optionBuilder, DhcpOptionTypes prevOption)

  {

    int offset = 0;

    DhcpOption prevOpt = getOptionData(prevOption);

    if (prevOpt.isNull())

    {

      offset = sizeof(dhcp_header);

    }

    else

    {

      offset = prevOpt.getRecordBasePtr() + prevOpt.getTotalSize() - m_Data;

    }

    return addOptionAt(optionBuilder, offset);

  }

  bool DhcpLayer::removeOption(DhcpOptionTypes optionType)

  {

    DhcpOption optToRemove = getOptionData(optionType);

    if (optToRemove.isNull())

    {

      return false;

    }

    int offset = optToRemove.getRecordBasePtr() - m_Data;

    if (!shortenLayer(offset, optToRemove.getTotalSize()))

    {

      return false;

    }

    m_OptionReader.changeTLVRecordCount(-1);

    return true;

  }

  bool DhcpLayer::removeAllOptions()

  {

    int offset = sizeof(dhcp_header);

    if (!shortenLayer(offset, getHeaderLen() - offset))

      return false;

    m_OptionReader.changeTLVRecordCount(0 - getOptionsCount());

    return true;

  }

}  // namespace pcpp