#pragma once

#include "Layer.h"

#include "IpAddress.h"

#include "MacAddress.h"

/// @file

/**

 * \namespace pcpp

 * \brief The main namespace for the PcapPlusPlus lib

 */

namespace pcpp

{

  /**

   * @struct arphdr

   * Represents an ARP protocol header

   */

#pragma pack(push, 1)

  struct arphdr

  {

    /** Hardware type (HTYPE) */

    uint16_t hardwareType;

    /** Protocol type (PTYPE). The permitted PTYPE values share a numbering space with those for EtherType */

    uint16_t protocolType;

    /** Hardware address length (HLEN). For IPv4, this has the value 0x0800 */

    uint8_t hardwareSize;

    /** Protocol length (PLEN). Length (in octets) of addresses used in the upper layer protocol. (The upper layer protocol specified in PTYPE.) IPv4 address size is 4 */

    uint8_t protocolSize;

    /** Specifies the operation that the sender is performing: 1 (::ARP_REQUEST) for request, 2 (::ARP_REPLY) for reply */

    uint16_t opcode;

    /** Sender hardware address (SHA) */

    uint8_t senderMacAddr[6];

    /** Sender protocol address (SPA) */

    uint32_t senderIpAddr;

    /** Target hardware address (THA) */

    uint8_t targetMacAddr[6];

    /** Target protocol address (TPA) */

    uint32_t targetIpAddr;

  };

#pragma pack(pop)

  /**

   * An enum for ARP message type

   */

  enum ArpOpcode

  {

    ARP_REQUEST = 0x0001, ///< ARP request

    ARP_REPLY   = 0x0002  ///< ARP reply (response)

  };

  /**

   * @class ArpLayer

   * Represents an ARP protocol layer. Currently only IPv4 ARP messages are supported

   */

  class ArpLayer : public Layer

  {

  public:

    /**

     * A constructor that creates the layer from an existing packet raw data

     * @param[in] data A pointer to the raw data (will be casted to @ref arphdr)

     * @param[in] dataLen Size of the data in bytes

     * @param[in] prevLayer A pointer to the previous layer

     * @param[in] packet A pointer to the Packet instance where layer will be stored in

     */

    ArpLayer(uint8_t* data, size_t dataLen, Layer* prevLayer, Packet* packet) : Layer(data, dataLen, prevLayer, packet) { m_Protocol = ARP; m_DataLen = sizeof(arphdr); }

    /**

     * A constructor that allocates a new ARP header

     * @param[in] opCode ARP message type (ARP request or ARP reply)

     * @param[in] senderMacAddr The sender MAC address (will be put in arphdr#senderMacAddr)

     * @param[in] targetMacAddr The target MAC address (will be put in arphdr#targetMacAddr)

     * @param[in] senderIpAddr The sender IP address (will be put in arphdr#senderIpAddr)

     * @param[in] targetIpAddr The target IP address (will be put in arphdr#targetIpAddr)

     */

    ArpLayer(ArpOpcode opCode, const MacAddress& senderMacAddr, const MacAddress& targetMacAddr, const IPv4Address& senderIpAddr, const IPv4Address& targetIpAddr);

    ~ArpLayer() {}

    /**

     * Get a pointer to the ARP header. Notice this points directly to the data, so every change will change the actual packet data

     * @return A pointer to the @ref arphdr

     */

    inline arphdr* getArpHeader() const { return (arphdr*)m_Data; }

    /**

     * Get the sender hardware address (SHA) in the form of MacAddress

     * @return A MacAddress containing the sender hardware address (SHA)

     */

    inline MacAddress getSenderMacAddress() const { return MacAddress(getArpHeader()->senderMacAddr); }

    /**

     * Get the target hardware address (THA) in the form of MacAddress

     * @return A MacAddress containing the target hardware address (THA)

     */

    inline MacAddress getTargetMacAddress() const { return MacAddress(getArpHeader()->targetMacAddr); }

    /**

     * Get the sender protocol address (SPA) in the form of IPv4Address

     * @return An IPv4Address containing the sender protocol address (SPA)

     */

    inline IPv4Address getSenderIpAddr() const { return getArpHeader()->senderIpAddr; }

    /**

     * Get the target protocol address (TPA) in the form of IPv4Address

     * @return An IPv4Address containing the target protocol address (TPA)

     */

    inline IPv4Address getTargetIpAddr() const { return getArpHeader()->targetIpAddr; }

    // implement abstract methods

    /**

     * Does nothing for this layer (ArpLayer is always last)

     */

    void parseNextLayer() {}

    /**

     * @return The size of @ref arphdr

     */

    size_t getHeaderLen() const { return sizeof(arphdr); }

    /**

     * Calculate the following fields:

     * - @ref arphdr#hardwareType = Ethernet (1)

     * - @ref arphdr#hardwareSize = 6

     * - @ref arphdr#protocolType = ETHERTYPE_IP (assume IPv4 over ARP)

     * - @ref arphdr#protocolSize = 4 (assume IPv4 over ARP)

     * - if it's an ARP request: @ref arphdr#targetMacAddr = MacAddress("00:00:00:00:00:00")

     */

    void computeCalculateFields();

    /**

     * Is this packet an ARP request?

     */

    bool isRequest() const;

    /**

     * Is this packet an ARP reply?

     */

    bool isReply() const;

    std::string toString() const;

    OsiModelLayer getOsiModelLayer() const { return OsiModelNetworkLayer; }

  };

} // namespace pcpp