#pragma once

#include "EthLayer.h"

#include "Layer.h"

namespace pcpp

{

/**

 * @struct s7commhdr

 * Represents a S7COMM protocol header

 */

#pragma pack(push, 1)

  typedef struct

  {

    /** protocol id */

    uint8_t protocolId;

    /** message type */

    uint8_t msgType;

    /** redundancy identification (reserved) */

    uint16_t reserved;

    /** protocol data unit reference */

    uint16_t pduRef;

    /** parameter length */

    uint16_t paramLength;

    /** data length */

    uint16_t dataLength;

  } s7commhdr;

#pragma pack(pop)

/**

 * @struct s7comm_ack_data_hdr

 * Represents a S7COMM protocol header with Ack-Data header

 */

#pragma pack(push, 1)

  struct s7comm_ack_data_hdr : s7commhdr

  {

    /** error class */

    uint8_t errorClass;

    /** error code */

    uint8_t errorCode;

  };

#pragma pack(pop)

  /**

   * @class S7CommParameter

   * Represents a S7COMM (S7 Communication) protocol Parameter

   */

  class S7CommParameter

  {

    friend class S7CommLayer;

    public:

    S7CommParameter() {}

    virtual ~S7CommParameter() {}

    /**

     * @return The data of the Parameter

     */

    uint8_t *getData() const { return m_Data; }

    /**

     * @return The length of the Parameter data

     */

    size_t getDataLength() const { return m_DataLen; }

    private:

    S7CommParameter(uint8_t *data, size_t dataLen) : m_Data(data), m_DataLen(dataLen) {}

    uint8_t *m_Data;

    size_t m_DataLen;

  };

  /**

   * @class S7CommLayer

   * Represents a S7COMM (S7 Communication) protocol

   */

  class S7CommLayer : public Layer

  {

  public:

    /**

     * A constructor that allocates a new S7comm header

     * @param[in] msgType The general type of the message

     * @param[in] pduRef Link responses to their requests

     * @param[in] paramLength The length of the parameter field

     * @param[in] dataLength The length of the data field

     * @param[in] errorClass The value of the error class

     * @param[in] errorCode The value of the error code

     */

    S7CommLayer(uint8_t msgType, uint16_t pduRef, uint16_t paramLength, uint16_t dataLength, uint8_t errorClass = 0,

          uint8_t errorCode = 0);

    /**

     * 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 s7commhdr)

     * @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

     */

    S7CommLayer(uint8_t *data, size_t dataLen, Layer *prevLayer, Packet *packet)

      : Layer(data, dataLen, prevLayer, packet)

    {

      m_Protocol = S7COMM;

      m_Parameter = nullptr;

    }

    virtual ~S7CommLayer()

    {

      if (m_Parameter)

        delete m_Parameter;

    }

    /**

     * @return S7comm protocol id

     */

    uint8_t getProtocolId() const;

    /**

     * @return S7comm message type

     */

    uint8_t getMsgType() const;

    /**

     * @return S7comm PDU ref

     */

    uint16_t getPduRef() const;

    /**

     * @return S7comm parameter length

     */

    uint16_t getParamLength() const;

    /**

     * @return S7comm data length

     */

    uint16_t getDataLength() const;

    /**

     * @return S7comm error code

     */

    uint8_t getErrorCode() const;

    /**

     * @return S7comm error class

     */

    uint8_t getErrorClass() const;

    /**

     * @return S7comm parameter

     */

    const S7CommParameter *getParameter();

    /**

     * Set the value of the message type

     * @param[in] msgType The value of the message type

     */

    void setMsgType(uint8_t msgType) const;

    /**

     * Set the value of the PDU ref

     * @param[in] pduRef The value of the PDU ref

     */

    void setPduRef(uint16_t pduRef) const;

    /**

     * Set the value of the error code

     * @param[in] errorCode The value of the error code

     */

    void setErrorCode(uint8_t errorCode) const;

    /**

     * Set the value of the error class

     * @param[in] errorClass The value of the error class

     */

    void setErrorClass(uint8_t errorClass) const;

    /**

     * @return Size of S7CommLayer

     */

    size_t getHeaderLen() const override { return m_DataLen; }

    /**

     * Does nothing for this layer (S7CommLayer is always last)

     */

    void computeCalculateFields() override {}

    /**

     * Does nothing for this layer (S7CommLayer is always last)

     */

    void parseNextLayer() override {}

    /**

     * A static method that takes a byte array and detects whether it is a S7COMM

     * @param[in] data A byte array

     * @param[in] dataSize The byte array size (in bytes)

     * @return True if the data looks like a valid S7COMM layer

     */

    static bool isDataValid(const uint8_t *data, size_t dataSize);

    std::string toString() const override;

    OsiModelLayer getOsiModelLayer() const override { return OsiModelApplicationLayer; }

  private:

    s7commhdr *getS7commHeader() const { return (s7commhdr *)m_Data; }

    s7comm_ack_data_hdr *getS7commAckDataHeader() const

    {

      if (getS7commHeader()->msgType == 0x03)

      {

        return (s7comm_ack_data_hdr *)m_Data;

      }

      return nullptr;

    }

    size_t getS7commHeaderLength() const;

    S7CommParameter *m_Parameter;

  };

} // namespace pcpp