#pragma once

#include "Device.h"

// forward declaration for the pcap descriptor defined in pcap.h

struct pcap;

typedef pcap pcap_t;

struct pcap_pkthdr;

/// @file

/// @namespace pcpp

/// @brief The main namespace for the PcapPlusPlus lib

namespace pcpp

{

  // Forward Declaration - required for IPcapDevice::matchPacketWithFilter

  class GeneralFilter;

  namespace internal

  {

    /// @struct PcapStats

    /// A container for pcap device statistics

    struct PcapStats

    {

      /// Number of packets received

      uint64_t packetsRecv;

      /// Number of packets dropped

      uint64_t packetsDrop;

      /// number of packets dropped by interface (not supported on all platforms)

      uint64_t packetsDropByInterface;

    };

    /// @class PcapHandle

    /// @brief A wrapper class for pcap_t* which is the libpcap packet capture descriptor.

    /// This class is used to manage the lifecycle of the pcap_t* object

    class PcapHandle

    {

    public:

      /// @brief Creates an empty handle.

      constexpr PcapHandle() noexcept = default;

      /// @brief Creates a handle from the provided pcap descriptor.

      /// @param pcapDescriptor The pcap descriptor to wrap.

      explicit PcapHandle(pcap_t* pcapDescriptor) noexcept;

      PcapHandle(const PcapHandle&) = delete;

      PcapHandle(PcapHandle&& other) noexcept;

      PcapHandle& operator=(const PcapHandle&) = delete;

      PcapHandle& operator=(PcapHandle&& other) noexcept;

      PcapHandle& operator=(std::nullptr_t) noexcept;

      ~PcapHandle();

      /// @return True if the handle is not null, false otherwise.

      bool isValid() const noexcept

      {

        return m_PcapDescriptor != nullptr;

      }

      /// @return The underlying pcap descriptor.

      pcap_t* get() const noexcept

      {

        return m_PcapDescriptor;

      }

      /// @brief Releases ownership of the handle and returns the pcap descriptor.

      /// @return The pcap descriptor or nullptr if no handle is owned.

      pcap_t* release() noexcept;

      /// @brief Replaces the managed handle with the provided one.

      /// @param pcapDescriptor A new pcap descriptor to manage.

      /// @remarks If the handle contains a non-null descriptor it will be closed.

      void reset(pcap_t* pcapDescriptor = nullptr) noexcept;

      /// @brief Helper function to retrieve a view of the last error string for this handle.

      /// @return A null-terminated view of the last error string.

      /// @remarks The returned view is only valid until the next call to a pcap function.

      char const* getLastError() const noexcept;

      /// @brief Sets a filter on the handle. Only packets that match the filter will be captured by the handle.

      ///

      /// The filter uses Berkeley Packet Filter (BPF) syntax (http://biot.com/capstats/bpf.html).

      ///

      /// @param[in] filter The filter to set in Berkeley Packet Filter (BPF) syntax.

      /// @return True if the filter was set successfully, false otherwise.

      bool setFilter(std::string const& filter);

      /// @brief Clears the filter currently set on the handle.

      /// @return True if the filter was removed successfully or if no filter was set, false otherwise.

      bool clearFilter();

      /// @brief Retrieves statistics from the pcap handle.

      ///

      /// The function internally calls pcap_stats() to retrieve the statistics and only works on live devices.

      ///

      /// @param stats Structure to store the statistics.

      /// @return True if the statistics were retrieved successfully, false otherwise.

      bool getStatistics(PcapStats& stats) const;

      /// @return True if the handle is not null, false otherwise.

      explicit operator bool() const noexcept

      {

        return isValid();

      }

      bool operator==(std::nullptr_t) const noexcept

      {

        return !isValid();

      }

      bool operator!=(std::nullptr_t) const noexcept

      {

        return isValid();

      }

    private:

      pcap_t* m_PcapDescriptor = nullptr;

    };

  }  // namespace internal

  /// @brief An interface for providing Pcap-based device statistics

  class IPcapStatisticsProvider

  {

  public:

    virtual ~IPcapStatisticsProvider() = default;

    using PcapStats = internal::PcapStats;

    /// @brief Get statistics from the device

    /// @return An object containing the stats

    PcapStats getStatistics() const;

    /// Get statistics from the device

    /// @param[out] stats An object containing the stats

    virtual void getStatistics(PcapStats& stats) const = 0;

  };

  /// @class IPcapDevice

  /// An abstract class representing all libpcap-based packet capturing devices: files, libPcap, WinPcap/Npcap and

  /// RemoteCapture. This class is abstract and cannot be instantiated

  class IPcapDevice : public IDevice, public IFilterableDevice, public IPcapStatisticsProvider

  {

  protected:

    internal::PcapHandle m_PcapDescriptor;

    // c'tor should not be public

    IPcapDevice() : IDevice()

    {}

  public:

    virtual ~IPcapDevice() = default;

    /// A static method for retrieving pcap lib (libpcap/WinPcap/etc.) version information. This method is actually

    /// a wrapper for [pcap_lib_version()](https://www.tcpdump.org/manpages/pcap_lib_version.3pcap.html)

    /// @return A string containing the pcap lib version information

    static std::string getPcapLibVersionInfo();

    /// Match a raw packet with a given BPF filter. Notice this method is static which means you don't need any

    /// device instance in order to perform this match

    /// @param[in] filter A filter class to test against

    /// @param[in] rawPacket A pointer to the raw packet to match the filter with

    /// @return True if raw packet matches the filter or false otherwise

    static bool matchPacketWithFilter(GeneralFilter& filter, RawPacket* rawPacket);

    // implement abstract methods

    using IFilterableDevice::setFilter;

    /// Set a filter for the device. When implemented by the device, only packets that match the filter will be

    /// received. Please note that when the device is closed the filter is reset so when reopening the device you

    /// need to call this method again in order to reactivate the filter

    /// @param[in] filterAsString The filter to be set in Berkeley Packet Filter (BPF) syntax

    /// (http://biot.com/capstats/bpf.html)

    /// @return True if filter set successfully, false otherwise

    bool setFilter(std::string filterAsString) override;

    /// Clear the filter currently set on device

    /// @return True if filter was removed successfully or if no filter was set, false otherwise

    bool clearFilter() override;

  };

}  // namespace pcpp