#ifndef ARP_H
#define ARP_H

#include <QThread>
#include <pcap.h>
#include <arpa/inet.h>
#include <netinet/if_ether.h>
#include <netinet/ip.h>
#include <net/if.h>
#include <sys/ioctl.h>
#include <netinet/ether.h>
#include <sys/socket.h>
#include <QString>
#include <QStringList>
#include <QDateTime>
#include <sys/time.h>

/* default snap length (maximum bytes per packet to capture) */
#define SNAP_LEN 1518

/* Definitions of codes used in operation field of ARP packet */
#define	ARP_AR_REQUEST      1	/* ARP request to resolve address	*/
#define	ARP_AR_REPLY        2	/* reply to a resolve request		*/
#define	ARP_RA_REQUEST      3	/* reverse ARP request (RARP packets)	*/
#define	ARP_RA_REPLY        4	/* reply to a reverse request (RARP ")	*/
#define ARP_DRARP_REQUEST   5   /* RFC 1931 */
#define ARP_DRARP_REPLY     6   /* RFC 1931 */
#define ARP_DRARP_ERROR     7   /* RFC 1931 */
#define ARP_INARP_REQUEST   8   /* RFC 1293 */
#define ARP_INARP_REPLY     9	/* RFC 1293 */
#define ARP_ARP_NAK         10  /* RFC 1577 */
#define ARP_MARS_REQUEST    11
#define ARP_MARS_MULTI      12
#define ARP_MARS_MSERV      13
#define ARP_MARS_JOIN       14
#define ARP_MARS_LEAVE      15
#define ARP_MARS_NAK        16
#define ARP_MARS_UNSERV     17
#define ARP_MARS_SJOIN      18
#define ARP_MARS_SLEAVE     19
#define ARP_MARS_GROUPLIST_REQUEST  20
#define ARP_MARS_GROUPLIST_REPLY    21
#define ARP_MARS_REDIRECT_MAP       22
#define ARP_MAPOS_UNARP     23  /* RFC 2176 */
#define ARP_OP_EXP1         25  /* RFC 5494 */
#define ARP_OP_EXP2         26

/* definition of MAC and IP address size */
#ifndef ETH_ALEN
    #define ETH_ALEN 6
#endif
#ifndef IP_ALEN
    #define IP_ALEN 4
#endif

/* definition of protocols */
#define HW_TYPE_ETHERNET 0x0001
#define PROTO_TYPE_IP 0x0800

/* ARP Header Structure */
struct arp_header
{
    u_int16_t hw_type; // hardware type
    u_int16_t proto_type; // protocol type
    u_int8_t ha_len; // hardware address length
    u_int8_t pa_len; // protocol address length
    u_int16_t opcode; // arp opcode
    u_int8_t source_add[ETH_ALEN]; // source mac
    unsigned char source_ip[IP_ALEN]; // source ip
    u_int8_t dest_add[ETH_ALEN]; // destination mac
    unsigned char dest_ip[IP_ALEN]; // destination ip
};

/* Custom struct for signal */
typedef struct {
    QDateTime time;
    QString ether_mac_src;
    QString ether_mac_dst;
    int arp_operation;
    QString arp_mac_src;
    QString arp_ip_src;
    QString arp_mac_dst;
    QString arp_ip_dst;

} arp_t;

class Arp : public QThread
{
    Q_OBJECT

public:
    Arp();
    ~Arp();
    /* Starts receiving arp packets on device in parameter */
    bool start(QString device);
    /* Stops receiving arp packets */
    void stop();
    /* Return list of devices on computer */
    QStringList getDeviceList();
    /* Return true if is receiving packets */
    bool isRunning();
    /* Send arp packet descreibing in parameter */
    bool sendArp(const arp_t &data);
    /* Copy content of arp_t struct */
    static void copyArp_t(arp_t *dst, const arp_t &src);
    /* Return textual information of arp opcode */
    static QString arpOperationtoQString(int arp_operation);
    /* Return description of the arp_t struct */
    static QString arp_tToQString(const arp_t &packet);
    /* Return MAC address on selected device */
    QString mac();
    /* Return IP address on selected device */
    QString ip();
    /* Return IP mask address on selected device */
    QString ipMask();
    /* Return IP broadcast address on selected device */
    QString ipBcast();
    /* Return first usable IP address on selected device */
    QString ipFrom();
    /* Return last usable IP address on selected device */
    QString ipTo();
    /* Return last error message */
    QString lastError();
    /* Convert 6 bytes representation of MAC to QString */
    static QString macToQString(const u_int8_t *pbyMacAddressInBytes);
    /* Convert 4 bytes representation of IP to QString */
    static QString ipToQString(const unsigned char *pbyIPAddressInBytes);
    /* Convert QString to 6 bytes representation of MAC */
    static u_int8_t* QStringToMac(QString mac);
    /* Convert QString to 4 bytes representation of IP */
    static u_int8_t* QStringToIp(QString ip);

signals:
    /* ARP packet received */
    void received(arp_t packet);
    /* ARP packet with opcode Request received */
    void requestArp(arp_t packet);
    /* ARP packet with opcode Reply received */
    void replyArp(arp_t packet);
    /* ARP packet with opcode Request reverse received */
    void requestRArp(arp_t packet);
    /* ARP packet with opcode Reply reverse received */
    void replyRArp(arp_t packet);

private:
    void parsePacket(const struct pcap_pkthdr *header, const u_char *packet);
    void run();
    void fillIfInfo();

    pcap_t *handle;
    struct bpf_program fp;
    bool terminated;
    char *device;
    char *errbuf;
    unsigned char _ip[IP_ALEN];
    unsigned char _ipMask[IP_ALEN];
    unsigned char _ipBcast[IP_ALEN];
};

#endif // ARP_H