#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include <string.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/time.h>
#include <sys/select.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <netdb.h>

#define MYPORT "20444"  // the port users will be connecting to
#define MAXBUFLEN 1024 //maximum packet length
#define SERVER_R 142.66.140.13 //Server to the "right" of current
#define RTEX_R_PORT "20445" //Port for routing table exchange

typedef enum {false, true} bool;

/*struct to store packet fields into
  seq: sequence number;
  type: message type; send get ACK
  src: client's unique 10 digit number
  dst: destination's unique 10 digit number
  payload: the message being transferred, if there is any
*/
struct packet
{
   char seq[4];
   char type[5];
   char src[11];
   char dst[11];
   char payload[MAXBUFLEN];
};

// get sockaddr, IPv4 or IPv6:
void *get_in_addr(struct sockaddr *sa)
{
    if (sa->sa_family == AF_INET) {
        return &(((struct sockaddr_in*)sa)->sin_addr);
    }

    return &(((struct sockaddr_in6*)sa)->sin6_addr);
}

int main(void)
{
   //rr: reading from server to the "right"
   //rw: writing to the server to the "right"
   int sockfd, rtex_rr_sockfd, rtex_rw_sockfd, rv, rrr, rrw, numbytes, i, j, first, max_fd;
   struct addrinfo hints, *servinfo, *p, *p2, *p3;
   struct sockaddr_storage their_addr, right_addr;
   fd_set readfds, writefds;
   char buf[MAXBUFLEN];
   char temp_buf[MAXBUFLEN];
   char d_to_s[MAXBUFLEN];
   char *field;
   socklen_t addr_len;
   char s[INET6_ADDRSTRLEN];
   FILE *m_storage;
   struct packet inet_packet;
   static const struct packet EmptyPacket;
   static int rt[51][4];
   bool re_exists=false;
   bool rt_empty=true;
   struct timeval tv;

   memset(&hints, 0, sizeof hints);//"zero out" the hints struct
   hints.ai_family = AF_UNSPEC; // set to AF_INET to force IPv4
   hints.ai_socktype = SOCK_DGRAM;
   hints.ai_flags = AI_PASSIVE; // use my IP

   //prepare socket address structures and store them in servinfo and store in linked list
   if ((rv = getaddrinfo(NULL, MYPORT, &hints, &servinfo)) != 0) {
      fprintf(stderr, "getaddrinfo: %sn", gai_strerror(rv));
      return 1;
   }

   // loop through all the results and bind to the first we can
   for(p = servinfo; p != NULL; p = p->ai_next) {
      if ((sockfd = socket(p->ai_family, p->ai_socktype,
               p->ai_protocol)) == -1) {
     perror("listener: socket");
     continue;
      }

      if (bind(sockfd, p->ai_addr, p->ai_addrlen) == -1) {
     close(sockfd);
     perror("listener: bind");
     continue;
      }

      break;
   }

   if (p == NULL) {
      fprintf(stderr, "listener: failed to bind socketn");
      return 2;
   }

   if ((rrr = getaddrinfo(NULL, RTEX_R_PORT, &hints, &servinfo)) != 0) {
      fprintf(stderr, "getaddrinfo: %sn", gai_strerror(rrr));
      return 1;
   }

   for(p2 = servinfo; p2 != NULL; p2 = p2->ai_next) {
      if ((rtex_rr_sockfd = socket(p2->ai_family, p2->ai_socktype,
               p2->ai_protocol)) == -1) {
     perror("listener: socket");
     continue;
      }

      if (bind(rtex_rr_sockfd, p2->ai_addr, p2->ai_addrlen) == -1) {
     close(rtex_rr_sockfd);
     perror("listener: bind");
     continue;
      }
      break;
   }

   if (p2 == NULL) {
      fprintf(stderr, "listener: failed to bind socketn");
      return 2;
   }

   if((rrw = getaddrinfo(NULL, RTEX_R_PORT, &hints, &servinfo)) != 0) {
      fprintf(stderr, "getaddrinfo: %sn", gai_strerror(rrw));
      return 1;
   }

   for(p3 = servinfo; p3 != NULL; p3 = p3->ai_next) {
      if((rtex_rw_sockfd = socket(p3->ai_family, p3->ai_socktype,
                  p3->ai_protocol)) == -1) {
     perror("server: socket");
     continue;
      }
      break;
   }

   if (p3 == NULL) {
      fprintf(stderr, "listener: failed to bind socketn");
      return 2;
   }

   //free up memory no longer needed after binding has completed
   freeaddrinfo(servinfo);

   FD_ZERO(&readfds);
   FD_ZERO(&writefds);
   FD_SET(rv, &readfds);
   FD_SET(rrr, &readfds);
   FD_SET(rrw, &writefds);

   printf("Listen Moden");

   //main while loop, listens for packets.
   //Upon receipt of packet, information is stored in a struct for processing.
   first=0;
   while(1)
   {
      i=0;
      inet_packet = EmptyPacket;
      rt_empty=true;
      tv.tv_sec = 50;
if(rv > rrr && rv > rrw)
     max_fd = (rv + 1);
      else if(rrr > rv && rrr > rrw)
     max_fd = (rrr + 1);
      else if(rrw > rv && rrw > rrr)
     max_fd = (rrw + 1);

      printf("before select...n");
      select(max_fd, &readfds, &writefds, NULL, NULL);
      printf("after select...n");
      addr_len = sizeof their_addr;

      if(FD_ISSET(rv, &readfds))
      {
     printf("rv is set...n");
     if((numbytes = recvfrom(sockfd, buf, sizeof(buf), 0,
                 (struct sockaddr *)&their_addr, &addr_len)) == -1) {
        perror("recvfrom");
        exit(1);
     }
      } else if(FD_ISSET(rrr, &readfds))
      {
     printf("rr read is set...n");
     if((numbytes = recvfrom(rtex_rr_sockfd, buf, sizeof(buf), 0,
                  (struct sockaddr *)&right_addr, &addr_len)) == -1) {
        perror("recvfrom");
        exit(1);
     }
      } else if(FD_ISSET(rrw, &writefds))
      {
     printf("rr write is set...n");
     if((numbytes = sendto(rtex_rw_sockfd, inet_packet.payload, sizeof(inet_packet.payload),
                   0, p3->ai_addr, p3->ai_addrlen)) == -1) {
        perror("sendto rr");
        exit(1);
     }
  }