#include <stdlib.h>
#include <stdio.h>
#include <time.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <string.h>

#define MAXLINE 4096   /*max text line length*/
#define SERV_PORT 3000 /*port*/
#define LISTENQ 900000 /*maximum number of client connections*/

int main(int argc, char **argv)
{
  int listenfd, connfd, n;
  pid_t childpid;
  socklen_t clilen;
  char buf[MAXLINE];
  struct sockaddr_in cliaddr, servaddr;

  //Create a socket for the soclet
  //If sockfd<0 there was an error in the creation of the socket
  if ((listenfd = socket(AF_INET, SOCK_STREAM, 0)) < 0)
  {
    perror("Problem in creating the socket");
    exit(2);
  }

  //preparation of the socket address
  servaddr.sin_family = AF_INET;
  servaddr.sin_addr.s_addr = htonl(INADDR_ANY);
  servaddr.sin_port = htons(SERV_PORT);

  //bind the socket
  bind(listenfd, (struct sockaddr *)&servaddr, sizeof(servaddr));

  //listen to the socket by creating a connection queue, then wait for clients
  listen(listenfd, LISTENQ);

  printf("%s\n", "Server running...waiting for connections.");

  for (;;)
  {

    clilen = sizeof(cliaddr);
    //accept a connection
    connfd = accept(listenfd, (struct sockaddr *)&cliaddr, &clilen);

    printf("%s\n", "Received request...");

    if ((childpid = fork()) == 0)
    { //if it’s 0, it’s child process

      printf("%s\n", "Child created for dealing with client requests");

      //close listening socket
      close(listenfd);

      while ((n = recv(connfd, buf, MAXLINE, 0)) > 0)
      {
        char msg[17] = "What is the time";
        char *ret = strstr(buf, msg);
        // char *message = ("%s", buf);
        // printf("%s\n", strstr(buf, msg));
        printf("%s", "String received from and resent to the client:");
        puts(buf);

        if (ret) //f the string inputed is indeed "What is the time?"
        {
          // variables to store date and time components
          int hours, minutes, seconds, day, month, year;

          // time_t is arithmetic time type
          time_t now;

          // Obtain current time
          // time() returns the current time of the system as a time_t value
          time(&now);

          // Convert to local time format and print to stdout
          // char *hello_world;
          // Prints "Hello world!" on hello_world
          // sprintf(hello_world, "Today is : %s", ctime(&now));

          printf("Today is : %s", ctime(&now));

          send(connfd, ctime(&now), 30, 0);
        }
        else
        {
          send(connfd, buf, n, 0); //else just return the string
        }
      }

      if (n < 0)
        printf("%s\n", "Read error");
      exit(0);
    }
    //close socket of the server
    close(connfd);
  }
}