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

int main(int argc, char * argv[])
{ 
  int s = socket(AF_INET, SOCK_STREAM, 0);
  if (s < 0)
  { perror("socket");
    exit(1); }
  printf("socket s is %d\n", s);

  struct sockaddr_in server_address;
  server_address.sin_len = sizeof(server_address);
  server_address.sin_family = AF_INET;
  server_address.sin_port = htons(atol(argv[1]));
  server_address.sin_addr.s_addr = htonl(INADDR_ANY);

  int r = bind(s, (struct sockaddr *) & server_address, sizeof(server_address));
  if (r < 0)
  { perror("bind");
    exit(1); }

  r = listen(s, 3);
  if (r < 0)
  { perror("listen");
    exit(1); }

  while (1)
  { struct sockaddr_in client_address;
    socklen_t size = sizeof(client_address);
    int cs = accept(s, (struct sockaddr *) & client_address, & size);
    if (cs < 0)
    { printf("it happened\n");
      sleep(1);
      continue; }
    printf("socket cs is %d\n", cs);
    int ipi = client_address.sin_addr.s_addr;
    unsigned char * ip = (unsigned char *) & ipi;
    printf("connection from %hhu.%hhu.%hhu.%hhu port %hu\n", ip[0], ip[1], ip[2], ip[3], ntohs(client_address.sin_port));
    printf("             or %s port %d\n", inet_ntoa(client_address.sin_addr), ntohs(client_address.sin_port));

    char received[1024];
    while (1)
    { r = read(cs, received, sizeof(received));
      printf("read returned %d\n", r);
      if (r <= 0)
        break;
      write(1, received, r); }

    const char * response = "HTTP/1.1 200 OK\r\nContent-Type: text/plain\r\n\r\n";
    write(cs, response, strlen(response));
    response = "hello\r\n";
    write(cs, response, strlen(response));

    close(cs); }

  close(s); }