/* ========================================================================== */
/*                                                                            */
/*   client.c                                                                 */
/*   (c) 2008 jocelyne.lecomte@alcatel-lucent.fr                              */
/*                                                                            */
/*   Description                                                              */
/*                                                                            */
/* ========================================================================== */
#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <string.h>

#include "client.h"

/*******************************************************************************/
/*  Initialize connection to one address/port */
/*******************************************************************************/
static int init_connection(const char *address, const int port, SOCKADDR_IN *sin)
{
  /* UDP protocol, so SOCK_DGRAM */
  SOCKET sock = socket(AF_INET, SOCK_DGRAM, 0);
  fprintf(stdout, "create socket\n");
  
  /* ERROR */
  if (sock == INVALID_SOCKET)
  {
    perror("socket()");
    exit(errno);
  }
  
  /* OK */
  struct hostent *hostinfo;
  hostinfo = gethostbyname(address);
  fprintf(stdout, "search for address\n");
  
  /* can't find host */
  if (hostinfo == NULL)
  {
    fprintf (stderr, "Unknown host %s.\n", address);
    exit(EXIT_FAILURE);
  }
  
  /* OK */
  sin->sin_addr = *(IN_ADDR *)hostinfo->h_addr;
  sin->sin_port = htons(port);
  sin->sin_family = AF_INET;
  fprintf(stdout, "socket OK\n");

  
  return sock;
}

/*******************************************************************************/
/*  close socket */
/*******************************************************************************/
static void end_connection(SOCKET sock)
{
  close(sock);
  fprintf(stdout, "close socket\n");

}

/*******************************************************************************/
/* read data from server */
/*******************************************************************************/
static int read_server(SOCKET sock, SOCKADDR_IN *sin, char *buffer)
{
  int n=0;
  size_t sinsize = sizeof *sin;
  /* error in reception */
  if ((n = recvfrom(sock, buffer, BUF_SIZE-1, 0, (SOCKADDR*)sin, &sinsize))<0)
  {
    perror("recvfrom()");
    exit(errno);
  }
  /* OK */
  fprintf(stdout, "read socket from server\n");
  buffer[n] = 0;
  return n;
}

/*******************************************************************************/
/* write data to server */
/*******************************************************************************/
static void write_server(SOCKET sock, SOCKADDR_IN *sin, const char* buffer)
{
   /* error in sending msg */
  if (sendto(sock, buffer, strlen(buffer), 0, (SOCKADDR*)sin, sizeof *sin)<0)
  {
    perror("sendto()");
    exit(errno);
  }
  fprintf(stdout, "write socket to server\n");

}

/*******************************************************************************/
/* etablish communication */
/*******************************************************************************/
void comm(const char *address, const int port)
{
  SOCKADDR_IN sin = {0};

  fprintf(stdout, "Comm function()\n");

  SOCKET sock = init_connection(address, port, &sin);
  
  char buffer[BUF_SIZE];
  fd_set readfs;
  char msg[30] = "Hello from Jocelyne !\n";
  fprintf(stdout, msg);
  
  write_server(sock, &sin, msg);
  
  while(1)
  {
    /* set the descripor to null */
    FD_ZERO(&readfs);

    /* add STDIN_FILENO */
    FD_SET(STDIN_FILENO, &readfs);
    
    /* add the socket */
    FD_SET(sock, &readfs);
    
    /* management of modication of descriptors */
    struct timeval timeout;
    timeout.tv_sec = 1;
    timeout.tv_usec = 01;
    
    if (select(sock+1, &readfs, NULL, NULL, &timeout)==-1)
    {
      perror("select()");
      exit(errno);
    }
    /* something from standard input */
    if (FD_ISSET(STDIN_FILENO, &readfs))
    {
      fgets(buffer, BUF_SIZE-1, stdin);
      {
        char *p = NULL;
        p = strstr(buffer, "\n");
        if (p != NULL)
        {
          *p = 0;
        }
        else
        {
          /* fclean */
          buffer[BUF_SIZE-1] = 0;
        }
      }
      write_server(sock, &sin, buffer);
    }
    else if (FD_ISSET(sock, &readfs))
    {
      int n=read_server(sock, &sin, buffer);
    
      /* if server is down */
      if (n==0)
      {
        printf("Server disconnected !\n");
        break;
      }
      puts(buffer);
    }
  }
  end_connection(sock);
}