/* Copyright (C) 2003  Martin J. Muench <mjm@codito.de> */

#include "config.h"
#include "chat.h"
#include "curses.h"
#include "sendicmp.h"
#include "cipherwrap.h"
#include "wrap.h"

static void chat_abort(const char *, ...);

extern WINDOW *input, *output;

int
chat(int rawsock,
     const char *host, 
     const char *nick, 
     int icmptype, 
     const unsigned char *key)
{
  /* generic stuff */
  int icmpseq=4, auth=0, af=0;
  unsigned char *payload=NULL;
  unsigned char buf[1024];
  char hostnick[16],   /* nick of chatpartner */
       text[CIPHERBUF-strlen(SID)]; /* plaintext buffer, fuck C89 ;) */
  fd_set readset; /* select handle */
  struct icmp *icmp=NULL;
  struct ip   *ip=NULL;

  memset(hostnick, 0, sizeof(hostnick));

  wprintw(output, ">>> Connecting to %s...\n", host);
  wrefresh(output);

  if(!encipher_send(rawsock, host, icmptype, icmpseq, key, "%s", PING)) 
  {
    chat_abort("Error in encipher_send()");
    return 0;
  }

  FD_ZERO(&readset);

  /* Start main chat */
  while(1)
  {
    FD_SET(rawsock, &readset);
    FD_SET(STDIN_FILENO, &readset);

    if(select(rawsock + 1, &readset, NULL, NULL, NULL) < 0)
    {
      chat_abort("Select failed: %s", strerror(errno));
      return 0;
    }

    /* Check for data on rawsock handle */
    if (FD_ISSET(rawsock, &readset))
    {

      memset(buf, 0, sizeof(buf));
      /* no cast for af, some systems do not have socklen_t */
      if (recvfrom(rawsock,buf,sizeof(buf)-1,0,(struct sockaddr *)&saddr,&af) < 0)
      {
	chat_abort("Recvfrom failed: %s", strerror(errno));
	return 0;
      }

      ip=(struct ip *)buf;
      icmp=(struct icmp *)(buf + sizeof(struct ip));

      if(ip == NULL || icmp == NULL)
	continue;

      /* 
       * If packet has our icmpseq it is probably a kernel reply
       * to one of our *_request packets and should be ignored 
       */
      if(auth > 0) 
      {
	if(icmp->icmp_seq == icmpseq)
	  continue;
      }

#ifdef DEBUG
      debug("Received valid packet from '%s' with icmp_type %d",
            inet_ntoa(ip->ip_src), icmp->icmp_type);
#endif
      
      payload = buf + sizeof(struct ip) + sizeof(struct icmp);
      if(payload == NULL)
	continue;
      
      if(!decipher_string(key, (unsigned char *)text, payload))
	continue;

      /* Received authentication request */
      if(!strcmp(text,PING) && (!auth || auth == 1))
      {

#ifdef DEBUG
	debug("Received authentication request from '%s'", 
	      inet_ntoa(ip->ip_src));
#endif

	/* Send authentication reply*/
	icmpseq=5;
	if(!encipher_send(rawsock, host, icmptype, icmpseq, key, "%s", PONG))
	{
	  chat_abort("encipher_send() failed.");
	  return 0;
	}
	auth=1;

        if(!encipher_send(rawsock, host, icmptype, icmpseq, key, "/hnick %s", nick))
	{
	  chat_abort("encipher_send() failed.");
	  return 0;
	}
      }
      /* Received authentication reply */
      else if(!strcmp(text,PONG) && (!auth || auth==1) && icmp->icmp_seq != icmpseq)
      {
#ifdef DEBUG
	debug("Received authentication reply from '%s'", 
	      inet_ntoa(ip->ip_src));
#endif

	if (!auth)
	{
	  icmpseq=4;

	  if(!encipher_send(rawsock, host, icmptype, icmpseq, key, "%s", PONG))
	  {
	    chat_abort("encipher_send() failed.");
	    return 0;
	  }

	  if(!encipher_send(rawsock, host, icmptype, icmpseq, key, "/hnick %s", nick))
	  {
	    chat_abort("encipher_send() failed.");
	    return 0;
	  }

	}
	auth=2;
      }

      /* Received special packet (leading '/') */
      else if(text[0] == '/')
      {
	if(!strncmp(text, "/quit", strlen("/quit")))
	{
	  wprintw(output, ">>> %s has left the chat\n", hostnick);
	  wrefresh(output);
	  /* reset authentication indicator */
	  auth=0;
	}

	/* Other side set nickname (first time) */
	else if(!strncmp(text, "/hnick", strlen("/hnick")))
	{
	  memset(hostnick, 0, sizeof(hostnick));
	  strncpy(hostnick, text + strlen("/hnick "), sizeof(hostnick)-1);
	  wprintw(output, ">>> %s is connected\n", hostnick);
	  wrefresh(output);
	}

	/* Other side changed nickname */
	else if(!strncmp(text, "/setname", strlen("/setname")))
	{
	  wprintw(output, ">>> %s is now known as %s\n", 
		  hostnick, text+strlen("/setname "));
	  wrefresh(output);
	  memset(hostnick, 0, sizeof(hostnick));
	  strncpy(hostnick, text + strlen("/setname "), sizeof(hostnick)-1);
	}
      }

      /* normal text, print */
      else if (auth)
      {	
	wprintw(output, "::: %s : %s\n", hostnick, text);
	wrefresh(output);
      }
    }


    /* Check for data on stdin */
    else if (FD_ISSET(STDIN_FILENO, &readset))
    {

      memset(text, 0, sizeof(text));
      if(wgetnstr(input, text, sizeof(text)-1) == ERR)
      {
	chat_abort("wgetnstr failed: %s\n", strerror(errno));
	return 0;
      }

      /* command detection */
      if(text[0] == '/')
      {
	/* user requests exit */
     	if(!strncmp(text, "/quit", strlen("/quit")))
	{

	  if(!encipher_send(rawsock, host, icmptype, icmpseq, key, "/quit"))
	  {
	    chat_abort("encipher_send() failed.");
	    return 0;
	  }
	  return 1;
	}
	/* user changes nickname */
	else if(!strncmp(text, "/setname", strlen("/setname")))
	{
	  if(!encipher_send(rawsock, host, icmptype, icmpseq, key, "%s", text))
	  {
	    chat_abort("encipher_send() failed.");
	    return 0;
	  }

	}

	/* change of icmp type */
        else if(!strncmp(text, "/setcode", strlen("/setcode")))
	{
	  icmptype=atoi(text+strlen("/setcode "));
	  wprintw(output, ">>> You are now using icmp_type %d\n", icmptype);
	  wrefresh(output);
	}
	/* display help screen */
        else if(!strncmp(text, "/help", strlen("/help")))
	{
          wprintw(output, "%s", HELP);
	  wrefresh(output);
	}
        else
	{
	  wprintw(output, ">>> Unknown command: %s\n", text);
	  wrefresh(output);
	}
      }

      /* Normal text, send to host */
      else
      {
	wprintw(output, "::: %s : %s\n", nick, text);
	wrefresh(output);

        if(!encipher_send(rawsock, host, icmptype, icmpseq, key, "%s", text))
	{
	  chat_abort("encipher_send() failed.");
	  return 0;
	}
      }

      /* Clear Input */
      werase(input);  
      wmove(input, 0, 0);
      wrefresh(input);

    } /* FD_ISSET */
  } /* while(1) */
  return 1;
}

static void 
chat_abort(const char *fmt, ...)
{
  char buffer[512];
  va_list ap;

  end_curses();

  memset(buffer, 0, sizeof(buffer));
  va_start(ap, fmt);
  vsnprintf(buffer, sizeof(buffer)-1, fmt, ap);
  va_end(ap);  
  fprintf(stderr, ">>> %s\n", buffer);
}