/*
 *  aim_txqueue.c
 *
 * Herein lies all the mangement routines for the transmit (Tx) queue.
 *
 */

#include <faim/aim.h>

/*
 * aim_tx_enqeue()
 *
 * The overall purpose here is to enqueue the passed in command struct
 * into the outgoing (tx) queue.  Basically...
 *   1) Make a scope-irrelevent copy of the struct
 *   2) Lock the struct
 *   3) Mark as not-sent-yet
 *   4) Enqueue the struct into the list
 *   5) Unlock the struct once it's linked in
 *   6) Return
 *
 */

int aim_tx_enqueue(struct aim_session_t *sess,
		   struct command_tx_struct *newpacket)
{
  struct command_tx_struct *workingPtr = NULL;
  struct command_tx_struct *newpacket_copy = NULL;

  if (newpacket->conn == NULL)
    {
      printf("aim_tx_enqueue: WARNING: enqueueing packet with no connecetion,  defaulting to BOS\n");
      newpacket->conn = aim_getconn_type(sess, AIM_CONN_TYPE_BOS);
    }
 
  newpacket_copy = (struct command_tx_struct *) malloc (sizeof(struct command_tx_struct));
  memcpy(newpacket_copy, newpacket, sizeof(struct command_tx_struct));

  /* assign seqnum */
  newpacket_copy->seqnum = aim_get_next_txseqnum(newpacket_copy->conn);
  /* set some more fields */
  newpacket_copy->lock = 1; /* lock */
  newpacket_copy->sent = 0; /* not sent yet */
  newpacket_copy->next = NULL; /* always last */

  if (sess->queue_outgoing == NULL)
    {
      sess->queue_outgoing = newpacket_copy;
    }
  else
    {
      workingPtr = sess->queue_outgoing;
      while (workingPtr->next != NULL)
	workingPtr = workingPtr->next;
      workingPtr->next = newpacket_copy;
    }

  newpacket_copy->lock = 0; /* unlock so it can be sent */

#if debug > 2
  printf("calling aim_tx_printqueue()\n");
  aim_tx_printqueue();
  printf("back from aim_tx_printqueue()\n");
#endif

  /* we'll force a flush for now -- this behavior probably will change */
#if debug > 1
  printf("calling aim_tx_flushqueue()\n");
#endif
  aim_tx_flushqueue(sess);
#if debug > 1
  printf("back from aim_tx_flushqueue()\n");
#endif

  return 0;
}

/* 
 *  aim_get_next_txseqnum()
 *
 *   This increments the tx command count, and returns the seqnum
 *   that should be stamped on the next FLAP packet sent.  This is
 *   normally called during the final step of packet preparation
 *   before enqueuement (in aim_tx_enqueue()).
 *
 */
u_int aim_get_next_txseqnum(struct aim_conn_t *conn)
{
  return ( ++conn->seqnum );
}

/*
 *  aim_tx_printqueue()
 *
 *  This is basically for debuging purposes only.  It dumps all the
 *  records in the tx queue and their current status.  Very helpful
 *  if the queue isn't working quite right.
 *
 */
#if debug > 2
int aim_tx_printqueue(void)
{
  struct command_tx_struct *workingPtr = NULL;

  workingPtr = sess->queue_outgoing;
#if debug > 2
  printf("\ncurrent aim_queue_outgoing...\n");
  printf("\ttype seqnum  len  lock sent\n");  
#endif
  if (workingPtr == NULL)
    printf("aim_tx_flushqueue(): queue empty");
  else
    {
      while (workingPtr != NULL)
	{
	  printf("\t  %2x   %4x %4x   %1d    %1d\n", workingPtr->type, workingPtr->seqnum, workingPtr->commandlen, workingPtr->lock, workingPtr->sent);
	  
	  workingPtr = workingPtr->next;
	}
    }

  printf("\n(done printing queue)\n");
  
  return 0;
}
#endif

/*
 *  aim_tx_flushqueue()
 *
 *  This the function is responsable for putting the queued commands
 *  onto the wire.  This function is critical to the operation of 
 *  the queue and therefore is the most prone to brokenness.  It
 *  seems to be working quite well at this point.
 *
 *  Procedure:
 *    1) Traverse the list, only operate on commands that are unlocked
 *       and haven't been sent yet.
 *    2) Lock the struct
 *    3) Allocate a temporary buffer to store the finished, fully
 *       processed packet in.
 *    4) Build the packet from the command_tx_struct data.
 *    5) Write the packet to the socket.
 *    6) If success, mark the packet sent, if fail report failure, do NOT
 *       mark the packet sent (so it will not get purged and therefore
 *       be attempted again on next call).
 *    7) Unlock the struct.
 *    8) Free the temp buffer
 *    9) Step to next struct in list and go back to 1.
 *
 */
int aim_tx_flushqueue(struct aim_session_t *sess)
{
  struct command_tx_struct *workingPtr = NULL;
  u_char *curPacket = NULL;
#if debug > 1
  int i = 0;
#endif

  workingPtr = sess->queue_outgoing;
#if debug > 1
  printf("beginning txflush...\n");
#endif
  while (workingPtr != NULL)
    {
      /* only process if its unlocked and unsent */
      if ( (workingPtr->lock == 0) &&
	   (workingPtr->sent == 0) )
	{

	  /*
	   * And now for the meager attempt to force transmit
	   * latency and avoid missed messages.
	   */
	  if ((workingPtr->conn->lastactivity + workingPtr->conn->forcedlatency) 
	      >= time(NULL))
	    {
	      /* FIXME FIXME -- should be a break! we dont want to block the upper layers */
	      sleep((workingPtr->conn->lastactivity + workingPtr->conn->forcedlatency) - time(NULL));
	    }

	  workingPtr->lock = 1; /* lock the struct */
	  
	  /* allocate full-packet buffer */
	  curPacket = (char *) malloc(workingPtr->commandlen + 6);
	  
	  /* command byte */
	  curPacket[0] = 0x2a;

	  /* type/family byte */
	  curPacket[1] = workingPtr->type;

	  /* bytes 3+4: word: FLAP sequence number */
	  aimutil_put16(curPacket+2, workingPtr->seqnum);

	  /* bytes 5+6: word: SNAC len */
	  aimutil_put16(curPacket+4, workingPtr->commandlen);

	  /* bytes 7 and on: raw: SNAC data */
	  memcpy(&(curPacket[6]), workingPtr->data, workingPtr->commandlen);
	  
	  /* full image of raw packet data now in curPacket */
	  if ( (u_int)write(workingPtr->conn->fd, curPacket, (workingPtr->commandlen + 6)) != (workingPtr->commandlen + 6))
	    {
	      printf("\nWARNING: Error in sending packet 0x%4x -- will try again next time\n\n", workingPtr->seqnum);
	      workingPtr->sent = 0; /* mark it unsent */
	      return -1;  /* bail out */
	    }
	  else
	    {
#if debug > 2
	      printf("\nSENT 0x%4x\n\n", workingPtr->seqnum);
#endif
	      workingPtr->sent = 1; /* mark the struct as sent */
	      workingPtr->conn->lastactivity = time(NULL);
	    }
#if debug > 2
	  printf("\nPacket:");
	  for (i = 0; i < (workingPtr->commandlen + 6); i++)
	    {
	      if ((i % 8) == 0)
		printf("\n\t");
	      if (curPacket[i] >= ' ' && curPacket[i]<127)
		 printf("%c=%02x ",curPacket[i], curPacket[i]);
	      else
		 printf("0x%2x ", curPacket[i]);
	    }
	  printf("\n");
#endif
	  workingPtr->lock = 0; /* unlock the struct */
	  free(curPacket); /* free up full-packet buffer */
	}
      workingPtr = workingPtr->next;
    }

  /* purge sent commands from queue */
  /*   this may not always occur explicitly--i may put this on a timer later */
#if debug > 1
  printf("calling aim_tx_purgequeue()\n");
#endif
  aim_tx_purgequeue(sess);
#if debug > 1
  printf("back from aim_tx_purgequeu() [you must be a lucky one]\n");
#endif

  return 0;
}

/*
 *  aim_tx_purgequeue()
 *  
 *  This is responsable for removing sent commands from the transmit 
 *  queue. This is not a required operation, but it of course helps
 *  reduce memory footprint at run time!  
 *
 */
int aim_tx_purgequeue(struct aim_session_t *sess)
{
  struct command_tx_struct *workingPtr = NULL;
  struct command_tx_struct *workingPtr2 = NULL;
#if debug > 1
  printf("purgequeue(): starting purge\n");
#endif
  /* Empty queue: nothing to do */
  if (sess->queue_outgoing == NULL)
    {
#if debug > 1
      printf("purgequeue(): purge done (len=0)\n");
#endif
      return 0;
    }
  /* One Node queue: free node and return */
  else if (sess->queue_outgoing->next == NULL)
    {
#if debug > 1
      printf("purgequeue(): entered case len=1\n");
#endif
      /* only free if sent AND unlocked -- dont assume sent structs are done */
      if ( (sess->queue_outgoing->lock == 0) &&
	   (sess->queue_outgoing->sent == 1) )
	{
#if debug > 1
	  printf("purgequeue(): purging seqnum 0x%04x\n", aim_queue_outgoing->seqnum);
#endif
	  workingPtr2 = sess->queue_outgoing;
	  sess->queue_outgoing = NULL;
	  free(workingPtr2->data);
	  free(workingPtr2);
	}
#if debug > 1
      printf("purgequeue(): purge done (len=1)\n");
#endif
      return 0;
    }
  else
    {
#if debug > 1
      printf("purgequeue(): entering case len>1\n");
#endif
      while(workingPtr->next != NULL)
	{
	  if ( (workingPtr->next->lock == 0) &&
	       (workingPtr->next->sent == 1) )
	    {
#if debug > 1
	      printf("purgequeue(): purging seqnum 0x%04x\n", workingPtr->next->seqnum);
#endif
	      workingPtr2 = workingPtr->next;
	      workingPtr->next = workingPtr2->next;
	      free(workingPtr2->data);
	      free(workingPtr2);
	    }
	}
#if debug > 1
      printf("purgequeue(): purge done (len>1)\n");
#endif
      return 0;
    }

  /* no reach */
}