/**
 * This is an asynchronous protocol driver for the protocol of 
 * the Phytron MCC-2 motor controller. 
 * The send format is:
 *   <STX> DATA <ETX>
 * the reply format is:
 *   <STX> NACK | ACK |& REPLY <ETX>
 * 
 * copyright: see file COPYRIGHT
 * 
 * Mark Koennecke, June 2009
 */
#include <errno.h>
#include <ascon.h>
#include <ascon.i>
#include <dynstring.h>

#define STX   '\2'
#define ETX   '\3'
#define NACK  '\5'
#define ACK   '\6'

/*---------------------------------------------------------------------------*/
static int PhytronHandler(Ascon * a)
{
  char *data = NULL;
  int ret, l;
  char chr;


  switch (a->state) {
  case AsconWriteStart:
	DynStringInsert(a->wrBuffer,"\2",0);
	DynStringConcatChar(a->wrBuffer,ETX);
	a->state = AsconWriting;
	a->wrPos = 0;
    break;
  case AsconReading:
    ret = AsconReadChar(a->fd, &chr);
    if (ret < 0) {
      /* EINTR means we must retry */
      if (errno != EINTR && errno != EAGAIN) {
        AsconError(a, "AsconReadChar failed:", errno);
      }
      return 1;
    } else if (ret > 0) {
    	if(chr == STX){
    		DynStringClear(a->rdBuffer);
    	} else if (chr == ACK){
    		DynStringConcat(a->rdBuffer,"ACK");
    	} else if(chr == NACK){
    		DynStringConcat(a->rdBuffer,"NACK");
    	} else if(chr == ETX){
    		a->state = AsconReadDone; 
    	} else {
    		DynStringConcatChar(a->rdBuffer,chr);
    	}
   } else if (ret == 0) {
      if (a->timeout > 0) {
        if (DoubleTime() - a->start > a->timeout) {
          AsconError(a, "read timeout", 0);
          a->state = AsconTimeout;
        }
      }
      return 0;
    }
    break;
  default:
	    return AsconStdHandler(a);
  }
  return 1;
}

/*------------------------------------------------------------------------*/
static int PhytronInit(Ascon * a, SConnection * con, int argc, char *argv[])
{
  a->fd = -1;
  a->state = AsconConnectStart;
  a->reconnectInterval = 10;
  a->hostport = strdup(argv[1]);
  if (argc > 2) {
    a->timeout = atof(argv[2]);
  } else {
    a->timeout = 2.0;           /* sec */
  }
  a->killPrivate = free;
  return 1;
}

/*------------------------------------------------------------------------*/
void AddPhytronProtocoll()
{
  AsconProtocol *prot = NULL;

  prot = calloc(sizeof(AsconProtocol), 1);
  prot->name = strdup("phytron");
  prot->init = PhytronInit;
  prot->handler = PhytronHandler;
  AsconInsertProtocol(prot);
}