/** @file Oxford protocol handler for script-context based controllers.
*
* If you 'send' commands to a oxford controller using this protocol you
* will get one of three possible responses,
* 1. A value
*   eg
* 2. An acknowledgement (ie 'OK')
*   eg
*     sct_mc2 send "MOG"
*     OK
* 3. An error message
*   eg
*     sct_mc2 send "BGG"
*     ASCERR: 20 Begin not valid with motor off (during read finished)
*/
#include <errno.h>
#include <ascon.h>
#include <ascon.i>
#include <dynstring.h>

enum {
  ProtocolOxford = 0,
  ProtocolHamilton = 1,
  ProtocolSyringe = 2
};

struct OxfordProtocol_t {
  unsigned int magic;
  Ascon* parent;
  double last_line_time;
  double last_char_time;
  double inter_line_time;
  double inter_char_time;
  int protocol_subtype;
};
typedef struct OxfordProtocol_t OxfordProtocol;

struct OxfordQProtocol_t {
  unsigned int magic;
  Ascon* parent;
  double last_line_time;
  double last_char_time;
  double inter_line_time;
  double inter_char_time;
};
typedef struct OxfordQProtocol_t OxfordQProtocol;

/** @brief Set line terminator before sending command
*/
int OxfordWriteStart(Ascon *a) {
  OxfordProtocol* private;
  double now;
  private = (OxfordProtocol*) a->private;
  assert(private->magic == 0xcafef00d);
  now = DoubleTime();
  if (now < private->last_line_time) {
    private->last_line_time = now;
  }
  private->last_char_time = now;
  /*
  if (now > private->last_line_time + private->inter_line_time) {
    return 1;
  }
  */
  DynStringConcat(a->wrBuffer,"\r");
  a->wrPos = 0;
  a->state = AsconWriting;
  /* if there is only the terminator, do not send it */
  if (GetDynStringLength(a->wrBuffer) <= 1) {
    a->state = AsconWriteDone;
  }
  return 1;
}

/** @brief Write the line one character at a time
*/
int OxfordWriting(Ascon *a) {
  OxfordProtocol* private;
  int ret;
  double now;
  private = (OxfordProtocol*) a->private;
  assert(private->magic == 0xcafef00d);
  now = DoubleTime();
  if (now < private->last_char_time) {
    private->last_char_time = now;
  }
  if (now < private->last_char_time + private->inter_char_time) {
    return 1;
  }
  if (a->wrPos == 0)
    AsconReadGarbage(a->fd);
  ret = AsconWriteChars(a->fd, GetCharArray(a->wrBuffer) + a->wrPos, 1);
  if (ret < 0) {
    AsconError(a, "send failed:", errno);
    /*
     * Ooops: which state shall we go to after a write fail?
     * This seems to retry.
     */
  } else {
    private->last_char_time = now;
    a->wrPos += ret;
    if (a->wrPos >= GetDynStringLength(a->wrBuffer)) {
      private->last_line_time = now;
      a->state = AsconWriteDone;
    }
  }
  return 1;
}

/** @brief Map oxford replies to OK, ASCERR: ..., value.
* You can use the first character to sort replies from a oxford controller
*/
int OxfordReading(Ascon *a) {
  int ret;
  char chr, ch[2];
  char* cp = NULL;
  char term;
  OxfordProtocol* private;

  private = (OxfordProtocol*) a->private;
  switch (private->protocol_subtype) {
  case ProtocolOxford:
  case ProtocolHamilton:
    term = '\r';
    break;
  case ProtocolSyringe:
    term = '\003';
    break;
  }

  ret = AsconReadChar(a->fd, &chr);
  while (ret > 0) {
    a->start = DoubleTime();

    /* Accept ASCII CR or ETX as terminator */
    if (chr != term) {
      DynStringConcatChar(a->rdBuffer, chr);
    }
    else {
      int ilen, olen;
      switch (private->protocol_subtype) {
      case ProtocolHamilton:
        ilen = GetDynStringLength(a->rdBuffer);
        olen = GetDynStringLength(a->wrBuffer) - 1; /* omit CR */
        if (olen == ilen) {
          char *itext, *otext;
          itext = GetCharArray(a->rdBuffer);
          otext = GetCharArray(a->wrBuffer);
          if (memcmp(itext, otext, ilen) == 0) { /* echo? */
            DynStringClear(a->rdBuffer);
            ret = AsconReadChar(a->fd, &chr);
            continue;
          }
        }
        break;
      }
      a->state = AsconReadDone;
      break;
    }
    ret = AsconReadChar(a->fd, &chr);
  }
  if (ret < 0) {
    AsconError(a, "AsconReadChar failed:", errno);
    return 0;
  }
  if (a->state == AsconReadDone) {
    DynStringConcatChar(a->rdBuffer, '\0');
  } else {
    if (a->timeout > 0) {
      if (DoubleTime() - a->start > a->timeout) {
        AsconError(a, "read timeout", 0);
        a->state = AsconTimeout;
      }
    }
  }
  return 0;
}

/** @brief Oxford protocol handler.
* This handler formats commands (ie adds cr line terminator) and
* sorts replies into standard responses of
* <value>
* OK
* ASCERR: ...
*/
int OxfordProtHandler(Ascon *a) {
  int ret;

  switch(a->state){
    case AsconWriteStart:
      ret = OxfordWriteStart(a);
      return ret;
      break;
    case AsconWriting:
      ret = OxfordWriting(a);
      return ret;
      break;
    case AsconReadStart:
      a->start = DoubleTime();
      ret = AsconStdHandler(a);
      return ret;
      break;
    case AsconReading:
      ret = OxfordReading(a);
      return ret;
      break;
    default:
      ret = AsconStdHandler(a);
      return ret;
      break;
  }
  return 1;
}

int OxfordQProtHandler(Ascon *a) {
  int ret;

  switch(a->state){
    case AsconWriteStart:
      ret = OxfordWriteStart(a);
      return ret;
      break;
    case AsconWriting:
      ret = OxfordWriting(a);
      return ret;
      break;
    case AsconReading:
      ret = OxfordReading(a);
      return ret;
      break;
    default:
      ret = AsconStdHandler(a);
      return ret;
  }
  return 1;
}

void OxfordKillPrivate(void *arg) {
  OxfordProtocol *private = (OxfordProtocol *) arg;
  assert(private->magic == 0xcafef00d);
  assert(private->parent->private == private);
  private->magic = 0;
  free(arg);
}

static int GenericInit(Ascon *a, SConnection *con,
    int argc, char *argv[], int subtype) {
  OxfordProtocol *private;
  int ret;
  ret = AsconStdInit(a, con, argc, argv);
  private = calloc(sizeof(OxfordProtocol), 1);
  a->private = (void *) private;
  private->magic = 0xcafef00d;
  private->parent = a;
  private->inter_line_time = 0.100;
  private->inter_char_time = 0.010;
  private->protocol_subtype = subtype;
  a->killPrivate = OxfordKillPrivate;
  return ret;
}

static int OxfordInit(Ascon *a, SConnection *con, int argc, char *argv[]) {
  return GenericInit(a, con, argc, argv, ProtocolOxford);
}

static int HamiltonInit(Ascon *a, SConnection *con, int argc, char *argv[]) {
  return GenericInit(a, con, argc, argv, ProtocolHamilton);
}

static int SyringeInit(Ascon *a, SConnection *con, int argc, char *argv[]) {
  return GenericInit(a, con, argc, argv, ProtocolSyringe);
}

void AddOxfordProtocoll(){
  AsconProtocol *prot = NULL;

  prot = calloc(sizeof(AsconProtocol), 1);
  prot->name = strdup("oxford");
  prot->init = OxfordInit;
  prot->handler = OxfordProtHandler;
  AsconInsertProtocol(prot);

  prot = calloc(sizeof(AsconProtocol), 1);
  prot->name = strdup("hamilton");
  prot->init = HamiltonInit;
  prot->handler = OxfordProtHandler;
  AsconInsertProtocol(prot);

  prot = calloc(sizeof(AsconProtocol), 1);
  prot->name = strdup("syringe");
  prot->init = SyringeInit;
  prot->handler = OxfordQProtHandler;
  AsconInsertProtocol(prot);
}