/* bmc.c */

#include "ptpd.h"

/* see spec table 18 */
void M1(PtpClock *ptpClock)
{
  /* Default data set */
  ptpClock->steps_removed = 0;
  ptpClock->offset_from_master.seconds = 0;
  ptpClock->offset_from_master.nanoseconds = 0;
  ptpClock->one_way_delay.seconds = 0;
  ptpClock->one_way_delay.nanoseconds = 0;
  
  /* Parent data set */
  ptpClock->parent_communication_technology = ptpClock->clock_communication_technology;
  memcpy(ptpClock->parent_uuid, ptpClock->clock_uuid_field, PTP_UUID_LENGTH);
  ptpClock->parent_port_id = ptpClock->clock_port_id_field;
  ptpClock->parent_last_sync_sequence_number = 0;
  ptpClock->parent_followup_capable = ptpClock->clock_followup_capable;
  ptpClock->parent_external_timing = ptpClock->external_timing;
  ptpClock->parent_variance = ptpClock->clock_variance;
  ptpClock->grandmaster_communication_technology = ptpClock->clock_communication_technology;
  memcpy(ptpClock->grandmaster_uuid_field, ptpClock->clock_uuid_field, PTP_UUID_LENGTH);
  ptpClock->grandmaster_port_id_field  = ptpClock->clock_port_id_field;
  ptpClock->grandmaster_stratum = ptpClock->clock_stratum;
  memcpy(ptpClock->grandmaster_identifier, ptpClock->clock_identifier, PTP_CODE_STRING_LENGTH);
  ptpClock->grandmaster_variance = ptpClock->clock_variance;
  ptpClock->grandmaster_preferred  = ptpClock->preferred;
  ptpClock->grandmaster_is_boundary_clock  = ptpClock->is_boundary_clock;
  ptpClock->grandmaster_sequence_number = ptpClock->last_sync_event_sequence_number;
}

/* see spec table 21 */
void S1(MsgHeader *header, MsgSync *sync, PtpClock *ptpClock)
{
  /* Current data set */
  ptpClock->steps_removed = sync->localStepsRemoved + 1;
  
  /* Parent data set */
  ptpClock->parent_communication_technology = header->sourceCommunicationTechnology;
  memcpy(ptpClock->parent_uuid,  header->sourceUuid, PTP_UUID_LENGTH);
  ptpClock->parent_port_id = header->sourcePortId;
  ptpClock->parent_last_sync_sequence_number = header->sequenceId;
  ptpClock->parent_followup_capable  = getFlag(header->flags, PTP_ASSIST);
  ptpClock->parent_external_timing = getFlag(header->flags, PTP_EXT_SYNC);
  ptpClock->parent_variance = sync->localClockVariance;
  ptpClock->grandmaster_communication_technology = sync->grandmasterCommunicationTechnology;
  memcpy(ptpClock->grandmaster_uuid_field, sync->grandmasterClockUuid, PTP_UUID_LENGTH);
  ptpClock->grandmaster_port_id_field = sync->grandmasterPortId;
  ptpClock->grandmaster_stratum = sync->grandmasterClockStratum;
  memcpy(ptpClock->grandmaster_identifier, sync->grandmasterClockIdentifier, PTP_CODE_STRING_LENGTH); 
  ptpClock->grandmaster_variance = sync->grandmasterClockVariance;
  ptpClock->grandmaster_preferred = sync->grandmasterPreferred;
  ptpClock->grandmaster_is_boundary_clock = sync->grandmasterIsBoundaryClock;
  ptpClock->grandmaster_sequence_number = sync->grandmasterSequenceId;
  
  /* Global time properties data set */
  ptpClock->current_utc_offset = sync->currentUTCOffset;
  ptpClock->leap_59 =  getFlag(header->flags, PTP_LI_59);
  ptpClock->leap_61 =  getFlag(header->flags, PTP_LI_61);
  ptpClock->epoch_number = sync->epochNumber;  
}

void copyD0(MsgHeader *header, MsgSync *sync, PtpClock *ptpClock)
{
  sync->grandmasterCommunicationTechnology = ptpClock->clock_communication_technology;
  memcpy(sync->grandmasterClockUuid, ptpClock->clock_uuid_field, PTP_UUID_LENGTH);
  sync->grandmasterPortId = ptpClock->clock_port_id_field;
  sync->grandmasterClockStratum = ptpClock->clock_stratum;
  memcpy(sync->grandmasterClockIdentifier, ptpClock->clock_identifier, PTP_CODE_STRING_LENGTH);
  sync->grandmasterClockVariance = ptpClock->clock_variance;
  sync->grandmasterIsBoundaryClock = ptpClock->is_boundary_clock;
  sync->grandmasterPreferred = ptpClock->preferred;
  sync->localStepsRemoved = ptpClock->steps_removed;
  header->sourceCommunicationTechnology= ptpClock->clock_communication_technology;
  memcpy(header->sourceUuid, ptpClock->clock_uuid_field, PTP_UUID_LENGTH); 
  header->sourcePortId = ptpClock->clock_port_id_field;
  sync->grandmasterSequenceId = ptpClock->grandmaster_sequence_number;
  header->sequenceId = ptpClock->grandmaster_sequence_number;
  header->sourcePortId = ptpClock->clock_port_id_field;
}

int getIdentifierOrder(Octet identifier[PTP_CODE_STRING_LENGTH])
{
  if(!memcmp(identifier, IDENTIFIER_ATOM, PTP_CODE_STRING_LENGTH))
    return 1;
  else if(!memcmp(identifier, IDENTIFIER_GPS, PTP_CODE_STRING_LENGTH))
    return 1;
  else if(!memcmp(identifier, IDENTIFIER_NTP, PTP_CODE_STRING_LENGTH))
    return 2;
  else if(!memcmp(identifier, IDENTIFIER_HAND, PTP_CODE_STRING_LENGTH))
    return 3;
  else if(!memcmp(identifier, IDENTIFIER_INIT, PTP_CODE_STRING_LENGTH))
    return 4;
  else if(!memcmp(identifier, IDENTIFIER_DFLT, PTP_CODE_STRING_LENGTH))
    return 5;
  
  return 6;
}

/* return similar to memcmp()s
   note: communicationTechnology can be ignored because 
   if they differed they would not have made it here */
Integer8 bmcDataSetComparison(MsgHeader *headerA, MsgSync *syncA,
  MsgHeader *headerB, MsgSync *syncB, PtpClock *ptpClock)
{
  DBGV("bmcDataSetComparison: start\n");
  if( !( syncA->grandmasterPortId == syncB->grandmasterPortId
    && !memcmp(syncA->grandmasterClockUuid, syncB->grandmasterClockUuid, PTP_UUID_LENGTH) ) )
  {
    if(syncA->grandmasterClockStratum < syncB->grandmasterClockStratum)
      goto A;
    else if(syncA->grandmasterClockStratum > syncB->grandmasterClockStratum)
      goto B;
    
    /* grandmasterClockStratums same */
    if(getIdentifierOrder(syncA->grandmasterClockIdentifier) < getIdentifierOrder(syncB->grandmasterClockIdentifier))
      goto A;
    if(getIdentifierOrder(syncA->grandmasterClockIdentifier) > getIdentifierOrder(syncB->grandmasterClockIdentifier))
      goto B;
    
    /* grandmasterClockIdentifiers same */
    if(syncA->grandmasterClockStratum > 2)
    {
      if(syncA->grandmasterClockVariance > syncB->grandmasterClockVariance + PTP_LOG_VARIANCE_THRESHOLD
        || syncA->grandmasterClockVariance < syncB->grandmasterClockVariance - PTP_LOG_VARIANCE_THRESHOLD)
      {
        /* grandmasterClockVariances are not similar */
        if(syncA->grandmasterClockVariance < syncB->grandmasterClockVariance)
          goto A;
        else
          goto B;
      }
      /* grandmasterClockVariances are similar */
      if(!syncA->grandmasterIsBoundaryClock != !syncB->grandmasterIsBoundaryClock) /* XOR */
      {
        if(syncA->grandmasterIsBoundaryClock)
          goto A;
        else
          goto B;
      }
      /* neither is grandmasterIsBoundaryClock */
      if(memcmp(syncA->grandmasterClockUuid, syncB->grandmasterClockUuid, PTP_UUID_LENGTH) < 0)
        goto A;
      else
        goto B;
    }
    
    /* syncA->grandmasterClockStratum <= 2 */
    if(!syncA->grandmasterPreferred != !syncB->grandmasterPreferred) /* XOR */
    {
      if(syncA->grandmasterPreferred)
        return 1;  /* A1 */
      else
        return -1;  /* B1 */
    }
    /* neither or both grandmasterPreferred */
  }
  
  DBGV("bmcDataSetComparison: X\n");
  if(syncA->localStepsRemoved > syncB->localStepsRemoved + 1
    || syncA->localStepsRemoved < syncB->localStepsRemoved -1)
  {
    /* localStepsRemoved not within 1 */
    if(syncA->localStepsRemoved < syncB->localStepsRemoved)
      return 1;  /* A1 */
    else
      return -1;  /* B1 */
  }
  
  /* localStepsRemoved within 1 */
  if(syncA->localStepsRemoved < syncB->localStepsRemoved)
  {
    DBGV("bmcDataSetComparison: A3\n");
    if(memcmp(ptpClock->port_uuid_field, headerB->sourceUuid, PTP_UUID_LENGTH) < 0)
      return 1;  /* A1 */
    else if(memcmp(ptpClock->port_uuid_field, headerB->sourceUuid, PTP_UUID_LENGTH) > 0)
      return 2;  /* A2 */
    
    /* this port_uuid_field same as headerB->sourceUuid */
    if(ptpClock->port_id_field < headerB->sourcePortId)
      return 1;  /* A1 */
    else if(ptpClock->port_id_field > headerB->sourcePortId)
      return 2;  /* A2 */
    
    /* this port_id_field same as headerB->sourcePortId */
    return 0;  /* same */
  }
  if(syncA->localStepsRemoved > syncB->localStepsRemoved)
  {
    DBGV("bmcDataSetComparison: B3\n");
    if(memcmp(ptpClock->port_uuid_field, headerA->sourceUuid, PTP_UUID_LENGTH) < 0)
      return -1;  /* B1 */
    else if(memcmp(ptpClock->port_uuid_field, headerB->sourceUuid, PTP_UUID_LENGTH) > 0)
      return -2;  /* B2 */
    
    /* this port_uuid_field same as headerA->sourceUuid */
    if(ptpClock->port_id_field < headerA->sourcePortId)
      return -1;  /* B1 */
    else if(ptpClock->port_id_field > headerA->sourcePortId)
      return -2;  /* B2 */
    
    /* this port_id_field same as headerA->sourcePortId */
    return 0;  /* same */
  }
  
  /* localStepsRemoved same */
  if(memcmp(headerA->sourceUuid, headerB->sourceUuid, PTP_UUID_LENGTH) < 0)
    return 2;  /* A2 */
  else if(memcmp(headerA->sourceUuid, headerB->sourceUuid, PTP_UUID_LENGTH) > 0)
    return -2;  /* B2 */
  
  /* sourceUuid same */
  DBGV("bmcDataSetComparison: Z\n");
  if(syncA->grandmasterSequenceId > syncB->grandmasterSequenceId)
    return 3;
  else if(syncA->grandmasterSequenceId < syncB->grandmasterSequenceId)
    return -3;
  
  /* grandmasterSequenceId same */
  if(headerA->sequenceId > headerB->sequenceId)
    return 3;
  else if(headerA->sequenceId < headerB->sequenceId)
    return -3;
  
  /* sequenceId same */
  return 0;  /* same */
  
  /* oh no, a goto label! the horror! */
A:
  if(!syncA->grandmasterPreferred && syncB->grandmasterPreferred)
    return -1;  /* B1 */
  else
    return 1;  /* A1 */
B:
  if(syncA->grandmasterPreferred && !syncB->grandmasterPreferred)
    return 1;  /* A1 */
  else
    return -1;  /* B1 */
}

UInteger8 bmcStateDecision(MsgHeader *header, MsgSync *sync, RunTimeOpts *rtOpts, PtpClock *ptpClock)
{
  if(rtOpts->slaveOnly)
  {
    S1(header, sync, ptpClock);
    return PTP_SLAVE;
  }
  
  copyD0(&ptpClock->msgTmpHeader, &ptpClock->msgTmp.sync, ptpClock);
  
  if(ptpClock->msgTmp.sync.grandmasterClockStratum < 3)
  {
    if(bmcDataSetComparison(&ptpClock->msgTmpHeader, &ptpClock->msgTmp.sync, header, sync, ptpClock) > 0)
    {
      M1(ptpClock);
      return PTP_MASTER;
    }
    S1(header, sync, ptpClock);
    return PTP_PASSIVE;
  }
  else if(bmcDataSetComparison(&ptpClock->msgTmpHeader, &ptpClock->msgTmp.sync, header, sync, ptpClock) > 0)
  {
    M1(ptpClock);
    return PTP_MASTER;
  }
  else
  {
    S1(header, sync, ptpClock);
    return PTP_SLAVE;
  }
}

UInteger8 bmc(ForeignMasterRecord *foreign, RunTimeOpts *rtOpts, PtpClock *ptpClock)
{
  int i, best;
  
  if(!ptpClock->number_foreign_records)
  {
    if(ptpClock->port_state == PTP_MASTER)
      M1(ptpClock);
    return ptpClock->port_state;  /* no change */
  }
  
  for(i = 1, best = 0; i < ptpClock->number_foreign_records; ++i)
  {
    if(bmcDataSetComparison(&foreign[i].header, &foreign[i].sync,
        &foreign[best].header, &foreign[best].sync, ptpClock) > 0)
      best = i;
  }
  
  DBGV("bmc: best record %d\n", best);
  ptpClock->foreign_record_best = best;
  
  return bmcStateDecision(&foreign[best].header, &foreign[best].sync, rtOpts, ptpClock);
}