/**************************************************************\

  Main program for the CTX G-APD HV supply, sends commands, 
  reads and monitors status of the G-APD HV supply

  Sebastian Commichau, Sabrina Stark, Oliver Grimm
  
\**************************************************************/

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <pthread.h>
#include <signal.h>

#include "ProcessIO.h"

#include <readline/readline.h>
#include <readline/history.h>

#define LOCKFILE "/tmp/CTX_HV_LOCK"

// Function prototypes
void ConsoleCommand(ProcessIO *);
void HVMonitor(ProcessIO *);
void DummyHandler(int);
void CrashHandler(int);
void ExitFunction();

// ================
//   Main program
// ================
//
// Several unlikely system call failures are handled via throwing an exception.

int main(int argc, char *argv[]) {

  char str[MAX_COM_SIZE];
  pthread_t thread_ConsoleCommand,thread_HVMonitor;
  int LockDescriptor;

  // Assure only one instance of the HV control program runs
  // The flag O_EXCL together with O_CREAT assure that the lock 
  // file cannot be opened by another instance, i.e. there are no parallel write accesses
  if((LockDescriptor = open(LOCKFILE,O_WRONLY|O_CREAT|O_EXCL,S_IWUSR|S_IRUSR|S_IRGRP|S_IROTH)) == -1) {
    if(errno==EEXIST) {
      printf("Error: Lock file already existing\n");
      sprintf(str,"paste %s -s -d ' '",LOCKFILE);
      system(str);
    }
    else printf("Could not create lock file %s (%s)\n", LOCKFILE, strerror(errno));
    exit(EXIT_FAILURE);
  }
  close(LockDescriptor);
  sprintf(str,"echo Created >%s; date >>%s; echo by $USER@$HOSTNAME>>%s",LOCKFILE,LOCKFILE,LOCKFILE);
  system(str);
  
  system("clear");                   
  printf("\n*** Bias control (%s, %s, O. Grimm, S.Commichau, S.Stark) ***\n\n",__DATE__,__TIME__);
 
  // Install signal handler and set signal SIGUSR1 to interrupt blocking system calls
  signal(SIGUSR1, &DummyHandler);
  siginterrupt (SIGUSR1, true);

  // Assure lock file is deleted in case of a program crash or call to exit()
  signal(SIGILL, &CrashHandler);
  signal(SIGABRT, &CrashHandler);
  signal(SIGFPE, &CrashHandler);
  signal(SIGSEGV, &CrashHandler);
  signal(SIGBUS, &CrashHandler);
  atexit(&ExitFunction);
  
  // Construct main instance and create mutex for thread synchronization
  ProcessIO pio;
  if (pthread_mutex_init(&pio.control_mutex, NULL) != 0) {
    perror("pthread_mutex_init failed");
    throw;
  }
  
  // These signals were set during construction of EvidenceServer
  signal(SIGQUIT, &CrashHandler);  // CTRL-Backspace
  signal(SIGINT, &CrashHandler);   // CTRL-C
  signal(SIGHUP, &CrashHandler);   // Terminal closed
  signal(SIGTERM, &CrashHandler);

  // Create threads
  if ((pthread_create(&thread_ConsoleCommand, NULL, (void * (*)(void *)) ConsoleCommand,(void *) &pio)) != 0) {
    perror("pthread_create failed with console thread");
    throw;
  }
  if ((pthread_create(&thread_HVMonitor, NULL, (void * (*)(void *)) HVMonitor,(void *) &pio)) != 0) {
    perror("pthread_create failed with HVMonitor thread");
    throw;
  }

  // Threads should be accessible for sending signals
  pio.HVMonitor = thread_HVMonitor;

  // Wait for threads to quit
  pthread_join(thread_ConsoleCommand, NULL);
  pthread_join(thread_HVMonitor, NULL);

  // Destruct mutex and main instance
  pthread_mutex_destroy (&pio.control_mutex);
  pio.~ProcessIO();

  // Remove lockfile
  if (remove(LOCKFILE)==-1) {
    sprintf(str, "Could not remove lock file %s", LOCKFILE);
    perror(str);
    exit(EXIT_FAILURE);
  }

  exit(EXIT_SUCCESS);
}


/********************************************************************\

  ConsoleCommand thread

  Handle console input using readline library functions to allow
  line editing and history capability

\********************************************************************/

void ConsoleCommand(ProcessIO *m) {

  char *Command;

  while (!m->Exit) {
        
    // Assemble prompt
    snprintf(m->Prompt, sizeof(m->Prompt),"\rHV");
    if (m->NumHVBoards == 0) sprintf(m->Prompt+strlen(m->Prompt),"> "); 
    else { 
      if (m->FirstChain == m->LastChain) sprintf(m->Prompt+strlen(m->Prompt),"|C%d",m->FirstChain); 
      else sprintf(m->Prompt+strlen(m->Prompt),"|C%d-%d",m->FirstChain,m->LastChain); 

      if (m->NumHVBoards == 0) sprintf(m->Prompt+strlen(m->Prompt),"> "); 
      else if (m->FirstBoard == m->LastBoard) sprintf(m->Prompt+strlen(m->Prompt),"|B%d> ",m->FirstBoard); 
      else snprintf(m->Prompt,sizeof(m->Prompt),"\rDAQ|B%d-%d> ",m->FirstBoard,m->LastBoard); 
    }

    // Read Command
    Command = readline(m->Prompt);
    if (Command==NULL) {
      m->PrintMessage("Error reading command line input\n");
      continue;
    }
    if(strlen(Command)>0) add_history(Command);

    // Process command (via DIM gives automatic serialisation)
	DimClient::sendCommand("Bias/Command", Command);
    free(Command);
  }
}


/********************************************************************\

  HVMonitor

  Monitor HV board status
  Sebastian Commichau, November 2008

\********************************************************************/

void HVMonitor(ProcessIO *m) {
  
  while (!m->Exit) {
    if (m->state == active) {
      pthread_mutex_lock(&m->control_mutex);
      m->Monitor();
      pthread_mutex_unlock(&m->control_mutex);	
    }
    usleep((unsigned long)floor(1000000./(m->NumHVBoards*m->fStatusRefreshRate)));
  }
}


/********************************************************************\

  Signal handlers

\********************************************************************/

// Remove lock file before running default signal code
void CrashHandler(int Signal) {
  remove(LOCKFILE);
  printf("Caught signal number %d. Removing lockfile and performing standard signal action. Good luck.\n",Signal);
  signal(Signal, SIG_DFL);
  raise(Signal);
}

// Dummy signal handler to return from blocking syscalls
void DummyHandler(int Signal) {
  return;          
}

// This function will be implicitly called by exit()
void ExitFunction() {
  remove(LOCKFILE);
  return;          
}