from   subprocess import PIPE, Popen

##################################################################

read_count  = 0
write_count = 0

##################################################################
def py_vme_init ( ) :

  # needs to be declared because we modify it
  global read_count
  global write_count

  read_count  = 0
  write_count = 0

  cmd = [ "which", "vme" ]
  subp = Popen ( cmd, stdout=PIPE, stderr=PIPE )
  stdout, stderr = subp.communicate()

  if ( stderr.find ( "no vme" ) != -1 ) :

    print "py_vme_exists: Detected that the 'vme' command is not defined."
    print "               Please setup the l1calo software and try again."
    return "Fail"

  else :

    return "Ok"

##################################################################

def py_vme_read ( vme_addr_hex,
                  return_stdout = False ) :

  # needs to be declared because we modify it
  global read_count

  read_count += 1
  #print "py_vme_read#%d: called to read %s"  % \
  #            ( read_count,
  #              vme_addr_hex )

  vme_addr_int = eval ( vme_addr_hex )
  cmd = [ "vme", "dump", hex(vme_addr_int), hex(vme_addr_int+1) ]

  subp = Popen ( cmd, stdout=PIPE, stderr=PIPE )

  stdout, stderr = subp.communicate()

  #print "stdout" + stdout
  #print "stderr" + stderr

  if ( stdout.find ( "bus error" ) != -1 ) :
    print "py_vme_read#%d: detected a bus error during 'vme dump' command:\n %s" %  \
              ( read_count,
                stdout )
    data_hex = "****"

  else :

    try:

      stdout_addr_target = "%s:"   %   vme_addr_hex[2:]
      loc_address = stdout.rfind ( stdout_addr_target.lower() )
      data_hex = "0x%s"  %  stdout[loc_address:].split()[1]

    except:

      print "py_vme_read#%d: error parsing 'stdout' from 'vme dump' command:\n%s" % \
              ( read_count,
                stdout )
      data_hex = "????"

  if ( stderr != "" ) : # this seems to never happen anyway
    print "py_vme_read#%d: 'stderr' from 'vme dump' command was not empty:\n %s" %  \
              ( read_count,
                stderr )

  if ( return_stdout == True ) :
    return data_hex, stdout
  else :
    return data_hex

##################################################################

def py_vme_write ( vme_addr_hex,
                   data_hex,
                   return_stdout = False ) :

  # needs to be declared because we modify it
  global write_count

  write_count += 1
  #print "py_vme_write#%d: called to write %s at %s"  % \
  #            ( write_count,
  #              data_hex,
  #              vme_addr_hex )

  if ( data_hex[:2] != "0x" ) :
    print "py_vme_write#%d: incorrect data parameter <%s> does not start with 0x"  %  \
              ( write_count,
                data_hex )
  if ( len(data_hex) != 6 ) :
    print "py_vme_write#%d: incorrect data parameter <%s> expected 4 digits after 0x"  %  \
              ( write_count,
                data_hex )

  vme_addr_int = eval ( vme_addr_hex )
  cmd = [ "vme", "edit", hex(vme_addr_int), hex(vme_addr_int+1) ]
  subp = Popen ( cmd, stdin=PIPE, stdout=PIPE, stderr=PIPE )

  stdout, stderr = subp.communicate( input = "%s\n" % data_hex[2:] )

  if ( stdout.find ( "bus error" ) != -1 ) :
    print "py_vme_write#%d: detected a bus error during 'vme edit' command:\n %s" %  \
              ( write_count,
                stdout )

  if ( stderr != "" ) : # this seems to never happen anyway
    print "py_vme_write#%d: 'stderr' from 'vme edit' command was not empty:\n %s" %  \
              ( write_count,
                stderr )

  if ( return_stdout == True ) :
    return stdout
  else :
    return


##################################################################

def py_vme_read_count ( ) :

 return read_count

def py_vme_write_count ( ) :

 return write_count