#! /usr/bin/python
'''
===============================================================================================
 Reads 9-track 1/2" tape from M4 Data mod. 9914R drive, with SCSI interface.
 Data assumed to be in SEG-C format.
 
 Note anomaly in file positioning using the 'mt' command.
 
 Tape drive operation is written as class library.
 
  Options:
	
   "-h",  "--help"    Print help message
   "-d=", "--dest="   Destination folder name
   "-a="              Append this number of files
   "-r="              Read this file no.
   "-n="              Number of repetitions if reading same file

 Dept. of Earth Science
 University of Bergen, Norway 

 ------------------------------------------------------------------------------
 Rev.  Date         By     Description
 ------------------------------------------------------------------------------
 0.1   1 Nov 2006 	 O.M.  First version.
                           Based on segcREAD.C (M.S., 2004)
================================================================================================   
'''

from string import split
import select
from time import time, gmtime, strftime, sleep
import sys
import os
from os.path import isdir, isfile, join, getsize
import getopt


#*****************************************************************
#                        C O N S T A N T S
#*****************************************************************

TAPE_A				= '/dev/nst0'
SEGC_HEADER_SIZE	= 142


#*****************************************************************
#                        C L A S S E S
#*****************************************************************


#-----------------------------------------------------------------
#             T a p e   D r i v e   C l a s s
#-----------------------------------------------------------------

class TapeDrive:
	
	
	#------------   "Constructor"  ---------------
	def __init__(self, TapeDevice, LogFile):
		self.Device = TapeDevice
		self.Status = self.GetStatus()
		
		if (not self.Status['Error']) and self.Status['Online']:
			print '>>> Tape drive %s seems OK' % self.Device
		else:
			print '>>> Is tape drive %s OFFLINE?' % self.Device
		self.LogFile = LogFile
		self.Directory = LogFile.filename().split('/')[0]
		self.TempDataFile = join(self.Directory, '.temp.dat')
		self.ErrorLog = join(self.Directory, '.errors.txt')

						
						
	#---- Get tape drive status
	def GetStatus(self):
		Status = {}
		w, r, e = os.popen3('mt -f ' + self.Device + ' status')
		w.close()
		Error = e.readlines()
		e.close()
		if len(Error) != 0:
			print '>>> Error checking status of tape drive %s' % self.Device
			for line in Error:
				if len(line) != 1:
					print '>>> ---> ' + line.strip()
			
		Status['Error'] = True
		Status['Online'] = False
		Response = r.readlines()
		r.close()
		for line in Response:
			s = line.split()
			if 'file number' in line:
				Status['FileNo']	= s[-1]
			if 'block number' in line:
				Status['BlockNo'] = s[-1]
			if 'Tape block size' in line:
				Status['BlockSize'] = s[3]
			if 'ONLINE' in line:
				Status['Online'] = True
				Status['Error']  = False			
		return Status
			
		
		
	#---- Print tape drive status  ----------------------
	def status(self):
		self.Status = self.GetStatus()
		print 'Tape drive status:'
		print '  Device: %s' % self.Device
		print '  BlockSize: %(BlockSize)s' % self.Status
		print '  Block number: %(BlockNo)s' % self.Status
		print '  File number: %(FileNo)s' % self.Status
		print '  Online:', self.Status['Online']
		
		
		
	#---- Get current position pointer on tape  --------------
	def current_file(self):
		self.Status = self.GetStatus()
		return int(self.Status['FileNo'])



	#---- Move to specified location on tape   -------------------------------
	def move_to(self,target):
		if target > 0:
			current = int(self.current_file())
			delta = (target - current) - 1
			
			if target == 1:										# Rewind tape
				os.system('mt -f ' + self.Device + ' rewind')	
				
			elif delta > 0:									# Forward to filenumber
				os.system('mt -f ' + self.Device + ' fsf %i' %  (int(delta)))
				
			elif (delta < 0):									# Rewind to filenumber
				os.system('mt -f %s bsf %s' % (self.Device, abs(delta)))
				self.Status = self.GetStatus()
				if self.Status['BlockNo'] == '-1':
					os.system('mt -f %s bsr %s 2>/dev/null' % (self.Device, '2'))		# Reverse a bit, otherwise we'll read zero bytes on next attempt
		else:
			print '>>>>>> TAPE Error: Can not move to file number <= 0'
			
			
		
	#---- Read file from specified location	on tape  ---------------------------
	def read_file(self,FileNo):
		self.move_to(FileNo)
		os.system('rm %s 2> /dev/null' % self.TempDataFile)
		os.system('dd if=%s of=%s ibs=1024k count=3 2<<%s' % (self.Device, self.TempDataFile, join(self.Directory, self.ErrorLog)))
		
		f = open(self.TempDataFile, 'rb')
		Destination = ''
		Size = 0
		if getsize(self.TempDataFile) == 0:
			print '>>>>>>>>>>>   Read 0 bytes from tape'
		else:
			s = f.read(2)								# Filename based on FLDR in SEGC file (positioned in two first bytes)
			FileName = ''								# this FLDR is BCD coded
			for byte in s:
				FileName += '%02X' % ord(byte)			# Build filename from these two bytes (convert to HEX as they are BCD coded)
			f.close()
			FileName += '.segc'
			Destination	= join(self.Directory, FileName)
			os.system('cp %s %s' % (self.TempDataFile, Destination))
			Size = getsize(Destination)
			self.LogFile.entry(FileNo, Destination, Size, 'QS-3416S')
			print 'No. %d : %s (%d)' % (FileNo, Destination, Size)
		
		return Destination, Size
		



#-----------------------------------------------------------------
#                  L o g   F i l e   C l a s s
#-----------------------------------------------------------------

class LogFileClass:


	#------------   "Constructor"  ---------------
	def __init__(self, LogFileName):
		self.FileName = LogFileName
		self.FileStatus = {}
		if not isfile(LogFileName):
			#print 'Log file %s does not exist, creating' % LogFileName
			os.system('touch ' + LogFileName)
		else:
			LogFile = open(LogFileName)
			for line in LogFile.readlines():
				#print line[:-1]
				if not (len(line) == 1 or (line[0] == '#')):
					FileInfo = {}
					try:
						s = line.split()
						FileSequenceNo				= s[0]
						FileInfo['FileSequenceNo']	= FileSequenceNo
						FileInfo['FileName']		= s[1]
						FileInfo['FileSize']		= s[2]
						t							= s[3:-1]
						FileInfo['FileDate']		= ''
						for item in t:
							FileInfo['FileDate']	+= item + ' '
						FileInfo['FileDate']		= FileInfo['FileDate'][:-1]		# Get rid of excess SPACCE char
						FileInfo['Source']			= s[-1]
						self.FileStatus[int(FileSequenceNo)]	= FileInfo
					except:
						print >> sys.stderr, 'Error parsing log file, exit'
						sys.exit(1)
			
			
		
	#------------   Print all entries in log file  ---------------		
	def printout(self):
		if len(self.FileStatus) == 0:
			print 'Empty log file'
		else:
			print 'From existing log file:'
			keys = self.FileStatus.keys()
			keys.sort()
			for key in keys:
				print '%(FileSequenceNo)03s  %(FileName)s  %(FileSize)s  %(FileDate)s  %(Source)s '  % (self.FileStatus[key])		
	
	
	
	#-------------   Return the last item number in list   -------------
	def last_file(self):
		keys = self.FileStatus.keys()
		keys.sort()
		if len(keys) != 0:
			#print 'max fileno in logfile:', max(keys)
			return max(keys)
		else:
			return 0

	
	
	#-------------   Return log filename  -------------
	def filename(self):
		return self.FileName

	
	
	#-------------   Modify existing or make new entry in logfile   -------------
	def entry(self, number, name, size, source):
		print '>>> Writing to log entry no.', number
		FileInfo = {}
		FileInfo['FileSequenceNo']	= str(number)
		FileInfo['FileName']		= name
		FileInfo['FileSize']		= size
		FileInfo['FileStatus']		= ''
		FileInfo['FileDate']		= strftime("%a %b %d %H:%M:%S %Y", gmtime())
		FileInfo['Source']			= source
		self.FileStatus[number]		= FileInfo
		f = open(self.FileName, 'w')
		keys = self.FileStatus.keys()
		keys.sort()
		for key in keys:
			f.write('%(FileSequenceNo)03s  %(FileName)s  %(FileSize)s  %(FileDate)s  %(Source)s\n' % (self.FileStatus[key]))
		f.close()

		

#*******************************************************************************************************
#
#                             S t a r t   o f   p r o g r a m
#
#*******************************************************************************************************

#------   Parse command line options

try:
	opts, args = getopt.getopt(sys.argv[1:], "hd:a:r:n:", ["help", "dest="])
except getopt.error, msg:
	print msg
	print "for help use --help (or -h)"
	sys.exit(1)

Append = False
Repeat = 1
ReadFileNo = 0
Reel_Directory = ''
No_Of_Files_To_Append = 0

for o, a in opts:
	
	if a[0] == '=':
		a = a[1:]
	
	if o in ("-h", "--help"):
		print __doc__
		sys.exit(0)
		
	if o in ("-d", "--dest"):
		Reel_Directory = a
		
	if o in ("-a"):
		Append = True
		No_Of_Files_To_Append = int(a)
		if not No_Of_Files_To_Append >= 1:
			print 'Append: Only positive integer, larger then 0'
			sys.exit(1)
			
	if o in ("-r"):
		Append = False
		ReadFileNo = int(a)
		if not ReadFileNo >= 1:
			print 'Read file no: Only positive integer, larger then 0'
			sys.exit(1)
		
	if o in ("-n"):
		Append = False
		Repeat = int(a)
		if not Repeat >= 1:
			print 'No of loops: Only positive integer, larger then 0'
			sys.exit(1)
		
if not Reel_Directory:
	print 'Not target directory'
	sys.exit(1)
if (not Append) and (ReadFileNo == 0):
	print 'Missing parameters'
	sys.exit(1)

if Append:
	print 'Appending %d files' % No_Of_Files_To_Append
else:
	print 'Reading file no %d on tape' % ReadFileNo
if Repeat != 0:
	print 'Repeat %d times' % Repeat


#--------   Check reel directory, create if needed
if not isdir(Reel_Directory):
	print 'Folder does not exist, creating'
	os.mkdir(Reel_Directory)


#--------   Compose logfile name ....
LogFileName = join(Reel_Directory, Reel_Directory + '.log')		# Log file name = name of reel directory + '.log'

#---------  Create logfile instance
LogFile = LogFileClass(LogFileName)
LogFile.printout()	


#---------  Create TapeDrive instance
TapeDrive = TapeDrive(TAPE_A, LogFile)


#--------------------------------------------------------------------------
#
#                             M a i n   l o o p
#
#--------------------------------------------------------------------------

if Append:
	LastFile		= LogFile.last_file()
	CurrentFile		= LastFile + 1
	while CurrentFile <= (LastFile + No_Of_Files_To_Append):
		TapeDrive.read_file(CurrentFile)
		CurrentFile += 1
else:
	for n in range(Repeat):
		TapeDrive.read_file(ReadFileNo)

sys.exit(0)