#!@PYTHON@
#
# Check the free space available on a writable DVD
# Should always exit with 0 status, otherwise it indicates a serious error.
# (wrong number of arguments, Python exception...)
#
# Prints on the first output line the free space available in bytes.
# If an error occurs, prints a negative number (-errno), followed,
# on the second line, by an error message.
# 
# $Id$

# Configurable values:
mkisofs="@MKISOFS@"
growisofs="@GROWISOFS@"
dvdrwmediainfo="@DVDRWMEDIAINFO@"

margin=10485760 # 10 mb security margin

growisofsparams=""

# Uncomment the following line if you have a Linux kernel >=2.6.8, and
# if you want to allow a session to start behind the 4gb boundary.
#growisofsparams = growisofsparams + " -use-the-force-luke=4gms"

# end of configurable values

import popen2
import os
import errno
import tempfile
import sys

if len(sys.argv) != 3:
   print "Wrong number of argument."
   sys.exit(1)

device=sys.argv[1]
part_num=int(sys.argv[2])

os.environ["MKISOFS"] = mkisofs

def gettotalsize():
   cmd=dvdrwmediainfo + " " + device
   processi = popen2.Popen4(cmd)
   status = processi.wait()
   if not os.WIFEXITED(status):
      print -errno.EPIPE
      print "Process has not exited correctly."
      sys.exit(0)
   if os.WEXITSTATUS(status) != 0:
      print -errno.EPIPE
      print 'Cannot get media info.'
      sys.exit(0)
   while 1:
      result = processi.fromchild.readline()
      if result.find("Legacy lead-out at:") > -1:
         index = result.find("=")
         if index > -1:
            res = result[index+1:-1]
            if not res.isdigit():
               print -errno.EPIPE
               print 'Invalid format in media info lead-out line.'
               sys.exit(0)
            return int(res)
         else:
            print -errno.EPIPE
            print 'Invalid format in media info lead-out line.'
            sys.exit(0)
      if not result:
         print -errno.EPIPE
         print 'Cannot get media lead-out index.'
         sys.exit(0)

tmpfile = tempfile.NamedTemporaryFile()
if part_num == 0:
   flag = "-Z"
else:
   flag = "-M"
cmd=growisofs + " " + growisofsparams + " -use-the-force-luke=tty -dry-run -quiet " + flag + " " + device + " -R " + tmpfile.name
process = popen2.Popen4(cmd)
status = process.wait()
if not os.WIFEXITED(status):
   print -errno.EPIPE
   print "Process has not exited correctly."
   sys.exit(0)

exitstat = os.WEXITSTATUS(status) & ~0x80
if exitstat == errno.ENOSPC:
   print "0"
   print os.strerror(exitstat)
   sys.exit(0)
if exitstat != 0:
   print -exitstat
   print os.strerror(exitstat)
   sys.exit(0)
while 1:
   result = process.fromchild.readline()
   if not result:
      print -errno.EPIPE
      print 'Cannot find the seek argument in the output.'
      sys.exit(0)
   index = result.find("seek=")
   if index > -1:
      res = result[index+5:-2]
      if not res.isdigit():
         print -errno.EPIPE
         print 'Wrong seek argument in the output.'
         sys.exit(0)
      size = int(res)*32*1024
      size = gettotalsize()-(size+margin)
      if size < 0:
         size = 0
      print size
      print "No error occured"
      sys.exit(0)