#!/usr/bin/env python
## @file csbackgen.py
# @brief Generate checksum files.
# 
# -----------------------------------------------------------------------------
# 
# $Id$
# @author Daniel Armbruster
# \date 11/09/2011
# 
# Purpose: Generate checksum files.
#
# ----
# This file is part of csback.
#
# csback is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
# 
# csback is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with csback.  If not, see <http://www.gnu.org/licenses/>.
# ----
# 
# Copyright (c) 2012 by Daniel Armbruster
# 
# REVISIONS and CHANGES 
# 02/01/2012  V0.1  Daniel Armbruster
# 05/01/2012  V0.2  added logging flag to enable a file logging mechanism
# 
# =============================================================================
 
import getopt
import os
import sys
import re
import pwd
import logging
import csfile
import csbacklog

__version__ = "V0.1"
__subversion__ = "$Id$"
__license__ = "GPLv2"
__author__ = "Daniel Armbruster"
__copyright__ = "Copyright (c) 2012 by Daniel Armbruster"

# -----------------------------------------------------------------------------
class Error(Exception):

  def __init__(self, msg):
    self.msg = msg

  def display(self):
    sys.stderr.write("csbackgen (ERROR): " + self.msg + "\n")


class Usage(Error):

  def display(self):
    usage_text = "Version: "+__version__+"\nLicense: "+__license__+ \
      "\n"+__subversion__+"\nAuthor: "+__author__+ """
 Usage: csbackgen [-v|--verbose] [-e REGEX [-e REGEX [...]]]
                  [-R|--notrecursive] [-d|--debug] [-f|--followlinks]
                  [-t|--target DIR] [-l|--logging] PATH
    or: csbackgen -h|--help\n"""
    sys.stderr.write("csbackgen: " + self.msg + "\n")
    sys.stderr.write(usage_text)

# -----------------------------------------------------------------------------
def help():
  """
  Printing helptext to stdout.
  """
  help_text = "Version: "+__version__+"\nLicense: "+__license__+"\n"+ \
    __subversion__+"\nAuthor: "+__author__+"""
 Usage: csbackgen [-v|--verbose] [-e REGEX [-e REGEX [...]]]
                  [-R|--notrecursive] [-d|--debug] [-f|--followlinks] 
                  [-t|--target DIR] [-l|--logging] PATH
    or: csbackgen -h|--help
-------------------------------------------------------------------------------
 -v|--verbose       Be verbose.
 -h|--help          Display this help.
 -e REGEX           While generating a checksumfile exclude files matching
                    REGEX(s).
 -R|--notrecursive  Do not generate checksumfiles for subdirectories.
 -d|--debug         Debug mode. Be really verbose.
 -f|--followlinks   Follow symbolic links. Only available if option -R is not
                    set. Note that this option can lead to infinite recursion.
 -t|--target        Target directory for checksumfile.
 -l|--logging       Switch on logging to files. Logfiles will be located in
                    ~/.csback/log/.
 PATH               Path to generate checksumfile for.
-------------------------------------------------------------------------------
csbackgen.py will either generate a checksumfile if still no checksumfile is
available or in case there is an existing checksumfile csbackgen.py will append
the not yet registered files to the current checksumfile. In the latter case
csbackgen.py is working in its update mode.\n"""
  sys.stdout.write(help_text)

# -----------------------------------------------------------------------------
def main(argv=None):
  # configure logger
  logger = csbacklog.CsbackLog('csbackgen')
  
  console = logging.StreamHandler()
  console.setFormatter(logging.Formatter( \
    '%(name)-8s [%(lineno)d]: %(levelname)-8s %(message)s'))

  if argv is None:
    argv = sys.argv
  try:
    try:
      opts, args = getopt.getopt(argv[1:], "vhe:Rdft:l", ["help", "verbose", \
        "notrecursive", "debug", "followlinks", "target=", "logging"])
    except getopt.GetoptError as err:
      raise Usage(err.msg)
    verbose = False
    debugMode = False
    notRecursive = False
    followLinks = False
    regexes = []
    targetSet = False
    enableLogging = False
    for opt, arg in opts:
      if opt in ("-v", "--verbose"):
        verbose = True
        console.setLevel(logging.INFO)
      elif opt in ("-h", "--help"):
        sys.exit(help())
      elif opt in ("-R", "--notrecursive"):
        notRecursive = True
      elif opt in ("-e"):
        regexes.append(arg)
      elif opt in ("-d", "--debug"):
        debugMode = True
        console.setLevel(logging.DEBUG)
      elif opt in ("-f", "--followlinks"):
        followLinks = True
      elif opt in ("-t", "--target"):
        targetSet = True
        targetDirectory = str(arg)
      elif opt in ("-l", "--logging"):
        logger.configure()
      else:
        raise Usage("Unhandled option chosen.")

    if verbose or debugMode:
      logger.addHandler(console)

    # fetch arguments   
    if 1 == len(args):
      srcpath = str(args[0]).rstrip(os.sep)+os.sep
    else:
      raise Usage("Invalid argument.")

    if not targetSet:
      targetDirectory = srcpath
    if not os.path.isdir(targetDirectory):
      raise Usage("Target directory not a valid directory.")

    # major part
    logger.getLogger().info("Start updating checksumfile in '%s'", srcpath)
    csfile.CsFile(targetDirectory, srcpath=srcpath, recursive=not notRecursive, \
      followLinks=followLinks).update(regexes)

  except Usage as err:
    err.display()
    return 2
  except csfile.CsFileError as err:
    logger.getLogger().error("%s", err.msg)
    err.display()
    return 2
  else:
    logger.getLogger().info("Checksumfile updated.")
    return 0
    

# -----------------------------------------------------------------------------
if __name__ == "__main__":
  sys.exit(main())

# ----- END OF csbackgen.py -----