#!/usr/bin/env python
## @file csbackchk.py
# @brief Check checksums or rather integrity of corresponding files. 
# 
# -----------------------------------------------------------------------------
# 
# $Id$
# @author Daniel Armbruster
# \date 03/01/2012
# 
# Purpose: Check checksums or rather integrity of corresponding 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 
# 03/01/2012  V0.1  Daniel Armbruster
# 10/01/2012  V0.2  adjustments because every subdirectory now contains its own
#                   checksumfile.
# 
# =============================================================================
 
import getopt
import os
import sys
import pwd
import logging
import csfile
import csbacklog

__version__ = "V0.2"
__subversion__ = "$Id$"
__license__ = "GPLv2"
__author__ = "Daniel Armbruster"
__copyright__ = "Copyright (c) 2012 by Daniel Armbruster"

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

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

  def display(self):
    sys.stderr.write("csbackchk (ERROR): " + self.msg + "\n")
    sys.stderr.write("triggered in line: " + self.line + "\n")


class Usage(Error):

  def display(self):
    usage_text = "Version: "+__version__+"\nLicense: "+__license__+ \
      "\n"+__subversion__+"\nAuthor: "+__author__+ """
 Usage: csbackchk [-v|--verbose] [-e REGEX [-e REGEX [...]]]
                  [-R|--notrecursive] [-d|--debug] [-f|--followlinks] 
                  [-t|--tolerant] [-l|--logging] [SOURCEPATH] PATH
    or: csbackchk -h|--help\n"""
    sys.stderr.write("csbackchk [line "+self.line+"]: "+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: csbackchk [-v|--verbose] [-e REGEX [-e REGEX [...]]]
                  [-R|--notrecursive] [-d|--debug] [-f|--followlinks]
                  [-t|--tolerant] [-l|--logging] [SOURCEPATH] PATH
    or: csbackchk -h|--help
-------------------------------------------------------------------------------
 -v|--verbose       Be verbose.
 -h|--help          Display this help.
 -e REGEX           While checking a checksumfile(s) exclude files and
                    directories matching REGEX(s).
 -R|--notrecursive  Do not search in subdirectories of PATH.
 -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|--tolerant      Be tolerant.
                    While checking don't report anything if a file listed in
                    the checksumfile is missing. This flag is useful if a test
                    of a directory is executed but this directory is realized
                    e.g. as a ring buffer.
 -l|--logging       Switch on logging to files. Logfiles will be located in
                    ~/.csback/log/.
 SOURCEPATH         Optional sourcepath for comparison with files backed up in
                    PATH. PATH and its subdirectories (if option '-R' had not
                    been selected) must contain the csback checksumfile(s).
                    Note that the directory structure (if option '-R' is not
                    set) bellow SOURCEPATH should be equal to those in PATH
                    because otherwise the files won't be found.
                    If SOURCEPATH is not passed a check of files located in
                    PATH with its checksumfiles will be performed.
 PATH               Path to perform check with its checksumfile(s). If option
                    '-R' had not been set the check will be performed
                    additionally for PATHs' subdirectories.
"""
  sys.stdout.write(help_text)

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

  # fetch arguments
  if argv is None:
    argv = sys.argv
  try:
    try:
      opts, args = getopt.getopt(argv[1:], "vhe:Rdftl", ["help", "verbose", \
        "notrecursive", "debug", "followlinks", "tolerant", "logging"])
    except getopt.GetoptError as err:
      raise Usage(135,err.msg)
    verbose = False
    debugMode = False
    notRecursive = False
    followLinks = False
    beTolerant = False
    regexes = []
    # collect arguments
    for opt, arg in opts:
      if opt in ("-v", "--verbose"):
        verbose = True
        console.setLevel(logging.INFO)
      elif opt in ("-h", "--help"):
        sys.exit(help())
        return 0
      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", "--tolerant"):
        beTolerant = True
      elif opt in ("-l", "--logging"):
        logger.configure()
      else:
        raise Usage(164,"Unhandled option chosen.")

    if verbose or debugMode:
      logger.addHandler(console)

    if 1 == len(args) or 2 == len(args) and \
      args[0].rstrip(os.sep)+os.sep == args[1].rstrip(os.sep)+os.sep:
      sourcepath = str(args[0]).rstrip(os.sep)+os.sep
      sourceDirs = [sourcepath]
      inputpath = sourcepath 
      inputDirs = sourceDirs
    elif 2 == len(args):
      sourcepath = str(args[0]).rstrip(os.sep)+os.sep 
      sourceDirs = [sourcepath] 
      inputpath = str(args[1]).rstrip(os.sep)+os.sep 
      inputDirs = [inputpath] 
    else:
      raise Usage(180,"Invalid argument(s).")

    # major part
    logger.getLogger().debug("Collecting subdirectories ...")
    # recursive
    if not notRecursive:
      sourceDirs.extend( \
        csfile.getSubDirectories(sourcepath, regexes, followLinks))
      if sourceDirs[0] != inputDirs[0]:
        inputDirs.extend( \
          csfile.getSubDirectories(inputpath, regexes, followLinks))
         
    if len(sourceDirs) != len(inputDirs):
      raise Error(194, \
        "Directory structure of inputpath and sourcepath different.")
      
    if not csfile.hasCsFile(inputpath):
      raise Error(198,"PATH does not contain a checksumfile.")

    paths = list(zip(inputDirs, sourceDirs))
  
    logger.getLogger().info("Start checking checksums ...")
    for path in paths:
      checksumfile = csfile.CsFile(path[0], path[1])
      checksumfile.read()
      checksumfile.check(regexes, beTolerant)

  except Usage as err:
    err.display()
    return 2
  except Error as err:
    logger.getLogger().error("message: %s [line %s]", err.msg, err.line)
    err.display()
    return 2
  except csfile.CsFileError as err:
    logger.getLogger().error("message: %s [line %s]", err.msg, err.line)
    err.display()
    return 2
  else:
    logger.getLogger().info("Checks performed.")
    return 0
    
# -----------------------------------------------------------------------------
if __name__ == "__main__":
  sys.exit(main())

# ----- END OF csbackchk.py -----