#!/usr/bin/env python
# encoding: utf-8
# $Id$
# $URL$

"""
Tools.py

Created by Marcus Stoegbauer on 2013-01-12.
Copyright (c) 2013 __MyCompanyName__. All rights reserved.
"""

import sys
import os
import cfgfile
import re
import time
import shutil
import itertools


class Debug(object):
  verbose = 0
  
  def __init__(self, verbose=0):
    self.setverbose(verbose)
  # def __init__
  
  def setverbose(self, verbose):
    """docstring for setverbose"""
    self.verbose = verbose
  # def setverbose
  
  def debug(self, out, level=0):
    """docstring for debug"""
    if self.verbose:
      if level > 0:
        print "*"*level,out
      else:
        print out
    # if verbose
  # def debug
# class Debug

def error(out):
  """Print error on stderr"""
  print >> sys.stderr, str(out)+"\n"
# def error

def getConfig(filename):
  """reads filename as config, checks for DEST parameter and returns cfgfile object"""
  ret = None
  try:
    ret = cfgfile.Conf(filename)
  except:
    error("Error reading config file %s" % filename)
    return False
  # try
  
  # check for DEST parameter
  if not ret.check("Main", "dest"):
    error("No DEST in config file %s" % filename)
    return False
  # if no DEST

  # replace $HOME with real home directory
  if ret.get("Main", "dest") == "$HOME":
    ret.set("Main", "dest", os.environ['HOME'])
  # if $HOME
  
  # make sure DEST ends with /
  if not ret.get("Main", "dest").endswith("/"):
    ret.set("Main", "dest", ret.get("Main", "dest")+"/")
  # if not /
  
  return ret
# def getConfig

def read_skip_comment(fp, commentstring):
  """Read line from filehandle fp and skip all empty (whitespace) lines and lines starting with commentstring
  """
  for line in fp:
    line = line[:-1]
    if (commentstring != "" and not re.match("^"+re.escape(commentstring), line)) and line !="" and not re.match("^\s+$", line):
      yield line
    # if not match
  # for line
# def read_skip_comment

def diff(destfile, tempfile, commentstring, debug):
  """diff destfile and tempfile, returns True if files differ, False if they are the same"""
  debug.debug("Diffing %s and %s" % (destfile, tempfile))
  if not os.path.isfile(destfile):
    debug.debug("Destfile %s does not exist, returning True." % destfile)
    # destfile does not exist -> copy tempfile over
    return True
  # if not destfile
  if not os.path.isfile(tempfile):
    # tempfile does not exist, this should never happen
    error("Temporary file %s does not exist, this should not happen." % tempfile)
    sys.exit(1)
  # if not tempfile
  
  fp1 = open(tempfile)
  fp2 = open(destfile)
  
  for line1, line2 in itertools.izip(read_skip_comment(fp1, commentstring), read_skip_comment(fp2, commentstring)):
    if line1 != line2:
      fp1.close()
      fp2.close()
      return True
    # if differ
  # for line
  fp1.close()
  fp2.close()
  return False
# def diff

def userConfigGenerated(filename, cfg):
  """returns True if filename has been generated by userconfig, False else"""

  if not os.path.isfile(filename):
    # filename does not exist, so it was not generated by userconfig
    return False
  # if not filename
  
  if not cfg.check("Main","stamp"):
    # no STAMP in userconfig.cfg, so no way to check if file was generated by userconfig
    return False
  # no STAMP

  fp = open(filename, "r")
  
  for line in fp:
    if re.search(re.escape(cfg.get("Main","stamp")), line):
      return True
    # if search
  # for line
  return False
# def userConfigGenerated

def backupFile(filename, debug):
  """make backup of filename, returns True if backup is successful, False else"""
  if os.path.isfile(filename):
    backupname = filename+".userconfig."+time.strftime("%F")
    testbackupname = backupname
    counter = 0
    while os.path.isfile(testbackupname):
      counter+=1
      testbackupname=backupname+"."+str(counter)
    # while
    debug.debug("Renaming %s to %s" % (filename, testbackupname))
    os.rename(filename, testbackupname)
    return True
  # if filename
  return False
# def backupFile

def copyFile(sourcefile, destfile, debug):
  """copy sourcefile to destfile, returns True if successful, False else"""
  
  if os.path.isfile(sourcefile):
    # sourcefile exists
    if not os.path.isfile(destfile) or os.access(destfile, os.W_OK):
      debug.debug("Copying %s to %s" % (sourcefile, destfile))
      shutil.copy(sourcefile, destfile)
      return True
      # destfile is writable
    # if write ok
  return False
# def copyFile