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

"""
userconfig.py

Created by Marcus Stoegbauer on 2013-01-10.
Copyright (c) 2013 __MyCompanyName__. All rights reserved.
"""

import sys
import os
import tempfile
import re
import getopt
# 
import cfgfile
from checks import checks

classchecks = checks()
cfg = cfgfile.Conf()
verbose = 0

hostclasses = classchecks.__classesForHost__()

class Usage(Exception):
  def __init__(self, msg):
    self.msg = msg


help_message = """
-h help
-d debug
-c userconfig.cfg config file
"""

def debug(out, level=0):
  """docstring for debug"""
  if verbose:
    if level > 0:
      print "*"*level,out
    else:
      print out
  # if verbose
# def 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"""
  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 workconf(directory, depth=2):
  """walks through directory, collecting all filenames, returns list of all filenames"""
  dirs = os.listdir(directory)
  ret = []
  for d in dirs:
    name = directory+"/"+d
    if os.path.isdir(name):
      # fixme: create name if it does not exist
      workconf(name, depth+1)
    # if dir
    ret.append(name)
    debug("workconf: found file %s" % name, depth)
  # for d
  return ret
# def workconf

def workdir(directory):
  """walks through all host classes, checking if the classes directory exists in directory
     then collect all filenames within this directory and return a dict of all files for this
     directory
  """
  debug("===============================", 1)
  
  # skip directory if no CONFIGFILE present
  if not os.path.isfile(directory+"/"+cfg.get("Main", "CONFIGFILE")):
    debug("No %s in %s, skipping." % (cfg.get("Main", "CONFIGFILE"), directory), 1)
    return {}
  # if not DEST
  
  # get config file for directory
  dirConfig = getConfig(directory+"/"+cfg.get("Main", "CONFIGFILE"))
  if not dirConfig:
    debug("Cannot read %s in %s, skipping." % (cfg.get("Main", "CONFIGFILE"), directory), 1)
    return {}
  # if not dirConfig
  
  destdir = dirConfig.get("Main","DEST")
  # destfiles is a dict of all files that will be created from the classes config
  # key is the destination filename, values are all classes filenames that are used to
  # build the file
  destfiles = {}
  
  # walk through all know classes in directory and find filenames
  for h in hostclasses:
    # build classes directory
    if h[0] != "":
      classdir = directory+"/"+h[0]+"_"+h[1]
    else:
      classdir = directory+"/"+h[1]
    # if all
    
    # if class directory exists
    if os.path.isdir(classdir):
      debug("workdir: %s" % classdir, 1)
      # get list of files within this class directory
      tempfiles = workconf(classdir)
      
      # put files into dict
      for f in tempfiles:
        destname = destdir+os.path.basename(f)  # destination filename
        if not destfiles.has_key(destname):
          destfiles[destname] = []
        # if not destname, create key with empty list
        destfiles[destname].append(f) # append each file to dict
      # for tempfiles
    # if classdir
  # for hostclasses
  
  debug("workdir: %s, Files: %s" % (directory, str(destfiles)))
  debug("^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^", 1)
  return destfiles
# def work

def buildFile(classfiles, destfile):
  """open all classfiles, assemble them and write the contents into a tempfile
    returns the name of tempfile"""
  content = []
  for f in classfiles:
    fp = open(f, "r")
    filecontent = fp.read()
    fp.close()
    
    # look for stamp in content, replace with real stamp
    if re.search(re.escape(cfg.get("Main","STAMPREPLACE")), filecontent):
      filecontent = re.sub(re.escape(cfg.get("Main","STAMPREPLACE")), cfg.get("Main","STAMP"), filecontent)
    # if match
    content.append(filecontent)
  # end f
  
  (tempfd, tempfilename) = tempfile.mkstemp(prefix=os.path.basename(destfile), dir="/tmp")

  fp = None
  try:
    fp = os.fdopen(tempfd, "w")
  except:
    error("Cannot write to temporary file %s" % tempfilename)
    os.remove(tempfilename)
    return False
  # try
  
  for block in content:
    fp.write(block)
    fp.write("\n")
  # for content
  fp.close()

  return tempfilename
# def buildFile

def diff(fileA, fileB):
  """diff fileA and fileB, returns True if files differ, False if they are the same"""
  # FIXME: write
  # FIXME: filter out comments?
  # FIXME: COMMENTSTRING in config?
  return False
# def diff

def userConfigGenerated(filename):
  """returns True if filename has been generated by userconfig, False else"""
  # FIXME: write
  return True
# def userConfigGenerated

def backupFile(filename):
  """make backup of filename, returns True if backup is successful, False else"""
  # FIXME: write
  return True
# def backupFile

def copyFile(sourcefile, destfile):
  """copy sourcefile to destfile, returns True if successful, False else"""
  return True
# def copyFile

def processAllFiles(destfiles):
  """processes all files in destfiles, generate files from classes, compare and copy if necessary"""
  for df in destfiles.keys():
    # assemble file to tmp
    tempfilename = buildFile(destfiles[df], df)
    if not tempfilename:
      debug("Error while creating temp file for %s, skipping." % df)
      continue
    # if not tempfilename
    
    # diff assembled file and config file
    if diff(df, tempfilename):
      if not userConfigGenerated(df):
        # file not generated from userconfig -> back up
        backupFile(df)
      # if not userConfigGenerated
      # copy tmp file to real location
      copyFile(tempfilename, df)
      # remove tmp
      os.remove(tempfilename)
    # if diff
  # for df
# def buildAllFiles

def main():
  configfile = ""
  global verbose
  
  try:
    try:
      opts, args = getopt.getopt(sys.argv[1:], "hdc:v", ["help", "debug", "config="])
    except getopt.error, msg:
      raise Usage(msg)
    # try getopt
    
    for option, value in opts:
      if option == "-v":
        verbose = 1
      if option in ("-h", "--help"):
        raise Usage(help_message)
      if option in ("-d", "--debug"):
        pass
      if option in ("-c", "--config"):
        configfile = value
      # if
    # for option, value
  except Usage, err:
    error(sys.argv[0].split("/")[-1] + ": " + str(err.msg))
    error("\t for help use --help")
    return 2
  # try
  
  if configfile == "":
    error( "No config file specified.")
    return 2
  # if configfile
  cfg.setfilename(configfile)

  debug("Classes for host: %s" % hostclasses)
  configdir = cfg.get("Main", "CONFIGDIR")
  for d in os.listdir(configdir):
    name = configdir+d
    if not os.path.isdir(name):
      continue
    elif d.startswith(".svn"):
      continue
    elif os.path.isfile(name+"/.ignore"):
      continue
    else:
      debug("main: %s" % name)
      destfiles = workdir(name)
      processAllFiles(destfiles)
    # if
  # for d
# def main


if __name__ == '__main__':
  main()