# -*- coding: UTF-8 -*-
#
# Copyright (C) 2007 by Jan Dittberner.
#
# This program 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 2 of the License, or
# (at your option) any later version.
#
# This program 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 this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
# USA.
#
# Version: $Id$

import getopt, sys

class CliCommand:
    """Base class for command line interface."""
    def usage(self):
        """This method should print usage information for the command."""
        raise NotImplementedError

    def shortopts(self):
        """This method should return an option string for the short
        options for getopt.gnu_getopt(...)."""
        raise NotImplementedError

    def longopts(self):
        """This method should return a list of long options for
        getopt.gnu_getopt(...)."""
        raise NotImplementedError

    def handleoption(self, option, argument):
        """This method should handle each option known to the command."""
        raise NotImplementedError

    def execute(self):
        """This method is called when the command is executed."""
        raise NotImplementedError

    def checkrequired(self):
        """This methode is called after handling command line options
        and should check whether all required values were set."""
        raise NotImplementedError

    def __parseopts(self, args):
        """This method parses the options given on the command line."""
        longopts = ["help", "verbose"]
        longopts.extend(self.longopts())
        try:
            opts, args = getopt.gnu_getopt(
                args,
                "hv" + self.shortopts(),
                longopts)
        except getopt.GetoptError:
            self.usage()
            sys.exit(2)
        self.verbose = False
        for o, a in opts:
            if o in ("-v", "--verbose"):
                self.verbose = True
            if o in ("-h", "--help"):
                self.usage()
                sys.exit()
            self.handleoption(o, a)

    def __init__(self, args):
        """This initializes the command with the given command line
        arguments and executes it."""
        self.__parseopts(args)
        if (self.checkrequired()):
            self.execute()
        else:
            self.usage()