/stdhome

# program.py

#

# Copyright (C) 2013 Tim Marston <tim@edm.am>

#

# This file is part of stdhome (hereafter referred to as "this program").

# See http://ed.am/dev/stdhome for more information.

#

# 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 3 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, see <http://www.gnu.org/licenses/>.

import os, sys, getopt

import the

class Program:

	def __init__( self, version ):

		self.name = os.path.basename( sys.argv[ 0 ] )

		self.version = version

	def die( self, error_message ):

		prefix = self.name + ( ' ' + the.command if the.command else '' )

		print >> sys.stderr, '%s: %s' % ( prefix, error_message )

		exit( 1 )

	def print_usage( self, error_message ):

		suffix = ' ' + the.command if the.command else ''

		self.die( error_message + \

				  "\nTry '%s%s --help' for more information." % \

				  ( self.name, suffix ) )

	def print_help( self ):

		print "Usage: " + self.name + " COMMAND [OPTION]..."

		print

		#      01234567890123456789012345678901234567890123456789012345678901234567890123456789

		print "Manage your home directories, across multiple computers, similar to how you"

		print "would software under version control."

		print

		print "Global options (for all commands):"

		print "     --help     display help and exit"

		print "     --version  output version information and exit"

		print

		print "Commands:"

		print "  init          initialise a local copy of your repositories"

		print "  update        update files in your home directory"

		print "  resolve       try to finish an update (that had conflicts)"

		print "  add           add local files/changes to the repository"

		print "  remove        remove a local file from the repository"

		print "  revert        undo changes made to a local file"

		print "  stage-add     stage local files/changes"

		print "  stage-remove  stage the removal of files"

		print "  stage-revert  revert staged changes"

		print "  stage-status  show status of staging area"

		print "  stage-commit  commit staged changes to repository"

		print

		print "For help about a particular command (including the additional options that the"

		print "command accepts) try typing:"

		print "  $ " + self.name + " COMMAND --help"

		exit( 0 )

	def print_version( self ):

		print "stdhome " + self.version

		print

		print "Copyright (C) 2013 Tim Marston"

		print

		#      01234567890123456789012345678901234567890123456789012345678901234567890123456789

		print "This program is free software, and you may use, modify and redistribute it"

		print "under the terms of the GNU General Public License version 3 or later.  This"

		print "program comes with ABSOLUTELY NO WARRANTY, to the extent permitted by law."

		print

		print "For more information, including documentation, please see the project website"

		print "at http://ed.am/dev/stdhome."

		print

		print "Please report bugs to <tim@ed.am>."

		exit( 0 )

	def check_command( self, command ):

		"""

		Check that the given command is valid and return the full name of the command.

		Arguments:

		- `command`: the given command

		"""

		# commands

		if [ 'init', 'update', 'resolve', 'add', 'remove', 'revert',

			 'stage-add', 'stage-remove', 'stage-revert', 'stage-status',

			 'stage-commit' ].count( command ) == 1:

			return command

		# resolve aliases

		elif command == 'up':

			return 'update'

		elif command == 'rm':

			return 'remove'

		# invalid

		else:

			return None

	def get_command_argument( self, args ):

		"""

		Find the first program argument what isn't an option argument.

        Arguments:

        - `args`: the program arguments

        """

		while args:

			if args[ 0 ] == '--':

				return args[ 1 ] if len( args ) > 1 else None

			if args[ 0 ][ 0 : 1 ] != '-':

				return args[ 0 ]

			args = args[ 1 : ]

		return None

	def run( self ):

		# make an initial attempt to parse the command line, looking only for

		# --help and --version, so that they have the chance to run without a

		# command being specified

		try:

			opts, args = getopt.gnu_getopt(

				sys.argv[ 1: ], "",

				[ "help", "version" ] )

			for opt, optarg in opts:

				# we only show help if there are no non-option arguments (e.g.,

				# a command) specified.  If a command has been specified it will

				# have to be parsed and --help will be handled by it, instead)

				if opt == "--help" and len( args ) == 0:

					self.print_help()

				elif opt == "--version":

					self.print_version()

		except getopt.GetoptError as e:

			# ignore errors -- we aren't parsing the command line properly yet

			pass

		# find the first non-option argument (the command)

		the.command = self.get_command_argument( sys.argv[ 1: ] )

		if the.command == None:

			self.print_usage( "missing command" )

		# check command is valid

		the.command = self.check_command( the.command )

		if the.command == None:

			self.print_usage( "bad command" )

		# calculate class name

		bits = the.command.split( '-' )

		class_name = 'Command'

		for bit in bits:

			class_name += bit[ 0 ].upper() + bit[ 1 : ]

		# instantiate the command class

		module = __import__( 'stdhome.command_' + the.command,

							 fromlist = [ class_name ] )

		instance = getattr( module, class_name )()

		# run it

		try:

			instance.parse_command_line()

			instance.run()

		except ( getopt.GetoptError, self.UsageError ) as e:

			self.print_usage( e.msg )

		except self.FatalError as e:

			message = e.msg

			if the.verbose and e.output:

				message += '\n\nOUTPUT:\n' + e.output

			self.die( message )

	class UsageError( Exception ):

		def __init__( self, error_message ):

			self.msg = error_message

	class FatalError( Exception ):

		def __init__( self, message, output = None ):

			self.msg = message

			self.output = output