/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 ):

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

		self.die( error_message + \

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

				  ( self.name, command ) )

	def print_help( self ):

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

		print

		#      01234567890123456789012345678901234567890123456789012345678901234567890123456789

		print "Tool to manage a set of files in your home directory and distribute them across"

		print "multiple computers, merging local changes (in the same way as you would manage"

		print "source code 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 "  status        list files that have changed locally"

		print "  diff          shows changes made to local files"

		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-diff    shows staged changes"

		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', 'status',

			 'diff', 'stage-add', 'stage-remove', 'stage-revert',

			 'stage-status', 'stage-diff', '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 module and class name

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

		class_name = 'Command'

		module_name = 'command'

		for bit in bits:

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

			module_name += '_' + bit

		# import module and instantiate the class

		module = __import__( 'stdhome.' + module_name,

							 fromlist = [ class_name ] )

		instance = getattr( module, class_name )()

		# run the command

		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.rstrip()

			if the.verbose and hasattr( e, 'output' ) and e.output:

				message += '\n\nOUTPUT:\n' + e.output.rstrip()

			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