# Copyright (c) 2009 Google Inc. All rights reserved.

# Copyright (c) 2009 Apple Inc. All rights reserved.

#

# Redistribution and use in source and binary forms, with or without

# modification, are permitted provided that the following conditions are

# met:

# 

#     * Redistributions of source code must retain the above copyright

# notice, this list of conditions and the following disclaimer.

#     * Redistributions in binary form must reproduce the above

# copyright notice, this list of conditions and the following disclaimer

# in the documentation and/or other materials provided with the

# distribution.

#     * Neither the name of Google Inc. nor the names of its

# contributors may be used to endorse or promote products derived from

# this software without specific prior written permission.

# 

# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS

# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT

# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR

# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT

# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,

# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT

# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,

# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY

# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT

# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE

# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

#

# MultiCommandTool provides a framework for writing svn-like/git-like tools

# which are called with the following format:

# tool-name [global options] command-name [command options]

import sys

from optparse import OptionParser, IndentedHelpFormatter, SUPPRESS_USAGE, make_option

from webkitpy.tool.grammar import pluralize

from webkitpy.common.system.deprecated_logging import log

class TryAgain(Exception):

    pass

class Command(object):

    name = None

    show_in_main_help = False

    def __init__(self, help_text, argument_names=None, options=None, long_help=None, requires_local_commits=False):

        self.help_text = help_text

        self.long_help = long_help

        self.argument_names = argument_names

        self.required_arguments = self._parse_required_arguments(argument_names)

        self.options = options

        self.requires_local_commits = requires_local_commits

        self.tool = None

        # option_parser can be overriden by the tool using set_option_parser

        # This default parser will be used for standalone_help printing.

        self.option_parser = HelpPrintingOptionParser(usage=SUPPRESS_USAGE, add_help_option=False, option_list=self.options)

    # This design is slightly awkward, but we need the

    # the tool to be able to create and modify the option_parser

    # before it knows what Command to run.

    def set_option_parser(self, option_parser):

        self.option_parser = option_parser

        self._add_options_to_parser()

    def _add_options_to_parser(self):

        options = self.options or []

        for option in options:

            self.option_parser.add_option(option)

    # The tool calls bind_to_tool on each Command after adding it to its list.

    def bind_to_tool(self, tool):

        # Command instances can only be bound to one tool at a time.

        if self.tool and tool != self.tool:

            raise Exception("Command already bound to tool!")

        self.tool = tool

    @staticmethod

    def _parse_required_arguments(argument_names):

        required_args = []

        if not argument_names:

            return required_args

        split_args = argument_names.split(" ")

        for argument in split_args:

            if argument[0] == '[':

                # For now our parser is rather dumb.  Do some minimal validation that

                # we haven't confused it.

                if argument[-1] != ']':

                    raise Exception("Failure to parse argument string %s.  Argument %s is missing ending ]" % (argument_names, argument))

            else:

                required_args.append(argument)

        return required_args

    def name_with_arguments(self):

        usage_string = self.name

        if self.options:

            usage_string += " [options]"

        if self.argument_names:

            usage_string += " " + self.argument_names

        return usage_string

    def parse_args(self, args):

        return self.option_parser.parse_args(args)

    def check_arguments_and_execute(self, options, args, tool=None):

        if len(args) < len(self.required_arguments):

            log("%s required, %s provided.  Provided: %s  Required: %s\nSee '%s help %s' for usage." % (

                pluralize("argument", len(self.required_arguments)),

                pluralize("argument", len(args)),

                "'%s'" % " ".join(args),

                " ".join(self.required_arguments),

                tool.name(),

                self.name))

            return 1

        return self.execute(options, args, tool) or 0

    def standalone_help(self):

        help_text = self.name_with_arguments().ljust(len(self.name_with_arguments()) + 3) + self.help_text + "\n\n"

        if self.long_help:

            help_text += "%s\n\n" % self.long_help

        help_text += self.option_parser.format_option_help(IndentedHelpFormatter())

        return help_text

    def execute(self, options, args, tool):

        raise NotImplementedError, "subclasses must implement"

    # main() exists so that Commands can be turned into stand-alone scripts.

    # Other parts of the code will likely require modification to work stand-alone.

    def main(self, args=sys.argv):

        (options, args) = self.parse_args(args)

        # Some commands might require a dummy tool

        return self.check_arguments_and_execute(options, args)

# FIXME: This should just be rolled into Command.  help_text and argument_names do not need to be instance variables.

class AbstractDeclarativeCommand(Command):

    help_text = None

    argument_names = None

    long_help = None

    def __init__(self, options=None, **kwargs):

        Command.__init__(self, self.help_text, self.argument_names, options=options, long_help=self.long_help, **kwargs)

class HelpPrintingOptionParser(OptionParser):

    def __init__(self, epilog_method=None, *args, **kwargs):

        self.epilog_method = epilog_method

        OptionParser.__init__(self, *args, **kwargs)

    def error(self, msg):

        self.print_usage(sys.stderr)

        error_message = "%s: error: %s\n" % (self.get_prog_name(), msg)

        # This method is overriden to add this one line to the output:

        error_message += "\nType \"%s --help\" to see usage.\n" % self.get_prog_name()

        self.exit(1, error_message)

    # We override format_epilog to avoid the default formatting which would paragraph-wrap the epilog

    # and also to allow us to compute the epilog lazily instead of in the constructor (allowing it to be context sensitive).

    def format_epilog(self, epilog):

        if self.epilog_method:

            return "\n%s\n" % self.epilog_method()

        return ""

class HelpCommand(AbstractDeclarativeCommand):

    name = "help"

    help_text = "Display information about this program or its subcommands"

    argument_names = "[COMMAND]"

    def __init__(self):

        options = [

            make_option("-a", "--all-commands", action="store_true", dest="show_all_commands", help="Print all available commands"),

        ]

        AbstractDeclarativeCommand.__init__(self, options)

        self.show_all_commands = False # A hack used to pass --all-commands to _help_epilog even though it's called by the OptionParser.

    def _help_epilog(self):

        # Only show commands which are relevant to this checkout's SCM system.  Might this be confusing to some users?

        if self.show_all_commands:

            epilog = "All %prog commands:\n"

            relevant_commands = self.tool.commands[:]

        else:

            epilog = "Common %prog commands:\n"

            relevant_commands = filter(self.tool.should_show_in_main_help, self.tool.commands)

        longest_name_length = max(map(lambda command: len(command.name), relevant_commands))

        relevant_commands.sort(lambda a, b: cmp(a.name, b.name))

        command_help_texts = map(lambda command: "   %s   %s\n" % (command.name.ljust(longest_name_length), command.help_text), relevant_commands)

        epilog += "%s\n" % "".join(command_help_texts)

        epilog += "See '%prog help --all-commands' to list all commands.\n"

        epilog += "See '%prog help COMMAND' for more information on a specific command.\n"

        return epilog.replace("%prog", self.tool.name()) # Use of %prog here mimics OptionParser.expand_prog_name().

    # FIXME: This is a hack so that we don't show --all-commands as a global option:

    def _remove_help_options(self):

        for option in self.options:

            self.option_parser.remove_option(option.get_opt_string())

    def execute(self, options, args, tool):

        if args:

            command = self.tool.command_by_name(args[0])

            if command:

                print command.standalone_help()

                return 0

        self.show_all_commands = options.show_all_commands

        self._remove_help_options()

        self.option_parser.print_help()

        return 0

class MultiCommandTool(object):

    global_options = None

    def __init__(self, name=None, commands=None):

        self._name = name or OptionParser(prog=name).get_prog_name() # OptionParser has nice logic for fetching the name.

        # Allow the unit tests to disable command auto-discovery.

        self.commands = commands or [cls() for cls in self._find_all_commands() if cls.name]

        self.help_command = self.command_by_name(HelpCommand.name)

        # Require a help command, even if the manual test list doesn't include one.

        if not self.help_command:

            self.help_command = HelpCommand()

            self.commands.append(self.help_command)

        for command in self.commands:

            command.bind_to_tool(self)

    @classmethod

    def _add_all_subclasses(cls, class_to_crawl, seen_classes):

        for subclass in class_to_crawl.__subclasses__():

            if subclass not in seen_classes:

                seen_classes.add(subclass)

                cls._add_all_subclasses(subclass, seen_classes)

    @classmethod

    def _find_all_commands(cls):

        commands = set()

        cls._add_all_subclasses(Command, commands)

        return sorted(commands)

    def name(self):

        return self._name

    def _create_option_parser(self):

        usage = "Usage: %prog [options] COMMAND [ARGS]"

        return HelpPrintingOptionParser(epilog_method=self.help_command._help_epilog, prog=self.name(), usage=usage)

    @staticmethod

    def _split_command_name_from_args(args):

        # Assume the first argument which doesn't start with "-" is the command name.

        command_index = 0

        for arg in args:

            if arg[0] != "-":

                break

            command_index += 1

        else:

            return (None, args[:])

        command = args[command_index]

        return (command, args[:command_index] + args[command_index + 1:])

    def command_by_name(self, command_name):

        for command in self.commands:

            if command_name == command.name:

                return command

        return None

    def path(self):

        raise NotImplementedError, "subclasses must implement"

    def command_completed(self):

        pass

    def should_show_in_main_help(self, command):

        return command.show_in_main_help

    def should_execute_command(self, command):

        return True

    def _add_global_options(self, option_parser):

        global_options = self.global_options or []

        for option in global_options:

            option_parser.add_option(option)

    def handle_global_options(self, options):

        pass

    def main(self, argv=sys.argv):

        (command_name, args) = self._split_command_name_from_args(argv[1:])

        option_parser = self._create_option_parser()

        self._add_global_options(option_parser)

        command = self.command_by_name(command_name) or self.help_command

        if not command:

            option_parser.error("%s is not a recognized command" % command_name)

        command.set_option_parser(option_parser)

        (options, args) = command.parse_args(args)

        self.handle_global_options(options)

        (should_execute, failure_reason) = self.should_execute_command(command)

        if not should_execute:

            log(failure_reason)

            return 0 # FIXME: Should this really be 0?

        while True:

            try:

                result = command.check_arguments_and_execute(options, args, self)

                break

            except TryAgain, e:

                pass

        self.command_completed()

        return result