# Copyright (C) 2007 Brendan Cully <brendan@kublai.com>

# This file is published under the GNU GPL.

'''allow user-defined command aliases

To use, create entries in your hgrc of the form

[alias]

mycmd = cmd --args

'''

from mercurial.cmdutil import findcmd, UnknownCommand, AmbiguousCommand

from mercurial import commands

cmdtable = {}

class RecursiveCommand(Exception): pass

class lazycommand(object):

    '''defer command lookup until needed, so that extensions loaded

    after alias can be aliased'''

    def __init__(self, ui, name, target):

        self._ui = ui

        self._name = name

        self._target = target

        self._cmd = None

    def __len__(self):

        self._resolve()

        return len(self._cmd)

    def __getitem__(self, key):

        self._resolve()

        return self._cmd[key]

    def __iter__(self):

        self._resolve()

        return self._cmd.__iter__()

    def _resolve(self):

        if self._cmd is not None:

            return

        try:

            self._cmd = findcmd(self._ui, self._target, commands.table)[1]

            if self._cmd == self:

                raise RecursiveCommand()

            if self._target in commands.norepo.split(' '):

                commands.norepo += ' %s' % self._name

            return

        except UnknownCommand:

            msg = '*** [alias] %s: command %s is unknown' % \

                  (self._name, self._target)

        except AmbiguousCommand:

            msg = '*** [alias] %s: command %s is ambiguous' % \

                  (self._name, self._target)

        except RecursiveCommand:

            msg = '*** [alias] %s: circular dependency on %s' % \

                  (self._name, self._target)

        def nocmd(*args, **opts):

            self._ui.warn(msg + '\n')

            return 1

        nocmd.__doc__ = msg

        self._cmd = (nocmd, [], '')

        commands.norepo += ' %s' % self._name

def uisetup(ui):

    for cmd, target in ui.configitems('alias'):

        if not target:

            ui.warn('*** [alias] %s: no definition\n' % cmd)

            continue

        args = target.split(' ')

        tcmd = args.pop(0)

        if args:

            ui.setconfig('defaults', cmd, ' '.join(args))

        cmdtable[cmd] = lazycommand(ui, cmd, tcmd)