# Copyright 2012 Logilab SA        <contact@logilab.fr>

#                Pierre-Yves David <pierre-yves.david@ens-lyon.org>

#                Octobus <contact@octobus.net>

#

# This software may be used and distributed according to the terms of the

# GNU General Public License version 2 or any later version.

#####################################################################

### Extension helper                                              ###

#####################################################################

from mercurial import (

    commands,

    error,

    extensions,

    registrar,

)

class exthelper(object):

    """Helper for modular extension setup

    A single helper should be instantiated for each module of an

    extension, where a command or function needs to be wrapped, or a

    command, extension hook, fileset, revset or template needs to be

    registered.  Helper methods are then used as decorators for

    these various purposes.  If an extension spans multiple modules,

    all helper instances should be merged in the main module.

    All decorators return the original function and may be chained.

    Aside from the helper functions with examples below, several

    registrar method aliases are available for adding commands,

    configitems, filesets, revsets, and templates.  Simply decorate

    the appropriate methods, and assign the corresponding exthelper

    variable to a module level variable of the extension.  The

    extension loading mechanism will handle the rest.

    example::

        # ext.py

        eh = exthelper.exthelper()

        # As needed:

        cmdtable = eh.cmdtable

        configtable = eh.configtable

        filesetpredicate = eh.filesetpredicate

        revsetpredicate = eh.revsetpredicate

        templatekeyword = eh.templatekeyword

        @eh.command('mynewcommand',

            [('r', 'rev', [], _('operate on these revisions'))],

            _('-r REV...'),

            helpcategory=command.CATEGORY_XXX)

        def newcommand(ui, repo, *revs, **opts):

            # implementation goes here

        eh.configitem('experimental', 'foo',

            default=False,

        )

        @eh.filesetpredicate('lfs()')

        def filesetbabar(mctx, x):

            return mctx.predicate(...)

        @eh.revsetpredicate('hidden')

        def revsetbabar(repo, subset, x):

            args = revset.getargs(x, 0, 0, 'babar accept no argument')

            return [r for r in subset if 'babar' in repo[r].description()]

        @eh.templatekeyword('babar')

        def kwbabar(ctx):

            return 'babar'

    """

    def __init__(self):

        self._uipopulatecallables = []

        self._uicallables = []

        self._extcallables = []

        self._repocallables = []

        self._commandwrappers = []

        self._extcommandwrappers = []

        self._functionwrappers = []

        self._duckpunchers = []

        self.cmdtable = {}

        self.command = registrar.command(self.cmdtable)

        if '^init' in commands.table:

            olddoregister = self.command._doregister

            def _newdoregister(self, name, *args, **kwargs):

                if kwargs.pop('helpbasic', False):

                    name = '^' + name

                return olddoregister(self, name, *args, **kwargs)

            self.command._doregister = _newdoregister

        self.configtable = {}

        self.configitem = registrar.configitem(self.configtable)

        self.filesetpredicate = registrar.filesetpredicate()

        self.revsetpredicate = registrar.revsetpredicate()

        self.templatekeyword = registrar.templatekeyword()

    def merge(self, other):

        self._uicallables.extend(other._uicallables)

        self._uipopulatecallables.extend(other._uipopulatecallables)

        self._extcallables.extend(other._extcallables)

        self._repocallables.extend(other._repocallables)

        self.filesetpredicate._table.update(other.filesetpredicate._table)

        self.revsetpredicate._table.update(other.revsetpredicate._table)

        self.templatekeyword._table.update(other.templatekeyword._table)

        self._commandwrappers.extend(other._commandwrappers)

        self._extcommandwrappers.extend(other._extcommandwrappers)

        self._functionwrappers.extend(other._functionwrappers)

        self._duckpunchers.extend(other._duckpunchers)

        self.cmdtable.update(other.cmdtable)

        for section, items in other.configtable.iteritems():

            if section in self.configtable:

                self.configtable[section].update(items)

            else:

                self.configtable[section] = items

    def finaluisetup(self, ui):

        """Method to be used as the extension uisetup

        The following operations belong here:

        - Changes to ui.__class__ . The ui object that will be used to run the

          command has not yet been created. Changes made here will affect ui

          objects created after this, and in particular the ui that will be

          passed to runcommand

        - Command wraps (extensions.wrapcommand)

        - Changes that need to be visible to other extensions: because

          initialization occurs in phases (all extensions run uisetup, then all

          run extsetup), a change made here will be visible to other extensions

          during extsetup

        - Monkeypatch or wrap function (extensions.wrapfunction) of dispatch

          module members

        - Setup of pre-* and post-* hooks

        - pushkey setup

        """

        for cont, funcname, func in self._duckpunchers:

            setattr(cont, funcname, func)

        for command, wrapper, opts in self._commandwrappers:

            entry = extensions.wrapcommand(commands.table, command, wrapper)

            if opts:

                for opt in opts:

                    entry[1].append(opt)

        for cont, funcname, wrapper in self._functionwrappers:

            extensions.wrapfunction(cont, funcname, wrapper)

        for c in self._uicallables:

            c(ui)

    def finaluipopulate(self, ui):

        """Method to be used as the extension uipopulate

        This is called once per ui instance to:

        - Set up additional ui members

        - Update configuration by ``ui.setconfig()``

        - Extend the class dynamically

        """

        for c in self._uipopulatecallables:

            c(ui)

    def finalextsetup(self, ui):

        """Method to be used as a the extension extsetup

        The following operations belong here:

        - Changes depending on the status of other extensions. (if

          extensions.find('mq'))

        - Add a global option to all commands

        """

        knownexts = {}

        for ext, command, wrapper, opts in self._extcommandwrappers:

            if ext not in knownexts:

                try:

                    e = extensions.find(ext)

                except KeyError:

                    # Extension isn't enabled, so don't bother trying to wrap

                    # it.

                    continue

                knownexts[ext] = e.cmdtable

            entry = extensions.wrapcommand(knownexts[ext], command, wrapper)

            if opts:

                for opt in opts:

                    entry[1].append(opt)

        for c in self._extcallables:

            c(ui)

    def finalreposetup(self, ui, repo):

        """Method to be used as the extension reposetup

        The following operations belong here:

        - All hooks but pre-* and post-*

        - Modify configuration variables

        - Changes to repo.__class__, repo.dirstate.__class__

        """

        for c in self._repocallables:

            c(ui, repo)

    def uisetup(self, call):

        """Decorated function will be executed during uisetup

        example::

            @eh.uisetup

            def setupbabar(ui):

                print 'this is uisetup!'

        """

        self._uicallables.append(call)

        return call

    def uipopulate(self, call):

        """Decorated function will be executed during uipopulate

        example::

            @eh.uipopulate

            def setupfoo(ui):

                print 'this is uipopulate!'

        """

        self._uipopulatecallables.append(call)

        return call

    def extsetup(self, call):

        """Decorated function will be executed during extsetup

        example::

            @eh.extsetup

            def setupcelestine(ui):

                print 'this is extsetup!'

        """

        self._extcallables.append(call)

        return call

    def reposetup(self, call):

        """Decorated function will be executed during reposetup

        example::

            @eh.reposetup

            def setupzephir(ui, repo):

                print 'this is reposetup!'

        """

        self._repocallables.append(call)

        return call

    def wrapcommand(self, command, extension=None, opts=None):

        """Decorated function is a command wrapper

        The name of the command must be given as the decorator argument.

        The wrapping is installed during `uisetup`.

        If the second option `extension` argument is provided, the wrapping

        will be applied in the extension commandtable. This argument must be a

        string that will be searched using `extension.find` if not found and

        Abort error is raised. If the wrapping applies to an extension, it is

        installed during `extsetup`.

        example::

            @eh.wrapcommand('summary')

            def wrapsummary(orig, ui, repo, *args, **kwargs):

                ui.note('Barry!')

                return orig(ui, repo, *args, **kwargs)

        The `opts` argument allows specifying a list of tuples for additional

        arguments for the command.  See ``mercurial.fancyopts.fancyopts()`` for

        the format of the tuple.

        """

        if opts is None:

            opts = []

        else:

            for opt in opts:

                if not isinstance(opt, tuple):

                    raise error.ProgrammingError('opts must be list of tuples')

                if len(opt) not in (4, 5):

                    msg = 'each opt tuple must contain 4 or 5 values'

                    raise error.ProgrammingError(msg)

        def dec(wrapper):

            if extension is None:

                self._commandwrappers.append((command, wrapper, opts))

            else:

                self._extcommandwrappers.append((extension, command, wrapper,

                                                 opts))

            return wrapper

        return dec

    def wrapfunction(self, container, funcname):

        """Decorated function is a function wrapper

        This function takes two arguments, the container and the name of the

        function to wrap. The wrapping is performed during `uisetup`.

        (there is no extension support)

        example::

            @eh.function(discovery, 'checkheads')

            def wrapfunction(orig, *args, **kwargs):

                ui.note('His head smashed in and his heart cut out')

                return orig(*args, **kwargs)

        """

        def dec(wrapper):

            self._functionwrappers.append((container, funcname, wrapper))

            return wrapper

        return dec

    def addattr(self, container, funcname):

        """Decorated function is to be added to the container

        This function takes two arguments, the container and the name of the

        function to wrap. The wrapping is performed during `uisetup`.

        Adding attributes to a container like this is discouraged, because the

        container modification is visible even in repositories that do not

        have the extension loaded.  Therefore, care must be taken that the

        function doesn't make assumptions that the extension was loaded for the

        current repository.  For `ui` and `repo` instances, a better option is

        to subclass the instance in `uipopulate` and `reposetup` respectively.

        https://www.mercurial-scm.org/wiki/WritingExtensions

        example::

            @eh.addattr(context.changectx, 'babar')

            def babar(ctx):

                return 'babar' in ctx.description

        """

        def dec(func):

            self._duckpunchers.append((container, funcname, func))

            return func

        return dec