#!/usr/bin/env python

# encoding: utf-8

# middleware to handle mercurial api calls

# Copyright (C) 2009-2010 Marcin Kuzminski <marcin@python-works.com>

#

# 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; version 2

# of the License or (at your opinion) any later version of the license.

# 

# 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, write to the Free Software

# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,

# MA  02110-1301, USA.

from dulwich.repo import Repo

from dulwich.server import DictBackend

from dulwich.web import HTTPGitApplication

from itertools import chain

from paste.auth.basic import AuthBasicAuthenticator

from paste.httpheaders import REMOTE_USER, AUTH_TYPE

from rhodecode.lib.auth import authfunc, HasPermissionAnyMiddleware, \

    get_user_cached

from rhodecode.lib.utils import action_logger, is_git, invalidate_cache, \

    check_repo_fast

from webob.exc import HTTPNotFound, HTTPForbidden, HTTPInternalServerError

import logging

import os

import traceback

"""

Created on 2010-04-28

@author: marcink

SimpleHG middleware for handling mercurial protocol request (push/clone etc.)

It's implemented with basic auth function

"""

log = logging.getLogger(__name__)

class SimpleGit(object):

    def __init__(self, application, config):

        self.application = application

        self.config = config

        #authenticate this mercurial request using 

        self.authenticate = AuthBasicAuthenticator('', authfunc)

    def __call__(self, environ, start_response):

        if not is_git(environ):

            return self.application(environ, start_response)

        #===================================================================

        # AUTHENTICATE THIS MERCURIAL REQUEST

        #===================================================================

        username = REMOTE_USER(environ)

        if not username:

            self.authenticate.realm = self.config['rhodecode_realm']

            result = self.authenticate(environ)

            if isinstance(result, str):

                AUTH_TYPE.update(environ, 'basic')

                REMOTE_USER.update(environ, result)

            else:

                return result.wsgi_application(environ, start_response)

        try:

            self.repo_name = environ['PATH_INFO'].split('/')[1]

            if self.repo_name.endswith('/'):

                self.repo_name = self.repo_name.rstrip('/')

        except:

            log.error(traceback.format_exc())

            return HTTPInternalServerError()(environ, start_response)

        #===================================================================

        # CHECK PERMISSIONS FOR THIS REQUEST

        #===================================================================

        action = self.__get_action(environ)

        if action:

            username = self.__get_environ_user(environ)

            try:

                user = self.__get_user(username)

            except:

                log.error(traceback.format_exc())

                return HTTPInternalServerError()(environ, start_response)

            #check permissions for this repository

            if action == 'push':

                if not HasPermissionAnyMiddleware('repository.write',

                                                  'repository.admin')\

                                                    (user, self.repo_name):

                    return HTTPForbidden()(environ, start_response)

            else:

                #any other action need at least read permission

                if not HasPermissionAnyMiddleware('repository.read',

                                                  'repository.write',

                                                  'repository.admin')\

                                                    (user, self.repo_name):

                    return HTTPForbidden()(environ, start_response)

            #log action

            if action in ('push', 'pull', 'clone'):

                proxy_key = 'HTTP_X_REAL_IP'

                def_key = 'REMOTE_ADDR'

                ipaddr = environ.get(proxy_key, environ.get(def_key, '0.0.0.0'))

                self.__log_user_action(user, action, self.repo_name, ipaddr)

        #===================================================================

        # GIT REQUEST HANDLING

        #===================================================================

        self.basepath = self.config['base_path']

        self.repo_path = os.path.join(self.basepath, self.repo_name)

        #quick check if that dir exists...

        if check_repo_fast(self.repo_name, self.basepath):

            return HTTPNotFound()(environ, start_response)

        try:

            app = self.__make_app()

        except Exception:

            log.error(traceback.format_exc())

            return HTTPInternalServerError()(environ, start_response)

        #invalidate cache on push

        if action == 'push':

            self.__invalidate_cache(self.repo_name)

            messages = []

            messages.append('thank you for using rhodecode')

            return app(environ, start_response)

            #TODO: check other alternatives for msg wrapping

            #return self.msg_wrapper(app, environ, start_response, messages)

        else:

            return app(environ, start_response)

    def msg_wrapper(self, app, environ, start_response, messages=[]):

        """

        Wrapper for custom messages that come out of mercurial respond messages

        is a list of messages that the user will see at the end of response 

        from merurial protocol actions that involves remote answers

        :param app:

        :param environ:

        :param start_response:

        """

        def custom_messages(msg_list):

            for msg in msg_list:

                yield msg + '\n'

        org_response = app(environ, start_response)

        return chain(org_response, custom_messages(messages))

    def __make_app(self):

        backend = DictBackend({'/' + self.repo_name: Repo(self.repo_path)})

        gitserve = HTTPGitApplication(backend)

        return gitserve

    def __get_environ_user(self, environ):

        return environ.get('REMOTE_USER')

    def __get_user(self, username):

        return get_user_cached(username)

    def __get_action(self, environ):

        """

        Maps git request commands into a pull or push command.

        :param environ:

        """

        service = environ['QUERY_STRING'].split('=')

        if len(service) > 1:

            service_cmd = service[1]

            mapping = {'git-receive-pack': 'pull',

                       'git-upload-pack': 'push',

                       }

            return mapping.get(service_cmd, service_cmd)

    def __log_user_action(self, user, action, repo, ipaddr):

        action_logger(user, action, repo, ipaddr)

    def __invalidate_cache(self, repo_name):

        """we know that some change was made to repositories and we should

        invalidate the cache to see the changes right away but only for

        push requests"""

        invalidate_cache('cached_repo_list')

        invalidate_cache('full_changelog', repo_name)