#!/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.

"""

Created on 2010-04-28

@author: marcink

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

It's implemented with basic auth function

"""

from itertools import chain

from mercurial.error import RepoError

from mercurial.hgweb import hgweb

from mercurial.hgweb.request import wsgiapplication

from paste.auth.basic import AuthBasicAuthenticator

from paste.httpheaders import REMOTE_USER, AUTH_TYPE

from rhodecode.lib.auth import authfunc, HasPermissionAnyMiddleware

from rhodecode.lib.utils import is_mercurial, make_ui, invalidate_cache, \

    check_repo_fast, ui_sections

from rhodecode.model.user import UserModel

from webob.exc import HTTPNotFound, HTTPForbidden, HTTPInternalServerError

import logging

import os

import traceback

log = logging.getLogger(__name__)

class SimpleHg(object):

    def __init__(self, application, config):

        self.application = application

        self.config = config

        #authenticate this mercurial request using authfunc

        self.authenticate = AuthBasicAuthenticator('', authfunc)

        self.ipaddr = '0.0.0.0'

        self.repository = None

        self.username = None

        self.action = None

    def __call__(self, environ, start_response):

        if not is_mercurial(environ):

            return self.application(environ, start_response)

        proxy_key = 'HTTP_X_REAL_IP'

        def_key = 'REMOTE_ADDR'

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

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

        # 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)

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

        # GET REPOSITORY

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

        try:

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

            if repo_name.endswith('/'):

                repo_name = repo_name.rstrip('/')

            self.repository = repo_name

        except:

            log.error(traceback.format_exc())

            return HTTPInternalServerError()(environ, start_response)

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

        # CHECK PERMISSIONS FOR THIS REQUEST

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

        self.action = self.__get_action(environ)

        if self.action:

            username = self.__get_environ_user(environ)

            try:

                user = self.__get_user(username)

                self.username = user.username

            except:

                log.error(traceback.format_exc())

                return HTTPInternalServerError()(environ, start_response)

            #check permissions for this repository

            if self.action == 'push':

                if not HasPermissionAnyMiddleware('repository.write',

                                                  'repository.admin')\

                                                    (user, 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, repo_name):

                    return HTTPForbidden()(environ, start_response)

        self.extras = {'ip':self.ipaddr,

                       'username':self.username,

                       'action':self.action,

                       'repository':self.repository}

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

        # MERCURIAL REQUEST HANDLING

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

        environ['PATH_INFO'] = '/'#since we wrap into hgweb, reset the path

        self.baseui = make_ui('db')

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

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

        #quick check if that dir exists...

        if check_repo_fast(repo_name, self.basepath):

            return HTTPNotFound()(environ, start_response)

        try:

            app = wsgiapplication(self.__make_app)

        except RepoError, e:

            if str(e).find('not found') != -1:

                return HTTPNotFound()(environ, start_response)

        except Exception:

            log.error(traceback.format_exc())

            return HTTPInternalServerError()(environ, start_response)

        #invalidate cache on push

        if self.action == 'push':

            self.__invalidate_cache(repo_name)

            return app(environ, start_response)

    def __make_app(self):

        hgserve = hgweb(str(self.repo_path), baseui=self.baseui)

        return  self.__load_web_settings(hgserve, self.extras)

    def __get_environ_user(self, environ):

        return environ.get('REMOTE_USER')

    def __get_user(self, username):

        return UserModel().get_by_username(username, cache=True)

    def __get_action(self, environ):

        """

        Maps mercurial request commands into a clone,pull or push command.

        This should always return a valid command string

        :param environ:

        """

        mapping = {'changegroup': 'pull',

                   'changegroupsubset': 'pull',

                   'stream_out': 'pull',

                   'listkeys': 'pull',

                   'unbundle': 'push',

                   'pushkey': 'push', }

        for qry in environ['QUERY_STRING'].split('&'):

            if qry.startswith('cmd'):

                cmd = qry.split('=')[-1]

                if mapping.has_key(cmd):

                    return mapping[cmd]

                else:

                    return cmd

    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('get_repo_cached_%s' % repo_name)

    def __load_web_settings(self, hgserve, extras={}):

        #set the global ui for hgserve instance passed

        hgserve.repo.ui = self.baseui

        hgrc = os.path.join(self.repo_path, '.hg', 'hgrc')

        #inject some additional parameters that will be available in ui

        #for hooks

        for k, v in extras.items():

            hgserve.repo.ui.setconfig('rhodecode_extras', k, v)

        repoui = make_ui('file', hgrc, False)

        if repoui:

            #overwrite our ui instance with the section from hgrc file

            for section in ui_sections:

                for k, v in repoui.configitems(section):

                    hgserve.repo.ui.setconfig(section, k, v)

        return hgserve