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, \

    get_user_cached

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

    check_repo_fast, ui_sections

from webob.exc import HTTPNotFound, HTTPForbidden, HTTPInternalServerError

from rhodecode.lib.utils import action_logger

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 

        self.authenticate = AuthBasicAuthenticator('', authfunc)

    def __call__(self, environ, start_response):

        if not is_mercurial(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:

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

            if repo_name.endswith('/'):

                repo_name = 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 not HasPermissionAnyMiddleware('repository.read',

                                                  'repository.write',

                                                  'repository.admin')\

                                                    (user, repo_name):

                    return HTTPForbidden()(environ, start_response)

            #log action    

            proxy_key = 'HTTP_X_REAL_IP'

            def_key = 'REMOTE_ADDR'

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

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

        # 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 action == 'push':

            self.__invalidate_cache(repo_name)

            messages = []

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

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

        else:

    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

        """

        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):

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

        return  self.__load_web_settings(hgserve)

    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 mercurial request commands into a pull or push command.

        """

        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]

    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)

    def __load_web_settings(self, hgserve):

        hgserve.repo.ui = self.baseui

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

        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