#!/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 datetime import datetime
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 pylons_app.lib.auth import authfunc, HasPermissionAnyMiddleware, \
    get_user_cached
from pylons_app.lib.utils import is_mercurial, make_ui, invalidate_cache, \
    check_repo_fast, ui_sections
from pylons_app.model import meta
from pylons_app.model.db import UserLog, User
from webob.exc import HTTPNotFound, HTTPForbidden, HTTPInternalServerError
import logging
import os
import pylons_app.lib.helpers as h
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 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['hg_app_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:])
        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 == 'pull':
                if not HasPermissionAnyMiddleware('repository.read',
                                                  'repository.write',
                                                  'repository.admin')\
                                                    (user, repo_name):
                    return HTTPForbidden()(environ, start_response)
            if action == 'push':
                if not HasPermissionAnyMiddleware('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'))
            self.__log_user_action(user, action, repo_name, ipaddr)            
        
        #===================================================================
        # 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 as 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 hg-app')
        
            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):
        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_size(self, repo_path, content_size):
        size = int(content_size)
        for path, dirs, files in os.walk(repo_path):
            if path.find('.hg') == -1:
                for f in files:
                    size += os.path.getsize(os.path.join(path, f))
        return size
        return h.format_byte_size(size)
        
    def __get_action(self, environ):
        """
        Maps mercurial request commands into a pull or push command.
        @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]
    
    def __log_user_action(self, user, action, repo, ipaddr):
        sa = meta.Session
        try:
            user_log = UserLog()
            user_log.user_id = user.user_id
            user_log.action = action
            user_log.repository = repo.replace('/', '')
            user_log.action_date = datetime.now()
            user_log.user_ip = ipaddr
            sa.add(user_log)
            sa.commit()
            log.info('Adding user %s, action %s on %s',
                                            user.username, action, repo)
        except Exception as e:
            sa.rollback()
            log.error('could not log user action:%s', str(e))
        finally:
            meta.Session.remove()
        
    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):
        #set the global ui for 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