# -*- coding: utf-8 -*-
# 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, either version 3 of the License, or
# (at your option) any later version.
#
# 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, see <http://www.gnu.org/licenses/>.
"""
kallithea.lib.middleware.simplegit
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

SimpleGit middleware for handling git protocol request (push/clone etc.)
It's implemented with basic auth function

This file was forked by the Kallithea project in July 2014.
Original author and date, and relevant copyright and licensing information is below:
:created_on: Apr 28, 2010
:author: marcink
:copyright: (c) 2013 RhodeCode GmbH, and others.
:license: GPLv3, see LICENSE.md for more details.

"""


import os
import re
import logging
import traceback

from paste.httpheaders import REMOTE_USER, AUTH_TYPE
from webob.exc import HTTPNotFound, HTTPForbidden, HTTPInternalServerError, \
    HTTPNotAcceptable
from kallithea.model.db import User, Ui

from kallithea.lib.utils2 import safe_str, safe_unicode, fix_PATH, get_server_url, \
    _set_extras
from kallithea.lib.base import BaseVCSController, WSGIResultCloseCallback
from kallithea.lib.utils import make_ui, is_valid_repo
from kallithea.lib.exceptions import HTTPLockedRC
from kallithea.lib.hooks import pre_pull
from kallithea.lib import auth_modules

log = logging.getLogger(__name__)


GIT_PROTO_PAT = re.compile(r'^/(.+)/(info/refs|git-upload-pack|git-receive-pack)')


def is_git(environ):
    path_info = environ['PATH_INFO']
    isgit_path = GIT_PROTO_PAT.match(path_info)
    log.debug('pathinfo: %s detected as Git %s',
        path_info, isgit_path is not None
    )
    return isgit_path


class SimpleGit(BaseVCSController):

    def _handle_request(self, environ, start_response):
        if not is_git(environ):
            return self.application(environ, start_response)
        if not self._check_ssl(environ):
            return HTTPNotAcceptable('SSL REQUIRED !')(environ, start_response)

        ip_addr = self._get_ip_addr(environ)
        username = None
        self._git_first_op = False
        # skip passing error to error controller
        environ['pylons.status_code_redirect'] = True

        #======================================================================
        # EXTRACT REPOSITORY NAME FROM ENV
        #======================================================================
        try:
            str_repo_name = self.__get_repository(environ)
            repo_name = safe_unicode(str_repo_name)
            log.debug('Extracted repo name is %s', repo_name)
        except Exception as e:
            log.error('error extracting repo_name: %r', e)
            return HTTPInternalServerError()(environ, start_response)

        # quick check if that dir exists...
        if not is_valid_repo(repo_name, self.basepath, 'git'):
            return HTTPNotFound()(environ, start_response)

        #======================================================================
        # GET ACTION PULL or PUSH
        #======================================================================
        action = self.__get_action(environ)

        #======================================================================
        # CHECK ANONYMOUS PERMISSION
        #======================================================================
        if action in ['pull', 'push']:
            anonymous_user = User.get_default_user(cache=True)
            username = anonymous_user.username
            if anonymous_user.active:
                # ONLY check permissions if the user is activated
                anonymous_perm = self._check_permission(action, anonymous_user,
                                                        repo_name, ip_addr)
            else:
                anonymous_perm = False

            if not anonymous_user.active or not anonymous_perm:
                if not anonymous_user.active:
                    log.debug('Anonymous access is disabled, running '
                              'authentication')

                if not anonymous_perm:
                    log.debug('Not enough credentials to access this '
                              'repository as anonymous user')

                username = None
                #==============================================================
                # DEFAULT PERM FAILED OR ANONYMOUS ACCESS IS DISABLED SO WE
                # NEED TO AUTHENTICATE AND ASK FOR AUTH USER PERMISSIONS
                #==============================================================

                # try to auth based on environ, container auth methods
                log.debug('Running PRE-AUTH for container based authentication')
                pre_auth = auth_modules.authenticate('', '', environ)
                if pre_auth is not None and pre_auth.get('username'):
                    username = pre_auth['username']
                log.debug('PRE-AUTH got %s as username', username)

                # If not authenticated by the container, running basic auth
                if not username:
                    self.authenticate.realm = \
                        safe_str(self.config['realm'])
                    result = self.authenticate(environ)
                    if isinstance(result, str):
                        AUTH_TYPE.update(environ, 'basic')
                        REMOTE_USER.update(environ, result)
                        username = result
                    else:
                        return result.wsgi_application(environ, start_response)

                #==============================================================
                # CHECK PERMISSIONS FOR THIS REQUEST USING GIVEN USERNAME
                #==============================================================
                try:
                    user = User.get_by_username_or_email(username)
                    if user is None or not user.active:
                        return HTTPForbidden()(environ, start_response)
                    username = user.username
                except Exception:
                    log.error(traceback.format_exc())
                    return HTTPInternalServerError()(environ, start_response)

                #check permissions for this repository
                perm = self._check_permission(action, user, repo_name, ip_addr)
                if not perm:
                    return HTTPForbidden()(environ, start_response)

        # extras are injected into UI object and later available
        # in hooks executed by kallithea
        from kallithea import CONFIG
        server_url = get_server_url(environ)
        extras = {
            'ip': ip_addr,
            'username': username,
            'action': action,
            'repository': repo_name,
            'scm': 'git',
            'config': CONFIG['__file__'],
            'server_url': server_url,
            'make_lock': None,
            'locked_by': [None, None]
        }

        #===================================================================
        # GIT REQUEST HANDLING
        #===================================================================
        repo_path = os.path.join(safe_str(self.basepath),str_repo_name)
        log.debug('Repository path is %s', repo_path)

        # CHECK LOCKING only if it's not ANONYMOUS USER
        if username != User.DEFAULT_USER:
            log.debug('Checking locking on repository')
            (make_lock,
             locked,
             locked_by) = self._check_locking_state(
                            environ=environ, action=action,
                            repo=repo_name, user_id=user.user_id
                       )
            # store the make_lock for later evaluation in hooks
            extras.update({'make_lock': make_lock,
                           'locked_by': locked_by})

        fix_PATH()
        log.debug('HOOKS extras is %s', extras)
        baseui = make_ui('db')
        self.__inject_extras(repo_path, baseui, extras)

        try:
            self._handle_githooks(repo_name, action, baseui, environ)
            log.info('%s action on Git repo "%s" by "%s" from %s',
                     action, str_repo_name, safe_str(username), ip_addr)
            app = self.__make_app(repo_name, repo_path, extras)
            result = app(environ, start_response)
            if action == 'push':
                result = WSGIResultCloseCallback(result,
                    lambda: self._invalidate_cache(repo_name))
            return result
        except HTTPLockedRC as e:
            log.debug('Locked, response %s: %s', e.code, e.title)
            return e(environ, start_response)
        except Exception:
            log.error(traceback.format_exc())
            return HTTPInternalServerError()(environ, start_response)

    def __make_app(self, repo_name, repo_path, extras):
        """
        Make an wsgi application using dulserver

        :param repo_name: name of the repository
        :param repo_path: full path to the repository
        """

        from kallithea.lib.middleware.pygrack import make_wsgi_app
        app = make_wsgi_app(
            repo_root=safe_str(self.basepath),
            repo_name=repo_name,
            extras=extras,
        )
        return app

    def __get_repository(self, environ):
        """
        Gets repository name out of PATH_INFO header

        :param environ: environ where PATH_INFO is stored
        """
        try:
            environ['PATH_INFO'] = self._get_by_id(environ['PATH_INFO'])
            repo_name = GIT_PROTO_PAT.match(environ['PATH_INFO']).group(1)
        except Exception:
            log.error(traceback.format_exc())
            raise

        return repo_name

    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': 'push',
                'git-upload-pack': 'pull',
            }
            op = mapping[service_cmd]
            self._git_stored_op = op
            return op
        else:
            # try to fallback to stored variable as we don't know if the last
            # operation is pull/push
            op = getattr(self, '_git_stored_op', 'pull')
        return op

    def _handle_githooks(self, repo_name, action, baseui, environ):
        """
        Handles pull action, push is handled by post-receive hook
        """
        from kallithea.lib.hooks import log_pull_action
        service = environ['QUERY_STRING'].split('=')

        if len(service) < 2:
            return

        from kallithea.model.db import Repository
        _repo = Repository.get_by_repo_name(repo_name)
        _repo = _repo.scm_instance

        _hooks = dict(baseui.configitems('hooks')) or {}
        if action == 'pull':
            # stupid git, emulate pre-pull hook !
            pre_pull(ui=baseui, repo=_repo._repo)
        if action == 'pull' and _hooks.get(Ui.HOOK_PULL):
            log_pull_action(ui=baseui, repo=_repo._repo)

    def __inject_extras(self, repo_path, baseui, extras=None):
        """
        Injects some extra params into baseui instance

        :param baseui: baseui instance
        :param extras: dict with extra params to put into baseui
        """
        _set_extras(extras or {})