# Copyright (c) 2012-2014 Red Hat, Inc.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#    http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
# implied.
# See the License for the specific language governing permissions and
# limitations under the License.

""" Object Server for Gluster for Swift """

from swift.common.swob import HTTPConflict, HTTPNotImplemented
from swift.common.utils import public, timing_stats, replication
from swift.common.request_helpers import get_name_and_placement
from swiftonfile.swift.common.exceptions import AlreadyExistsAsFile, \
    AlreadyExistsAsDir
from swift.common.request_helpers import split_and_validate_path

from swift.obj import server

from swiftonfile.swift.obj.diskfile import DiskFileManager
from swiftonfile.swift.common.constraints import check_object_creation


class ObjectController(server.ObjectController):
    """
    Subclass of the object server's ObjectController which replaces the
    container_update method with one that is a no-op (information is simply
    stored on disk and already updated by virtue of performing the file system
    operations directly).
    """
    def setup(self, conf):
        """
        Implementation specific setup. This method is called at the very end
        by the constructor to allow a specific implementation to modify
        existing attributes or add its own attributes.

        :param conf: WSGI configuration parameter
        """
        # Common on-disk hierarchy shared across account, container and object
        # servers.
        self._diskfile_mgr = DiskFileManager(conf, self.logger)

    def get_diskfile(self, device, partition, account, container, obj,
                     policy_idx, **kwargs):
        """
        Utility method for instantiating a DiskFile object supporting a given
        REST API.

        An implementation of the object server that wants to use a different
        DiskFile class would simply over-ride this method to provide that
        behavior.
        """
        return self._diskfile_mgr.get_diskfile(
            device, partition, account, container, obj, policy_idx, **kwargs)

    @public
    @timing_stats()
    def PUT(self, request):
        try:
            device, partition, account, container, obj, policy_idx = \
                get_name_and_placement(request, 5, 5, True)

            # check swiftonfile constraints first
            error_response = check_object_creation(request, obj)
            if error_response:
                return error_response

            # now call swift's PUT method
            return server.ObjectController.PUT(self, request)
        except (AlreadyExistsAsFile, AlreadyExistsAsDir):
            device = \
                split_and_validate_path(request, 1, 5, True)
            return HTTPConflict(drive=device, request=request)

    @public
    @replication
    @timing_stats(sample_rate=0.1)
    def REPLICATE(self, request):
        """
        In Swift, this method handles REPLICATE requests for the Swift
        Object Server.  This is used by the object replicator to get hashes
        for directories.

        Swiftonfile does not support this as it expects the underlying
        filesystem to take care of replication. Also, swiftonfile has no
        notion of hashes for directories.
        """
        return HTTPNotImplemented(request=request)

    @public
    @replication
    @timing_stats(sample_rate=0.1)
    def REPLICATION(self, request):
        return HTTPNotImplemented(request=request)


def app_factory(global_conf, **local_conf):
    """paste.deploy app factory for creating WSGI object server apps"""
    conf = global_conf.copy()
    conf.update(local_conf)
    return ObjectController(conf)