# Copyright (c) 2016 The Johns Hopkins University/Applied Physics Laboratory
# All Rights Reserved.
#
# 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.

import mock
import socket
import testtools
import time

from kmip.core import enums
from kmip.core import exceptions
from kmip.core import utils

from kmip.core.messages import contents
from kmip.core.messages import messages

from kmip.services.server import engine
from kmip.services.server import session


class TestKmipSession(testtools.TestCase):
    """
    A test suite for the KmipSession.
    """

    def setUp(self):
        super(TestKmipSession, self).setUp()

    def tearDown(self):
        super(TestKmipSession, self).tearDown()

    def test_init(self):
        """
        Test that a KmipSession can be created without errors.
        """
        session.KmipSession(None, None, 'name')

    def test_init_without_name(self):
        """
        Test that a KmipSession without 'name' can be created without errors.
        """
        session.KmipSession(None, None, None)

    def test_run(self):
        """
        Test that the message handling loop is handled properly on normal
        execution.
        """
        kmip_session = session.KmipSession(None, None, 'name')
        kmip_session._logger = mock.MagicMock()
        kmip_session._handle_message_loop = mock.MagicMock(
            side_effect=[
                None,
                exceptions.ConnectionClosed()
            ]
        )
        kmip_session._connection = mock.MagicMock()

        kmip_session.run()

        kmip_session._logger.info.assert_any_call("Starting session: name")
        self.assertTrue(kmip_session._handle_message_loop.called)
        kmip_session._connection.shutdown.assert_called_once_with(
            socket.SHUT_RDWR
        )
        kmip_session._connection.close.assert_called_once_with()
        kmip_session._logger.info.assert_called_with("Stopping session: name")

    def test_run_with_failure(self):
        """
        Test that the correct logging and error handling occurs when the
        thread encounters an error with the message handling loop.
        """
        kmip_session = session.KmipSession(None, None, 'name')
        kmip_session._logger = mock.MagicMock()
        kmip_session._connection = mock.MagicMock()

        test_exception = Exception("test")
        kmip_session._handle_message_loop = mock.MagicMock(
            side_effect=[
                test_exception,
                exceptions.ConnectionClosed()
            ]
        )

        kmip_session.run()

        kmip_session._logger.info.assert_any_call("Starting session: name")
        self.assertTrue(kmip_session._handle_message_loop.called)
        kmip_session._logger.info.assert_any_call(
            "Failure handling message loop"
        )
        kmip_session._logger.exception.assert_called_once_with(test_exception)
        kmip_session._connection.shutdown.assert_called_once_with(
            socket.SHUT_RDWR
        )
        kmip_session._connection.close.assert_called_once_with()
        kmip_session._logger.info.assert_called_with("Stopping session: name")

    @mock.patch('kmip.core.messages.messages.RequestMessage')
    def test_handle_message_loop(self, request_mock):
        """
        Test that the correct logging and error handling occurs during the
        message handling loop.
        """
        data = utils.BytearrayStream()

        # Build a response and use it as a dummy processing result.
        batch_item = messages.ResponseBatchItem(
            result_status=contents.ResultStatus(
                enums.ResultStatus.SUCCESS
            ),
            result_reason=contents.ResultReason(
                enums.ResultReason.OBJECT_ARCHIVED
            ),
            result_message=contents.ResultMessage("Test message.")
        )
        batch_items = [batch_item]
        header = messages.ResponseHeader(
            protocol_version=contents.ProtocolVersion.create(1, 0),
            time_stamp=contents.TimeStamp(int(time.time())),
            batch_count=contents.BatchCount(len(batch_items))
        )
        message = messages.ResponseMessage(
            response_header=header,
            batch_items=batch_items
        )

        kmip_engine = engine.KmipEngine()
        kmip_engine._logger = mock.MagicMock()
        kmip_session = session.KmipSession(kmip_engine, None, 'name')
        kmip_session._engine = mock.MagicMock()
        kmip_session._engine.process_request = mock.MagicMock(
            return_value=(message, kmip_session._max_response_size)
        )
        kmip_session._logger = mock.MagicMock()
        kmip_session._connection = mock.MagicMock()
        kmip_session._receive_request = mock.MagicMock(return_value=data)
        kmip_session._send_response = mock.MagicMock()

        kmip_session._handle_message_loop()

        kmip_session._receive_request.assert_called_once_with()
        kmip_session._logger.info.assert_not_called()
        kmip_session._logger.warning.assert_not_called()
        kmip_session._logger.exception.assert_not_called()
        self.assertTrue(kmip_session._send_response.called)

    @mock.patch('kmip.core.messages.messages.RequestMessage.read',
                mock.MagicMock(side_effect=Exception()))
    def test_handle_message_loop_with_parse_failure(self):
        """
        Test that the correct logging and error handling occurs during the
        message handling loop.
        """
        data = utils.BytearrayStream(())

        kmip_engine = engine.KmipEngine()
        kmip_session = session.KmipSession(kmip_engine, None, 'name')
        kmip_session._logger = mock.MagicMock()
        kmip_session._connection = mock.MagicMock()
        kmip_session._receive_request = mock.MagicMock(return_value=data)
        kmip_session._send_response = mock.MagicMock()

        kmip_session._handle_message_loop()

        kmip_session._receive_request.assert_called_once_with()
        kmip_session._logger.warning.assert_called_once_with(
            "Failure parsing request message."
        )
        self.assertTrue(kmip_session._logger.exception.called)
        kmip_session._logger.error.assert_not_called()
        self.assertTrue(kmip_session._send_response.called)

    @mock.patch('kmip.core.messages.messages.RequestMessage')
    def test_handle_message_loop_with_response_too_long(self, request_mock):
        """
        Test that the correct logging and error handling occurs during the
        message handling loop.
        """
        data = utils.BytearrayStream(())

        kmip_engine = engine.KmipEngine()
        kmip_session = session.KmipSession(kmip_engine, None, 'name')
        kmip_session._logger = mock.MagicMock()
        kmip_session._connection = mock.MagicMock()
        kmip_session._receive_request = mock.MagicMock(return_value=data)
        kmip_session._send_response = mock.MagicMock()
        kmip_session._max_response_size = 0

        kmip_session._handle_message_loop()

        kmip_session._receive_request.assert_called_once_with()
        kmip_session._logger.info.assert_not_called()
        self.assertTrue(kmip_session._logger.warning.called)
        kmip_session._logger.exception.assert_not_called()
        self.assertTrue(kmip_session._send_response.called)

    @mock.patch('kmip.core.messages.messages.RequestMessage')
    def test_handle_message_loop_with_unexpected_error(self, request_mock):
        """
        Test that the correct logging and error handling occurs when an
        unexpected error is generated while processing a request.
        """
        data = utils.BytearrayStream(())

        kmip_engine = engine.KmipEngine()
        kmip_engine._logger = mock.MagicMock()
        kmip_session = session.KmipSession(kmip_engine, None, 'name')
        kmip_session._engine = mock.MagicMock()
        test_exception = Exception("Unexpected error.")
        kmip_session._engine.process_request = mock.MagicMock(
            side_effect=test_exception
        )
        kmip_session._logger = mock.MagicMock()
        kmip_session._connection = mock.MagicMock()
        kmip_session._receive_request = mock.MagicMock(return_value=data)
        kmip_session._send_response = mock.MagicMock()

        kmip_session._handle_message_loop()

        kmip_session._receive_request.assert_called_once_with()
        kmip_session._logger.info.assert_not_called()
        kmip_session._logger.warning.assert_called_once_with(
            "An unexpected error occurred while processing request."
        )
        kmip_session._logger.exception.assert_called_once_with(test_exception)
        self.assertTrue(kmip_session._send_response.called)

    def test_receive_request(self):
        """
        Test that the session can correctly receive and parse a message
        encoding.
        """
        content = b'\x00\x00\x00\x00\x00\x00\x00\x00'
        expected = utils.BytearrayStream((content))

        kmip_session = session.KmipSession(None, None, 'name')
        kmip_session._receive_bytes = mock.MagicMock(
            side_effect=[content, b'']
        )

        observed = kmip_session._receive_request()

        kmip_session._receive_bytes.assert_any_call(8)
        kmip_session._receive_bytes.assert_any_call(0)

        self.assertEqual(expected.buffer, observed.buffer)

    def test_receive_bytes(self):
        """
        Test that the session can receive a message.
        """
        content = b'\x00\x00\x00\x00\x00\x00\x00\x00'

        kmip_session = session.KmipSession(None, None, 'name')
        kmip_session._connection = mock.MagicMock()
        kmip_session._connection.recv = mock.MagicMock(
            side_effect=[content, content]
        )

        observed = kmip_session._receive_bytes(16)

        kmip_session._connection.recv.assert_any_call(16)
        kmip_session._connection.recv.assert_called_with(8)
        self.assertEqual(content + content, observed)

        kmip_session._connection.recv = mock.MagicMock(
            side_effect=['']
        )

        args = (8, )
        self.assertRaises(
            exceptions.ConnectionClosed,
            kmip_session._receive_bytes,
            *args
        )

    def test_receive_bytes_with_bad_length(self):
        """
        Test that the session generates an error on an incorrectly sized
        message.
        """
        content = b'\x00\x00\x00\x00\x00\x00\x00\x00'

        kmip_session = session.KmipSession(None, None, 'name')
        kmip_session._connection = mock.MagicMock()
        kmip_session._connection.recv = mock.MagicMock(
            side_effect=[content, content, None]
        )

        args = [32]
        self.assertRaises(ValueError, kmip_session._receive_bytes, *args)

        kmip_session._connection.recv.assert_any_call(16)
        kmip_session._connection.recv.assert_called_with(16)

    def test_send_message(self):
        """
        Test that a data buffer, regardless of length, is sent correctly.
        """
        buffer_full = utils.BytearrayStream((
            b'\x00\x00\x00\x00\x00\x00\x00\x00'
        ))
        buffer_empty = utils.BytearrayStream()

        kmip_session = session.KmipSession(None, None, 'name')
        kmip_session._connection = mock.MagicMock()

        kmip_session._send_response(buffer_empty.buffer)
        kmip_session._connection.sendall.assert_not_called()

        kmip_session._send_response(buffer_full.buffer)
        kmip_session._connection.sendall.assert_called_once_with(
            bytes(buffer_full.buffer)
        )