"""
Licensed to the Apache Software Foundation (ASF) under one
or more contributor license agreements.  See the NOTICE file
distributed with this work for additional information
regarding copyright ownership.  The ASF licenses this file
to you 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 uuid
from concurrent.futures import Future
from six.moves import queue

from gremlin_python.driver import resultset

__author__ = 'David M. Brown (davebshow@gmail.com)'


class Connection:

    def __init__(self, url, traversal_source, protocol, transport_factory,
                 executor, pool):
        self._url = url
        self._traversal_source = traversal_source
        self._protocol = protocol
        self._transport_factory = transport_factory
        self._executor = executor
        self._transport = None
        self._pool = pool
        self._results = {}
        self.connect()

    def connect(self):
        if self._transport:
            self._transport.close()
        self._transport = self._transport_factory()
        self._transport.connect(self._url)
        self._protocol.connection_made(self._transport)

    def close(self):
        self._transport.close()

    def write(self, request_message):
        request_id = str(uuid.uuid4())
        result_set = resultset.ResultSet(queue.Queue(), request_id)
        self._results[request_id] = result_set
        # Create write task
        future = Future()
        future_write = self._executor.submit(
            self._protocol.write, request_id, request_message)

        def cb(f):
            try:
                f.result()
            except Exception as e:
                future.set_exception(e)
                self._pool.put_nowait(self)
            else:
                # Start receive task
                done = self._executor.submit(self._receive)
                result_set.done = done
                future.set_result(result_set)

        future_write.add_done_callback(cb)
        return future

    def _receive(self):
        try:
            while True:
                data = self._transport.read()
                status_code = self._protocol.data_received(data, self._results)
                if status_code != 206:
                    break
        finally:
            self._pool.put_nowait(self)
