##
# Copyright (c) 2010-2017 Apple Inc. 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.
##

from StringIO import StringIO

from zope.interface import implements

from twisted.internet.protocol import Protocol
from twisted.internet.defer import Deferred, succeed
from twisted.web.iweb import IBodyProducer
from twisted.internet.interfaces import IConsumer


class _BufferReader(Protocol):

    def __init__(self, finished):
        self.finished = finished
        self.received = StringIO()

    def dataReceived(self, bytes):
        self.received.write(bytes)

    def connectionLost(self, reason):
        self.finished.callback(self.received.getvalue())


def readBody(response):
    if response.length == 0:
        return succeed(None)
    finished = Deferred()
    response.deliverBody(_BufferReader(finished))
    return finished


class StringProducer(object):
    implements(IBodyProducer)

    def __init__(self, body):
        if not isinstance(body, str):
            raise TypeError(
                "StringProducer body must be str, not %r" % (type(body),))
        self._body = body
        self.length = len(self._body)

    def startProducing(self, consumer):
        consumer.write(self._body)
        return succeed(None)

    def stopProducing(self):
        pass

    def resumeProducing(self):
        pass

    def pauseProducing(self):
        pass


class MemoryConsumer(object):
    implements(IConsumer)

    def __init__(self):
        self._buffer = []

    def write(self, bytes):
        self._buffer.append(bytes)

    def value(self):
        if len(self._buffer) > 1:
            self._buffer = ["".join(self._buffer)]
        return "".join(self._buffer)