# Copyright 2013, Google Inc.  All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions are
# met:
#
#     * Redistributions of source code must retain the above copyright
# notice, this list of conditions and the following disclaimer.
#     * Redistributions in binary form must reproduce the above
# copyright notice, this list of conditions and the following disclaimer
# in the documentation and/or other materials provided with the
# distribution.
#     * Neither the name of Google Inc. nor the names of its
# contributors may be used to endorse or promote products derived from
# this software without specific prior written permission.
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

from urllib import parse

import zlib
from pywebsocket3 import common
from pywebsocket3 import util
from pywebsocket3.extensions import PerMessageDeflateExtensionProcessor
from pywebsocket3.extensions import ExtensionProcessorInterface
from pywebsocket3.common import ExtensionParameter

_GOODBYE_MESSAGE = u'Goodbye'
_ENABLE_MESSAGE = u'EnableCompression'
_DISABLE_MESSAGE = u'DisableCompression'
_bfinal = False
_client_max_window_bits = 15


def _get_permessage_deflate_extension_processor(request):
    for extension_processor in request.ws_extension_processors:
        if isinstance(extension_processor, PerMessageDeflateExtensionProcessor):
            return extension_processor
    return None


def web_socket_do_extra_handshake(request):
    global _bfinal
    global _client_max_window_bits
    processor = _get_permessage_deflate_extension_processor(request)
    # Remove extension processors other than
    # PerMessageDeflateExtensionProcessor to avoid conflict.
    request.ws_extension_processors = [processor]
    if not processor:
        return
    r = request.ws_resource.split('?', 1)
    if len(r) == 1:
        return
    parameters = parse.parse_qs(r[1], keep_blank_values=True)
    if 'client_max_window_bits' in parameters:
        window_bits = int(parameters['client_max_window_bits'][0])
        processor.set_client_max_window_bits(window_bits)
        _client_max_window_bits = window_bits
    if 'client_no_context_takeover' in parameters:
        processor.set_client_no_context_takeover(True)
    if 'set_bfinal' in parameters:
        _bfinal = True


def receive(request):
    stream = request.ws_stream
    possibly_compressed_body = b''
    compress = False
    while True:
        frame = stream._receive_frame_as_frame_object()
        if frame.opcode == common.OPCODE_CLOSE:
            message = stream._get_message_from_frame(frame)
            stream._process_close_message(message)
            return (False, None)
        compress = compress or frame.rsv1
        possibly_compressed_body += frame.payload
        if frame.fin:
            break
    if compress:
        return (compress, possibly_compressed_body + b'\x00\x00\xff\xff')
    else:
        return (compress, possibly_compressed_body)


def web_socket_transfer_data(request):
    processor = _get_permessage_deflate_extension_processor(request)
    processor.set_bfinal(_bfinal)
    inflater = util._Inflater(_client_max_window_bits)
    while True:
        compress, possibly_compressed_body = receive(request)
        body = None
        if possibly_compressed_body is None:
            return
        if compress:
            inflater.append(possibly_compressed_body)
            body = inflater.decompress(-1)
        else:
            body = possibly_compressed_body

        text = body.decode('utf-8')
        if processor:
            if text == _ENABLE_MESSAGE:
                processor.enable_outgoing_compression()
            elif text == _DISABLE_MESSAGE:
                processor.disable_outgoing_compression()
        request.ws_stream.send_message(text, binary=False)
        if text == _GOODBYE_MESSAGE:
            return


# vi:sts=4 sw=4 et