# Copyright (c) 2012 OpenStack Foundation
# 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.

'''
Websocket proxy that is compatible with OpenStack Nova.
Leverages websockify.py by Joel Martin
'''

import Cookie
import socket

import websockify

from nova.consoleauth import rpcapi as consoleauth_rpcapi
from nova import context
from nova.openstack.common.gettextutils import _
from nova.openstack.common import log as logging

LOG = logging.getLogger(__name__)


class NovaProxyRequestHandlerBase(object):
    def new_websocket_client(self):
        """Called after a new WebSocket connection has been established."""
        # Reopen the eventlet hub to make sure we don't share an epoll
        # fd with parent and/or siblings, which would be bad
        from eventlet import hubs
        hubs.use_hub()

        cookie = Cookie.SimpleCookie()
        cookie.load(self.headers.getheader('cookie'))
        token = cookie['token'].value
        ctxt = context.get_admin_context()
        rpcapi = consoleauth_rpcapi.ConsoleAuthAPI()
        connect_info = rpcapi.check_token(ctxt, token=token)

        if not connect_info:
            raise Exception(_("Invalid Token"))

        self.msg(_('connect info: %s'), str(connect_info))
        host = connect_info['host']
        port = int(connect_info['port'])

        # Connect to the target
        self.msg(_("connecting to: %(host)s:%(port)s") % {'host': host,
                                                          'port': port})
        tsock = self.socket(host, port, connect=True)

        # Handshake as necessary
        if connect_info.get('internal_access_path'):
            tsock.send("CONNECT %s HTTP/1.1\r\n\r\n" %
                        connect_info['internal_access_path'])
            while True:
                data = tsock.recv(4096, socket.MSG_PEEK)
                if data.find("\r\n\r\n") != -1:
                    if not data.split("\r\n")[0].find("200"):
                        raise Exception(_("Invalid Connection Info"))
                    tsock.recv(len(data))
                    break

        # Start proxying
        try:
            self.do_proxy(tsock)
        except Exception:
            if tsock:
                tsock.shutdown(socket.SHUT_RDWR)
                tsock.close()
                self.vmsg(_("%(host)s:%(port)s: Target closed") %
                          {'host': host, 'port': port})
            raise


# TODO(sross): when the websockify version is bumped to be >=0.6,
#              remove the if-else statement and make the if branch
#              contents the only code.
if getattr(websockify, 'ProxyRequestHandler', None) is not None:
    class NovaProxyRequestHandler(NovaProxyRequestHandlerBase,
                                  websockify.ProxyRequestHandler):
        def __init__(self, *args, **kwargs):
            websockify.ProxyRequestHandler.__init__(self, *args, **kwargs)

        def socket(self, *args, **kwargs):
            return websockify.WebSocketServer.socket(*args, **kwargs)

    class NovaWebSocketProxy(websockify.WebSocketProxy):
        @staticmethod
        def get_logger():
            return LOG

else:
    import sys

    class NovaWebSocketProxy(NovaProxyRequestHandlerBase,
                             websockify.WebSocketProxy):
        def __init__(self, *args, **kwargs):
            del kwargs['traffic']
            del kwargs['RequestHandlerClass']
            websockify.WebSocketProxy.__init__(self, *args,
                                               target_host='ignore',
                                               target_port='ignore',
                                               unix_target=None,
                                               target_cfg=None,
                                               ssl_target=None,
                                               **kwargs)

        def new_client(self):
            self.new_websocket_client()

        def msg(self, *args, **kwargs):
            LOG.info(*args, **kwargs)

        def vmsg(self, *args, **kwargs):
            LOG.debug(*args, **kwargs)

        def warn(self, *args, **kwargs):
            LOG.warn(*args, **kwargs)

        def print_traffic(self, token="."):
            if self.traffic:
                sys.stdout.write(token)
                sys.stdout.flush()

    class NovaProxyRequestHandler(object):
        pass