#!/usr/bin/env python
# pylint: disable=C0103
# vim: tabstop=4 shiftwidth=4 softtabstop=4

# Copyright 2010 United States Government as represented by the
# Administrator of the National Aeronautics and Space Administration.
# 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.

"""Ajax Console Proxy Server"""

from eventlet import greenthread
from eventlet.green import urllib2

import exceptions
import gettext
import os
import sys
import time
import urlparse

# If ../nova/__init__.py exists, add ../ to Python search path, so that
# it will override what happens to be installed in /usr/(local/)lib/python...
possible_topdir = os.path.normpath(os.path.join(os.path.abspath(sys.argv[0]),
                                   os.pardir,
                                   os.pardir))
if os.path.exists(os.path.join(possible_topdir, 'nova', '__init__.py')):
    sys.path.insert(0, possible_topdir)

gettext.install('nova', unicode=1)

from nova import flags
from nova import log as logging
from nova import rpc
from nova import utils
from nova import wsgi

FLAGS = flags.FLAGS
flags.DEFINE_integer('ajax_console_idle_timeout', 300,
                     'Seconds before idle connection destroyed')
flags.DEFINE_flag(flags.HelpFlag())
flags.DEFINE_flag(flags.HelpshortFlag())
flags.DEFINE_flag(flags.HelpXMLFlag())

LOG = logging.getLogger('nova.ajax_console_proxy')
LOG.setLevel(logging.DEBUG)
LOG.addHandler(logging.StreamHandler())


class AjaxConsoleProxy(object):
    tokens = {}

    def __call__(self, env, start_response):
        try:
            if 'QUERY_STRING' in env:
                req_url = '%s://%s%s?%s' % (env['wsgi.url_scheme'],
                                            env['HTTP_HOST'],
                                            env['PATH_INFO'],
                                            env['QUERY_STRING'])
            else:
                req_url = '%s://%s%s' % (env['wsgi.url_scheme'],
                                         env['HTTP_HOST'],
                                         env['PATH_INFO'])

            if 'HTTP_REFERER' in env:
                auth_url = env['HTTP_REFERER']
            else:
                auth_url = req_url

            auth_params = urlparse.parse_qs(urlparse.urlparse(auth_url).query)
            parsed_url = urlparse.urlparse(req_url)

            auth_info = AjaxConsoleProxy.tokens[auth_params['token'][0]]
            args = auth_info['args']
            auth_info['last_activity'] = time.time()

            remote_url = ("http://%s:%s%s?token=%s" % (
                          str(args['host']),
                          str(args['port']),
                          parsed_url.path,
                          str(args['token'])))

            opener = urllib2.urlopen(remote_url, env['wsgi.input'].read())
            body = opener.read()
            info = opener.info()

            start_response("200 OK", info.dict.items())
            return body
        except (exceptions.KeyError):
            if env['PATH_INFO'] != '/favicon.ico':
                LOG.audit("Unauthorized request %s, %s"
                          % (req_url, str(env)))
            start_response("401 NOT AUTHORIZED", [])
            return "Not Authorized"
        except Exception:
            start_response("500 ERROR", [])
            return "Server Error"

    def register_listeners(self):
        class TopicProxy():
            @staticmethod
            def authorize_ajax_console(context, **kwargs):
                AjaxConsoleProxy.tokens[kwargs['token']] =  \
                    {'args': kwargs, 'last_activity': time.time()}

        conn = rpc.Connection.instance(new=True)
        consumer = rpc.TopicAdapterConsumer(
                       connection=conn,
                       proxy=TopicProxy,
                       topic=FLAGS.ajax_console_proxy_topic)

        def delete_expired_tokens():
            now = time.time()
            to_delete = []
            for k, v in AjaxConsoleProxy.tokens.items():
                if now - v['last_activity'] > FLAGS.ajax_console_idle_timeout:
                    to_delete.append(k)

            for k in to_delete:
                del AjaxConsoleProxy.tokens[k]

        utils.LoopingCall(consumer.fetch, enable_callbacks=True).start(0.1)
        utils.LoopingCall(delete_expired_tokens).start(1)

if __name__ == '__main__':
    utils.default_flagfile()
    FLAGS(sys.argv)
    logging.setup()
    server = wsgi.Server()
    acp = AjaxConsoleProxy()
    acp.register_listeners()
    server.start(acp, FLAGS.ajax_console_proxy_port, host='0.0.0.0')
    server.wait()