# Copyright 2012 OpenStack Foundation
# Copyright 2010 United States Government as represented by the
# Administrator of the National Aeronautics and Space Administration.
# Copyright 2010 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.

import socket
import ssl
import sys

import eventlet
import eventlet.wsgi
import greenlet

from keystone.openstack.common import log


LOG = log.getLogger(__name__)


class Server(object):
    """Server class to manage multiple WSGI sockets and applications."""

    def __init__(self, application, host=None, port=None, threads=1000,
                 keepalive=False, keepidle=None):
        self.application = application
        self.host = host or '0.0.0.0'
        self.port = port or 0
        self.pool = eventlet.GreenPool(threads)
        self.socket_info = {}
        self.greenthread = None
        self.do_ssl = False
        self.cert_required = False
        self.keepalive = keepalive
        self.keepidle = keepidle

    def start(self, key=None, backlog=128):
        """Run a WSGI server with the given application."""
        LOG.info(_('Starting %(arg0)s on %(host)s:%(port)s'),
                 {'arg0': sys.argv[0],
                  'host': self.host,
                  'port': self.port})

        # TODO(dims): eventlet's green dns/socket module does not actually
        # support IPv6 in getaddrinfo(). We need to get around this in the
        # future or monitor upstream for a fix
        info = socket.getaddrinfo(self.host,
                                  self.port,
                                  socket.AF_UNSPEC,
                                  socket.SOCK_STREAM)[0]
        _socket = eventlet.listen(info[-1],
                                  family=info[0],
                                  backlog=backlog)
        if key:
            self.socket_info[key] = _socket.getsockname()
        # SSL is enabled
        if self.do_ssl:
            if self.cert_required:
                cert_reqs = ssl.CERT_REQUIRED
            else:
                cert_reqs = ssl.CERT_NONE
            sslsocket = eventlet.wrap_ssl(_socket, certfile=self.certfile,
                                          keyfile=self.keyfile,
                                          server_side=True,
                                          cert_reqs=cert_reqs,
                                          ca_certs=self.ca_certs)
            _socket = sslsocket

        # Optionally enable keepalive on the wsgi socket.
        if self.keepalive:
            _socket.setsockopt(socket.SOL_SOCKET, socket.SO_KEEPALIVE, 1)

            # This option isn't available in the OS X version of eventlet
            if hasattr(socket, 'TCP_KEEPIDLE') and self.keepidle is not None:
                _socket.setsockopt(socket.IPPROTO_TCP, socket.TCP_KEEPIDLE,
                                   self.keepidle)

        self.greenthread = self.pool.spawn(self._run,
                                           self.application,
                                           _socket)

    def set_ssl(self, certfile, keyfile=None, ca_certs=None,
                cert_required=True):
        self.certfile = certfile
        self.keyfile = keyfile
        self.ca_certs = ca_certs
        self.cert_required = cert_required
        self.do_ssl = True

    def kill(self):
        if self.greenthread is not None:
            self.greenthread.kill()

    def wait(self):
        """Wait until all servers have completed running."""
        try:
            self.pool.waitall()
        except KeyboardInterrupt:
            pass
        except greenlet.GreenletExit:
            pass

    def _run(self, application, socket):
        """Start a WSGI server in a new green thread."""
        logger = log.getLogger('eventlet.wsgi.server')
        try:
            eventlet.wsgi.server(socket, application, custom_pool=self.pool,
                                 log=log.WritableLogger(logger))
        except Exception:
            LOG.exception(_('Server error'))
            raise