"""
Socket server forwarding request to internal server
"""
import logging
try:
    # we prefer to use bundles asyncio version, otherwise fallback to trollius
    import asyncio
except ImportError:
    import trollius as asyncio


from opcua import ua
import opcua.ua.ua_binary as uabin
from opcua.server.uaprocessor import UaProcessor

logger = logging.getLogger(__name__)



class OPCUAProtocol(asyncio.Protocol):

    """Interface for OPCUA protocol.
    """

    iserver = None
    loop = None
    logger = None
    policies = None
    clients = None

    def __str__(self):
        return "OPCUAProtocol({}, {})".format(self.peername, self.processor.session)
    __repr__ = __str__

    def connection_made(self, transport):
        self.peername = transport.get_extra_info('peername')
        self.logger.info('New connection from %s', self.peername)
        self.transport = transport
        self.processor = UaProcessor(self.iserver, self.transport)
        self.processor.set_policies(self.policies)
        self.data = b""
        self.iserver.asyncio_transports.append(transport)
        self.clients.append(self)

    def connection_lost(self, ex):
        self.logger.info('Lost connection from %s, %s', self.peername, ex)
        self.transport.close()
        self.iserver.asyncio_transports.remove(self.transport)
        self.processor.close()
        if self in self.clients:
            self.clients.remove(self)

    def data_received(self, data):
        logger.debug("received %s bytes from socket", len(data))
        if self.data:
            data = self.data + data
            self.data = b""
        self._process_data(data)

    def _process_data(self, data):
        buf = ua.utils.Buffer(data)
        while True:
            try:
                backup_buf = buf.copy()
                try:
                    hdr = uabin.header_from_binary(buf)
                except ua.utils.NotEnoughData:
                    logger.info("We did not receive enough data from client, waiting for more")
                    self.data = backup_buf.read(len(backup_buf))
                    return
                if len(buf) < hdr.body_size:
                    logger.info("We did not receive enough data from client, waiting for more")
                    self.data = backup_buf.read(len(backup_buf))
                    return
                ret = self.processor.process(hdr, buf)
                if not ret:
                    logger.info("processor returned False, we close connection from %s", self.peername)
                    self.transport.close()
                    return
                if len(buf) == 0:
                    return
            except Exception:
                logger.exception("Exception raised while parsing message from client, closing")
                return


class BinaryServer(object):

    def __init__(self, internal_server, hostname, port):
        self.logger = logging.getLogger(__name__)
        self.hostname = hostname
        self.port = port
        self.iserver = internal_server
        self.loop = None
        self._server = None
        self._policies = []
        self.clients = []

    def set_policies(self, policies):
        self._policies = policies

    def set_loop(self, loop):
        self.loop = loop

    def start(self):
        prop = dict(
                iserver=self.iserver,
                loop=self.loop,
                logger=self.logger,
                policies=self._policies,
                clients=self.clients
            )
        protocol_factory = type('OPCUAProtocol', (OPCUAProtocol,), prop)

        coro = self.loop.create_server(protocol_factory, self.hostname, self.port)
        self._server = self.loop.run_coro_and_wait(coro)
        # get the port and the hostname from the created server socket
        # only relevant for dynamic port asignment (when self.port == 0)
        if self.port == 0 and len(self._server.sockets) == 1:
            # will work for AF_INET and AF_INET6 socket names
            # these are to only families supported by the create_server call
            sockname = self._server.sockets[0].getsockname()
            self.hostname = sockname[0]
            self.port = sockname[1]
        self.logger.warning('Listening on {0}:{1}'.format(self.hostname, self.port))

    def stop(self):
        self.logger.info("Closing asyncio socket server")
        for transport in self.iserver.asyncio_transports:
            transport.close()
        if self._server:
            self.loop.call_soon(self._server.close)
            self.loop.run_coro_and_wait(self._server.wait_closed())
        self.loop = None