"""
EIP Connection Class
"""

from leap.OpenVPNConnection import OpenVPNConnection, MissingSocketError, ConnectionRefusedError
from leap.Connection import ConnectionError

class EIPConnection(OpenVPNConnection):
    """
    Manages the execution of the OpenVPN process, auto starts, monitors the
    network connection, handles configuration, fixes leaky hosts, handles
    errors, etc.
    Preferences will be stored via the Storage API. (TBD)
    Status updates (connected, bandwidth, etc) are signaled to the GUI.
    """

    def __init__(self, *args, **kwargs):
        self.settingsfile = kwargs.get('settingsfile', None)
        self.logfile = kwargs.get('logfile', None)
        self.error_queue = []
        self.desired_con_state = None  # ???

        status_signals = kwargs.pop('status_signals', None)
        self.status = EIPConnectionStatus(callbacks=status_signals)

        super(EIPConnection, self).__init__(*args, **kwargs)

    def connect(self):
        """
        entry point for connection process
        """
        self.forget_errors()
        self._try_connection()
        # XXX should capture errors?

    def disconnect(self):
        """
        disconnects client
        """
        self._disconnect()
        self.status.change_to(self.status.DISCONNECTED)
        pass

    def shutdown(self):
        """
        shutdown and quit
        """
        self.desired_con_state = self.status.DISCONNECTED

    def connection_state(self):
        """
        returns the current connection state
        """
        return self.status.current

    def desired_connection_state(self):
        """
        returns the desired_connection state
        """
        return self.desired_con_state

    def poll_connection_state(self):
        """
        """
        try:
            state = self.get_connection_state()
        except ConnectionRefusedError:
            # connection refused. might be not ready yet.
            return
        if not state:
            return
        (ts, status_step,
         ok, ip, remote) = state
        self.status.set_vpn_state(status_step)
        status_step = self.status.get_readable_status()
        return (ts, status_step, ok, ip, remote)

    def get_icon_name(self):
        """
        get icon name from status object
        """
        return self.status.get_state_icon()

    #
    # private methods
    #

    def _disconnect(self):
        """
        private method for disconnecting
        """
        if self.subp is not None:
            self.subp.terminate()
            self.subp = None
        # XXX signal state changes! :)

    def _is_alive(self):
        """
        don't know yet
        """
        pass

    def _connect(self):
        """
        entry point for connection cascade methods.
        """
        #conn_result = ConState.DISCONNECTED
        try:
            conn_result = self._try_connection()
        except UnrecoverableError as except_msg:
            logger.error("FATAL: %s" % unicode(except_msg))
            conn_result = self.status.UNRECOVERABLE
        except Exception as except_msg:
            self.error_queue.append(except_msg)
            logger.error("Failed Connection: %s" %
                         unicode(except_msg))
        return conn_result

"""generic watcher object that keeps track of connection status"""
# This should be deprecated in favor of daemon mode + management
# interface. But we can leave it here for debug purposes.


class EIPConnectionStatus(object):
    """
    Keep track of client (gui) and openvpn
    states.

    These are the OpenVPN states:
    CONNECTING    -- OpenVPN's initial state.
    WAIT          -- (Client only) Waiting for initial response
                     from server.
    AUTH          -- (Client only) Authenticating with server.
    GET_CONFIG    -- (Client only) Downloading configuration options
                     from server.
    ASSIGN_IP     -- Assigning IP address to virtual network
                     interface.
    ADD_ROUTES    -- Adding routes to system.
    CONNECTED     -- Initialization Sequence Completed.
    RECONNECTING  -- A restart has occurred.
    EXITING       -- A graceful exit is in progress.

    We add some extra states:

    DISCONNECTED  -- GUI initial state.
    UNRECOVERABLE -- An unrecoverable error has been raised
                     while invoking openvpn service.
    """
    CONNECTING = 1
    WAIT = 2
    AUTH = 3
    GET_CONFIG = 4
    ASSIGN_IP = 5
    ADD_ROUTES = 6
    CONNECTED = 7
    RECONNECTING = 8
    EXITING = 9

    # gui specific states:
    UNRECOVERABLE = 11
    DISCONNECTED = 0

    def __init__(self, callbacks=None):
        """
        EIPConnectionStatus is initialized with a tuple
        of signals to be triggered.
        :param callbacks: a tuple of (callable) observers
        :type callbacks: tuple
        """
        # (callbacks to connect to signals in Qt-land)
        self.current = self.DISCONNECTED
        self.previous = None
        self.callbacks = callbacks

    def get_readable_status(self):
        # XXX DRY status / labels a little bit.
        # think we'll want to i18n this.
        human_status = {
            0: 'disconnected',
            1: 'connecting',
            2: 'waiting',
            3: 'authenticating',
            4: 'getting config',
            5: 'assigning ip',
            6: 'adding routes',
            7: 'connected',
            8: 'reconnecting',
            9: 'exiting',
            11: 'unrecoverable error',
        }
        return human_status[self.current]

    def get_state_icon(self):
        """
        returns the high level icon
        for each fine-grain openvpn state
        """
        connecting = (self.CONNECTING,
                      self.WAIT,
                      self.AUTH,
                      self.GET_CONFIG,
                      self.ASSIGN_IP,
                      self.ADD_ROUTES)
        connected = (self.CONNECTED,)
        disconnected = (self.DISCONNECTED,
                        self.UNRECOVERABLE)

        # this can be made smarter,
        # but it's like it'll change,
        # so +readability.

        if self.current in connecting:
            return "connecting"
        if self.current in connected:
            return "connected"
        if self.current in disconnected:
            return "disconnected"

    def set_vpn_state(self, status):
        """
        accepts a state string from the management
        interface, and sets the internal state.
        :param status: openvpn STATE (uppercase).
        :type status: str
        """
        if hasattr(self, status):
            self.change_to(getattr(self, status))

    def set_current(self, to):
        """
        setter for the 'current' property
        :param to: destination state
        :type to: int
        """
        self.current = to

    def change_to(self, to):
        """
        :param to: destination state
        :type to: int
        """
        if to == self.current:
            return
        changed = False
        from_ = self.current
        self.current = to

        # We can add transition restrictions
        # here to ensure no transitions are
        # allowed outside the fsm.

        self.set_current(to)
        changed = True

        #trigger signals (as callbacks)
        #print('current state: %s' % self.current)
        if changed:
            self.previous = from_
            if self.callbacks:
                for cb in self.callbacks:
                    if callable(cb):
                        cb(self)



class EIPClientError(ConnectionError):
    """
    base EIPClient Exception
    """
    pass