#!/usr/bin/env python2
#-*- coding: utf-8 -*-

# SAT: a jabber client
# Copyright (C) 2009-2016 Jérôme Poisson (goffi@goffi.org)

# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Affero General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.

# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU Affero General Public License for more details.

# You should have received a copy of the GNU Affero General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.

from sat.core.i18n import _
from bridge import Bridge
import dbus
import dbus.service
import dbus.mainloop.glib
import inspect
from sat.core.log import getLogger
log = getLogger(__name__)
from twisted.internet.defer import Deferred
from sat.core.exceptions import BridgeInitError

const_INT_PREFIX = "org.goffi.SAT"  # Interface prefix
const_ERROR_PREFIX = const_INT_PREFIX + ".error"
const_OBJ_PATH = '/org/goffi/SAT/bridge'
const_CORE_SUFFIX = ".core"
const_PLUGIN_SUFFIX = ".plugin"


class ParseError(Exception):
    pass


class MethodNotRegistered(dbus.DBusException):
    _dbus_error_name = const_ERROR_PREFIX + ".MethodNotRegistered"


class InternalError(dbus.DBusException):
    _dbus_error_name = const_ERROR_PREFIX + ".InternalError"


class AsyncNotDeferred(dbus.DBusException):
    _dbus_error_name = const_ERROR_PREFIX + ".AsyncNotDeferred"


class DeferredNotAsync(dbus.DBusException):
    _dbus_error_name = const_ERROR_PREFIX + ".DeferredNotAsync"


class GenericException(dbus.DBusException):
    def __init__(self, twisted_error):
        """

        @param twisted_error (Failure): instance of twisted Failure
        @return: DBusException
        """
        super(GenericException, self).__init__()
        try:
            # twisted_error.value is a class
            class_ = twisted_error.value().__class__
        except TypeError:
            # twisted_error.value is an instance
            class_ = twisted_error.value.__class__
            message = twisted_error.getErrorMessage()
            try:
                self.args = (message, twisted_error.value.condition)
            except AttributeError:
                self.args = (message,)
        self._dbus_error_name = '.'.join([const_ERROR_PREFIX, class_.__module__, class_.__name__])


class DbusObject(dbus.service.Object):

    def __init__(self, bus, path):
        dbus.service.Object.__init__(self, bus, path)
        log.debug("Init DbusObject...")
        self.cb = {}

    def register(self, name, cb):
        self.cb[name] = cb

    def _callback(self, name, *args, **kwargs):
        """call the callback if it exists, raise an exception else
        if the callback return a deferred, use async methods"""
        if not name in self.cb:
            raise MethodNotRegistered

        if "callback" in kwargs:
            #we must have errback too
            if not "errback" in kwargs:
                log.error("errback is missing in method call [%s]" % name)
                raise InternalError
            callback = kwargs.pop("callback")
            errback = kwargs.pop("errback")
            async = True
        else:
            async = False
        result = self.cb[name](*args, **kwargs)
        if async:
            if not isinstance(result, Deferred):
                log.error("Asynchronous method [%s] does not return a Deferred." % name)
                raise AsyncNotDeferred
            result.addCallback(lambda result: callback() if result is None else callback(result))
            result.addErrback(lambda err: errback(GenericException(err)))
        else:
            if isinstance(result, Deferred):
                log.error("Synchronous method [%s] return a Deferred." % name)
                raise DeferredNotAsync
            return result
    ### signals ###

    @dbus.service.signal(const_INT_PREFIX + const_PLUGIN_SUFFIX,
                         signature='')
    def dummySignal(self):
        #FIXME: workaround for addSignal (doesn't work if one method doensn't
        #       already exist for plugins), probably missing some initialisation, need
        #       further investigations
        pass

##SIGNALS_PART##
    ### methods ###

##METHODS_PART##
    def __attributes(self, in_sign):
        """Return arguments to user given a in_sign
        @param in_sign: in_sign in the short form (using s,a,i,b etc)
        @return: list of arguments that correspond to a in_sign (e.g.: "sss" return "arg1, arg2, arg3")"""
        i = 0
        idx = 0
        attr = []
        while i < len(in_sign):
            if in_sign[i] not in ['b', 'y', 'n', 'i', 'x', 'q', 'u', 't', 'd', 's', 'a']:
                raise ParseError("Unmanaged attribute type [%c]" % in_sign[i])

            attr.append("arg_%i" % idx)
            idx += 1

            if in_sign[i] == 'a':
                i += 1
                if in_sign[i] != '{' and in_sign[i] != '(':  # FIXME: must manage tuples out of arrays
                    i += 1
                    continue  # we have a simple type for the array
                opening_car = in_sign[i]
                assert(opening_car in ['{', '('])
                closing_car = '}' if opening_car == '{' else ')'
                opening_count = 1
                while (True):  # we have a dict or a list of tuples
                    i += 1
                    if i >= len(in_sign):
                        raise ParseError("missing }")
                    if in_sign[i] == opening_car:
                        opening_count += 1
                    if in_sign[i] == closing_car:
                        opening_count -= 1
                        if opening_count == 0:
                            break
            i += 1
        return attr

    def addMethod(self, name, int_suffix, in_sign, out_sign, method, async=False):
        """Dynamically add a method to Dbus Bridge"""
        inspect_args = inspect.getargspec(method)

        _arguments = inspect_args.args
        _defaults = list(inspect_args.defaults or [])

        if inspect.ismethod(method):
            #if we have a method, we don't want the first argument (usually 'self')
            del(_arguments[0])

        #first arguments are for the _callback method
        arguments_callback = ', '.join([repr(name)] + ((_arguments + ['callback=callback', 'errback=errback']) if async else _arguments))

        if async:
            _arguments.extend(['callback', 'errback'])
            _defaults.extend([None, None])

        #now we create a second list with default values
        for i in range(1, len(_defaults) + 1):
            _arguments[-i] = "%s = %s" % (_arguments[-i], repr(_defaults[-i]))

        arguments_defaults = ', '.join(_arguments)

        code = compile('def %(name)s (self,%(arguments_defaults)s): return self._callback(%(arguments_callback)s)' %
                       {'name': name, 'arguments_defaults': arguments_defaults, 'arguments_callback': arguments_callback}, '<DBus bridge>', 'exec')
        exec (code)  # FIXME: to the same thing in a cleaner way, without compile/exec
        method = locals()[name]
        async_callbacks = ('callback', 'errback') if async else None
        setattr(DbusObject, name, dbus.service.method(
            const_INT_PREFIX + int_suffix, in_signature=in_sign, out_signature=out_sign,
            async_callbacks=async_callbacks)(method))
        function = getattr(self, name)
        func_table = self._dbus_class_table[self.__class__.__module__ + '.' + self.__class__.__name__][function._dbus_interface]
        func_table[function.__name__] = function  # Needed for introspection

    def addSignal(self, name, int_suffix, signature, doc={}):
        """Dynamically add a signal to Dbus Bridge"""
        attributes = ', '.join(self.__attributes(signature))
        #TODO: use doc parameter to name attributes

        #code = compile ('def '+name+' (self,'+attributes+'): log.debug ("'+name+' signal")', '<DBus bridge>','exec') #XXX: the log.debug is too annoying with xmllog
        code = compile('def ' + name + ' (self,' + attributes + '): pass', '<DBus bridge>', 'exec')
        exec (code)
        signal = locals()[name]
        setattr(DbusObject, name, dbus.service.signal(
            const_INT_PREFIX + int_suffix, signature=signature)(signal))
        function = getattr(self, name)
        func_table = self._dbus_class_table[self.__class__.__module__ + '.' + self.__class__.__name__][function._dbus_interface]
        func_table[function.__name__] = function  # Needed for introspection


class DBusBridge(Bridge):
    def __init__(self):
        dbus.mainloop.glib.DBusGMainLoop(set_as_default=True)
        Bridge.__init__(self)
        log.info("Init DBus...")
        try:
            self.session_bus = dbus.SessionBus()
        except dbus.DBusException as e:
            if e._dbus_error_name == 'org.freedesktop.DBus.Error.NotSupported':
                log.error(_(u"D-Bus is not launched, please see README to see instructions on how to launch it"))
            raise BridgeInitError
        self.dbus_name = dbus.service.BusName(const_INT_PREFIX, self.session_bus)
        self.dbus_bridge = DbusObject(self.session_bus, const_OBJ_PATH)

##DIRECT_CALLS##
    def register(self, name, callback):
        log.debug("registering DBus bridge method [%s]" % name)
        self.dbus_bridge.register(name, callback)

    def addMethod(self, name, int_suffix, in_sign, out_sign, method, async=False, doc={}):
        """Dynamically add a method to Dbus Bridge"""
        #FIXME: doc parameter is kept only temporary, the time to remove it from calls
        log.debug("Adding method [%s] to DBus bridge" % name)
        self.dbus_bridge.addMethod(name, int_suffix, in_sign, out_sign, method, async)
        self.register(name, method)

    def addSignal(self, name, int_suffix, signature, doc={}):
        self.dbus_bridge.addSignal(name, int_suffix, signature, doc)
        setattr(DBusBridge, name, getattr(self.dbus_bridge, name))
