from __future__ import print_function

import sys

import re

from pybindgen.typehandlers import base as typehandlers

from pybindgen import ReturnValue, Parameter

from pybindgen.cppmethod import CustomCppMethodWrapper, CustomCppConstructorWrapper

from pybindgen.typehandlers.codesink import MemoryCodeSink

from pybindgen.typehandlers import ctypeparser

from pybindgen.typehandlers.base import ForwardWrapperBase

from pybindgen import cppclass

import warnings

from pybindgen.typehandlers.base import CodeGenerationError

import sys

class SmartPointerTransformation(typehandlers.TypeTransformation):

    """

    This class provides a "type transformation" that tends to support

    NS-3 smart pointers.  Parameters such as "Ptr<Foo> foo" are

    transformed into something like Parameter.new("Foo*", "foo",

    transfer_ownership=False).  Return values such as Ptr<Foo> are

    transformed into ReturnValue.new("Foo*",

    caller_owns_return=False).  Since the underlying objects have

    reference counting, PyBindGen does the right thing.

    """

    def __init__(self):

        super(SmartPointerTransformation, self).__init__()

        self.rx = re.compile(r'(ns3::|::ns3::|)Ptr<([^>]+)>\s*$')

        print("{0!r}".format(self), file=sys.stderr)

    def _get_untransformed_type_traits(self, name):

        m = self.rx.match(name)

        is_const = False

        if m is None:

            print("{0!r} did not match".format(name), file=sys.stderr)

            return None, False

        else:

            name1 = m.group(2).strip()

            if name1.startswith('const '):

                name1 = name1[len('const '):]

                is_const = True

            if name1.endswith(' const'):

                name1 = name1[:-len(' const')]

                is_const = True

            new_name = name1+' *'

            if new_name.startswith('::'):

                new_name = new_name[2:]

            return new_name, is_const

    def get_untransformed_name(self, name):

        new_name, dummy_is_const = self._get_untransformed_type_traits(name)

        return new_name

    def create_type_handler(self, type_handler, *args, **kwargs):

        if issubclass(type_handler, Parameter):

            kwargs['transfer_ownership'] = False

        elif issubclass(type_handler, ReturnValue):

            kwargs['caller_owns_return'] = False

        else:

            raise AssertionError

        ## fix the ctype, add ns3:: namespace

        orig_ctype, is_const = self._get_untransformed_type_traits(args[0])

        if is_const:

            correct_ctype = 'ns3::Ptr< {0} const >'.format(orig_ctype[:-2])

        else:

            correct_ctype = 'ns3::Ptr< {0} >'.format(orig_ctype[:-2])

        args = tuple([correct_ctype] + list(args[1:]))

        handler = type_handler(*args, **kwargs)

        handler.set_tranformation(self, orig_ctype)

        return handler

    def untransform(self, type_handler, declarations, code_block, expression):

        return 'const_cast<%s> (ns3::PeekPointer (%s))' % (type_handler.untransformed_ctype, expression)

    def transform(self, type_handler, declarations, code_block, expression):

        assert type_handler.untransformed_ctype[-1] == '*'

        return 'ns3::Ptr< %s > (%s)' % (type_handler.untransformed_ctype[:-1], expression)

## register the type transformation

transf = SmartPointerTransformation()

typehandlers.return_type_matcher.register_transformation(transf)

typehandlers.param_type_matcher.register_transformation(transf)

del transf

class CallbackImplProxyMethod(typehandlers.ReverseWrapperBase):

    """

    Class that generates a proxy virtual method that calls a similarly named python method.

    """

    def __init__(self, return_value, parameters):

        super(CallbackImplProxyMethod, self).__init__(return_value, parameters)

    def generate_python_call(self):

        """code to call the python method"""

        build_params = self.build_params.get_parameters(force_tuple_creation=True)

        if build_params[0][0] == '"':

            build_params[0] = '(char *) ' + build_params[0]

        args = self.before_call.declare_variable('PyObject*', 'args')

        self.before_call.write_code('%s = Py_BuildValue(%s);'

                                    % (args, ', '.join(build_params)))

        self.before_call.add_cleanup_code('Py_DECREF(%s);' % args)

        self.before_call.write_code('py_retval = PyObject_CallObject(m_callback, %s);' % args)

        self.before_call.write_error_check('py_retval == NULL')

        self.before_call.add_cleanup_code('Py_DECREF(py_retval);')

def register_callback_classes(out, callbacks):

    for callback_impl_num, template_parameters in enumerate(callbacks):

        cls_name = "ns3::Callback< %s >" % ', '.join(template_parameters)

        #print >> sys.stderr, "***** trying to register callback: %r" % cls_name

        class_name = "PythonCallbackImpl%i" % callback_impl_num

        class PythonCallbackParameter(Parameter):

            "Class handlers"

            CTYPES = [cls_name]

            print("***** registering callback handler: %r (%r)" % (ctypeparser.normalize_type_string(cls_name), cls_name), file=sys.stderr)

            DIRECTIONS = [Parameter.DIRECTION_IN]

            PYTHON_CALLBACK_IMPL_NAME = class_name

            TEMPLATE_ARGS = template_parameters

            DISABLED = False

            def convert_python_to_c(self, wrapper):

                "parses python args to get C++ value"

                assert isinstance(wrapper, typehandlers.ForwardWrapperBase)

                if self.DISABLED:

                    raise CodeGenerationError("wrapper could not be generated")

                if self.default_value is None:

                    py_callback = wrapper.declarations.declare_variable('PyObject*', self.name)

                    wrapper.parse_params.add_parameter('O', ['&'+py_callback], self.name)

                    wrapper.before_call.write_error_check(

                        '!PyCallable_Check(%s)' % py_callback,

                        'PyErr_SetString(PyExc_TypeError, "parameter \'%s\' must be callbale");' % self.name)

                    callback_impl = wrapper.declarations.declare_variable(

                        'ns3::Ptr<%s>' % self.PYTHON_CALLBACK_IMPL_NAME,

                        '%s_cb_impl' % self.name)

                    wrapper.before_call.write_code("%s = ns3::Create<%s> (%s);"

                                                   % (callback_impl, self.PYTHON_CALLBACK_IMPL_NAME, py_callback))

                    wrapper.call_params.append(

                        'ns3::Callback<%s> (%s)' % (', '.join(self.TEMPLATE_ARGS), callback_impl))

                else:

                    py_callback = wrapper.declarations.declare_variable('PyObject*', self.name, 'NULL')

                    wrapper.parse_params.add_parameter('O', ['&'+py_callback], self.name, optional=True)

                    value = wrapper.declarations.declare_variable(

                        'ns3::Callback<%s>' % ', '.join(self.TEMPLATE_ARGS),

                        self.name+'_value',

                        self.default_value)

                    wrapper.before_call.write_code("if (%s) {" % (py_callback,))

                    wrapper.before_call.indent()

                    wrapper.before_call.write_error_check(

                        '!PyCallable_Check(%s)' % py_callback,

                        'PyErr_SetString(PyExc_TypeError, "parameter \'%s\' must be callbale");' % self.name)

                    wrapper.before_call.write_code("%s = ns3::Callback<%s> (ns3::Create<%s> (%s));"

                                                   % (value, ', '.join(self.TEMPLATE_ARGS),

                                                      self.PYTHON_CALLBACK_IMPL_NAME, py_callback))

                    wrapper.before_call.unindent()

                    wrapper.before_call.write_code("}") # closes: if (py_callback) {

                    wrapper.call_params.append(value)

            def convert_c_to_python(self, wrapper):

                raise typehandlers.NotSupportedError("Reverse wrappers for ns3::Callback<...> types "

                                                     "(python using callbacks defined in C++) not implemented.")

def generate_callback_classes(module, callbacks):

    out = module.after_forward_declarations

    for callback_impl_num, template_parameters in enumerate(callbacks):

        sink = MemoryCodeSink()

        cls_name = "ns3::Callback< %s >" % ', '.join(template_parameters)

        #print >> sys.stderr, "***** trying to register callback: %r" % cls_name

        class_name = "PythonCallbackImpl%i" % callback_impl_num

        sink.writeln('''

class %s : public ns3::CallbackImpl<%s>

{

public:

    PyObject *m_callback;

    %s(PyObject *callback)

    {

        Py_INCREF(callback);

        m_callback = callback;

    }

    virtual ~%s()

    {

        PyGILState_STATE __py_gil_state;

        __py_gil_state = (PyEval_ThreadsInitialized() ? PyGILState_Ensure() : (PyGILState_STATE) 0);

        Py_DECREF(m_callback);

        m_callback = NULL;

        PyGILState_Release(__py_gil_state);

    }

    virtual bool IsEqual(ns3::Ptr<const ns3::CallbackImplBase> other_base) const

    {

        const %s *other = dynamic_cast<const %s*> (ns3::PeekPointer (other_base));

        if (other != NULL)

            return (other->m_callback == m_callback);

        else

            return false;

    }

''' % (class_name, ', '.join(template_parameters), class_name, class_name, class_name, class_name))

        sink.indent()

        callback_return = template_parameters[0]

        return_ctype = ctypeparser.parse_type(callback_return)

        if ('const' in return_ctype.remove_modifiers()):

            kwargs = {'is_const': True}

        else:

            kwargs = {}

        try:

            return_type = ReturnValue.new(str(return_ctype), **kwargs)

        except (typehandlers.TypeLookupError, typehandlers.TypeConfigurationError) as ex:

            warnings.warn("***** Unable to register callback; Return value '%s' error (used in %s): %r"

                          % (callback_return, cls_name, ex),

                          Warning)

            continue

        arguments = []

        ok = True

        callback_parameters = [arg for arg in template_parameters[1:] if arg != 'ns3::empty']

        for arg_num, arg_type in enumerate(callback_parameters):

            arg_name = 'arg%i' % (arg_num+1)

            param_ctype = ctypeparser.parse_type(arg_type)

            if ('const' in param_ctype.remove_modifiers()):

                kwargs = {'is_const': True}

            else:

                kwargs = {}

            try:

                arguments.append(Parameter.new(str(param_ctype), arg_name, **kwargs))

            except (typehandlers.TypeLookupError, typehandlers.TypeConfigurationError) as ex:

                warnings.warn("***** Unable to register callback; parameter '%s %s' error (used in %s): %r"

                              % (arg_type, arg_name, cls_name, ex),

                              Warning)

                ok = False

        if not ok:

            try:

                typehandlers.return_type_matcher.lookup(cls_name)[0].DISABLED = True

            except typehandlers.TypeLookupError:

                pass

            try:

                typehandlers.param_type_matcher.lookup(cls_name)[0].DISABLED = True

            except typehandlers.TypeLookupError:

                pass

            continue

        wrapper = CallbackImplProxyMethod(return_type, arguments)

        wrapper.generate(sink, 'operator()', decl_modifiers=[])

        sink.unindent()

        sink.writeln('};\n')

        print("Flushing to ", out, file=sys.stderr)

        sink.flush_to(out)

# def write_preamble(out):

#     pybindgen.write_preamble(out)

#     out.writeln("#include \"ns3/everything.h\"")

def Simulator_customizations(module):

    Simulator = module['ns3::Simulator']

    ## Simulator::Schedule(delay, callback, ...user..args...)

    Simulator.add_custom_method_wrapper("Schedule", "_wrap_Simulator_Schedule",

                                        flags=["METH_VARARGS", "METH_KEYWORDS", "METH_STATIC"])

    ## Simulator::ScheduleNow(callback, ...user..args...)

    Simulator.add_custom_method_wrapper("ScheduleNow", "_wrap_Simulator_ScheduleNow",

                                        flags=["METH_VARARGS", "METH_KEYWORDS", "METH_STATIC"])

    ## Simulator::ScheduleDestroy(callback, ...user..args...)

    Simulator.add_custom_method_wrapper("ScheduleDestroy", "_wrap_Simulator_ScheduleDestroy",

                                        flags=["METH_VARARGS", "METH_KEYWORDS", "METH_STATIC"])

    Simulator.add_custom_method_wrapper("Run", "_wrap_Simulator_Run",

                                        flags=["METH_VARARGS", "METH_KEYWORDS", "METH_STATIC"])

def CommandLine_customizations(module):

    CommandLine = module['ns3::CommandLine']

    CommandLine.add_method('Parse', None, [ArgvParam(None, 'argv')],

                           is_static=False)

    CommandLine.add_custom_method_wrapper("AddValue", "_wrap_CommandLine_AddValue",

                                          flags=["METH_VARARGS", "METH_KEYWORDS"])

def Object_customizations(module):

    ## ---------------------------------------------------------------------

    ## Here we generate custom constructor code for all classes that

    ## derive from ns3::Object.  The custom constructors are needed in

    ## order to support kwargs only and to translate kwargs into ns3

    ## attributes, etc.

    ## ---------------------------------------------------------------------

    try:

        Object = module['ns3::Object']

    except KeyError:

        return

    ## add a GetTypeId method to all generatd helper classes

    def helper_class_hook(helper_class):

        decl = """

static ns3::TypeId GetTypeId (void)

{

  static ns3::TypeId tid = ns3::TypeId ("%s")

    .SetParent< %s > ()

    ;

  return tid;

}"""  % (helper_class.name, helper_class.class_.full_name)

        helper_class.add_custom_method(decl)

        helper_class.add_post_generation_code(

            "NS_OBJECT_ENSURE_REGISTERED (%s);" % helper_class.name)

    Object.add_helper_class_hook(helper_class_hook)

    def ns3_object_instance_creation_function(cpp_class, code_block, lvalue,

                                              parameters, construct_type_name):

        assert lvalue

        assert not lvalue.startswith('None')

        if cpp_class.cannot_be_constructed:

            raise CodeGenerationError("%s cannot be constructed (%s)"

                                      % cpp_class.full_name)

        if cpp_class.incomplete_type:

            raise CodeGenerationError("%s cannot be constructed (incomplete type)"

                                      % cpp_class.full_name)

        code_block.write_code("%s = new %s(%s);" % (lvalue, construct_type_name, parameters))

        code_block.write_code("%s->Ref ();" % (lvalue))

    def ns3_object_post_instance_creation_function(cpp_class, code_block, lvalue,

                                                   parameters, construct_type_name):

        code_block.write_code("ns3::CompleteConstruct(%s);" % (lvalue, ))

    Object.set_instance_creation_function(ns3_object_instance_creation_function)

    Object.set_post_instance_creation_function(ns3_object_post_instance_creation_function)

def Attribute_customizations(module):

    # Fix up for the "const AttributeValue &v = EmptyAttribute()"

    # case, as used extensively by helper classes.

    # Here's why we need to do this: pybindgen.gccxmlscanner, when

    # scanning parameter default values, is only provided with the

    # value as a simple C expression string.  (py)gccxml does not

    # report the type of the default value.

    # As a workaround, here we iterate over all parameters of all

    # methods of all classes and tell pybindgen what is the type of

    # the default value for attributes.

    for cls in module.classes:

        for meth in cls.get_all_methods():

            for param in meth.parameters:

                if isinstance(param, cppclass.CppClassRefParameter):

                    if param.cpp_class.name == 'AttributeValue' \

                            and param.default_value is not None \

                            and param.default_value_type is None:

                        param.default_value_type = 'ns3::EmptyAttributeValue'

def TypeId_customizations(module):

    TypeId = module['ns3::TypeId']

    TypeId.add_custom_method_wrapper("LookupByNameFailSafe", "_wrap_TypeId_LookupByNameFailSafe",

                                     flags=["METH_VARARGS", "METH_KEYWORDS", "METH_STATIC"])

def add_std_ofstream(module):

    module.add_include('<fstream>')

    ostream = module.add_class('ostream', foreign_cpp_namespace='::std')

    ostream.set_cannot_be_constructed("abstract base class")

    ofstream = module.add_class('ofstream', foreign_cpp_namespace='::std', parent=ostream)

    ofstream.add_enum('openmode', [

            ('app', 'std::ios_base::app'),

            ('ate', 'std::ios_base::ate'),

            ('binary', 'std::ios_base::binary'),

            ('in', 'std::ios_base::in'),

            ('out', 'std::ios_base::out'),

            ('trunc', 'std::ios_base::trunc'),

            ])

    ofstream.add_constructor([Parameter.new("const char *", 'filename'),

                              Parameter.new("::std::ofstream::openmode", 'mode', default_value="std::ios_base::out")])

    ofstream.add_method('close', None, [])

    add_std_ios_openmode(module)

class IosOpenmodeParam(Parameter):

    DIRECTIONS = [Parameter.DIRECTION_IN]

    CTYPES = ['std::ios::openmode', 'std::_Ios_Openmode']

    def convert_c_to_python(self, wrapper):

        assert isinstance(wrapper, ReverseWrapperBase)

        wrapper.build_params.add_parameter('i', [self.value])

    def convert_python_to_c(self, wrapper):

        assert isinstance(wrapper, ForwardWrapperBase)

        name = wrapper.declarations.declare_variable("std::ios::openmode", self.name, self.default_value)

        wrapper.parse_params.add_parameter('i', ['&'+name], self.name, optional=bool(self.default_value))

        wrapper.call_params.append(name)

def add_std_ios_openmode(module):

    for flag in 'in', 'out', 'ate', 'app', 'trunc', 'binary':

        module.after_init.write_code('PyModule_AddIntConstant(m, (char *) "STD_IOS_%s", std::ios::%s);'

                                     % (flag.upper(), flag))

def add_ipv4_address_tp_hash(module):

    module.body.writeln('''

long

_ns3_Ipv4Address_tp_hash (PyObject *obj)

{

   PyNs3Ipv4Address *addr = reinterpret_cast<PyNs3Ipv4Address *> (obj);

   return static_cast<long> (ns3::Ipv4AddressHash () (*addr->obj));

}

''')

    module.header.writeln('long _ns3_Ipv4Address_tp_hash (PyObject *obj);')

    module['Ipv4Address'].pytype.slots['tp_hash'] = "_ns3_Ipv4Address_tp_hash"