#     Copyright 2018, Kay Hayen, mailto:kay.hayen@gmail.com
#
#     Part of "Nuitka", an optimizing Python compiler that is compatible and
#     integrates with CPython, but also works on its own.
#
#     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.
#
""" The type1 node.

This one just determines types. It's great for optimization. We may be able to
predict its value, but knowing it. In that case, we have a built-in name
reference for that type to convert to, or when checking the result of it, we
will then know it's limited after the fact.

"""

from nuitka.Builtins import builtin_names

from .BuiltinRefNodes import (
    ExpressionBuiltinAnonymousRef,
    ExpressionBuiltinRef,
    makeExpressionBuiltinRef
)
from .ExpressionBases import (
    ExpressionBuiltinSingleArgBase,
    ExpressionChildrenHavingBase
)
from .NodeMakingHelpers import wrapExpressionWithNodeSideEffects
from .shapes.BuiltinTypeShapes import ShapeTypeType


class ExpressionBuiltinType1(ExpressionBuiltinSingleArgBase):
    kind = "EXPRESSION_BUILTIN_TYPE1"

    def computeExpression(self, trace_collection):
        value = self.getValue()

        type_shape = value.getTypeShape()

        if type_shape is not None:
            type_name = type_shape.getTypeName()

            if type_name is not None and type_name in __builtins__:
                result = ExpressionBuiltinRef(
                    builtin_name = type_name,
                    source_ref   = value.getSourceReference(),
                )

                result = wrapExpressionWithNodeSideEffects(
                    new_node = result,
                    old_node = value
                )

                return (
                    result,
                    "new_builtin",
                    "Replaced predictable type lookup with builtin type '%s'." % (
                        type_name
                    )
                )

        if value.isCompileTimeConstant():
            # The above code is supposed to catch these in a better way.
            value = value.getCompileTimeConstant()

            type_name = value.__class__.__name__


            if type_name in builtin_names:
                new_node = makeExpressionBuiltinRef(
                    builtin_name = type_name,
                    source_ref   = self.getSourceReference()
                )
            else:
                new_node = ExpressionBuiltinAnonymousRef(
                    builtin_name = type_name,
                    source_ref   = self.getSourceReference()
                )

            return (
                new_node,
                "new_builtin",
                "Replaced predictable type lookup with builtin type '%s'." % (
                    type_name
                )
            )

        return self, None, None

    def getTypeShape(self):
        return ShapeTypeType

    def computeExpressionDrop(self, statement, trace_collection):
        from .NodeMakingHelpers import \
          makeStatementExpressionOnlyReplacementNode

        result = makeStatementExpressionOnlyReplacementNode(
            expression = self.getValue(),
            node       = statement
        )

        return result, "new_statements", """\
Removed type taking for unused result."""

    def mayRaiseException(self, exception_type):
        return self.getValue().mayRaiseException(exception_type)

    def mayHaveSideEffects(self):
        return self.getValue().mayHaveSideEffects()


class ExpressionBuiltinSuper(ExpressionChildrenHavingBase):
    kind = "EXPRESSION_BUILTIN_SUPER"

    named_children = (
        "type",
        "object"
    )

    def __init__(self, super_type, super_object, source_ref):
        ExpressionChildrenHavingBase.__init__(
            self,
            values     = {
                "type"   : super_type,
                "object" : super_object

            },
            source_ref = source_ref )

    getType = ExpressionChildrenHavingBase.childGetter("type")
    getObject = ExpressionChildrenHavingBase.childGetter("object")

    def computeExpression(self, trace_collection):
        trace_collection.onExceptionRaiseExit(BaseException)

        # TODO: Quite some cases should be possible to predict.
        return self, None, None


class ExpressionBuiltinIsinstance(ExpressionChildrenHavingBase):
    kind = "EXPRESSION_BUILTIN_ISINSTANCE"

    named_children = (
        "instance",
        "classes"
    )

    def __init__(self, instance, classes, source_ref):
        ExpressionChildrenHavingBase.__init__(
            self,
            values     = {
                "instance" : instance,
                "classes"  : classes

            },
            source_ref = source_ref
        )

    getInstance = ExpressionChildrenHavingBase.childGetter("instance")
    getCls = ExpressionChildrenHavingBase.childGetter("classes")

    def computeExpression(self, trace_collection):
        # TODO: Quite some cases should be possible to predict.

        instance = self.getInstance()

        # TODO: Should be possible to query run time type instead, but we don't
        # have that method yet. Later this will be essential.
        if not instance.isCompileTimeConstant():
            trace_collection.onExceptionRaiseExit(BaseException)

            return self, None, None

        cls = self.getCls()

        if not cls.isCompileTimeConstant():
            trace_collection.onExceptionRaiseExit(BaseException)

            return self, None, None

        # So if both are compile time constant, we are able to compute it.
        return trace_collection.getCompileTimeComputationResult(
            node        = self,
            computation = lambda : isinstance(
                instance.getCompileTimeConstant(),
                cls.getCompileTimeConstant()
            ),
            description = "Built-in call to 'isinstance' computed."
        )
