#     Copyright 2020, 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.
#
""" Code generation for implicit and explicit exception raises.

Exceptions from other operations are consider ErrorCodes domain.

"""

from nuitka.Options import isDebug

from .CodeHelpers import (
    generateChildExpressionsCode,
    generateExpressionCode,
    withObjectCodeTemporaryAssignment,
)
from .ErrorCodes import getFrameVariableTypeDescriptionCode
from .LabelCodes import getGotoCode
from .LineNumberCodes import (
    emitErrorLineNumberUpdateCode,
    getErrorLineNumberUpdateCode,
)
from .PythonAPICodes import getReferenceExportCode


def generateReraiseCode(statement, emit, context):
    old_source_ref = context.setCurrentSourceCodeReference(
        value=statement.getCompatibleSourceReference()
    )

    getReRaiseExceptionCode(emit=emit, context=context)

    context.setCurrentSourceCodeReference(old_source_ref)


def generateRaiseCode(statement, emit, context):
    exception_type = statement.getExceptionType()
    exception_value = statement.getExceptionValue()
    exception_tb = statement.getExceptionTrace()
    exception_cause = statement.getExceptionCause()

    # Exception cause is only possible with simple raise form.
    if exception_cause is not None:
        assert exception_type is not None
        assert exception_value is None
        assert exception_tb is None

        raise_type_name = context.allocateTempName("raise_type")

        generateExpressionCode(
            to_name=raise_type_name,
            expression=exception_type,
            emit=emit,
            context=context,
        )

        raise_cause_name = context.allocateTempName("raise_cause")

        generateExpressionCode(
            to_name=raise_cause_name,
            expression=exception_cause,
            emit=emit,
            context=context,
        )

        old_source_ref = context.setCurrentSourceCodeReference(
            exception_cause.getSourceReference()
        )

        _getRaiseExceptionWithCauseCode(
            raise_type_name=raise_type_name,
            raise_cause_name=raise_cause_name,
            emit=emit,
            context=context,
        )

        context.setCurrentSourceCodeReference(old_source_ref)
    elif exception_type is None:
        assert False, statement
    elif exception_value is None and exception_tb is None:
        raise_type_name = context.allocateTempName("raise_type")

        generateExpressionCode(
            to_name=raise_type_name,
            expression=exception_type,
            emit=emit,
            context=context,
        )

        old_source_ref = context.setCurrentSourceCodeReference(
            value=exception_type.getCompatibleSourceReference()
        )

        _getRaiseExceptionWithTypeCode(
            raise_type_name=raise_type_name, emit=emit, context=context
        )

        context.setCurrentSourceCodeReference(old_source_ref)
    elif exception_tb is None:
        raise_type_name = context.allocateTempName("raise_type")

        generateExpressionCode(
            to_name=raise_type_name,
            expression=exception_type,
            emit=emit,
            context=context,
        )

        raise_value_name = context.allocateTempName("raise_value")

        generateExpressionCode(
            to_name=raise_value_name,
            expression=exception_value,
            emit=emit,
            context=context,
        )

        old_source_ref = context.setCurrentSourceCodeReference(
            exception_value.getSourceReference()
        )

        context.setCurrentSourceCodeReference(statement.getCompatibleSourceReference())

        _getRaiseExceptionWithValueCode(
            raise_type_name=raise_type_name,
            raise_value_name=raise_value_name,
            implicit=statement.isStatementRaiseExceptionImplicit(),
            emit=emit,
            context=context,
        )

        context.setCurrentSourceCodeReference(old_source_ref)
    else:
        raise_type_name = context.allocateTempName("raise_type")

        generateExpressionCode(
            to_name=raise_type_name,
            expression=exception_type,
            emit=emit,
            context=context,
        )

        raise_value_name = context.allocateTempName("raise_value")

        generateExpressionCode(
            to_name=raise_value_name,
            expression=exception_value,
            emit=emit,
            context=context,
        )

        raise_tb_name = context.allocateTempName("raise_tb")

        generateExpressionCode(
            to_name=raise_tb_name, expression=exception_tb, emit=emit, context=context
        )

        old_source_ref = context.setCurrentSourceCodeReference(
            exception_tb.getSourceReference()
        )

        _getRaiseExceptionWithTracebackCode(
            raise_type_name=raise_type_name,
            raise_value_name=raise_value_name,
            raise_tb_name=raise_tb_name,
            emit=emit,
            context=context,
        )

        context.setCurrentSourceCodeReference(old_source_ref)


def generateRaiseExpressionCode(to_name, expression, emit, context):
    arg_names = generateChildExpressionsCode(
        expression=expression, emit=emit, context=context
    )

    # Missed optimization opportunity, please report it, this should not
    # normally happen. We are supposed to propagate this upwards.
    if isDebug():
        # TODO: Need to optimize ExpressionLocalsVariableRefOrFallback once we know
        # it handles cases where the value is not in locals dict properly.

        parent = expression.parent
        assert (
            parent.isExpressionSideEffects()
            or parent.isExpressionConditional()
            or parent.isExpressionLocalsVariableRefOrFallback()
        ), (expression, expression.parent, expression.asXmlText())

    with withObjectCodeTemporaryAssignment(
        to_name, "raise_exception_result", expression, emit, context
    ) as value_name:

        # That's how we indicate exception to the surrounding world.
        emit("%s = NULL;" % value_name)

        _getRaiseExceptionWithValueCode(
            raise_type_name=arg_names[0],
            raise_value_name=arg_names[1],
            implicit=True,
            emit=emit,
            context=context,
        )


def getReRaiseExceptionCode(emit, context):
    (
        exception_type,
        exception_value,
        exception_tb,
        exception_lineno,
    ) = context.variable_storage.getExceptionVariableDescriptions()

    keeper_variables = context.getExceptionKeeperVariables()

    if keeper_variables[0] is None:
        emit(
            """\
%(bool_res_name)s = RERAISE_EXCEPTION(&%(exception_type)s, &%(exception_value)s, &%(exception_tb)s);
if (unlikely(%(bool_res_name)s == false)) {
    %(update_code)s
}
"""
            % {
                "exception_type": exception_type,
                "exception_value": exception_value,
                "exception_tb": exception_tb,
                "bool_res_name": context.getBoolResName(),
                "update_code": getErrorLineNumberUpdateCode(context),
            }
        )

        frame_handle = context.getFrameHandle()

        if frame_handle:
            emit(
                """\
if (%(exception_tb)s && %(exception_tb)s->tb_frame == &%(frame_identifier)s->m_frame) \
%(frame_identifier)s->m_frame.f_lineno = %(exception_tb)s->tb_lineno;"""
                % {
                    "exception_tb": exception_tb,
                    "frame_identifier": context.getFrameHandle(),
                }
            )

            emit(getFrameVariableTypeDescriptionCode(context))
    else:
        (
            keeper_type,
            keeper_value,
            keeper_tb,
            keeper_lineno,
        ) = context.getExceptionKeeperVariables()

        emit(
            """\
// Re-raise.
%(exception_type)s = %(keeper_type)s;
%(exception_value)s = %(keeper_value)s;
%(exception_tb)s = %(keeper_tb)s;
%(exception_lineno)s = %(keeper_lineno)s;
"""
            % {
                "exception_type": exception_type,
                "exception_value": exception_value,
                "exception_tb": exception_tb,
                "exception_lineno": exception_lineno,
                "keeper_type": keeper_type,
                "keeper_value": keeper_value,
                "keeper_tb": keeper_tb,
                "keeper_lineno": keeper_lineno,
            }
        )

    getGotoCode(context.getExceptionEscape(), emit)


def _getRaiseExceptionWithCauseCode(raise_type_name, raise_cause_name, emit, context):
    (
        exception_type,
        exception_value,
        exception_tb,
        _exception_lineno,
    ) = context.variable_storage.getExceptionVariableDescriptions()

    emit("%s = %s;" % (exception_type, raise_type_name))
    getReferenceExportCode(raise_type_name, emit, context)

    emit("%s = NULL;" % exception_value)

    getReferenceExportCode(raise_cause_name, emit, context)

    emitErrorLineNumberUpdateCode(emit, context)
    emit(
        "RAISE_EXCEPTION_WITH_CAUSE(&%s, &%s, &%s, %s);"
        % (exception_type, exception_value, exception_tb, raise_cause_name)
    )

    emit(getFrameVariableTypeDescriptionCode(context))

    getGotoCode(context.getExceptionEscape(), emit)

    if context.needsCleanup(raise_type_name):
        context.removeCleanupTempName(raise_type_name)
    if context.needsCleanup(raise_cause_name):
        context.removeCleanupTempName(raise_cause_name)


def _getRaiseExceptionWithTypeCode(raise_type_name, emit, context):
    (
        exception_type,
        exception_value,
        exception_tb,
        _exception_lineno,
    ) = context.variable_storage.getExceptionVariableDescriptions()

    emit("%s = %s;" % (exception_type, raise_type_name))
    getReferenceExportCode(raise_type_name, emit, context)

    emitErrorLineNumberUpdateCode(emit, context)
    emit(
        "RAISE_EXCEPTION_WITH_TYPE(&%s, &%s, &%s);"
        % (exception_type, exception_value, exception_tb)
    )

    emit(getFrameVariableTypeDescriptionCode(context))

    getGotoCode(context.getExceptionEscape(), emit)

    if context.needsCleanup(raise_type_name):
        context.removeCleanupTempName(raise_type_name)


def _getRaiseExceptionWithValueCode(
    raise_type_name, raise_value_name, implicit, emit, context
):
    (
        exception_type,
        exception_value,
        exception_tb,
        _exception_lineno,
    ) = context.variable_storage.getExceptionVariableDescriptions()

    emit("%s = %s;" % (exception_type, raise_type_name))
    getReferenceExportCode(raise_type_name, emit, context)
    emit("%s = %s;" % (exception_value, raise_value_name))
    getReferenceExportCode(raise_value_name, emit, context)

    emitErrorLineNumberUpdateCode(emit, context)
    emit(
        "RAISE_EXCEPTION_%s(&%s, &%s, &%s);"
        % (
            ("IMPLICIT" if implicit else "WITH_VALUE"),
            exception_type,
            exception_value,
            exception_tb,
        )
    )

    emit(getFrameVariableTypeDescriptionCode(context))

    getGotoCode(context.getExceptionEscape(), emit)

    if context.needsCleanup(raise_type_name):
        context.removeCleanupTempName(raise_type_name)
    if context.needsCleanup(raise_value_name):
        context.removeCleanupTempName(raise_value_name)


def _getRaiseExceptionWithTracebackCode(
    raise_type_name, raise_value_name, raise_tb_name, emit, context
):
    (
        exception_type,
        exception_value,
        exception_tb,
        _exception_lineno,
    ) = context.variable_storage.getExceptionVariableDescriptions()

    emit("%s = %s;" % (exception_type, raise_type_name))
    getReferenceExportCode(raise_type_name, emit, context)
    emit("%s = %s;" % (exception_value, raise_value_name))
    getReferenceExportCode(raise_value_name, emit, context)

    emit("%s = (PyTracebackObject *)%s;" % (exception_tb, raise_tb_name))
    getReferenceExportCode(raise_tb_name, emit, context)

    emit(
        "RAISE_EXCEPTION_WITH_TRACEBACK( &%s, &%s, &%s);"
        % (exception_type, exception_value, exception_tb)
    )

    # If anything is wrong, that will be used.
    emitErrorLineNumberUpdateCode(emit, context)

    emit(getFrameVariableTypeDescriptionCode(context))

    getGotoCode(context.getExceptionEscape(), emit)

    if context.needsCleanup(raise_type_name):
        context.removeCleanupTempName(raise_type_name)
    if context.needsCleanup(raise_value_name):
        context.removeCleanupTempName(raise_value_name)
    if context.needsCleanup(raise_tb_name):
        context.removeCleanupTempName(raise_tb_name)
