#     Copyright 2019, 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.
#
""" Reformulation of Python3 class statements.

Consult the developer manual for information. TODO: Add ability to sync
source code comments with developer manual sections.

"""

from nuitka.nodes.AssignNodes import (
    StatementAssignmentVariable,
    StatementAssignmentVariableName,
    StatementReleaseVariable,
)
from nuitka.nodes.AttributeNodes import (
    ExpressionAttributeCheck,
    ExpressionAttributeLookup,
    ExpressionBuiltinGetattr,
)
from nuitka.nodes.BuiltinIteratorNodes import ExpressionBuiltinIter1
from nuitka.nodes.BuiltinNextNodes import ExpressionBuiltinNext1
from nuitka.nodes.BuiltinRefNodes import makeExpressionBuiltinRef
from nuitka.nodes.BuiltinTypeNodes import ExpressionBuiltinTuple
from nuitka.nodes.CallNodes import makeExpressionCall
from nuitka.nodes.ClassNodes import ExpressionClassBody, ExpressionSelectMetaclass
from nuitka.nodes.CodeObjectSpecs import CodeObjectSpec
from nuitka.nodes.ComparisonNodes import makeComparisonExpression
from nuitka.nodes.ConditionalNodes import (
    ExpressionConditional,
    makeStatementConditional,
)
from nuitka.nodes.ConstantRefNodes import makeConstantRefNode
from nuitka.nodes.ContainerMakingNodes import ExpressionMakeTuple
from nuitka.nodes.ContainerOperationNodes import (
    ExpressionListOperationExtend,
    StatementListOperationAppend,
)
from nuitka.nodes.DictionaryNodes import (
    ExpressionDictOperationGet,
    ExpressionDictOperationIn,
    StatementDictOperationRemove,
    StatementDictOperationUpdate,
)
from nuitka.nodes.FunctionNodes import (
    ExpressionFunctionCall,
    ExpressionFunctionCreation,
    ExpressionFunctionQualnameRef,
    ExpressionFunctionRef,
)
from nuitka.nodes.GlobalsLocalsNodes import ExpressionBuiltinLocalsRef
from nuitka.nodes.LocalsDictNodes import (
    StatementLocalsDictOperationSet,
    StatementReleaseLocals,
    StatementSetLocals,
)
from nuitka.nodes.LoopNodes import StatementLoop, StatementLoopBreak
from nuitka.nodes.NodeMakingHelpers import (
    makeRaiseExceptionExpressionFromTemplate,
    mergeStatements,
)
from nuitka.nodes.ReturnNodes import StatementReturn
from nuitka.nodes.StatementNodes import StatementExpressionOnly
from nuitka.nodes.SubscriptNodes import ExpressionSubscriptLookup
from nuitka.nodes.TypeNodes import ExpressionBuiltinIsinstance, ExpressionBuiltinType1
from nuitka.nodes.VariableRefNodes import (
    ExpressionTempVariableRef,
    ExpressionVariableRef,
)
from nuitka.PythonVersions import python_version
from nuitka.specs.ParameterSpecs import ParameterSpec

from .InternalModule import (
    internal_source_ref,
    makeInternalHelperFunctionBody,
    once_decorator,
)
from .ReformulationSequenceCreation import buildTupleCreationNode
from .ReformulationTryExceptStatements import makeTryExceptSingleHandlerNode
from .ReformulationTryFinallyStatements import makeTryFinallyStatement
from .TreeHelpers import (
    buildFrameNode,
    buildNode,
    buildNodeList,
    extractDocFromBody,
    makeDictCreationOrConstant2,
    makeSequenceCreationOrConstant,
    makeStatementsSequenceFromStatement,
    makeStatementsSequenceFromStatements,
    mangleName,
)


def buildClassNode3(provider, node, source_ref):
    # Many variables, due to the huge re-formulation that is going on here,
    # which just has the complexity and optimization checks:
    # pylint: disable=I0021,too-many-branches,too-many-locals,too-many-statements

    # This function is the Python3 special case with special re-formulation as
    # according to developer manual.
    class_statement_nodes, class_doc = extractDocFromBody(node)

    # We need a scope for the temporary variables, and they might be closured.
    temp_scope = provider.allocateTempScope(name="class_creation")

    tmp_class_decl_dict = provider.allocateTempVariable(
        temp_scope=temp_scope, name="class_decl_dict"
    )
    tmp_metaclass = provider.allocateTempVariable(
        temp_scope=temp_scope, name="metaclass"
    )
    tmp_prepared = provider.allocateTempVariable(temp_scope=temp_scope, name="prepared")

    class_creation_function = ExpressionClassBody(
        provider=provider, name=node.name, doc=class_doc, source_ref=source_ref
    )

    class_variable = class_creation_function.getVariableForAssignment("__class__")

    class_variable_ref = ExpressionVariableRef(
        variable=class_variable, source_ref=source_ref
    )

    parent_module = provider.getParentModule()

    code_object = CodeObjectSpec(
        co_name=node.name,
        co_kind="Class",
        co_varnames=(),
        co_argcount=0,
        co_kwonlyargcount=0,
        co_has_starlist=False,
        co_has_stardict=False,
        co_filename=parent_module.getRunTimeFilename(),
        co_lineno=source_ref.getLineNumber(),
        future_spec=parent_module.getFutureSpec(),
    )

    body = buildFrameNode(
        provider=class_creation_function,
        nodes=class_statement_nodes,
        code_object=code_object,
        source_ref=source_ref,
    )

    source_ref_orig = source_ref

    if body is not None:
        # The frame guard has nothing to tell its line number to.
        body.source_ref = source_ref

    locals_scope = class_creation_function.getFunctionLocalsScope()

    statements = [
        StatementSetLocals(
            locals_scope=locals_scope,
            new_locals=ExpressionTempVariableRef(
                variable=tmp_prepared, source_ref=source_ref
            ),
            source_ref=source_ref,
        ),
        StatementAssignmentVariableName(
            provider=class_creation_function,
            variable_name="__module__",
            source=makeConstantRefNode(
                constant=provider.getParentModule().getFullName(),
                source_ref=source_ref,
                user_provided=True,
            ),
            source_ref=source_ref,
        ),
    ]

    if class_doc is not None:
        statements.append(
            StatementAssignmentVariableName(
                provider=class_creation_function,
                variable_name="__doc__",
                source=makeConstantRefNode(
                    constant=class_doc, source_ref=source_ref, user_provided=True
                ),
                source_ref=source_ref,
            )
        )

    # The "__qualname__" attribute is new in Python 3.3.
    if python_version >= 300:
        qualname = class_creation_function.getFunctionQualname()

        if python_version < 340:
            qualname_ref = makeConstantRefNode(
                constant=qualname, source_ref=source_ref, user_provided=True
            )
        else:
            qualname_ref = ExpressionFunctionQualnameRef(
                function_body=class_creation_function, source_ref=source_ref
            )

        statements.append(
            StatementLocalsDictOperationSet(
                locals_scope=locals_scope,
                variable_name="__qualname__",
                value=qualname_ref,
                source_ref=source_ref,
            )
        )

        if python_version >= 340:
            qualname_assign = statements[-1]

    if python_version >= 360 and class_creation_function.needsAnnotationsDictionary():
        statements.append(
            StatementLocalsDictOperationSet(
                locals_scope=locals_scope,
                variable_name="__annotations__",
                value=makeConstantRefNode(
                    constant={}, source_ref=source_ref, user_provided=True
                ),
                source_ref=source_ref,
            )
        )

    statements.append(body)

    if node.bases:
        tmp_bases = provider.allocateTempVariable(temp_scope=temp_scope, name="bases")

        if python_version >= 370:
            tmp_bases_orig = provider.allocateTempVariable(
                temp_scope=temp_scope, name="bases_orig"
            )

        def makeBasesRef():
            return ExpressionTempVariableRef(variable=tmp_bases, source_ref=source_ref)

    else:

        def makeBasesRef():
            return makeConstantRefNode(constant=(), source_ref=source_ref)

    if python_version >= 370 and node.bases:
        statements.append(
            makeStatementConditional(
                condition=makeComparisonExpression(
                    comparator="NotEq",
                    left=ExpressionTempVariableRef(
                        variable=tmp_bases, source_ref=source_ref
                    ),
                    right=ExpressionTempVariableRef(
                        variable=tmp_bases_orig, source_ref=source_ref
                    ),
                    source_ref=source_ref,
                ),
                yes_branch=StatementLocalsDictOperationSet(
                    locals_scope=locals_scope,
                    variable_name="__orig_bases__",
                    value=ExpressionTempVariableRef(
                        variable=tmp_bases_orig, source_ref=source_ref
                    ),
                    source_ref=source_ref,
                ),
                no_branch=None,
                source_ref=source_ref,
            )
        )

    statements += [
        StatementAssignmentVariable(
            variable=class_variable,
            source=makeExpressionCall(
                called=ExpressionTempVariableRef(
                    variable=tmp_metaclass, source_ref=source_ref
                ),
                args=makeSequenceCreationOrConstant(
                    sequence_kind="tuple",
                    elements=(
                        makeConstantRefNode(
                            constant=node.name,
                            source_ref=source_ref,
                            user_provided=True,
                        ),
                        makeBasesRef(),
                        ExpressionBuiltinLocalsRef(
                            locals_scope=locals_scope, source_ref=source_ref
                        ),
                    ),
                    source_ref=source_ref,
                ),
                kw=ExpressionTempVariableRef(
                    variable=tmp_class_decl_dict, source_ref=source_ref
                ),
                source_ref=source_ref,
            ),
            source_ref=source_ref,
        ),
        StatementReturn(expression=class_variable_ref, source_ref=source_ref),
    ]

    body = makeStatementsSequenceFromStatement(
        statement=makeTryFinallyStatement(
            provider=class_creation_function,
            tried=mergeStatements(statements, True),
            final=StatementReleaseLocals(
                locals_scope=locals_scope, source_ref=source_ref
            ),
            source_ref=source_ref,
        )
    )

    # The class body is basically a function that implicitly, at the end
    # returns its locals and cannot have other return statements contained.
    class_creation_function.setBody(body)

    # The class body is basically a function that implicitly, at the end
    # returns its created class and cannot have other return statements
    # contained.

    decorated_body = class_creation_function

    for decorator in buildNodeList(provider, reversed(node.decorator_list), source_ref):
        decorated_body = makeExpressionCall(
            called=decorator,
            args=ExpressionMakeTuple(elements=(decorated_body,), source_ref=source_ref),
            kw=None,
            source_ref=decorator.getSourceReference(),
        )

    if node.keywords and node.keywords[-1].arg is None:
        keywords = node.keywords[:-1]
    else:
        keywords = node.keywords

    statements = []

    if node.bases:
        statements.append(
            StatementAssignmentVariable(
                variable=tmp_bases if python_version < 370 else tmp_bases_orig,
                source=buildTupleCreationNode(
                    provider=provider, elements=node.bases, source_ref=source_ref
                ),
                source_ref=source_ref,
            )
        )

        if python_version >= 370:
            bases_conversion = ExpressionFunctionCall(
                function=ExpressionFunctionCreation(
                    function_ref=ExpressionFunctionRef(
                        function_body=getClassBasesMroConversionHelper(),
                        source_ref=source_ref,
                    ),
                    defaults=(),
                    kw_defaults=None,
                    annotations=None,
                    source_ref=source_ref,
                ),
                values=(
                    ExpressionTempVariableRef(
                        variable=tmp_bases_orig, source_ref=source_ref
                    ),
                ),
                source_ref=source_ref,
            )

            statements.append(
                StatementAssignmentVariable(
                    variable=tmp_bases, source=bases_conversion, source_ref=source_ref
                )
            )

    statements.append(
        StatementAssignmentVariable(
            variable=tmp_class_decl_dict,
            source=makeDictCreationOrConstant2(
                keys=[keyword.arg for keyword in keywords],
                values=[
                    buildNode(provider, keyword.value, source_ref)
                    for keyword in keywords
                ],
                source_ref=source_ref,
            ),
            source_ref=source_ref,
        )
    )

    if node.keywords and node.keywords[-1].arg is None:
        statements.append(
            StatementDictOperationUpdate(
                dict_arg=ExpressionVariableRef(
                    variable=tmp_class_decl_dict, source_ref=source_ref
                ),
                value=buildNode(provider, node.keywords[-1].value, source_ref),
                source_ref=source_ref,
            )
        )

    # Check if there are bases, and if there are, go with the type of the
    # first base class as a metaclass unless it was specified in the class
    # decl dict of course.
    if node.bases:
        unspecified_metaclass_expression = ExpressionBuiltinType1(
            value=ExpressionSubscriptLookup(
                subscribed=ExpressionTempVariableRef(
                    variable=tmp_bases, source_ref=source_ref
                ),
                subscript=makeConstantRefNode(
                    constant=0, source_ref=source_ref, user_provided=True
                ),
                source_ref=source_ref,
            ),
            source_ref=source_ref,
        )

        # Might become empty behind our back during conversion, therefore make the
        # check at run time for 3.7 or higher.
        if python_version >= 370:
            unspecified_metaclass_expression = ExpressionConditional(
                condition=ExpressionTempVariableRef(
                    variable=tmp_bases, source_ref=source_ref
                ),
                expression_yes=unspecified_metaclass_expression,
                expression_no=makeExpressionBuiltinRef(
                    builtin_name="type", source_ref=source_ref
                ),
                source_ref=source_ref,
            )
    else:
        unspecified_metaclass_expression = makeExpressionBuiltinRef(
            builtin_name="type", source_ref=source_ref
        )

    call_prepare = StatementAssignmentVariable(
        variable=tmp_prepared,
        source=makeExpressionCall(
            called=ExpressionAttributeLookup(
                source=ExpressionTempVariableRef(
                    variable=tmp_metaclass, source_ref=source_ref
                ),
                attribute_name="__prepare__",
                source_ref=source_ref,
            ),
            args=ExpressionMakeTuple(
                elements=(
                    makeConstantRefNode(
                        constant=node.name, source_ref=source_ref, user_provided=True
                    ),
                    makeBasesRef(),
                ),
                source_ref=source_ref,
            ),
            kw=ExpressionTempVariableRef(
                variable=tmp_class_decl_dict, source_ref=source_ref
            ),
            source_ref=source_ref,
        ),
        source_ref=source_ref,
    )

    if python_version >= 364:
        call_prepare = makeStatementsSequenceFromStatements(
            call_prepare,
            makeStatementConditional(
                condition=ExpressionAttributeCheck(
                    object_arg=ExpressionTempVariableRef(
                        variable=tmp_prepared, source_ref=source_ref
                    ),
                    attribute_name="__getitem__",
                    source_ref=source_ref,
                ),
                yes_branch=None,
                no_branch=makeRaiseExceptionExpressionFromTemplate(
                    exception_type="TypeError",
                    template="%s.__prepare__() must return a mapping, not %s",
                    template_args=(
                        ExpressionBuiltinGetattr(
                            object_arg=ExpressionTempVariableRef(
                                variable=tmp_metaclass, source_ref=source_ref
                            ),
                            name=makeConstantRefNode(
                                constant="__name__", source_ref=source_ref
                            ),
                            default=makeConstantRefNode(
                                constant="<metaclass>", source_ref=source_ref
                            ),
                            source_ref=source_ref,
                        ),
                        ExpressionAttributeLookup(
                            source=ExpressionBuiltinType1(
                                value=ExpressionTempVariableRef(
                                    variable=tmp_prepared, source_ref=source_ref
                                ),
                                source_ref=source_ref,
                            ),
                            attribute_name="__name__",
                            source_ref=source_ref,
                        ),
                    ),
                    source_ref=source_ref,
                ).asStatement(),
                source_ref=source_ref,
            ),
        )

    statements += [
        StatementAssignmentVariable(
            variable=tmp_metaclass,
            source=ExpressionSelectMetaclass(
                metaclass=ExpressionConditional(
                    condition=ExpressionDictOperationIn(
                        key=makeConstantRefNode(
                            constant="metaclass",
                            source_ref=source_ref,
                            user_provided=True,
                        ),
                        dict_arg=ExpressionTempVariableRef(
                            variable=tmp_class_decl_dict, source_ref=source_ref
                        ),
                        source_ref=source_ref,
                    ),
                    expression_yes=ExpressionDictOperationGet(
                        dict_arg=ExpressionTempVariableRef(
                            variable=tmp_class_decl_dict, source_ref=source_ref
                        ),
                        key=makeConstantRefNode(
                            constant="metaclass",
                            source_ref=source_ref,
                            user_provided=True,
                        ),
                        source_ref=source_ref,
                    ),
                    expression_no=unspecified_metaclass_expression,
                    source_ref=source_ref,
                ),
                bases=makeBasesRef(),
                source_ref=source_ref,
            ),
            source_ref=source_ref_orig,
        ),
        makeStatementConditional(
            condition=ExpressionDictOperationIn(
                key=makeConstantRefNode(
                    constant="metaclass", source_ref=source_ref, user_provided=True
                ),
                dict_arg=ExpressionTempVariableRef(
                    variable=tmp_class_decl_dict, source_ref=source_ref
                ),
                source_ref=source_ref,
            ),
            no_branch=None,
            yes_branch=StatementDictOperationRemove(
                dict_arg=ExpressionTempVariableRef(
                    variable=tmp_class_decl_dict, source_ref=source_ref
                ),
                key=makeConstantRefNode(
                    constant="metaclass", source_ref=source_ref, user_provided=True
                ),
                source_ref=source_ref,
            ),
            source_ref=source_ref,
        ),
        makeStatementConditional(
            condition=ExpressionAttributeCheck(
                object_arg=ExpressionTempVariableRef(
                    variable=tmp_metaclass, source_ref=source_ref
                ),
                attribute_name="__prepare__",
                source_ref=source_ref,
            ),
            yes_branch=call_prepare,
            no_branch=StatementAssignmentVariable(
                variable=tmp_prepared,
                source=makeConstantRefNode(
                    constant={}, source_ref=source_ref, user_provided=True
                ),
                source_ref=source_ref,
            ),
            source_ref=source_ref,
        ),
        StatementAssignmentVariableName(
            provider=provider,
            variable_name=mangleName(node.name, provider),
            source=decorated_body,
            source_ref=source_ref,
        ),
    ]

    if python_version >= 340:
        class_creation_function.qualname_setup = node.name, qualname_assign

    final = [tmp_class_decl_dict, tmp_metaclass, tmp_prepared]
    if node.bases:
        final.insert(0, tmp_bases)
        if python_version >= 370:
            final.insert(0, tmp_bases_orig)

    return makeTryFinallyStatement(
        provider=provider,
        tried=statements,
        final=tuple(
            StatementReleaseVariable(variable=variable, source_ref=source_ref)
            for variable in final
        ),
        source_ref=source_ref,
    )


# Note: This emulates Python/bltinmodule.c/update_bases function. We have it
# here, so we can hope to statically optimize it later on.
@once_decorator
def getClassBasesMroConversionHelper():
    helper_name = "_mro_entries_conversion"

    result = makeInternalHelperFunctionBody(
        name=helper_name,
        parameters=ParameterSpec(
            ps_name=helper_name,
            ps_normal_args=("bases",),
            ps_list_star_arg=None,
            ps_dict_star_arg=None,
            ps_default_count=0,
            ps_kw_only_args=(),
        ),
    )

    temp_scope = None

    tmp_result_variable = result.allocateTempVariable(temp_scope, "list")
    tmp_iter_variable = result.allocateTempVariable(temp_scope, "iter")
    tmp_item_variable = result.allocateTempVariable(temp_scope, "base")

    args_variable = result.getVariableForAssignment(variable_name="bases")

    non_type_case = makeStatementConditional(
        condition=ExpressionAttributeCheck(
            object_arg=ExpressionTempVariableRef(
                variable=tmp_item_variable, source_ref=internal_source_ref
            ),
            attribute_name="__mro_entries__",
            source_ref=internal_source_ref,
        ),
        yes_branch=StatementExpressionOnly(
            expression=ExpressionListOperationExtend(
                list_arg=ExpressionTempVariableRef(
                    variable=tmp_result_variable, source_ref=internal_source_ref
                ),
                value=makeExpressionCall(
                    called=ExpressionAttributeLookup(
                        source=ExpressionTempVariableRef(
                            variable=tmp_item_variable, source_ref=internal_source_ref
                        ),
                        attribute_name="__mro_entries__",
                        source_ref=internal_source_ref,
                    ),
                    args=ExpressionMakeTuple(
                        elements=(
                            ExpressionVariableRef(
                                variable=args_variable, source_ref=internal_source_ref
                            ),
                        ),
                        source_ref=internal_source_ref,
                    ),
                    kw=None,
                    source_ref=internal_source_ref,
                ),
                source_ref=internal_source_ref,
            ),
            source_ref=internal_source_ref,
        ),
        no_branch=StatementListOperationAppend(
            list_arg=ExpressionTempVariableRef(
                variable=tmp_result_variable, source_ref=internal_source_ref
            ),
            value=ExpressionTempVariableRef(
                variable=tmp_item_variable, source_ref=internal_source_ref
            ),
            source_ref=internal_source_ref,
        ),
        source_ref=internal_source_ref,
    )

    type_case = StatementListOperationAppend(
        list_arg=ExpressionTempVariableRef(
            variable=tmp_result_variable, source_ref=internal_source_ref
        ),
        value=ExpressionTempVariableRef(
            variable=tmp_item_variable, source_ref=internal_source_ref
        ),
        source_ref=internal_source_ref,
    )

    loop_body = makeStatementsSequenceFromStatements(
        makeTryExceptSingleHandlerNode(
            tried=StatementAssignmentVariable(
                variable=tmp_item_variable,
                source=ExpressionBuiltinNext1(
                    value=ExpressionTempVariableRef(
                        variable=tmp_iter_variable, source_ref=internal_source_ref
                    ),
                    source_ref=internal_source_ref,
                ),
                source_ref=internal_source_ref,
            ),
            exception_name="StopIteration",
            handler_body=StatementLoopBreak(source_ref=internal_source_ref),
            source_ref=internal_source_ref,
        ),
        makeStatementConditional(
            condition=ExpressionBuiltinIsinstance(
                instance=ExpressionTempVariableRef(
                    variable=tmp_item_variable, source_ref=internal_source_ref
                ),
                classes=makeConstantRefNode(
                    constant=type, source_ref=internal_source_ref
                ),
                source_ref=internal_source_ref,
            ),
            yes_branch=type_case,
            no_branch=non_type_case,
            source_ref=internal_source_ref,
        ),
    )

    final = (
        StatementReleaseVariable(
            variable=args_variable, source_ref=internal_source_ref
        ),
        StatementReleaseVariable(
            variable=tmp_result_variable, source_ref=internal_source_ref
        ),
        StatementReleaseVariable(
            variable=tmp_iter_variable, source_ref=internal_source_ref
        ),
        StatementReleaseVariable(
            variable=tmp_item_variable, source_ref=internal_source_ref
        ),
    )

    tried = makeStatementsSequenceFromStatements(
        StatementAssignmentVariable(
            variable=tmp_iter_variable,
            source=ExpressionBuiltinIter1(
                value=ExpressionVariableRef(
                    variable=args_variable, source_ref=internal_source_ref
                ),
                source_ref=internal_source_ref,
            ),
            source_ref=internal_source_ref,
        ),
        StatementAssignmentVariable(
            variable=tmp_result_variable,
            source=makeConstantRefNode(constant=[], source_ref=internal_source_ref),
            source_ref=internal_source_ref,
        ),
        StatementLoop(body=loop_body, source_ref=internal_source_ref),
        StatementReturn(
            expression=ExpressionBuiltinTuple(
                value=ExpressionTempVariableRef(
                    variable=tmp_result_variable, source_ref=internal_source_ref
                ),
                source_ref=internal_source_ref,
            ),
            source_ref=internal_source_ref,
        ),
    )

    result.setBody(
        makeStatementsSequenceFromStatement(
            makeTryFinallyStatement(
                provider=result,
                tried=tried,
                final=final,
                source_ref=internal_source_ref,
            )
        )
    )

    return result
