#     Copyright 2016, 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.
#
""" Loop codes.

Code generation for loops, breaking them, or continuing them. In Nuitka, there
are no for-loops or while-loops at this point. They have been re-formulated in
a simpler loop without a condition, and statements there-in that break under
certain conditions.

See Developer Manual for how the CPython loops are mapped to these nodes.
"""

from .ErrorCodes import getErrorExitBoolCode
from .ExceptionCodes import getExceptionUnpublishedReleaseCode
from .LabelCodes import getGotoCode, getLabelCode


def generateLoopBreakCode(statement, emit, context):
    # Functions used for generation all accept statement, but this one does
    # not use it. pylint: disable=W0613

    getExceptionUnpublishedReleaseCode(emit, context)

    break_target = context.getLoopBreakTarget()
    getGotoCode(break_target, emit)


def generateLoopContinueCode(statement, emit, context):
    # Functions used for generation all accept statement, but this one does
    # not use it. pylint: disable=W0613

    getExceptionUnpublishedReleaseCode(emit, context)

    continue_target = context.getLoopContinueTarget()
    getGotoCode(continue_target, emit)


def generateLoopCode(statement, emit, context):
    loop_start_label = context.allocateLabel("loop_start")

    if not statement.isStatementAborting():
        loop_end_label = context.allocateLabel("loop_end")
    else:
        loop_end_label = None

    getLabelCode(loop_start_label, emit)

    old_loop_break = context.setLoopBreakTarget(loop_end_label)
    old_loop_continue = context.setLoopContinueTarget(loop_start_label)


    # TODO: Should come from registry instead.
    from .CodeGeneration import generateStatementSequenceCode

    generateStatementSequenceCode(
        statement_sequence = statement.getLoopBody(),
        allow_none         = True,
        emit               = emit,
        context            = context
    )

    context.setLoopBreakTarget(old_loop_break)
    context.setLoopContinueTarget(old_loop_continue)

    # Note: We are using the wrong line here, but it's an exception, it's unclear what line it would be anyway.
    old_source_ref = context.setCurrentSourceCodeReference(statement.getSourceReference())

    getErrorExitBoolCode(
        condition = "CONSIDER_THREADING() == false",
        emit      = emit,
        context   = context
    )

    context.setCurrentSourceCodeReference(old_source_ref)

    getGotoCode(loop_start_label, emit)

    if loop_end_label is not None:
        getLabelCode(loop_end_label, emit)
