#     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 try/finally statements.

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

"""

from nuitka.nodes.LoopNodes import StatementLoopBreak, StatementLoopContinue
from nuitka.nodes.ReturnNodes import ExpressionReturnedValueRef, StatementReturn
from nuitka.nodes.StatementNodes import (
    StatementPreserveFrameException,
    StatementPublishException,
    StatementRestoreFrameException,
    StatementsSequence,
)
from nuitka.nodes.TryNodes import StatementTry
from nuitka.Options import isDebug
from nuitka.PythonVersions import python_version

from .TreeHelpers import (
    buildStatementsNode,
    getStatementsAppended,
    getStatementsPrepended,
    makeReraiseExceptionStatement,
    makeStatementsSequence,
    makeStatementsSequenceFromStatement,
    makeStatementsSequenceFromStatements,
    mergeStatements,
    popBuildContext,
    pushBuildContext,
)


def _checkCloning(final, provider):
    final2 = final.makeClone()
    final2.parent = provider

    import nuitka.TreeXML

    if nuitka.TreeXML.Element is not None:
        f1 = final.asXml()
        f2 = final2.asXml()

        def compare(a, b):
            for c1, c2 in zip(a, b):
                compare(c1, c2)

            assert a.attrib == b.attrib, (a.attrib, b.attrib)

        compare(f1, f2)


def makeTryFinallyStatement(provider, tried, final, source_ref, public_exc=False):
    # Complex handling, due to the many variants, pylint: disable=too-many-branches

    if type(tried) in (tuple, list):
        if tried:
            tried = makeStatementsSequenceFromStatements(*tried)
        else:
            tried = None
    if type(final) in (tuple, list):
        if final:
            final = StatementsSequence(
                statements=mergeStatements(final, False), source_ref=source_ref
            )
        else:
            final = None

    if tried is not None and not tried.isStatementsSequence():
        tried = makeStatementsSequenceFromStatement(tried)
    if final is not None and not final.isStatementsSequence():
        final = makeStatementsSequenceFromStatement(final)

    # Trivial case, nothing tried needs only do the final stuff.
    if tried is None:
        return final

    # Trivial case, nothing final needs nothing but the tried stuff.
    if final is None:
        return tried

    # Parent them to us already.
    if provider is not None:
        tried.parent = provider
        final.parent = provider

    # TODO: Currently it's not possible anymore to get at XML for all codes
    # during the building phase. So this error catcher cannot work currently.
    if False and isDebug():
        _checkCloning(final, provider)

    def getFinal():
        # Make a clone of "final" only if necessary.
        if hasattr(getFinal, "used"):
            return final.makeClone()
        else:
            getFinal.used = True
            return final

    if tried.mayRaiseException(BaseException):
        except_handler = getStatementsAppended(
            statement_sequence=getFinal(),
            statements=makeReraiseExceptionStatement(source_ref=source_ref),
        )

        if public_exc:
            preserver_id = provider.allocatePreserverId()

            except_handler = getStatementsPrepended(
                statement_sequence=except_handler,
                statements=(
                    StatementPreserveFrameException(
                        preserver_id=preserver_id, source_ref=source_ref.atInternal()
                    ),
                    StatementPublishException(source_ref=source_ref),
                ),
            )

            except_handler = makeTryFinallyStatement(
                provider=provider,
                tried=except_handler,
                final=StatementRestoreFrameException(
                    preserver_id=preserver_id, source_ref=source_ref.atInternal()
                ),
                public_exc=False,
                source_ref=source_ref,
            )

            except_handler = makeStatementsSequenceFromStatement(
                statement=except_handler
            )
    else:
        except_handler = None

    if tried.mayBreak():
        break_handler = getStatementsAppended(
            statement_sequence=getFinal(),
            statements=StatementLoopBreak(source_ref=source_ref),
        )
    else:
        break_handler = None

    if tried.mayContinue():
        continue_handler = getStatementsAppended(
            statement_sequence=getFinal(),
            statements=StatementLoopContinue(source_ref=source_ref),
        )
    else:
        continue_handler = None

    if tried.mayReturn():
        return_handler = getStatementsAppended(
            statement_sequence=getFinal(),
            statements=StatementReturn(
                expression=ExpressionReturnedValueRef(source_ref=source_ref),
                source_ref=source_ref,
            ),
        )
    else:
        return_handler = None

    result = StatementTry(
        tried=tried,
        except_handler=except_handler,
        break_handler=break_handler,
        continue_handler=continue_handler,
        return_handler=return_handler,
        source_ref=source_ref,
    )

    if result.isStatementAborting():
        return result
    else:
        return makeStatementsSequence(
            statements=(result, getFinal()), allow_none=False, source_ref=source_ref
        )


def buildTryFinallyNode(provider, build_tried, node, source_ref):

    if python_version < 300:
        # Prevent "continue" statements in the final blocks
        pushBuildContext("finally")
        final = buildStatementsNode(
            provider=provider, nodes=node.finalbody, source_ref=source_ref
        )
        popBuildContext()

        return makeTryFinallyStatement(
            provider=provider, tried=build_tried(), final=final, source_ref=source_ref
        )
    else:
        tried = build_tried()

        # Prevent "continue" statements in the final blocks, these have to
        # become "SyntaxError".
        pushBuildContext("finally")
        final = buildStatementsNode(
            provider=provider, nodes=node.finalbody, source_ref=source_ref
        )
        popBuildContext()

        return makeTryFinallyStatement(
            provider=provider,
            tried=tried,
            final=final,
            public_exc=True,
            source_ref=source_ref,
        )
