#     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.
#
""" Import related codes.

That is import as expression, and star import.
"""

from .CodeHelpers import generateChildExpressionsCode, generateExpressionCode
from .ErrorCodes import (
    getErrorExitBoolCode,
    getErrorExitCode,
    getReleaseCode,
    getReleaseCodes
)
from .LineNumberCodes import emitLineNumberUpdateCode
from .ModuleCodes import getModuleAccessCode


def generateBuiltinImportCode(to_name, expression, emit, context):
    # We know that 5 expressions are created, pylint: disable=W0632
    module_name, globals_name, locals_name, import_list_name, level_name = \
      generateChildExpressionsCode(
        expression = expression,
        emit       = emit,
        context    = context
    )

    getBuiltinImportCode(
        to_name          = to_name,
        module_name      = module_name,
        globals_name     = globals_name,
        locals_name      = locals_name,
        import_list_name = import_list_name,
        level_name       = level_name,
        needs_check      = expression.mayRaiseException(BaseException),
        emit             = emit,
        context          = context
    )


def getCountedArgumentsHelperCallCode(helper_prefix, to_name, args, min_args,
                                      needs_check, emit, context):
    orig_args = args
    args = list(args)
    while args[-1] is None:
        del args[-1]

    if None in args:
        emit(
            "%s = %s_KW( %s );" % (
                to_name,
                helper_prefix,
                ", ".join(
                    "NULL" if arg is None else arg
                    for arg in
                    orig_args
                )
            )
        )
    else:
        # Check that no following arguments are not None.
        assert len(args) >= min_args

        emit(
            "%s = %s%d( %s );" % (
                to_name,
                helper_prefix,
                len(args),
                ", ".join(args)
            )
        )

    getReleaseCodes(
        release_names = args,
        emit          = emit,
        context       = context
    )

    getErrorExitCode(
        check_name  = to_name,
        needs_check = needs_check,
        emit        = emit,
        context     = context
    )

    context.addCleanupTempName(to_name)


def getBuiltinImportCode(to_name, module_name, globals_name, locals_name,
                         import_list_name, level_name, needs_check, emit,
                         context):

    emitLineNumberUpdateCode(emit, context)

    getCountedArgumentsHelperCallCode(
        helper_prefix = "IMPORT_MODULE",
        to_name       = to_name,
        args          = (
            module_name,
            globals_name,
            locals_name,
            import_list_name,
            level_name
        ),
        min_args      = 1,
        needs_check   = needs_check,
        emit          = emit,
        context       = context
    )


def generateImportModuleHardCode(to_name, expression, emit, context):
    module_name = expression.getModuleName()
    needs_check = expression.mayRaiseException(BaseException)

    emitLineNumberUpdateCode(emit, context)

    emit(
        """%s = PyImport_ImportModule("%s");""" % (
            to_name,
            module_name
        )
    )

    getErrorExitCode(
        check_name  = to_name,
        needs_check = needs_check,
        emit        = emit,
        context     = context
    )


def generateImportModuleNameHardCode(to_name, expression, emit, context):
    module_name = expression.getModuleName()
    import_name = expression.getImportName()
    needs_check = expression.mayRaiseException(BaseException)

    if module_name == "sys":
        emit(
            """%s = PySys_GetObject( (char *)"%s" );""" % (
                to_name,
                import_name
            )
        )
    elif module_name in ("os", "__future__", "importlib._bootstrap"):
        emitLineNumberUpdateCode(emit, context)

        emit(
             """\
{
    PyObject *module = PyImport_ImportModule("%(module_name)s");
    if (likely( module != NULL ))
    {
        %(to_name)s = PyObject_GetAttr( module, %(import_name)s );
    }
    else
    {
        %(to_name)s = NULL;
    }
}
""" % {
                "to_name"     : to_name,
                "module_name" : module_name,
                "import_name" : context.getConstantCode(import_name)
            }
        )
    else:
        assert False, module_name

    getErrorExitCode(
        check_name  = to_name,
        needs_check = needs_check,
        emit        = emit,
        context     = context
    )


def generateImportStarCode(statement, emit, context):
    module_name = context.allocateTempName("star_imported")

    generateExpressionCode(
        to_name    = module_name,
        expression = statement.getSourceModule(),
        emit       = emit,
        context    = context
    )

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

    res_name = context.getBoolResName()

    if statement.getLocalsDictScope() is None:
        emit(
            "%s = IMPORT_MODULE_STAR( %s, true, %s );" % (
                res_name,
                getModuleAccessCode(
                    context = context
                ),
                module_name
            )
        )
    else:
        locals_dict_name = statement.getLocalsDictScope().getCodeName()

        emit(
            """
%(res_name)s = IMPORT_MODULE_STAR( %(locals_dict)s, false, %(module_name)s );
""" % {
                "res_name"    : res_name,
                "locals_dict" : locals_dict_name,
                "module_name" : module_name
            }
        )

        context.addLocalsDictName(locals_dict_name)

    getReleaseCode(
        release_name = module_name,
        emit         = emit,
        context      = context
    )

    getErrorExitBoolCode(
        condition = "%s == false" % res_name,
        emit      = emit,
        context   = context
    )

    context.setCurrentSourceCodeReference(old_source_ref)


def generateImportNameCode(to_name, expression, emit, context):
    from_arg_name = context.allocateTempName("import_name_from")

    generateExpressionCode(
        to_name    = from_arg_name,
        expression = expression.getModule(),
        emit       = emit,
        context    = context
    )

    emit(
        "%s = IMPORT_NAME( %s, %s );" % (
            to_name,
            from_arg_name,
            context.getConstantCode(
                constant = expression.getImportName()
            )
        )
    )

    getReleaseCode(
        release_name = from_arg_name,
        emit         = emit,
        context      = context
    )

    getErrorExitCode(
        check_name  = to_name,
        needs_check = expression.mayRaiseException(BaseException),
        emit        = emit,
        context     = context
    )

    context.addCleanupTempName(to_name)
