#
# SPDX-FileCopyrightText: Copyright (c) 1993-2024 NVIDIA CORPORATION & AFFILIATES. All rights reserved.
# SPDX-License-Identifier: Apache-2.0
#
# 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.
#
from polygraphy import mod, util
from polygraphy.backend.base import BaseLoader


@mod.export(funcify=True)
class BytesFromPath(BaseLoader):
    """
    Functor that can load a file in binary mode ('rb').
    """

    def __init__(self, path):
        """
        Loads a file in binary mode ('rb').

        Args:
            path (str): The file path.
        """
        self._path = path

    @util.check_called_by("__call__")
    def call_impl(self):
        """
        Returns:
            bytes: The contents of the file.
        """
        return util.load_file(self._path, description="bytes")


@mod.export(funcify=True)
class SaveBytes(BaseLoader):
    """
    Functor that can save bytes to a file.
    """

    def __init__(self, obj, path):
        """
        Saves bytes to a file.

        Args:
            obj (Union[bytes, Callable() -> bytes]):
                    The bytes to save or a callable that returns them.
            path (str): The file path.
        """
        self._bytes = obj
        self._path = path

    @util.check_called_by("__call__")
    def call_impl(self):
        """
        Returns:
            bytes: The bytes saved.
        """
        obj, _ = util.invoke_if_callable(self._bytes)
        util.save_file(obj, self._path)
        return obj


@mod.export(funcify=True)
class InvokeFromScript(BaseLoader):
    """
    Functor that invokes a function (or functor) from a Python script.
    """

    def __init__(self, path, name):
        """
        Invokes the specified function from the specified Python script.

        The imported symbol is instantiated with no arguments if it is a class, so it may be a
        plain function, a functor instance, or a functor class (e.g. a ``BaseCompareFunc``
        subclass). Calling this functor invokes the loaded object, and attribute access is
        forwarded to it (so, for example, a loaded ``BaseCompareFunc`` exposes its
        ``thresholds_for`` method).

        If you intend to use the imported object more than once, you should import it using
        ``polygraphy.mod.import_from_script`` instead, since it is re-imported on each use here.

        Args:
            path (str): The path to the Python script. The path must include a '.py' extension.
            name (str): The name of the function (or functor) to import and invoke.
        """
        self._path = path
        self._name = name

    @property
    def __name__(self):
        return self._name

    def _load(self):
        obj = mod.import_from_script(self._path, self._name)
        if isinstance(obj, type):
            obj = obj()
        return obj

    @util.check_called_by("__call__")
    def call_impl(self, *args, **kwargs):
        """
        Returns:
            object:
                    The return value of the imported function (or functor).
        """
        return self._load()(*args, **kwargs)

    def __getattr__(self, name):
        # Forward attribute access to the loaded object so that functor APIs (e.g. a
        # BaseCompareFunc's thresholds_for) are accessible through this wrapper.
        # Private/dunder names are not forwarded, which also avoids recursion during init.
        if name.startswith("_"):
            raise AttributeError(name)
        return getattr(self._load(), name)