# Copyright The PyTorch Lightning team.
#
# 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 pytest

from pytorch_lightning import Trainer
from pytorch_lightning.plugins import DDPPlugin, DeepSpeedPlugin, TrainingTypePluginsRegistry
from tests.helpers.runif import RunIf


def test_training_type_plugins_registry_with_new_plugin():

    class TestPlugin:

        distributed_backend = "test_plugin"

        def __init__(self, param1, param2):
            self.param1 = param1
            self.param2 = param2

    plugin_name = "test_plugin"
    plugin_description = "Test Plugin"

    TrainingTypePluginsRegistry.register(
        plugin_name, TestPlugin, description=plugin_description, param1="abc", param2=123
    )

    assert plugin_name in TrainingTypePluginsRegistry
    assert TrainingTypePluginsRegistry[plugin_name]["description"] == plugin_description
    assert TrainingTypePluginsRegistry[plugin_name]["init_params"] == {"param1": "abc", "param2": 123}
    assert TrainingTypePluginsRegistry[plugin_name]["distributed_backend"] == "test_plugin"
    assert isinstance(TrainingTypePluginsRegistry.get(plugin_name), TestPlugin)

    TrainingTypePluginsRegistry.remove(plugin_name)
    assert plugin_name not in TrainingTypePluginsRegistry


@pytest.mark.parametrize(
    "plugin_name, init_params",
    [
        ("deepspeed", {}),
        ("deepspeed_stage_2", {
            "stage": 2
        }),
        ("deepspeed_stage_2_offload", {
            "stage": 2,
            "cpu_offload": True
        }),
        ("deepspeed_stage_3", {
            "stage": 3
        }),
        ("deepspeed_stage_3_offload", {
            "stage": 3,
            "cpu_offload": True
        }),
    ],
)
def test_training_type_plugins_registry_with_deepspeed_plugins(plugin_name, init_params):

    assert plugin_name in TrainingTypePluginsRegistry
    assert TrainingTypePluginsRegistry[plugin_name]["init_params"] == init_params
    assert TrainingTypePluginsRegistry[plugin_name]["plugin"] == DeepSpeedPlugin


@RunIf(deepspeed=True)
@pytest.mark.parametrize("plugin", ["deepspeed", "deepspeed_stage_2_offload", "deepspeed_stage_3"])
def test_deepspeed_training_type_plugins_registry_with_trainer(tmpdir, plugin):

    trainer = Trainer(
        default_root_dir=tmpdir,
        plugins=plugin,
        precision=16,
    )

    assert isinstance(trainer.training_type_plugin, DeepSpeedPlugin)


def test_ddp_training_type_plugins_registry_with_trainer(tmpdir):

    trainer = Trainer(
        default_root_dir=tmpdir,
        plugins="ddp_find_unused_parameters_false",
    )

    assert isinstance(trainer.training_type_plugin, DDPPlugin)