# 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 re

import pytest
import torch

from pytorch_lightning import Trainer
from pytorch_lightning.tuner.auto_gpu_select import pick_multiple_gpus
from pytorch_lightning.utilities.exceptions import MisconfigurationException


@pytest.mark.skipif(torch.cuda.device_count() < 2, reason="test requires a number of GPU machine greater than 1")
@pytest.mark.parametrize(
    ["auto_select_gpus", "gpus", "expected_error"],
    [
        (True, 0, MisconfigurationException),
        (True, -1, None),
        (False, 0, None),
        (False, -1, None),
    ],
)
def test_trainer_with_gpus_options_combination_at_available_gpus_env(auto_select_gpus, gpus, expected_error):
    if expected_error:
        with pytest.raises(
            expected_error,
            match=re.escape(
                r"auto_select_gpus=True, gpus=0 is not a valid configuration.\
            Please select a valid number of GPU resources when using auto_select_gpus."
            ),
        ):
            Trainer(auto_select_gpus=auto_select_gpus, gpus=gpus)
    else:
        Trainer(auto_select_gpus=auto_select_gpus, gpus=gpus)


@pytest.mark.skipif(torch.cuda.device_count() < 2, reason="test requires a number of GPU machine greater than 1")
@pytest.mark.parametrize(
    ["nb", "expected_gpu_idxs", "expected_error"],
    [
        (0, [], MisconfigurationException),
        (-1, [i for i in range(torch.cuda.device_count())], None),
        (1, [0], None),
    ],
)
def test_pick_multiple_gpus(nb, expected_gpu_idxs, expected_error):
    if expected_error:
        with pytest.raises(
            expected_error,
            match=re.escape(
                r"auto_select_gpus=True, gpus=0 is not a valid configuration.\
            Please select a valid number of GPU resources when using auto_select_gpus."
            ),
        ):
            pick_multiple_gpus(nb)
    else:
        assert expected_gpu_idxs == pick_multiple_gpus(nb)