# Copyright 2023 HuggingFace Inc.
#
# 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 unittest

import numpy as np

from transformers.image_utils import PILImageResampling
from transformers.testing_utils import require_torch, require_vision
from transformers.utils import is_torch_available

from ...test_image_processing_common import ImageProcessingTester, ImageProcessingTestMixin


if is_torch_available():
    import torch


class EfficientNetImageProcessingTester(ImageProcessingTester):
    def __init__(self, **kwargs):
        # Random test inputs kwargs
        kwargs.setdefault("batch_size", 13)

        # Image processor init kwargs
        kwargs.setdefault("rescale_offset", True)
        kwargs.setdefault("rescale_factor", 1 / 127.5)
        kwargs.setdefault("size", {"height": 18, "width": 18})
        kwargs.setdefault("resample", PILImageResampling.BILINEAR)

        super().__init__(**kwargs)


@require_torch
@require_vision
class EfficientNetImageProcessorTest(ImageProcessingTestMixin, unittest.TestCase):
    image_processor_tester_class = EfficientNetImageProcessingTester

    def test_rescale(self):
        # EfficientNet optionally rescales between -1 and 1 instead of the usual 0 and 1
        image_np = np.arange(0, 256, 1, dtype=np.uint8).reshape(1, 8, 32)

        for backend_name, image_processing_class in self.image_processing_classes.items():
            image_processor = image_processing_class(**self.image_processor_dict)
            if backend_name == "torchvision":
                image = torch.from_numpy(image_np)
                # Scale between [-1, 1] with rescale_factor 1/127.5 and rescale_offset=True
                rescaled_image = image_processor.rescale(image, scale=1 / 127.5, offset=True)
                expected_image = (image * (1 / 127.5)) - 1
                self.assertTrue(torch.allclose(rescaled_image, expected_image))
                # Scale between [0, 1] with rescale_factor 1/255 and rescale_offset=False
                rescaled_image = image_processor.rescale(image, scale=1 / 255, offset=False)
                expected_image = image / 255.0
                self.assertTrue(torch.allclose(rescaled_image, expected_image))
            else:
                image = image_np
                rescaled_image = image_processor.rescale(image, scale=1 / 127.5, offset=True)
                expected_image = (image.astype(np.float64) * (1 / 127.5)) - 1
                self.assertTrue(np.allclose(rescaled_image, expected_image, rtol=1e-5, atol=1e-5))
                rescaled_image = image_processor.rescale(image, scale=1 / 255, offset=False)
                expected_image = image.astype(np.float64) / 255.0
                self.assertTrue(np.allclose(rescaled_image, expected_image, rtol=1e-5, atol=1e-5))

    @require_vision
    @require_torch
    def test_rescale_normalize(self):
        if "torchvision" not in self.image_processing_classes:
            self.skipTest(reason="Skipping rescale_normalize test as torchvision backend is not available")

        image = torch.arange(0, 256, 1, dtype=torch.uint8).reshape(1, 8, 32).repeat(3, 1, 1)
        image_mean_0 = (0.0, 0.0, 0.0)
        image_std_0 = (1.0, 1.0, 1.0)
        image_mean_1 = (0.5, 0.5, 0.5)
        image_std_1 = (0.5, 0.5, 0.5)

        image_processor = self.image_processing_classes["torchvision"](**self.image_processor_dict)

        # Rescale between [-1, 1] with rescale_factor=1/127.5 and rescale_offset=True. Then normalize
        rescaled_normalized = image_processor.rescale_and_normalize_efficientnet(
            image, True, 1 / 127.5, True, image_mean_0, image_std_0, True
        )
        expected_image = (image * (1 / 127.5)) - 1
        expected_image = (expected_image - torch.tensor(image_mean_0).view(3, 1, 1)) / torch.tensor(image_std_0).view(
            3, 1, 1
        )
        self.assertTrue(torch.allclose(rescaled_normalized, expected_image, rtol=1e-3))

        # Rescale between [0, 1] with rescale_factor=1/255 and rescale_offset=False. Then normalize
        rescaled_normalized = image_processor.rescale_and_normalize_efficientnet(
            image, True, 1 / 255, True, image_mean_1, image_std_1, False
        )
        expected_image = image * (1 / 255.0)
        expected_image = (expected_image - torch.tensor(image_mean_1).view(3, 1, 1)) / torch.tensor(image_std_1).view(
            3, 1, 1
        )
        self.assertTrue(torch.allclose(rescaled_normalized, expected_image, rtol=1e-3))