# Copyright 2022 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.testing_utils import require_torch, require_vision
from transformers.utils import is_torch_available, is_vision_available

from ...test_image_processing_common import ImageProcessingTester, ImageProcessingTestMixin


if is_torch_available():
    import torch

if is_vision_available():
    from PIL import Image

    from transformers.image_transforms import get_image_size


class Swin2SRImageProcessingTester(ImageProcessingTester):
    def __init__(self, **kwargs):
        # Image processor init kwargs
        kwargs.setdefault("size_divisor", 8)

        super().__init__(**kwargs)

    def expected_output_image_shape(self, images):
        img = images[0]

        if isinstance(img, Image.Image):
            input_width, input_height = img.size
        elif isinstance(img, np.ndarray):
            input_height, input_width = img.shape[-3:-1]
        else:
            input_height, input_width = img.shape[-2:]

        pad_height = (input_height // self.size_divisor + 1) * self.size_divisor - input_height
        pad_width = (input_width // self.size_divisor + 1) * self.size_divisor - input_width

        return self.num_channels, input_height + pad_height, input_width + pad_width


@require_torch
@require_vision
class Swin2SRImageProcessingTest(ImageProcessingTestMixin, unittest.TestCase):
    image_processor_tester_class = Swin2SRImageProcessingTester

    def calculate_expected_size(self, image):
        old_height, old_width = get_image_size(image)
        size = self.image_processor_tester.size_divisor

        pad_height = (old_height // size + 1) * size - old_height
        pad_width = (old_width // size + 1) * size - old_width
        return old_height + pad_height, old_width + pad_width

    # Swin2SRImageProcessor does not support batched input
    def test_call_pil(self):
        for image_processing_class in self.image_processing_classes.values():
            image_processing = image_processing_class(**self.image_processor_dict)
            # create random PIL images
            image_inputs = self.image_processor_tester.prepare_image_inputs(equal_resolution=False)
            for image in image_inputs:
                self.assertIsInstance(image, Image.Image)

            # Test not batched input
            encoded_images = image_processing(image_inputs[0], return_tensors="pt").pixel_values
            expected_output_image_shape = self.image_processor_tester.expected_output_image_shape([image_inputs[0]])
            self.assertEqual(tuple(encoded_images.shape), (1, *expected_output_image_shape))

    # Swin2SRImageProcessor does not support batched input
    def test_call_numpy(self):
        for image_processing_class in self.image_processing_classes.values():
            image_processing = image_processing_class(**self.image_processor_dict)
            # create random numpy tensors
            image_inputs = self.image_processor_tester.prepare_image_inputs(equal_resolution=False, numpify=True)
            for image in image_inputs:
                self.assertIsInstance(image, np.ndarray)

            # Test not batched input
            encoded_images = image_processing(image_inputs[0], return_tensors="pt").pixel_values
            expected_output_image_shape = self.image_processor_tester.expected_output_image_shape([image_inputs[0]])
            self.assertEqual(tuple(encoded_images.shape), (1, *expected_output_image_shape))

    # Swin2SRImageProcessor does not support batched input
    def test_call_numpy_4_channels(self):
        for image_processing_class in self.image_processing_classes.values():
            image_processing = image_processing_class(**self.image_processor_dict)
            # create random numpy tensors
            self.image_processor_tester.num_channels = 4
            image_inputs = self.image_processor_tester.prepare_image_inputs(equal_resolution=False, numpify=True)
            for image in image_inputs:
                self.assertIsInstance(image, np.ndarray)

            # Test not batched input
            encoded_images = image_processing(
                image_inputs[0], return_tensors="pt", input_data_format="channels_last"
            ).pixel_values
            expected_output_image_shape = self.image_processor_tester.expected_output_image_shape([image_inputs[0]])
            self.assertEqual(tuple(encoded_images.shape), (1, *expected_output_image_shape))
            self.image_processor_tester.num_channels = 3

    # Swin2SRImageProcessor does not support batched input
    def test_call_pytorch(self):
        for image_processing_class in self.image_processing_classes.values():
            image_processing = image_processing_class(**self.image_processor_dict)
            # create random PyTorch tensors
            image_inputs = self.image_processor_tester.prepare_image_inputs(equal_resolution=False, torchify=True)

            for image in image_inputs:
                self.assertIsInstance(image, torch.Tensor)

            # Test not batched input
            encoded_images = image_processing(image_inputs[0], return_tensors="pt").pixel_values
            expected_output_image_shape = self.image_processor_tester.expected_output_image_shape([image_inputs[0]])
            self.assertEqual(tuple(encoded_images.shape), (1, *expected_output_image_shape))

    def test_backends_equivalence_batched(self):
        """Swin2SR requires equal-resolution images for batched processing (returns stacked tensor)."""
        if len(self.image_processing_classes) < 2:
            self.skipTest(reason="Skipping backends equivalence test as there are less than 2 backends")

        image_inputs = self.image_processor_tester.prepare_image_inputs(equal_resolution=True, torchify=True)

        encodings = {}
        for backend_name, image_processing_class in self.image_processing_classes.items():
            image_processor = image_processing_class(**self.image_processor_dict)
            encodings[backend_name] = image_processor(image_inputs, return_tensors="pt")

        backend_names = list(encodings.keys())
        reference_encoding = encodings[backend_names[0]].pixel_values
        for backend_name in backend_names[1:]:
            self._assert_tensors_equivalence(reference_encoding, encodings[backend_name].pixel_values)