# Copyright 2025 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 torch
from PIL import Image

from transformers.image_utils import IMAGENET_STANDARD_MEAN, IMAGENET_STANDARD_STD
from transformers.testing_utils import require_torch, require_torchvision, require_vision
from transformers.utils import is_torchvision_available, is_vision_available

from ...test_video_processing_common import VideoProcessingTestMixin, prepare_video_inputs


if is_vision_available():
    if is_torchvision_available():
        from transformers import VideoMAEImageProcessor, VideoMAEVideoProcessor


class VideoMAEVideoProcessingTester:
    def __init__(
        self,
        parent,
        batch_size=5,
        num_frames=8,
        num_channels=3,
        image_size=18,
        min_resolution=30,
        max_resolution=80,
        do_resize=True,
        size=None,
        do_center_crop=True,
        crop_size=None,
        do_rescale=True,
        rescale_factor=1 / 255,
        do_normalize=True,
        image_mean=IMAGENET_STANDARD_MEAN,
        image_std=IMAGENET_STANDARD_STD,
        do_convert_rgb=True,
    ):
        super().__init__()
        size = size if size is not None else {"shortest_edge": 20}
        crop_size = crop_size if crop_size is not None else {"height": 18, "width": 18}
        self.parent = parent
        self.batch_size = batch_size
        self.num_frames = num_frames
        self.num_channels = num_channels
        self.image_size = image_size
        self.min_resolution = min_resolution
        self.max_resolution = max_resolution
        self.do_resize = do_resize
        self.size = size
        self.do_center_crop = do_center_crop
        self.crop_size = crop_size
        self.do_rescale = do_rescale
        self.rescale_factor = rescale_factor
        self.do_normalize = do_normalize
        self.image_mean = image_mean
        self.image_std = image_std
        self.do_convert_rgb = do_convert_rgb

    def prepare_video_processor_dict(self):
        return {
            "do_resize": self.do_resize,
            "size": self.size,
            "do_center_crop": self.do_center_crop,
            "crop_size": self.crop_size,
            "do_rescale": self.do_rescale,
            "rescale_factor": self.rescale_factor,
            "do_normalize": self.do_normalize,
            "image_mean": self.image_mean,
            "image_std": self.image_std,
            "do_convert_rgb": self.do_convert_rgb,
        }

    def expected_output_video_shape(self, videos):
        return self.num_frames, self.num_channels, self.crop_size["height"], self.crop_size["width"]

    def prepare_video_inputs(self, equal_resolution=False, return_tensors="pil"):
        videos = prepare_video_inputs(
            batch_size=self.batch_size,
            num_frames=self.num_frames,
            num_channels=self.num_channels,
            min_resolution=self.min_resolution,
            max_resolution=self.max_resolution,
            equal_resolution=equal_resolution,
            return_tensors=return_tensors,
        )

        return videos


@require_torch
@require_vision
@require_torchvision
class VideoMAEVideoProcessingTest(VideoProcessingTestMixin, unittest.TestCase):
    fast_video_processing_class = VideoMAEVideoProcessor if is_torchvision_available() else None
    input_name = "pixel_values"

    def setUp(self):
        super().setUp()
        self.video_processor_tester = VideoMAEVideoProcessingTester(self)

    @property
    def video_processor_dict(self):
        return self.video_processor_tester.prepare_video_processor_dict()

    def test_video_processor_properties(self):
        video_processing = self.fast_video_processing_class(**self.video_processor_dict)
        self.assertTrue(hasattr(video_processing, "do_resize"))
        self.assertTrue(hasattr(video_processing, "size"))
        self.assertTrue(hasattr(video_processing, "do_center_crop"))
        self.assertTrue(hasattr(video_processing, "center_crop"))
        self.assertTrue(hasattr(video_processing, "do_normalize"))
        self.assertTrue(hasattr(video_processing, "image_mean"))
        self.assertTrue(hasattr(video_processing, "image_std"))
        self.assertTrue(hasattr(video_processing, "do_convert_rgb"))
        self.assertTrue(hasattr(video_processing, "model_input_names"))
        self.assertIn("pixel_values", video_processing.model_input_names)

    def test_pixel_value_identity(self):
        """
        Verify that VideoMAEVideoProcessor (TorchCodec-based) produces pixel tensors
        numerically similar to those from VideoMAEImageProcessor (PIL-based).
        Minor (<1%) differences are expected due to color conversion and interpolation.
        """
        video = self.video_processor_tester.prepare_video_inputs(return_tensors="np")
        video_processor = VideoMAEVideoProcessor(**self.video_processor_dict)
        image_processor = VideoMAEImageProcessor(**self.video_processor_dict)

        video_frames_np = video[0]
        video_frames_pil = [Image.fromarray(frame.astype("uint8")) for frame in video_frames_np]
        video_out = video_processor(video_frames_pil, return_tensors="pt")
        image_out = image_processor(video_frames_pil, return_tensors="pt")

        torch.testing.assert_close(
            video_out["pixel_values"],
            image_out["pixel_values"],
            rtol=5e-2,
            atol=1e-2,
            msg=(
                "Pixel values differ slightly between VideoMAEVideoProcessor "
                "and VideoMAEImageProcessor. "
                "Differences ≤1% are expected due to YUV→RGB conversion and "
                "interpolation behavior in different decoders."
            ),
        )