# Copyright 2021 The HuggingFace Inc. 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 base64
import os
from collections.abc import Iterable
from dataclasses import dataclass
from io import BytesIO
from typing import Optional, Union

import numpy as np
import requests

from .utils import (
    ExplicitEnum,
    is_jax_tensor,
    is_numpy_array,
    is_tf_tensor,
    is_torch_available,
    is_torch_tensor,
    is_torchvision_available,
    is_vision_available,
    logging,
    requires_backends,
    to_numpy,
)
from .utils.constants import (  # noqa: F401
    IMAGENET_DEFAULT_MEAN,
    IMAGENET_DEFAULT_STD,
    IMAGENET_STANDARD_MEAN,
    IMAGENET_STANDARD_STD,
    OPENAI_CLIP_MEAN,
    OPENAI_CLIP_STD,
)


if is_vision_available():
    import PIL.Image
    import PIL.ImageOps

    PILImageResampling = PIL.Image.Resampling

    if is_torchvision_available():
        from torchvision.transforms import InterpolationMode

        pil_torch_interpolation_mapping = {
            PILImageResampling.NEAREST: InterpolationMode.NEAREST_EXACT,
            PILImageResampling.BOX: InterpolationMode.BOX,
            PILImageResampling.BILINEAR: InterpolationMode.BILINEAR,
            PILImageResampling.HAMMING: InterpolationMode.HAMMING,
            PILImageResampling.BICUBIC: InterpolationMode.BICUBIC,
            PILImageResampling.LANCZOS: InterpolationMode.LANCZOS,
        }
    else:
        pil_torch_interpolation_mapping = {}


if is_torch_available():
    import torch


logger = logging.get_logger(__name__)


ImageInput = Union[
    "PIL.Image.Image", np.ndarray, "torch.Tensor", list["PIL.Image.Image"], list[np.ndarray], list["torch.Tensor"]
]


class ChannelDimension(ExplicitEnum):
    FIRST = "channels_first"
    LAST = "channels_last"


class AnnotationFormat(ExplicitEnum):
    COCO_DETECTION = "coco_detection"
    COCO_PANOPTIC = "coco_panoptic"


class AnnotionFormat(ExplicitEnum):
    COCO_DETECTION = AnnotationFormat.COCO_DETECTION.value
    COCO_PANOPTIC = AnnotationFormat.COCO_PANOPTIC.value


AnnotationType = dict[str, Union[int, str, list[dict]]]


def is_pil_image(img):
    return is_vision_available() and isinstance(img, PIL.Image.Image)


class ImageType(ExplicitEnum):
    PIL = "pillow"
    TORCH = "torch"
    NUMPY = "numpy"
    TENSORFLOW = "tensorflow"
    JAX = "jax"


def get_image_type(image):
    if is_pil_image(image):
        return ImageType.PIL
    if is_torch_tensor(image):
        return ImageType.TORCH
    if is_numpy_array(image):
        return ImageType.NUMPY
    if is_tf_tensor(image):
        return ImageType.TENSORFLOW
    if is_jax_tensor(image):
        return ImageType.JAX
    raise ValueError(f"Unrecognized image type {type(image)}")


def is_valid_image(img):
    return is_pil_image(img) or is_numpy_array(img) or is_torch_tensor(img) or is_tf_tensor(img) or is_jax_tensor(img)


def is_valid_list_of_images(images: list):
    return images and all(is_valid_image(image) for image in images)


def concatenate_list(input_list):
    if isinstance(input_list[0], list):
        return [item for sublist in input_list for item in sublist]
    elif isinstance(input_list[0], np.ndarray):
        return np.concatenate(input_list, axis=0)
    elif isinstance(input_list[0], torch.Tensor):
        return torch.cat(input_list, dim=0)


def valid_images(imgs):
    # If we have an list of images, make sure every image is valid
    if isinstance(imgs, (list, tuple)):
        for img in imgs:
            if not valid_images(img):
                return False
    # If not a list of tuple, we have been given a single image or batched tensor of images
    elif not is_valid_image(imgs):
        return False
    return True


def is_batched(img):
    if isinstance(img, (list, tuple)):
        return is_valid_image(img[0])
    return False


def is_scaled_image(image: np.ndarray) -> bool:
    """
    Checks to see whether the pixel values have already been rescaled to [0, 1].
    """
    if image.dtype == np.uint8:
        return False

    # It's possible the image has pixel values in [0, 255] but is of floating type
    return np.min(image) >= 0 and np.max(image) <= 1


def make_list_of_images(images, expected_ndims: int = 3) -> list[ImageInput]:
    """
    Ensure that the output is a list of images. If the input is a single image, it is converted to a list of length 1.
    If the input is a batch of images, it is converted to a list of images.

    Args:
        images (`ImageInput`):
            Image of images to turn into a list of images.
        expected_ndims (`int`, *optional*, defaults to 3):
            Expected number of dimensions for a single input image. If the input image has a different number of
            dimensions, an error is raised.
    """
    if is_batched(images):
        return images

    # Either the input is a single image, in which case we create a list of length 1
    if is_pil_image(images):
        # PIL images are never batched
        return [images]

    if is_valid_image(images):
        if images.ndim == expected_ndims + 1:
            # Batch of images
            images = list(images)
        elif images.ndim == expected_ndims:
            # Single image
            images = [images]
        else:
            raise ValueError(
                f"Invalid image shape. Expected either {expected_ndims + 1} or {expected_ndims} dimensions, but got"
                f" {images.ndim} dimensions."
            )
        return images
    raise ValueError(
        "Invalid image type. Expected either PIL.Image.Image, numpy.ndarray, torch.Tensor, tf.Tensor or "
        f"jax.ndarray, but got {type(images)}."
    )


def make_flat_list_of_images(
    images: Union[list[ImageInput], ImageInput],
    expected_ndims: int = 3,
) -> ImageInput:
    """
    Ensure that the output is a flat list of images. If the input is a single image, it is converted to a list of length 1.
    If the input is a nested list of images, it is converted to a flat list of images.
    Args:
        images (`Union[list[ImageInput], ImageInput]`):
            The input image.
        expected_ndims (`int`, *optional*, defaults to 3):
            The expected number of dimensions for a single input image.
    Returns:
        list: A list of images or a 4d array of images.
    """
    # If the input is a nested list of images, we flatten it
    if (
        isinstance(images, (list, tuple))
        and all(isinstance(images_i, (list, tuple)) for images_i in images)
        and all(is_valid_list_of_images(images_i) or not images_i for images_i in images)
    ):
        return [img for img_list in images for img in img_list]

    if isinstance(images, (list, tuple)) and is_valid_list_of_images(images):
        if is_pil_image(images[0]) or images[0].ndim == expected_ndims:
            return images
        if images[0].ndim == expected_ndims + 1:
            return [img for img_list in images for img in img_list]

    if is_valid_image(images):
        if is_pil_image(images) or images.ndim == expected_ndims:
            return [images]
        if images.ndim == expected_ndims + 1:
            return list(images)

    raise ValueError(f"Could not make a flat list of images from {images}")


def make_nested_list_of_images(
    images: Union[list[ImageInput], ImageInput],
    expected_ndims: int = 3,
) -> list[ImageInput]:
    """
    Ensure that the output is a nested list of images.
    Args:
        images (`Union[list[ImageInput], ImageInput]`):
            The input image.
        expected_ndims (`int`, *optional*, defaults to 3):
            The expected number of dimensions for a single input image.
    Returns:
        list: A list of list of images or a list of 4d array of images.
    """
    # If it's a list of batches, it's already in the right format
    if (
        isinstance(images, (list, tuple))
        and all(isinstance(images_i, (list, tuple)) for images_i in images)
        and all(is_valid_list_of_images(images_i) or not images_i for images_i in images)
    ):
        return images

    # If it's a list of images, it's a single batch, so convert it to a list of lists
    if isinstance(images, (list, tuple)) and is_valid_list_of_images(images):
        if is_pil_image(images[0]) or images[0].ndim == expected_ndims:
            return [images]
        if images[0].ndim == expected_ndims + 1:
            return [list(image) for image in images]

    # If it's a single image, convert it to a list of lists
    if is_valid_image(images):
        if is_pil_image(images) or images.ndim == expected_ndims:
            return [[images]]
        if images.ndim == expected_ndims + 1:
            return [list(images)]

    raise ValueError("Invalid input type. Must be a single image, a list of images, or a list of batches of images.")


def to_numpy_array(img) -> np.ndarray:
    if not is_valid_image(img):
        raise ValueError(f"Invalid image type: {type(img)}")

    if is_vision_available() and isinstance(img, PIL.Image.Image):
        return np.array(img)
    return to_numpy(img)


def infer_channel_dimension_format(
    image: np.ndarray, num_channels: Optional[Union[int, tuple[int, ...]]] = None
) -> ChannelDimension:
    """
    Infers the channel dimension format of `image`.

    Args:
        image (`np.ndarray`):
            The image to infer the channel dimension of.
        num_channels (`int` or `tuple[int, ...]`, *optional*, defaults to `(1, 3)`):
            The number of channels of the image.

    Returns:
        The channel dimension of the image.
    """
    num_channels = num_channels if num_channels is not None else (1, 3)
    num_channels = (num_channels,) if isinstance(num_channels, int) else num_channels

    if image.ndim == 3:
        first_dim, last_dim = 0, 2
    elif image.ndim == 4:
        first_dim, last_dim = 1, 3
    elif image.ndim == 5:
        first_dim, last_dim = 2, 4
    else:
        raise ValueError(f"Unsupported number of image dimensions: {image.ndim}")

    if image.shape[first_dim] in num_channels and image.shape[last_dim] in num_channels:
        logger.warning(
            f"The channel dimension is ambiguous. Got image shape {image.shape}. Assuming channels are the first dimension. Use the [input_data_format](https://huggingface.co/docs/transformers/main/internal/image_processing_utils#transformers.image_transforms.rescale.input_data_format) parameter to assign the channel dimension."
        )
        return ChannelDimension.FIRST
    elif image.shape[first_dim] in num_channels:
        return ChannelDimension.FIRST
    elif image.shape[last_dim] in num_channels:
        return ChannelDimension.LAST
    raise ValueError("Unable to infer channel dimension format")


def get_channel_dimension_axis(
    image: np.ndarray, input_data_format: Optional[Union[ChannelDimension, str]] = None
) -> int:
    """
    Returns the channel dimension axis of the image.

    Args:
        image (`np.ndarray`):
            The image to get the channel dimension axis of.
        input_data_format (`ChannelDimension` or `str`, *optional*):
            The channel dimension format of the image. If `None`, will infer the channel dimension from the image.

    Returns:
        The channel dimension axis of the image.
    """
    if input_data_format is None:
        input_data_format = infer_channel_dimension_format(image)
    if input_data_format == ChannelDimension.FIRST:
        return image.ndim - 3
    elif input_data_format == ChannelDimension.LAST:
        return image.ndim - 1
    raise ValueError(f"Unsupported data format: {input_data_format}")


def get_image_size(image: np.ndarray, channel_dim: Optional[ChannelDimension] = None) -> tuple[int, int]:
    """
    Returns the (height, width) dimensions of the image.

    Args:
        image (`np.ndarray`):
            The image to get the dimensions of.
        channel_dim (`ChannelDimension`, *optional*):
            Which dimension the channel dimension is in. If `None`, will infer the channel dimension from the image.

    Returns:
        A tuple of the image's height and width.
    """
    if channel_dim is None:
        channel_dim = infer_channel_dimension_format(image)

    if channel_dim == ChannelDimension.FIRST:
        return image.shape[-2], image.shape[-1]
    elif channel_dim == ChannelDimension.LAST:
        return image.shape[-3], image.shape[-2]
    else:
        raise ValueError(f"Unsupported data format: {channel_dim}")


def get_image_size_for_max_height_width(
    image_size: tuple[int, int],
    max_height: int,
    max_width: int,
) -> tuple[int, int]:
    """
    Computes the output image size given the input image and the maximum allowed height and width. Keep aspect ratio.
    Important, even if image_height < max_height and image_width < max_width, the image will be resized
    to at least one of the edges be equal to max_height or max_width.

    For example:
        - input_size: (100, 200), max_height: 50, max_width: 50 -> output_size: (25, 50)
        - input_size: (100, 200), max_height: 200, max_width: 500 -> output_size: (200, 400)

    Args:
        image_size (`tuple[int, int]`):
            The image to resize.
        max_height (`int`):
            The maximum allowed height.
        max_width (`int`):
            The maximum allowed width.
    """
    height, width = image_size
    height_scale = max_height / height
    width_scale = max_width / width
    min_scale = min(height_scale, width_scale)
    new_height = int(height * min_scale)
    new_width = int(width * min_scale)
    return new_height, new_width


def is_valid_annotation_coco_detection(annotation: dict[str, Union[list, tuple]]) -> bool:
    if (
        isinstance(annotation, dict)
        and "image_id" in annotation
        and "annotations" in annotation
        and isinstance(annotation["annotations"], (list, tuple))
        and (
            # an image can have no annotations
            len(annotation["annotations"]) == 0 or isinstance(annotation["annotations"][0], dict)
        )
    ):
        return True
    return False


def is_valid_annotation_coco_panoptic(annotation: dict[str, Union[list, tuple]]) -> bool:
    if (
        isinstance(annotation, dict)
        and "image_id" in annotation
        and "segments_info" in annotation
        and "file_name" in annotation
        and isinstance(annotation["segments_info"], (list, tuple))
        and (
            # an image can have no segments
            len(annotation["segments_info"]) == 0 or isinstance(annotation["segments_info"][0], dict)
        )
    ):
        return True
    return False


def valid_coco_detection_annotations(annotations: Iterable[dict[str, Union[list, tuple]]]) -> bool:
    return all(is_valid_annotation_coco_detection(ann) for ann in annotations)


def valid_coco_panoptic_annotations(annotations: Iterable[dict[str, Union[list, tuple]]]) -> bool:
    return all(is_valid_annotation_coco_panoptic(ann) for ann in annotations)


def load_image(image: Union[str, "PIL.Image.Image"], timeout: Optional[float] = None) -> "PIL.Image.Image":
    """
    Loads `image` to a PIL Image.

    Args:
        image (`str` or `PIL.Image.Image`):
            The image to convert to the PIL Image format.
        timeout (`float`, *optional*):
            The timeout value in seconds for the URL request.

    Returns:
        `PIL.Image.Image`: A PIL Image.
    """
    requires_backends(load_image, ["vision"])
    if isinstance(image, str):
        if image.startswith("http://") or image.startswith("https://"):
            # We need to actually check for a real protocol, otherwise it's impossible to use a local file
            # like http_huggingface_co.png
            image = PIL.Image.open(BytesIO(requests.get(image, timeout=timeout).content))
        elif os.path.isfile(image):
            image = PIL.Image.open(image)
        else:
            if image.startswith("data:image/"):
                image = image.split(",")[1]

            # Try to load as base64
            try:
                b64 = base64.decodebytes(image.encode())
                image = PIL.Image.open(BytesIO(b64))
            except Exception as e:
                raise ValueError(
                    f"Incorrect image source. Must be a valid URL starting with `http://` or `https://`, a valid path to an image file, or a base64 encoded string. Got {image}. Failed with {e}"
                )
    elif not isinstance(image, PIL.Image.Image):
        raise TypeError(
            "Incorrect format used for image. Should be an url linking to an image, a base64 string, a local path, or a PIL image."
        )
    image = PIL.ImageOps.exif_transpose(image)
    image = image.convert("RGB")
    return image


def load_images(
    images: Union[list, tuple, str, "PIL.Image.Image"], timeout: Optional[float] = None
) -> Union["PIL.Image.Image", list["PIL.Image.Image"], list[list["PIL.Image.Image"]]]:
    """Loads images, handling different levels of nesting.

    Args:
      images: A single image, a list of images, or a list of lists of images to load.
      timeout: Timeout for loading images.

    Returns:
      A single image, a list of images, a list of lists of images.
    """
    if isinstance(images, (list, tuple)):
        if len(images) and isinstance(images[0], (list, tuple)):
            return [[load_image(image, timeout=timeout) for image in image_group] for image_group in images]
        else:
            return [load_image(image, timeout=timeout) for image in images]
    else:
        return load_image(images, timeout=timeout)


def validate_preprocess_arguments(
    do_rescale: Optional[bool] = None,
    rescale_factor: Optional[float] = None,
    do_normalize: Optional[bool] = None,
    image_mean: Optional[Union[float, list[float]]] = None,
    image_std: Optional[Union[float, list[float]]] = None,
    do_pad: Optional[bool] = None,
    pad_size: Optional[Union[dict[str, int], int]] = None,
    do_center_crop: Optional[bool] = None,
    crop_size: Optional[dict[str, int]] = None,
    do_resize: Optional[bool] = None,
    size: Optional[dict[str, int]] = None,
    resample: Optional["PILImageResampling"] = None,
    interpolation: Optional["InterpolationMode"] = None,
):
    """
    Checks validity of typically used arguments in an `ImageProcessor` `preprocess` method.
    Raises `ValueError` if arguments incompatibility is caught.
    Many incompatibilities are model-specific. `do_pad` sometimes needs `size_divisor`,
    sometimes `size_divisibility`, and sometimes `size`. New models and processors added should follow
    existing arguments when possible.

    """
    if do_rescale and rescale_factor is None:
        raise ValueError("`rescale_factor` must be specified if `do_rescale` is `True`.")

    if do_pad and pad_size is None:
        # Processors pad images using different args depending on the model, so the below check is pointless
        # but we keep it for BC for now. TODO: remove in v5
        # Usually padding can be called with:
        #   - "pad_size/size" if we're padding to specific values
        #   - "size_divisor" if we're padding to any value divisible by X
        #   - "None" if we're padding to the maximum size image in batch
        raise ValueError(
            "Depending on the model, `size_divisor` or `pad_size` or `size` must be specified if `do_pad` is `True`."
        )

    if do_normalize and (image_mean is None or image_std is None):
        raise ValueError("`image_mean` and `image_std` must both be specified if `do_normalize` is `True`.")

    if do_center_crop and crop_size is None:
        raise ValueError("`crop_size` must be specified if `do_center_crop` is `True`.")

    if interpolation is not None and resample is not None:
        raise ValueError(
            "Only one of `interpolation` and `resample` should be specified, depending on image processor type."
        )

    if do_resize and not (size is not None and (resample is not None or interpolation is not None)):
        raise ValueError("`size` and `resample/interpolation` must be specified if `do_resize` is `True`.")


# In the future we can add a TF implementation here when we have TF models.
class ImageFeatureExtractionMixin:
    """
    Mixin that contain utilities for preparing image features.
    """

    def _ensure_format_supported(self, image):
        if not isinstance(image, (PIL.Image.Image, np.ndarray)) and not is_torch_tensor(image):
            raise ValueError(
                f"Got type {type(image)} which is not supported, only `PIL.Image.Image`, `np.ndarray` and "
                "`torch.Tensor` are."
            )

    def to_pil_image(self, image, rescale=None):
        """
        Converts `image` to a PIL Image. Optionally rescales it and puts the channel dimension back as the last axis if
        needed.

        Args:
            image (`PIL.Image.Image` or `numpy.ndarray` or `torch.Tensor`):
                The image to convert to the PIL Image format.
            rescale (`bool`, *optional*):
                Whether or not to apply the scaling factor (to make pixel values integers between 0 and 255). Will
                default to `True` if the image type is a floating type, `False` otherwise.
        """
        self._ensure_format_supported(image)

        if is_torch_tensor(image):
            image = image.numpy()

        if isinstance(image, np.ndarray):
            if rescale is None:
                # rescale default to the array being of floating type.
                rescale = isinstance(image.flat[0], np.floating)
            # If the channel as been moved to first dim, we put it back at the end.
            if image.ndim == 3 and image.shape[0] in [1, 3]:
                image = image.transpose(1, 2, 0)
            if rescale:
                image = image * 255
            image = image.astype(np.uint8)
            return PIL.Image.fromarray(image)
        return image

    def convert_rgb(self, image):
        """
        Converts `PIL.Image.Image` to RGB format.

        Args:
            image (`PIL.Image.Image`):
                The image to convert.
        """
        self._ensure_format_supported(image)
        if not isinstance(image, PIL.Image.Image):
            return image

        return image.convert("RGB")

    def rescale(self, image: np.ndarray, scale: Union[float, int]) -> np.ndarray:
        """
        Rescale a numpy image by scale amount
        """
        self._ensure_format_supported(image)
        return image * scale

    def to_numpy_array(self, image, rescale=None, channel_first=True):
        """
        Converts `image` to a numpy array. Optionally rescales it and puts the channel dimension as the first
        dimension.

        Args:
            image (`PIL.Image.Image` or `np.ndarray` or `torch.Tensor`):
                The image to convert to a NumPy array.
            rescale (`bool`, *optional*):
                Whether or not to apply the scaling factor (to make pixel values floats between 0. and 1.). Will
                default to `True` if the image is a PIL Image or an array/tensor of integers, `False` otherwise.
            channel_first (`bool`, *optional*, defaults to `True`):
                Whether or not to permute the dimensions of the image to put the channel dimension first.
        """
        self._ensure_format_supported(image)

        if isinstance(image, PIL.Image.Image):
            image = np.array(image)

        if is_torch_tensor(image):
            image = image.numpy()

        rescale = isinstance(image.flat[0], np.integer) if rescale is None else rescale

        if rescale:
            image = self.rescale(image.astype(np.float32), 1 / 255.0)

        if channel_first and image.ndim == 3:
            image = image.transpose(2, 0, 1)

        return image

    def expand_dims(self, image):
        """
        Expands 2-dimensional `image` to 3 dimensions.

        Args:
            image (`PIL.Image.Image` or `np.ndarray` or `torch.Tensor`):
                The image to expand.
        """
        self._ensure_format_supported(image)

        # Do nothing if PIL image
        if isinstance(image, PIL.Image.Image):
            return image

        if is_torch_tensor(image):
            image = image.unsqueeze(0)
        else:
            image = np.expand_dims(image, axis=0)
        return image

    def normalize(self, image, mean, std, rescale=False):
        """
        Normalizes `image` with `mean` and `std`. Note that this will trigger a conversion of `image` to a NumPy array
        if it's a PIL Image.

        Args:
            image (`PIL.Image.Image` or `np.ndarray` or `torch.Tensor`):
                The image to normalize.
            mean (`list[float]` or `np.ndarray` or `torch.Tensor`):
                The mean (per channel) to use for normalization.
            std (`list[float]` or `np.ndarray` or `torch.Tensor`):
                The standard deviation (per channel) to use for normalization.
            rescale (`bool`, *optional*, defaults to `False`):
                Whether or not to rescale the image to be between 0 and 1. If a PIL image is provided, scaling will
                happen automatically.
        """
        self._ensure_format_supported(image)

        if isinstance(image, PIL.Image.Image):
            image = self.to_numpy_array(image, rescale=True)
        # If the input image is a PIL image, it automatically gets rescaled. If it's another
        # type it may need rescaling.
        elif rescale:
            if isinstance(image, np.ndarray):
                image = self.rescale(image.astype(np.float32), 1 / 255.0)
            elif is_torch_tensor(image):
                image = self.rescale(image.float(), 1 / 255.0)

        if isinstance(image, np.ndarray):
            if not isinstance(mean, np.ndarray):
                mean = np.array(mean).astype(image.dtype)
            if not isinstance(std, np.ndarray):
                std = np.array(std).astype(image.dtype)
        elif is_torch_tensor(image):
            import torch

            if not isinstance(mean, torch.Tensor):
                if isinstance(mean, np.ndarray):
                    mean = torch.from_numpy(mean)
                else:
                    mean = torch.tensor(mean)
            if not isinstance(std, torch.Tensor):
                if isinstance(std, np.ndarray):
                    std = torch.from_numpy(std)
                else:
                    std = torch.tensor(std)

        if image.ndim == 3 and image.shape[0] in [1, 3]:
            return (image - mean[:, None, None]) / std[:, None, None]
        else:
            return (image - mean) / std

    def resize(self, image, size, resample=None, default_to_square=True, max_size=None):
        """
        Resizes `image`. Enforces conversion of input to PIL.Image.

        Args:
            image (`PIL.Image.Image` or `np.ndarray` or `torch.Tensor`):
                The image to resize.
            size (`int` or `tuple[int, int]`):
                The size to use for resizing the image. If `size` is a sequence like (h, w), output size will be
                matched to this.

                If `size` is an int and `default_to_square` is `True`, then image will be resized to (size, size). If
                `size` is an int and `default_to_square` is `False`, then smaller edge of the image will be matched to
                this number. i.e, if height > width, then image will be rescaled to (size * height / width, size).
            resample (`int`, *optional*, defaults to `PILImageResampling.BILINEAR`):
                The filter to user for resampling.
            default_to_square (`bool`, *optional*, defaults to `True`):
                How to convert `size` when it is a single int. If set to `True`, the `size` will be converted to a
                square (`size`,`size`). If set to `False`, will replicate
                [`torchvision.transforms.Resize`](https://pytorch.org/vision/stable/transforms.html#torchvision.transforms.Resize)
                with support for resizing only the smallest edge and providing an optional `max_size`.
            max_size (`int`, *optional*, defaults to `None`):
                The maximum allowed for the longer edge of the resized image: if the longer edge of the image is
                greater than `max_size` after being resized according to `size`, then the image is resized again so
                that the longer edge is equal to `max_size`. As a result, `size` might be overruled, i.e the smaller
                edge may be shorter than `size`. Only used if `default_to_square` is `False`.

        Returns:
            image: A resized `PIL.Image.Image`.
        """
        resample = resample if resample is not None else PILImageResampling.BILINEAR

        self._ensure_format_supported(image)

        if not isinstance(image, PIL.Image.Image):
            image = self.to_pil_image(image)

        if isinstance(size, list):
            size = tuple(size)

        if isinstance(size, int) or len(size) == 1:
            if default_to_square:
                size = (size, size) if isinstance(size, int) else (size[0], size[0])
            else:
                width, height = image.size
                # specified size only for the smallest edge
                short, long = (width, height) if width <= height else (height, width)
                requested_new_short = size if isinstance(size, int) else size[0]

                if short == requested_new_short:
                    return image

                new_short, new_long = requested_new_short, int(requested_new_short * long / short)

                if max_size is not None:
                    if max_size <= requested_new_short:
                        raise ValueError(
                            f"max_size = {max_size} must be strictly greater than the requested "
                            f"size for the smaller edge size = {size}"
                        )
                    if new_long > max_size:
                        new_short, new_long = int(max_size * new_short / new_long), max_size

                size = (new_short, new_long) if width <= height else (new_long, new_short)

        return image.resize(size, resample=resample)

    def center_crop(self, image, size):
        """
        Crops `image` to the given size using a center crop. Note that if the image is too small to be cropped to the
        size given, it will be padded (so the returned result has the size asked).

        Args:
            image (`PIL.Image.Image` or `np.ndarray` or `torch.Tensor` of shape (n_channels, height, width) or (height, width, n_channels)):
                The image to resize.
            size (`int` or `tuple[int, int]`):
                The size to which crop the image.

        Returns:
            new_image: A center cropped `PIL.Image.Image` or `np.ndarray` or `torch.Tensor` of shape: (n_channels,
            height, width).
        """
        self._ensure_format_supported(image)

        if not isinstance(size, tuple):
            size = (size, size)

        # PIL Image.size is (width, height) but NumPy array and torch Tensors have (height, width)
        if is_torch_tensor(image) or isinstance(image, np.ndarray):
            if image.ndim == 2:
                image = self.expand_dims(image)
            image_shape = image.shape[1:] if image.shape[0] in [1, 3] else image.shape[:2]
        else:
            image_shape = (image.size[1], image.size[0])

        top = (image_shape[0] - size[0]) // 2
        bottom = top + size[0]  # In case size is odd, (image_shape[0] + size[0]) // 2 won't give the proper result.
        left = (image_shape[1] - size[1]) // 2
        right = left + size[1]  # In case size is odd, (image_shape[1] + size[1]) // 2 won't give the proper result.

        # For PIL Images we have a method to crop directly.
        if isinstance(image, PIL.Image.Image):
            return image.crop((left, top, right, bottom))

        # Check if image is in (n_channels, height, width) or (height, width, n_channels) format
        channel_first = image.shape[0] in [1, 3]

        # Transpose (height, width, n_channels) format images
        if not channel_first:
            if isinstance(image, np.ndarray):
                image = image.transpose(2, 0, 1)
            if is_torch_tensor(image):
                image = image.permute(2, 0, 1)

        # Check if cropped area is within image boundaries
        if top >= 0 and bottom <= image_shape[0] and left >= 0 and right <= image_shape[1]:
            return image[..., top:bottom, left:right]

        # Otherwise, we may need to pad if the image is too small. Oh joy...
        new_shape = image.shape[:-2] + (max(size[0], image_shape[0]), max(size[1], image_shape[1]))
        if isinstance(image, np.ndarray):
            new_image = np.zeros_like(image, shape=new_shape)
        elif is_torch_tensor(image):
            new_image = image.new_zeros(new_shape)

        top_pad = (new_shape[-2] - image_shape[0]) // 2
        bottom_pad = top_pad + image_shape[0]
        left_pad = (new_shape[-1] - image_shape[1]) // 2
        right_pad = left_pad + image_shape[1]
        new_image[..., top_pad:bottom_pad, left_pad:right_pad] = image

        top += top_pad
        bottom += top_pad
        left += left_pad
        right += left_pad

        new_image = new_image[
            ..., max(0, top) : min(new_image.shape[-2], bottom), max(0, left) : min(new_image.shape[-1], right)
        ]

        return new_image

    def flip_channel_order(self, image):
        """
        Flips the channel order of `image` from RGB to BGR, or vice versa. Note that this will trigger a conversion of
        `image` to a NumPy array if it's a PIL Image.

        Args:
            image (`PIL.Image.Image` or `np.ndarray` or `torch.Tensor`):
                The image whose color channels to flip. If `np.ndarray` or `torch.Tensor`, the channel dimension should
                be first.
        """
        self._ensure_format_supported(image)

        if isinstance(image, PIL.Image.Image):
            image = self.to_numpy_array(image)

        return image[::-1, :, :]

    def rotate(self, image, angle, resample=None, expand=0, center=None, translate=None, fillcolor=None):
        """
        Returns a rotated copy of `image`. This method returns a copy of `image`, rotated the given number of degrees
        counter clockwise around its centre.

        Args:
            image (`PIL.Image.Image` or `np.ndarray` or `torch.Tensor`):
                The image to rotate. If `np.ndarray` or `torch.Tensor`, will be converted to `PIL.Image.Image` before
                rotating.

        Returns:
            image: A rotated `PIL.Image.Image`.
        """
        resample = resample if resample is not None else PIL.Image.NEAREST

        self._ensure_format_supported(image)

        if not isinstance(image, PIL.Image.Image):
            image = self.to_pil_image(image)

        return image.rotate(
            angle, resample=resample, expand=expand, center=center, translate=translate, fillcolor=fillcolor
        )


def validate_annotations(
    annotation_format: AnnotationFormat,
    supported_annotation_formats: tuple[AnnotationFormat, ...],
    annotations: list[dict],
) -> None:
    if annotation_format not in supported_annotation_formats:
        raise ValueError(f"Unsupported annotation format: {format} must be one of {supported_annotation_formats}")

    if annotation_format is AnnotationFormat.COCO_DETECTION:
        if not valid_coco_detection_annotations(annotations):
            raise ValueError(
                "Invalid COCO detection annotations. Annotations must a dict (single image) or list of dicts "
                "(batch of images) with the following keys: `image_id` and `annotations`, with the latter "
                "being a list of annotations in the COCO format."
            )

    if annotation_format is AnnotationFormat.COCO_PANOPTIC:
        if not valid_coco_panoptic_annotations(annotations):
            raise ValueError(
                "Invalid COCO panoptic annotations. Annotations must a dict (single image) or list of dicts "
                "(batch of images) with the following keys: `image_id`, `file_name` and `segments_info`, with "
                "the latter being a list of annotations in the COCO format."
            )


def validate_kwargs(valid_processor_keys: list[str], captured_kwargs: list[str]):
    unused_keys = set(captured_kwargs).difference(set(valid_processor_keys))
    if unused_keys:
        unused_key_str = ", ".join(unused_keys)
        # TODO raise a warning here instead of simply logging?
        logger.warning(f"Unused or unrecognized kwargs: {unused_key_str}.")


@dataclass(frozen=True)
class SizeDict:
    """
    Hashable dictionary to store image size information.
    """

    height: Optional[int] = None
    width: Optional[int] = None
    longest_edge: Optional[int] = None
    shortest_edge: Optional[int] = None
    max_height: Optional[int] = None
    max_width: Optional[int] = None

    def __getitem__(self, key):
        if hasattr(self, key):
            return getattr(self, key)
        raise KeyError(f"Key {key} not found in SizeDict.")
