# coding=utf-8
# Copyright 2022 The HuggingFace Inc. team. All rights reserved.
#
# 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.
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"""Image processor class for DPT."""

import math
from typing import Dict, Iterable, List, Optional, Tuple, Union

import numpy as np

from transformers.utils import is_vision_available
from transformers.utils.generic import TensorType

from ...image_processing_utils import BaseImageProcessor, BatchFeature, get_size_dict
from ...image_transforms import normalize, rescale, resize, to_channel_dimension_format
from ...image_utils import (
    IMAGENET_STANDARD_MEAN,
    IMAGENET_STANDARD_STD,
    ChannelDimension,
    ImageInput,
    PILImageResampling,
    get_image_size,
    is_batched,
    is_torch_available,
    is_torch_tensor,
    to_numpy_array,
    valid_images,
)
from ...utils import logging


if is_torch_available():
    import torch

if is_vision_available():
    import PIL


logger = logging.get_logger(__name__)


def get_resize_output_image_size(
    input_image: np.ndarray, output_size: Union[int, Iterable[int]], keep_aspect_ratio: bool, multiple: int
) -> Tuple[int, int]:
    def constraint_to_multiple_of(val, multiple, min_val=0, max_val=None):
        x = round(val / multiple) * multiple

        if max_val is not None and x > max_val:
            x = math.floor(val / multiple) * multiple

        if x < min_val:
            x = math.ceil(val / multiple) * multiple

        return x

    output_size = (output_size, output_size) if isinstance(output_size, int) else output_size

    input_height, input_width = get_image_size(input_image)
    output_height, output_width = output_size

    # determine new height and width
    scale_height = output_height / input_height
    scale_width = output_width / input_width

    if keep_aspect_ratio:
        # scale as little as possible
        if abs(1 - scale_width) < abs(1 - scale_height):
            # fit width
            scale_height = scale_width
        else:
            # fit height
            scale_width = scale_height

    new_height = constraint_to_multiple_of(scale_height * input_height, multiple=multiple)
    new_width = constraint_to_multiple_of(scale_width * input_width, multiple=multiple)

    return (new_height, new_width)


class DPTImageProcessor(BaseImageProcessor):
    r"""
    Constructs a DPT image processor.

    Args:
        do_resize (`bool`, *optional*, defaults to `True`):
            Whether to resize the image's (height, width) dimensions. Can be overidden by `do_resize` in `preprocess`.
        size (`Dict[str, int]` *optional*, defaults to `{"height": 384, "width": 384}`):
            Size of the image after resizing. Can be overidden by `size` in `preprocess`.
        keep_aspect_ratio (`bool`, *optional*, defaults to `False`):
            If `True`, the image is resized to the largest possible size such that the aspect ratio is preserved. Can
            be overidden by `keep_aspect_ratio` in `preprocess`.
        ensure_multiple_of (`int`, *optional*, defaults to `1`):
            If `do_resize` is `True`, the image is resized to a size that is a multiple of this value. Can be overidden
            by `ensure_multiple_of` in `preprocess`.
        resample (`PILImageResampling`, *optional*, defaults to `PILImageResampling.BILINEAR`):
            Defines the resampling filter to use if resizing the image. Can be overidden by `resample` in `preprocess`.
        do_rescale (`bool`, *optional*, defaults to `True`):
            Whether to rescale the image by the specified scale `rescale_factor`. Can be overidden by `do_rescale` in
            `preprocess`.
        rescale_factor (`int` or `float`, *optional*, defaults to `1/255`):
            Scale factor to use if rescaling the image. Can be overidden by `rescale_factor` in `preprocess`.
        do_normalize (`bool`, *optional*, defaults to `True`):
            Whether to normalize the image. Can be overridden by the `do_normalize` parameter in the `preprocess`
            method.
        image_mean (`float` or `List[float]`, *optional*, defaults to `IMAGENET_STANDARD_MEAN`):
            Mean to use if normalizing the image. This is a float or list of floats the length of the number of
            channels in the image. Can be overridden by the `image_mean` parameter in the `preprocess` method.
        image_std (`float` or `List[float]`, *optional*, defaults to `IMAGENET_STANDARD_STD`):
            Standard deviation to use if normalizing the image. This is a float or list of floats the length of the
            number of channels in the image. Can be overridden by the `image_std` parameter in the `preprocess` method.
    """

    model_input_names = ["pixel_values"]

    def __init__(
        self,
        do_resize: bool = True,
        size: Dict[str, int] = None,
        resample: PILImageResampling = PILImageResampling.BILINEAR,
        keep_aspect_ratio: bool = False,
        ensure_multiple_of: int = 1,
        do_rescale: bool = True,
        rescale_factor: Union[int, float] = 1 / 255,
        do_normalize: bool = True,
        image_mean: Optional[Union[float, List[float]]] = None,
        image_std: Optional[Union[float, List[float]]] = None,
        **kwargs
    ) -> None:
        super().__init__(**kwargs)
        size = size if size is not None else {"height": 384, "width": 384}
        size = get_size_dict(size)
        self.do_resize = do_resize
        self.size = size
        self.keep_aspect_ratio = keep_aspect_ratio
        self.ensure_multiple_of = ensure_multiple_of
        self.resample = resample
        self.do_rescale = do_rescale
        self.rescale_factor = rescale_factor
        self.do_normalize = do_normalize
        self.image_mean = image_mean if image_mean is not None else IMAGENET_STANDARD_MEAN
        self.image_std = image_std if image_std is not None else IMAGENET_STANDARD_STD

    def resize(
        self,
        image: np.ndarray,
        size: Dict[str, int],
        keep_aspect_ratio: bool = False,
        ensure_multiple_of: int = 1,
        resample: PILImageResampling = PILImageResampling.BICUBIC,
        data_format: Optional[Union[str, ChannelDimension]] = None,
        **kwargs
    ) -> np.ndarray:
        """
        Resize an image to target size `(size["height"], size["width"])`. If `keep_aspect_ratio` is `True`, the image
        is resized to the largest possible size such that the aspect ratio is preserved. If `ensure_multiple_of` is
        set, the image is resized to a size that is a multiple of this value.

        Args:
            image (`np.ndarray`):
                Image to resize.
            size (`Dict[str, int]`):
                Target size of the output image.
            keep_aspect_ratio (`bool`, *optional*, defaults to `False`):
                If `True`, the image is resized to the largest possible size such that the aspect ratio is preserved.
            ensure_multiple_of (`int`, *optional*, defaults to `1`):
                The image is resized to a size that is a multiple of this value.
            resample (`PILImageResampling`, *optional*, defaults to `PILImageResampling.BICUBIC`):
                Defines the resampling filter to use if resizing the image. Otherwise, the image is resized to size
                specified in `size`.
            resample (`PILImageResampling`, *optional*, defaults to `PILImageResampling.BICUBIC`):
                Resampling filter to use when resiizing the image.
            data_format (`str` or `ChannelDimension`, *optional*):
                The channel dimension format of the image. If not provided, it will be the same as the input image.
        """
        size = get_size_dict(size)
        if "height" not in size or "width" not in size:
            raise ValueError(f"The size dictionary must contain the keys 'height' and 'width'. Got {size.keys()}")
        output_size = get_resize_output_image_size(
            image,
            output_size=(size["height"], size["width"]),
            keep_aspect_ratio=keep_aspect_ratio,
            multiple=ensure_multiple_of,
        )
        return resize(image, size=output_size, resample=resample, data_format=data_format, **kwargs)

    def rescale(
        self,
        image: np.ndarray,
        scale: Union[int, float],
        data_format: Optional[Union[str, ChannelDimension]] = None,
        **kwargs
    ):
        """
        Rescale an image by a scale factor. image = image * scale.

        Args:
            image (`np.ndarray`):
                Image to rescale.
            scale (`int` or `float`):
                Scale to apply to the image.
            data_format (`str` or `ChannelDimension`, *optional*):
                The channel dimension format of the image. If not provided, it will be the same as the input image.
        """
        return rescale(image, scale=scale, data_format=data_format, **kwargs)

    def normalize(
        self,
        image: np.ndarray,
        mean: Union[float, List[float]],
        std: Union[float, List[float]],
        data_format: Optional[Union[str, ChannelDimension]] = None,
        **kwargs
    ) -> np.ndarray:
        """
        Normalize an image. image = (image - image_mean) / image_std.

        Args:
            image (`np.ndarray`):
                Image to normalize.
            image_mean (`float` or `List[float]`):
                Image mean.
            image_std (`float` or `List[float]`):
                Image standard deviation.
            data_format (`str` or `ChannelDimension`, *optional*):
                The channel dimension format of the image. If not provided, it will be the same as the input image.
        """
        return normalize(image, mean=mean, std=std, data_format=data_format, **kwargs)

    def preprocess(
        self,
        images: ImageInput,
        do_resize: bool = None,
        size: int = None,
        keep_aspect_ratio: bool = None,
        ensure_multiple_of: int = None,
        resample: PILImageResampling = None,
        do_rescale: bool = None,
        rescale_factor: float = None,
        do_normalize: bool = None,
        image_mean: Optional[Union[float, List[float]]] = None,
        image_std: Optional[Union[float, List[float]]] = None,
        return_tensors: Optional[Union[str, TensorType]] = None,
        data_format: ChannelDimension = ChannelDimension.FIRST,
        **kwargs,
    ) -> PIL.Image.Image:
        """
        Preprocess an image or batch of images.

        Args:
            images (`ImageInput`):
                Image to preprocess.
            do_resize (`bool`, *optional*, defaults to `self.do_resize`):
                Whether to resize the image.
            size (`Dict[str, int]`, *optional*, defaults to `self.size`):
                Size of the image after reszing. If `keep_aspect_ratio` is `True`, the image is resized to the largest
                possible size such that the aspect ratio is preserved. If `ensure_multiple_of` is set, the image is
                resized to a size that is a multiple of this value.
            keep_aspect_ratio (`bool`, *optional*, defaults to `self.keep_aspect_ratio`):
                Whether to keep the aspect ratio of the image. If False, the image will be resized to (size, size). If
                True, the image will be resized to keep the aspect ratio and the size will be the maximum possible.
            ensure_multiple_of (`int`, *optional*, defaults to `self.ensure_multiple_of`):
                Ensure that the image size is a multiple of this value.
            resample (`int`, *optional*, defaults to `self.resample`):
                Resampling filter to use if resizing the image. This can be one of the enum `PILImageResampling`, Only
                has an effect if `do_resize` is set to `True`.
            do_rescale (`bool`, *optional*, defaults to `self.do_rescale`):
                Whether to rescale the image values between [0 - 1].
            rescale_factor (`float`, *optional*, defaults to `self.rescale_factor`):
                Rescale factor to rescale the image by if `do_rescale` is set to `True`.
            do_normalize (`bool`, *optional*, defaults to `self.do_normalize`):
                Whether to normalize the image.
            image_mean (`float` or `List[float]`, *optional*, defaults to `self.image_mean`):
                Image mean.
            image_std (`float` or `List[float]`, *optional*, defaults to `self.image_std`):
                Image standard deviation.
            return_tensors (`str` or `TensorType`, *optional*):
                The type of tensors to return. Can be one of:
                    - Unset: Return a list of `np.ndarray`.
                    - `TensorType.TENSORFLOW` or `'tf'`: Return a batch of type `tf.Tensor`.
                    - `TensorType.PYTORCH` or `'pt'`: Return a batch of type `torch.Tensor`.
                    - `TensorType.NUMPY` or `'np'`: Return a batch of type `np.ndarray`.
                    - `TensorType.JAX` or `'jax'`: Return a batch of type `jax.numpy.ndarray`.
            data_format (`ChannelDimension` or `str`, *optional*, defaults to `ChannelDimension.FIRST`):
                The channel dimension format for the output image. Can be one of:
                    - `ChannelDimension.FIRST`: image in (num_channels, height, width) format.
                    - `ChannelDimension.LAST`: image in (height, width, num_channels) format.
        """
        do_resize = do_resize if do_resize is not None else self.do_resize
        size = size if size is not None else self.size
        size = get_size_dict(size)
        keep_aspect_ratio = keep_aspect_ratio if keep_aspect_ratio is not None else self.keep_aspect_ratio
        ensure_multiple_of = ensure_multiple_of if ensure_multiple_of is not None else self.ensure_multiple_of
        resample = resample if resample is not None else self.resample
        do_rescale = do_rescale if do_rescale is not None else self.do_rescale
        rescale_factor = rescale_factor if rescale_factor is not None else self.rescale_factor
        do_normalize = do_normalize if do_normalize is not None else self.do_normalize
        image_mean = image_mean if image_mean is not None else self.image_mean
        image_std = image_std if image_std is not None else self.image_std

        if not is_batched(images):
            images = [images]

        if not valid_images(images):
            raise ValueError(
                "Invalid image type. Must be of type PIL.Image.Image, numpy.ndarray, "
                "torch.Tensor, tf.Tensor or jax.ndarray."
            )

        if do_resize and size is None or resample is None:
            raise ValueError("Size and resample must be specified if do_resize is True.")

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

        if do_normalize and (image_mean is None or image_std is None):
            raise ValueError("Image mean and std must be specified if do_normalize is True.")

        # All transformations expect numpy arrays.
        images = [to_numpy_array(image) for image in images]

        if do_resize:
            images = [self.resize(image=image, size=size, resample=resample) for image in images]

        if do_rescale:
            images = [self.rescale(image=image, scale=rescale_factor) for image in images]

        if do_normalize:
            images = [self.normalize(image=image, mean=image_mean, std=image_std) for image in images]

        images = [to_channel_dimension_format(image, data_format) for image in images]

        data = {"pixel_values": images}
        return BatchFeature(data=data, tensor_type=return_tensors)

    def post_process_semantic_segmentation(self, outputs, target_sizes: List[Tuple] = None):
        """
        Converts the output of [`DPTForSemanticSegmentation`] into semantic segmentation maps. Only supports PyTorch.

        Args:
            outputs ([`DPTForSemanticSegmentation`]):
                Raw outputs of the model.
            target_sizes (`List[Tuple]` of length `batch_size`, *optional*):
                List of tuples corresponding to the requested final size (height, width) of each prediction. If unset,
                predictions will not be resized.

        Returns:
            semantic_segmentation: `List[torch.Tensor]` of length `batch_size`, where each item is a semantic
            segmentation map of shape (height, width) corresponding to the target_sizes entry (if `target_sizes` is
            specified). Each entry of each `torch.Tensor` correspond to a semantic class id.
        """
        # TODO: add support for other frameworks
        logits = outputs.logits

        # Resize logits and compute semantic segmentation maps
        if target_sizes is not None:
            if len(logits) != len(target_sizes):
                raise ValueError(
                    "Make sure that you pass in as many target sizes as the batch dimension of the logits"
                )

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

            semantic_segmentation = []

            for idx in range(len(logits)):
                resized_logits = torch.nn.functional.interpolate(
                    logits[idx].unsqueeze(dim=0), size=target_sizes[idx], mode="bilinear", align_corners=False
                )
                semantic_map = resized_logits[0].argmax(dim=0)
                semantic_segmentation.append(semantic_map)
        else:
            semantic_segmentation = logits.argmax(dim=1)
            semantic_segmentation = [semantic_segmentation[i] for i in range(semantic_segmentation.shape[0])]

        return semantic_segmentation
