from __future__ import annotations

from typing import Any, List, Optional, Sequence, Tuple, Union

import torch
from torchvision._utils import StrEnum
from torchvision.transforms import InterpolationMode
from torchvision.transforms.functional import _get_inverse_affine_matrix
from torchvision.transforms.functional_tensor import _compute_output_size

from ._feature import _Feature


class BoundingBoxFormat(StrEnum):
    XYXY = StrEnum.auto()
    XYWH = StrEnum.auto()
    CXCYWH = StrEnum.auto()


class BoundingBox(_Feature):
    format: BoundingBoxFormat
    image_size: Tuple[int, int]

    def __new__(
        cls,
        data: Any,
        *,
        format: Union[BoundingBoxFormat, str],
        image_size: Tuple[int, int],
        dtype: Optional[torch.dtype] = None,
        device: Optional[Union[torch.device, str, int]] = None,
        requires_grad: bool = False,
    ) -> BoundingBox:
        bounding_box = super().__new__(cls, data, dtype=dtype, device=device, requires_grad=requires_grad)

        if isinstance(format, str):
            format = BoundingBoxFormat.from_str(format.upper())
        bounding_box.format = format

        bounding_box.image_size = image_size

        return bounding_box

    @classmethod
    def new_like(
        cls,
        other: BoundingBox,
        data: Any,
        *,
        format: Optional[Union[BoundingBoxFormat, str]] = None,
        image_size: Optional[Tuple[int, int]] = None,
        **kwargs: Any,
    ) -> BoundingBox:
        return super().new_like(
            other,
            data,
            format=format if format is not None else other.format,
            image_size=image_size if image_size is not None else other.image_size,
            **kwargs,
        )

    def to_format(self, format: Union[str, BoundingBoxFormat]) -> BoundingBox:
        # TODO: this is useful for developing and debugging but we should remove or at least revisit this before we
        #  promote this out of the prototype state

        # import at runtime to avoid cyclic imports
        from torchvision.prototype.transforms.functional import convert_bounding_box_format

        if isinstance(format, str):
            format = BoundingBoxFormat.from_str(format.upper())

        return BoundingBox.new_like(
            self, convert_bounding_box_format(self, old_format=self.format, new_format=format), format=format
        )

    def horizontal_flip(self) -> BoundingBox:
        from torchvision.prototype.transforms import functional as _F

        output = _F.horizontal_flip_bounding_box(self, format=self.format, image_size=self.image_size)
        return BoundingBox.new_like(self, output)

    def vertical_flip(self) -> BoundingBox:
        from torchvision.prototype.transforms import functional as _F

        output = _F.vertical_flip_bounding_box(self, format=self.format, image_size=self.image_size)
        return BoundingBox.new_like(self, output)

    def resize(  # type: ignore[override]
        self,
        size: List[int],
        interpolation: InterpolationMode = InterpolationMode.BILINEAR,
        max_size: Optional[int] = None,
        antialias: bool = False,
    ) -> BoundingBox:
        from torchvision.prototype.transforms import functional as _F

        output = _F.resize_bounding_box(self, size, image_size=self.image_size, max_size=max_size)
        image_size = (size[0], size[0]) if len(size) == 1 else (size[0], size[1])
        return BoundingBox.new_like(self, output, image_size=image_size, dtype=output.dtype)

    def crop(self, top: int, left: int, height: int, width: int) -> BoundingBox:
        from torchvision.prototype.transforms import functional as _F

        output = _F.crop_bounding_box(self, self.format, top, left)
        return BoundingBox.new_like(self, output, image_size=(height, width))

    def center_crop(self, output_size: List[int]) -> BoundingBox:
        from torchvision.prototype.transforms import functional as _F

        output = _F.center_crop_bounding_box(
            self, format=self.format, output_size=output_size, image_size=self.image_size
        )
        image_size = (output_size[0], output_size[0]) if len(output_size) == 1 else (output_size[0], output_size[1])
        return BoundingBox.new_like(self, output, image_size=image_size)

    def resized_crop(
        self,
        top: int,
        left: int,
        height: int,
        width: int,
        size: List[int],
        interpolation: InterpolationMode = InterpolationMode.BILINEAR,
        antialias: bool = False,
    ) -> BoundingBox:
        from torchvision.prototype.transforms import functional as _F

        output = _F.resized_crop_bounding_box(self, self.format, top, left, height, width, size=size)
        image_size = (size[0], size[0]) if len(size) == 1 else (size[0], size[1])
        return BoundingBox.new_like(self, output, image_size=image_size, dtype=output.dtype)

    def pad(
        self,
        padding: Union[int, Sequence[int]],
        fill: Optional[Union[int, float, Sequence[int], Sequence[float]]] = None,
        padding_mode: str = "constant",
    ) -> BoundingBox:
        from torchvision.prototype.transforms import functional as _F

        if padding_mode not in ["constant"]:
            raise ValueError(f"Padding mode '{padding_mode}' is not supported with bounding boxes")

        # This cast does Sequence[int] -> List[int] and is required to make mypy happy
        if not isinstance(padding, int):
            padding = list(padding)

        output = _F.pad_bounding_box(self, padding, format=self.format)

        # Update output image size:
        # TODO: remove the import below and make _parse_pad_padding available
        from torchvision.transforms.functional_tensor import _parse_pad_padding

        left, top, right, bottom = _parse_pad_padding(padding)
        height, width = self.image_size
        height += top + bottom
        width += left + right

        return BoundingBox.new_like(self, output, image_size=(height, width))

    def rotate(
        self,
        angle: float,
        interpolation: InterpolationMode = InterpolationMode.NEAREST,
        expand: bool = False,
        fill: Optional[Union[int, float, Sequence[int], Sequence[float]]] = None,
        center: Optional[List[float]] = None,
    ) -> BoundingBox:
        from torchvision.prototype.transforms import functional as _F

        output = _F.rotate_bounding_box(
            self, format=self.format, image_size=self.image_size, angle=angle, expand=expand, center=center
        )
        image_size = self.image_size
        if expand:
            # The way we recompute image_size is not optimal due to redundant computations of
            # - rotation matrix (_get_inverse_affine_matrix)
            # - points dot matrix (_compute_output_size)
            # Alternatively, we could return new image size by _F.rotate_bounding_box
            height, width = image_size
            rotation_matrix = _get_inverse_affine_matrix([0.0, 0.0], angle, [0.0, 0.0], 1.0, [0.0, 0.0])
            new_width, new_height = _compute_output_size(rotation_matrix, width, height)
            image_size = (new_height, new_width)

        return BoundingBox.new_like(self, output, dtype=output.dtype, image_size=image_size)

    def affine(
        self,
        angle: float,
        translate: List[float],
        scale: float,
        shear: List[float],
        interpolation: InterpolationMode = InterpolationMode.NEAREST,
        fill: Optional[Union[int, float, Sequence[int], Sequence[float]]] = None,
        center: Optional[List[float]] = None,
    ) -> BoundingBox:
        from torchvision.prototype.transforms import functional as _F

        output = _F.affine_bounding_box(
            self,
            self.format,
            self.image_size,
            angle,
            translate=translate,
            scale=scale,
            shear=shear,
            center=center,
        )
        return BoundingBox.new_like(self, output, dtype=output.dtype)

    def perspective(
        self,
        perspective_coeffs: List[float],
        interpolation: InterpolationMode = InterpolationMode.BILINEAR,
        fill: Optional[Union[int, float, Sequence[int], Sequence[float]]] = None,
    ) -> BoundingBox:
        from torchvision.prototype.transforms import functional as _F

        output = _F.perspective_bounding_box(self, self.format, perspective_coeffs)
        return BoundingBox.new_like(self, output, dtype=output.dtype)

    def elastic(
        self,
        displacement: torch.Tensor,
        interpolation: InterpolationMode = InterpolationMode.BILINEAR,
        fill: Optional[Union[int, float, Sequence[int], Sequence[float]]] = None,
    ) -> BoundingBox:
        from torchvision.prototype.transforms import functional as _F

        output = _F.elastic_bounding_box(self, self.format, displacement)
        return BoundingBox.new_like(self, output, dtype=output.dtype)
