from collections.abc import Sequence
from dataclasses import dataclass
from typing import Any, TypedDict

import numpy as np
import numpy.typing as npt
import torch
from jaxtyping import Bool
from torch import Tensor, nn

NDArrayUInt8 = npt.NDArray[np.uint8]
NDArray = npt.NDArray[Any]


class SAMInput(TypedDict):
    image: Tensor
    original_size: tuple[int, int]
    point_coords: Tensor | None
    point_labels: Tensor | None
    boxes: Tensor | None
    mask_inputs: Tensor | None


class SAMOutput(TypedDict):
    masks: Tensor
    iou_predictions: Tensor
    low_res_logits: Tensor


class FacebookSAM(nn.Module):
    image_encoder: nn.Module
    prompt_encoder: nn.Module
    mask_decoder: nn.Module

    def __call__(self, batched_input: list[SAMInput], multimask_output: bool) -> list[SAMOutput]:
        ...

    @property
    def device(self) -> Any:
        ...


class FacebookSAMPredictor:
    model: FacebookSAM

    def set_image(self, image: NDArrayUInt8, image_format: str = "RGB") -> None:
        ...

    def predict(
        self,
        point_coords: NDArray | None = None,
        point_labels: NDArray | None = None,
        box: NDArray | None = None,
        mask_input: NDArray | None = None,
        multimask_output: bool = True,
        return_logits: bool = False,
    ) -> tuple[NDArray, NDArray, NDArray]:
        ...


@dataclass
class SAMPrompt:
    foreground_points: Sequence[tuple[float, float]] | None = None
    background_points: Sequence[tuple[float, float]] | None = None
    box_points: Sequence[Sequence[tuple[float, float]]] | None = None
    # TODO: support masks
    # masks: Sequence[Image.Image] | None = None

    def facebook_predict_kwargs(self) -> dict[str, NDArray]:
        prompt: dict[str, NDArray] = {}
        # Note: the order matters since `points_to_tensor` processes points that way (background -> foreground -> etc)
        if self.background_points:
            prompt["point_coords"] = np.array(self.background_points)
            prompt["point_labels"] = np.array([0] * len(self.background_points))
        if self.foreground_points:
            coords = np.array(self.foreground_points)
            prompt["point_coords"] = (
                coords if "point_coords" not in prompt else np.concatenate((prompt["point_coords"], coords))
            )
            labels = np.array([1] * len(self.foreground_points))
            prompt["point_labels"] = (
                labels if "point_labels" not in prompt else np.concatenate((prompt["point_labels"], labels))
            )
        if self.box_points:
            prompt["box"] = np.array([coord for batch in self.box_points for xy in batch for coord in xy]).reshape(
                len(self.box_points), 4
            )
        return prompt

    def facebook_prompt_encoder_kwargs(self, device: torch.device | None = None):
        prompt = self.facebook_predict_kwargs()
        coords: Tensor | None = None
        labels: Tensor | None = None
        boxes: Tensor | None = None
        if "point_coords" in prompt:
            coords = torch.as_tensor(prompt["point_coords"], dtype=torch.float, device=device).unsqueeze(0)
        if "point_labels" in prompt:
            labels = torch.as_tensor(prompt["point_labels"], dtype=torch.int, device=device).unsqueeze(0)
        if "box" in prompt:
            boxes = torch.as_tensor(prompt["box"], dtype=torch.float, device=device).unsqueeze(0)
        points = (coords, labels) if coords is not None else None
        # TODO: support masks
        return {"points": points, "boxes": boxes, "masks": None}


def intersection_over_union(
    input_mask: Bool[Tensor, "height width"], other_mask: Bool[Tensor, "height width"]
) -> float:
    inter = (input_mask & other_mask).sum(dtype=torch.float32).item()
    union = (input_mask | other_mask).sum(dtype=torch.float32).item()
    return inter / union if union > 0 else 1.0