from dataclasses import dataclass, field
from typing import Generic, Optional, TypeVar

import cv2
import imgutils
import numpy as np
from imgutils.generic.yolo import (
    _image_preprocess,
    _rtdetr_postprocess,
    _yolo_postprocess,
    rgb_encode,
)
from PIL import Image, ImageDraw

T = TypeVar("T", int, float)

REPO_IDS = {
    "head": "deepghs/anime_head_detection",
    "face": "deepghs/anime_face_detection",
    "eye": "deepghs/anime_eye_detection",
}


@dataclass
class DetectorOutput(Generic[T]):
    bboxes: list[list[T]] = field(default_factory=list)
    masks: list[Image.Image] = field(default_factory=list)
    confidences: list[float] = field(default_factory=list)
    previews: Optional[Image.Image] = None


class AnimeDetector:
    """
    A class used to perform object detection on anime images.
    Please refer to the `imgutils` documentation for more information on the available models.
    """

    def __init__(self, repo_id: str, model_name: str, hf_token: Optional[str] = None):
        model_manager = imgutils.generic.yolo._open_models_for_repo_id(
            repo_id, hf_token=hf_token
        )
        model, max_infer_size, labels = model_manager._open_model(model_name)

        self.model = model

        self.max_infer_size = max_infer_size
        self.labels = labels
        self.model_type = model_manager._get_model_type(model_name)

    def __call__(
        self,
        image: Image.Image,
        conf_threshold: float = 0.3,
        iou_threshold: float = 0.7,
        allow_dynamic: bool = False,
    ) -> DetectorOutput[float]:
        """
        Perform object detection on the given image.

        Args:
            image (Image.Image): The input image on which to perform detection.
            conf_threshold (float, optional): Confidence threshold for detection. Defaults to 0.3.
            iou_threshold (float, optional): Intersection over Union (IoU) threshold for detection. Defaults to 0.7.
            allow_dynamic (bool, optional): Whether to allow dynamic resizing of the image. Defaults to False.

        Returns:
            DetectorOutput[float]: The detection results, including bounding boxes, masks, confidences, and a preview image.

        Raises:
            ValueError: If the model type is unknown.
        """
        # Preprocessing
        new_image, old_size, new_size = _image_preprocess(
            image, self.max_infer_size, allow_dynamic=allow_dynamic
        )
        data = rgb_encode(new_image)[None, ...]

        # Start detection
        (output,) = self.model.run(["output0"], {"images": data})

        # Postprocessing
        if self.model_type == "yolo":
            output = _yolo_postprocess(
                output=output[0],
                conf_threshold=conf_threshold,
                iou_threshold=iou_threshold,
                old_size=old_size,
                new_size=new_size,
                labels=self.labels,
            )
        elif self.model_type == "rtdetr":
            output = _rtdetr_postprocess(
                output=output[0],
                conf_threshold=conf_threshold,
                iou_threshold=iou_threshold,
                old_size=old_size,
                new_size=new_size,
                labels=self.labels,
            )
        else:
            raise ValueError(
                f"Unknown object detection model type - {self.model_type!r}."
            )  # pragma: no cover

        if len(output) == 0:
            return DetectorOutput()

        bboxes = [x[0] for x in output]  # [x0, y0, x1, y1]
        masks = create_mask_from_bbox(bboxes, image.size)
        confidences = [x[2] for x in output]

        # Create a preview image
        previews = []
        for mask in masks:
            np_image = np.array(image)
            np_mask = np.array(mask)
            preview = cv2.bitwise_and(
                np_image, cv2.cvtColor(np_mask, cv2.COLOR_GRAY2BGR)
            )
            preview = Image.fromarray(preview)
            previews.append(preview)

        return DetectorOutput(
            bboxes=bboxes, masks=masks, confidences=confidences, previews=previews
        )


def create_mask_from_bbox(
    bboxes: list[list[float]], shape: tuple[int, int]
) -> list[Image.Image]:
    """
    Creates a list of binary masks from bounding boxes.

    Args:
        bboxes (list[list[float]]): A list of bounding boxes, where each bounding box is represented
                                    by a list of four float values [x_min, y_min, x_max, y_max].
        shape (tuple[int, int]): The shape of the mask (height, width).

    Returns:
        list[Image.Image]: A list of PIL Image objects representing the binary masks.
    """
    masks = []
    for bbox in bboxes:
        mask = Image.new("L", shape, 0)
        mask_draw = ImageDraw.Draw(mask)
        mask_draw.rectangle(bbox, fill=255)
        masks.append(mask)
    return masks


def create_bbox_from_mask(
    masks: list[Image.Image], shape: tuple[int, int]
) -> list[list[int]]:
    """
    Create bounding boxes from a list of mask images.

    Args:
        masks (list[Image.Image]): A list of PIL Image objects representing the masks.
        shape (tuple[int, int]): A tuple representing the desired shape (width, height) to resize the masks.

    Returns:
        list[list[int]]: A list of bounding boxes, where each bounding box is represented as a list of four integers [left, upper, right, lower].
    """
    bboxes = []
    for mask in masks:
        mask = mask.resize(shape)
        bbox = mask.getbbox()
        if bbox is not None:
            bboxes.append(list(bbox))
    return bboxes