"""The display state: the frame, the overlays drawn on it, and the window."""

from dataclasses import dataclass, field

import cv2
import numpy as np

WINDOW = "Dora Node: opencv-plot"
GREEN = (0, 255, 0)
WHITE = (255, 255, 255)
FONT = cv2.FONT_HERSHEY_SIMPLEX
FONT_SCALE = 0.5


@dataclass
class Bboxes:
    """One overlay's worth of boxes, always stored as xyxy corners."""

    corners: np.ndarray = field(default_factory=lambda: np.empty((0, 4)))
    conf: np.ndarray = field(default_factory=lambda: np.empty(0))
    labels: np.ndarray = field(default_factory=lambda: np.empty(0, dtype=object))


@dataclass
class Plot:
    """Overlay state, plus the window it is displayed in.

    `headless` suppresses the window; the node still decodes every input.
    """

    width: int | None = None
    height: int | None = None
    headless: bool = False
    bboxes: Bboxes = field(default_factory=Bboxes)
    text: str = ""

    def show(self, frame: np.ndarray) -> bool:
        """Draw the overlays on `frame`, resize it, and display it.

        Returns whether the viewer asked to quit by pressing `q`.
        """
        self._draw(frame)

        if self.width and self.height:
            frame = cv2.resize(frame, (self.width, self.height))

        if self.headless:
            return False

        cv2.imshow(WINDOW, frame)
        return cv2.waitKey(1) & 0xFF == ord("q")

    def _draw(self, frame: np.ndarray) -> None:
        for corners, conf, label in zip(
            self.bboxes.corners,
            self.bboxes.conf,
            self.bboxes.labels,
            strict=False,
        ):
            min_x, min_y, max_x, max_y = (int(value) for value in corners)
            cv2.rectangle(frame, (min_x, min_y), (max_x, max_y), GREEN, 2)
            cv2.putText(
                frame,
                f"{label}, {conf:0.2f}",
                (max_x - 120, max_y - 10),
                FONT,
                FONT_SCALE,
                GREEN,
                1,
            )

        cv2.putText(frame, self.text, (20, 20), FONT, FONT_SCALE, WHITE, 1)