"""A dora display sink: overlays bounding boxes and text on an image input.

An `image` event decodes the frame and immediately redraws. `bbox` and `text`
events only update stored state, which the next `image` event draws.
"""

import argparse
import os

from dora import Node

from opencv_plot import bbox, decode
from opencv_plot.plot import Plot


def main() -> None:
    """Connect to the dataflow and display every frame that arrives."""
    args = _parse_args()

    plot = Plot(
        width=_size("PLOT_WIDTH", args.plot_width),
        height=_size("PLOT_HEIGHT", args.plot_height),
        headless=os.getenv("CI") == "true",
    )

    # Passing the name lets the node also run standalone as a dynamic node; when
    # dora spawns it, the id from the dataflow wins.
    node = Node(args.name)

    for event in node:
        if event["type"] == "ERROR":
            raise RuntimeError(event["error"])
        if event["type"] != "INPUT":
            continue

        event_id = event["id"]
        metadata = event["metadata"]

        if event_id == "image":
            frame = decode.to_bgr(
                event["value"],
                metadata.get("encoding", "bgr8").lower(),
                metadata.get("width"),
                metadata.get("height"),
            )
            if plot.show(frame):
                break
        elif event_id == "bbox":
            plot.bboxes = bbox.parse(event["value"], metadata.get("format", "xyxy").lower())
        elif event_id == "text":
            plot.text = event["value"][0].as_py()
        else:
            print(f"ignoring unexpected input `{event_id}`")


def _parse_args() -> argparse.Namespace:
    parser = argparse.ArgumentParser(
        description="OpenCV plotter: draws text and bounding boxes on an image.",
    )
    parser.add_argument(
        "--name",
        default="opencv-plot",
        help="The name of the node in the dataflow, used when running as a dynamic node.",
    )
    parser.add_argument(
        "--plot-width",
        type=int,
        help="Resize the displayed frame to this width. Overridden by PLOT_WIDTH.",
    )
    parser.add_argument(
        "--plot-height",
        type=int,
        help="Resize the displayed frame to this height. Overridden by PLOT_HEIGHT.",
    )
    return parser.parse_args()


def _size(name: str, fallback: int | None) -> int | None:
    value = os.getenv(name)
    return int(value) if value and value.isnumeric() else fallback


if __name__ == "__main__":
    main()