"""The dora event loop: one reading published per tick.

Every tick, changed or not. That is deliberate — the stream is also a heartbeat,
and it is what lets a consumer tell "the pad is being held still" from "this node
died". A consumer driving anything that moves needs both answers, and only one of
them can be inferred from silence.

Nothing here decides what a reading means. The pad is read in
:mod:`dora_joy.gamepad` and packed in :mod:`dora_joy.message`, and that is the
whole node.
"""

import argparse

from dora import Node

from dora_joy import message
from dora_joy.config import Config
from dora_joy.gamepad import Gamepad
from dora_joy.log import log


def main() -> None:
    """Start reading the pad and publish it until the tick closes."""
    args = _parse_args()
    config = Config.from_env()

    # 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)
    gamepad = Gamepad(config.joystick_index)
    gamepad.start()
    log(f"publishing joystick {config.joystick_index} on every tick")

    present = None

    try:
        for event in node:
            if event["type"] == "ERROR":
                raise RuntimeError(event["error"])
            if event["type"] == "INPUT_CLOSED" and event.get("id") == "tick":
                break
            if event["type"] != "INPUT" or event["id"] != "tick":
                continue

            sample = gamepad.read()
            # A pad arriving or going away is worth one line each; the readings
            # themselves are on the wire for anyone who wants them.
            if sample.present != present:
                present = sample.present
                log("gamepad connected" if present else "no gamepad")
            node.send_output("joy", message.pack(sample))
    finally:
        gamepad.shutdown()


def _parse_args() -> argparse.Namespace:
    """Read the node name, for when dora did not spawn us."""
    parser = argparse.ArgumentParser(description="Publish a gamepad's axes and buttons into a dataflow.")
    parser.add_argument(
        "--name",
        default="joy",
        help="The name of the node in the dataflow, used when running as a dynamic node.",
    )
    return parser.parse_args()


if __name__ == "__main__":
    main()