"""A minimal caller: what using the node's services looks like.

Run by `dataflow.yml`. It sends a motion with `wait: false`, follows it on
`motion_state`, and then sends a second one that preempts it. That is the whole
convention:

- a request carries a `request_id` you choose, and gets exactly one `response`
  under that id — an acknowledgement when `wait` is false, the outcome when it
  is true;
- a motion's progress is on `motion_state`, keyed by the same request_id, so a
  non-blocking caller can tell "mine has not started" from "mine has finished"
  without a race;
- a new motion replaces the one in play, because the arm is one resource.
"""

import pyarrow as pa
from dora import Node


def main() -> None:
    """Send a non-blocking motion, follow it, preempt it, and exit."""
    node = Node("caller")
    sent_first = False
    sent_second = False

    for event in node:
        if event["type"] != "INPUT":
            continue

        if event["id"] == "tick" and not sent_first:
            sent_first = True
            _move(node, "move-1", z=200.0)

        elif event["id"] == "response":
            row = event["value"][0].as_py()
            print(
                f"response to {event['metadata'].get('request_id')}: "
                f"ok={row['ok']} {row['message']}",
                flush=True,
            )

        elif event["id"] == "motion_state":
            row = event["value"][0].as_py()
            print(f"{row['request_id']} is {row['state']}", flush=True)

            # Once the first one is really under way, change our mind.
            if row["request_id"] == "move-1" and row["state"] == "moving" and not sent_second:
                sent_second = True
                _move(node, "move-2", z=120.0)
            elif row["request_id"] == "move-2" and row["state"] in ("done", "failed"):
                break


def _move(node: Node, request_id: str, z: float) -> None:
    """Ask for a move and come straight back, rather than waiting it out."""
    node.send_output(
        "request",
        pa.array([{"service": "move_to", "x": 250.0, "y": 0.0, "z": z, "wait": False}]),
        metadata={"request_id": request_id},
    )


if __name__ == "__main__":
    main()