#!/usr/bin/env python3
"""A bot that names a unit which cannot act, on purpose.

The turn-order reply may carry a `unit`, and the host acts on that unit instead
of its own first-eligible pick. That opens a failure the harness has to refuse
rather than obey: a bot naming a unit MegaMek will not accept this turn. If the
host substituted its own pick silently, the decision log would say one machine
moved while another one did - the same failure class as an illegal path.

So this bot answers every question it is asked - it is not a passthrough, and
its decisions must not come back `defaulted` - and names a unit id that exists
in no game. Every movement and firing decision should come back `answered`, on
the host's own pick, with `substituted` equal to the number of those decisions,
and a line on stderr for each. Anything else means the refusal is not working.

No environment switch, because the harness passes the bot an allowlist of
variables and a test switch does not belong in it. This is a whole bot instead,
and it is named for the one thing it does.

    ./sds.sh one --sds-seat North --bot /work/bots/ineligible_bot.py
"""

import json
import sys

# Not a unit id. MegaMek numbers entities from zero and never negatively, so
# nothing in any game can collide with this.
INELIGIBLE = -99999


def main() -> None:
    for line in sys.stdin:
        line = line.strip()
        if not line:
            continue
        message = json.loads(line)
        if message.get("type") != "observation":
            continue
        phase = message.get("phase", "")
        reply = {"type": "action", "seq": message["seq"]}
        if phase == "MOVEMENT":
            # Stand still, but claim it is for a unit that cannot act. An empty
            # step list is a legal path, so the only thing left for the host to
            # object to is the unit.
            reply.update({"kind": "move", "steps": [], "unit": INELIGIBLE})
        elif phase == "FIRING":
            reply.update({"kind": "fire", "attacks": [], "unit": INELIGIBLE})
        else:
            reply["kind"] = "pass"
        sys.stdout.write(json.dumps(reply) + "\n")
        sys.stdout.flush()


if __name__ == "__main__":
    main()