#!/usr/bin/python3
"""ft-gazectl: turn the gaze pointer on or off, and ask the gaze service how it's doing.

  ft-gazectl on|off|toggle   gaze mode in the pointer helper (until it restarts; the
                             setting is POINTER_GAZE in ~/.config/frametop.conf)
  ft-gazectl status          the gaze service (ft-gazed): samples, lessons, the correction
  ft-gazectl forget          drop what the pointer's lessons taught (the calibration stays)
  ft-gazectl reload          the service reads calibration.json again
"""

import json
import os
import socket
import sys


def ask(name, msg, timeout=1.0):
    s = socket.socket(socket.AF_UNIX, socket.SOCK_DGRAM | socket.SOCK_CLOEXEC)
    s.bind(f"\0ft_gazectl.{os.getpid()}")
    s.settimeout(timeout)
    try:
        s.sendto(msg.encode(), "\0" + name)
        return s.recv(4096).decode()
    except ConnectionRefusedError:
        return None
    except socket.timeout:
        return ""
    finally:
        s.close()


def main():
    cmd = sys.argv[1] if len(sys.argv) > 1 else "status"
    if cmd in ("on", "off", "toggle"):
        r = ask("ft_pointer_helper", f"gaze {cmd}")
        if r is None:
            sys.exit("the pointer helper isn't running")
        print(f"gaze mode {r.removeprefix('ok ')}" if r else "no answer (an older pointer helper without gaze mode?)")
        if ask("ft_gazed", "status", 0.3) is None:
            print("note: the gaze service (ft-gazed) isn't running, so the pointer has no gaze to follow")
    elif cmd in ("status", "forget", "reload"):
        r = ask("ft_gazed", cmd)
        if r is None:
            sys.exit("the gaze service (ft-gazed) isn't running")
        try:
            print(json.dumps(json.loads(r), indent=1))
        except ValueError:
            print(r)
    else:
        sys.exit(__doc__)


if __name__ == "__main__":
    main()