#!/usr/bin/env python3
"""stay_active.py — keep Microsoft Teams (and any OS-idle-based presence) showing 'Available'.

Teams marks you 'Away' when the OS reports no keyboard/mouse activity for ~5 minutes.
This tool resets the X11 idle timer periodically by tapping a harmless key (F15 by
default — it has no visible effect and is not bound to anything on a normal desktop).

No third-party packages required: it calls the X11 XTest extension directly via ctypes.
X11 sessions only (XDG_SESSION_TYPE=x11). Press Ctrl+C to stop.
"""

import argparse
import ctypes
import os
import sys
import time

# --- X11 / XTest bindings via ctypes -----------------------------------------

try:
    _x11 = ctypes.CDLL("libX11.so.6")
    _xtst = ctypes.CDLL("libXtst.so.6")
except OSError as e:
    sys.exit(f"Could not load X11 libraries: {e}\nThis tool requires an X11 session.")

_x11.XOpenDisplay.restype = ctypes.c_void_p
_x11.XOpenDisplay.argtypes = [ctypes.c_char_p]
_x11.XKeysymToKeycode.restype = ctypes.c_uint
_x11.XKeysymToKeycode.argtypes = [ctypes.c_void_p, ctypes.c_ulong]
_x11.XFlush.argtypes = [ctypes.c_void_p]
_xtst.XTestFakeKeyEvent.argtypes = [
    ctypes.c_void_p, ctypes.c_uint, ctypes.c_int, ctypes.c_ulong
]
_xtst.XTestFakeRelativeMotionEvent.argtypes = [
    ctypes.c_void_p, ctypes.c_int, ctypes.c_int, ctypes.c_ulong
]

# X keysyms for a few no-op keys. F15 is the safest default.
KEYSYMS = {
    "f13": 0xFFCA,
    "f14": 0xFFCB,
    "f15": 0xFFCC,
    "shift": 0xFFE1,  # Shift_L — no character, but modifies if held with another key
}


def open_display():
    disp = _x11.XOpenDisplay(None)
    if not disp:
        display = os.environ.get("DISPLAY", "(unset)")
        sys.exit(f"Could not open X display (DISPLAY={display}). Run inside your desktop session.")
    return disp


def tap_key(disp, keycode):
    _xtst.XTestFakeKeyEvent(disp, keycode, True, 0)   # press
    _xtst.XTestFakeKeyEvent(disp, keycode, False, 0)  # release
    _x11.XFlush(disp)


def nudge_mouse(disp):
    # Move 1px, then back — resets the idle timer without the cursor visibly moving.
    _xtst.XTestFakeRelativeMotionEvent(disp, 1, 0, 0)
    _xtst.XTestFakeRelativeMotionEvent(disp, -1, 0, 0)
    _x11.XFlush(disp)


def main():
    p = argparse.ArgumentParser(description="Keep Teams presence 'Available' by resetting the idle timer.")
    p.add_argument("-i", "--interval", type=float, default=120,
                   help="seconds between key taps (default: 120; keep under Teams' ~300s Away threshold)")
    p.add_argument("-m", "--method", choices=["mouse", "key"], default="mouse",
                   help="how to signal activity (default: mouse — a 1px nudge that returns)")
    p.add_argument("-k", "--key", choices=KEYSYMS.keys(), default="shift",
                   help="key to tap when --method key is used (default: shift — always mapped)")
    p.add_argument("-q", "--quiet", action="store_true", help="don't print heartbeat messages")
    args = p.parse_args()

    if os.environ.get("XDG_SESSION_TYPE", "").lower() not in ("x11", ""):
        print(f"Warning: session type is '{os.environ.get('XDG_SESSION_TYPE')}', not x11. "
              "XTest may not reset the idle timer under Wayland.", file=sys.stderr)

    disp = open_display()

    if args.method == "key":
        keycode = _x11.XKeysymToKeycode(disp, KEYSYMS[args.key])
        if keycode == 0:
            sys.exit(f"Key '{args.key}' has no keycode on this layout. Try --method mouse.")
        action = lambda: tap_key(disp, keycode)
        label = f"tapping '{args.key}'"
    else:
        action = lambda: nudge_mouse(disp)
        label = "nudging mouse 1px"

    if not args.quiet:
        print(f"stay_active: {label} every {args.interval:g}s. Press Ctrl+C to stop.")

    taps = 0
    try:
        while True:
            action()
            taps += 1
            if not args.quiet:
                print(f"\r  active — {taps} signal(s) sent, last at {time.strftime('%H:%M:%S')}",
                      end="", flush=True)
            time.sleep(args.interval)
    except KeyboardInterrupt:
        if not args.quiet:
            print("\nstay_active: stopped.")


if __name__ == "__main__":
    main()