import signal, sys
from AppKit import NSWorkspace
from Foundation import NSRunLoop, NSDate
import hid

VID, PID = 0x3384, 0x0009
USAGE_PAGE, USAGE = 0xFF60, 0x61
CMD_SET_FOCUSED_APP = 0x80

def find_keyboard_path():
    for info in hid.enumerate(VID, PID):
        if info["usage_page"] == USAGE_PAGE and info["usage"] == USAGE:
            return info["path"]
    return None

def send_app_name(dev, name):
    payload = name.encode("utf-8", errors="ignore")[:31]
    payload = payload.decode("utf-8", errors="ignore").encode("utf-8")
    data = bytes([0x00, CMD_SET_FOCUSED_APP]) + payload + b"\x00" * (32 - 1 - len(payload))
    dev.write(data)
    dev.read(32, timeout=1000)

def main():
    signal.signal(signal.SIGINT, lambda *_: sys.exit(0))
    ws = NSWorkspace.sharedWorkspace()
    dev = None
    last_app = None

    while True:
        connected = find_keyboard_path() is not None

        # Detect disconnect
        if dev is not None and not connected:
            print("Keyboard disconnected")
            dev = None
            last_app = None

        # Connect and send current app
        if dev is None and connected:
            try:
                dev = hid.Device(path=find_keyboard_path())
                print("Keyboard connected")
                last_app = ws.frontmostApplication().localizedName()
                print(f"App: {last_app}")
                send_app_name(dev, last_app)
            except Exception:
                dev = None

        # App change
        if dev is not None:
            app = ws.frontmostApplication().localizedName()
            if app != last_app:
                print(f"App: {app}")
                last_app = app
                try:
                    send_app_name(dev, app)
                except Exception:
                    print("Keyboard disconnected")
                    dev = None
                    last_app = None

        NSRunLoop.currentRunLoop().runUntilDate_(
            NSDate.dateWithTimeIntervalSinceNow_(0.25)
        )

if __name__ == "__main__":
    main()