import signal, sys, objc
from AppKit import NSWorkspace
from Foundation import NSRunLoop, NSDate, NSObject
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)

class AppObserver(NSObject):
    def init(self):
        self = objc.super(AppObserver, self).init()
        self.dev = None
        self.last_app = None
        self.current_app = NSWorkspace.sharedWorkspace().frontmostApplication().localizedName()
        return self

    def appChanged_(self, notification):
        app = notification.userInfo()["NSWorkspaceApplicationKey"].localizedName()
        self.current_app = app
        if self.dev is not None:
            self.last_app = app
            print(f"App: {app}")
            try:
                send_app_name(self.dev, app)
            except Exception:
                print("Keyboard disconnected")
                self.dev = None
                self.last_app = None

def main():
    signal.signal(signal.SIGINT, lambda *_: sys.exit(0))
    ws = NSWorkspace.sharedWorkspace()

    observer = AppObserver.alloc().init()
    ws.notificationCenter().addObserver_selector_name_object_(
        observer, "appChanged:", "NSWorkspaceDidActivateApplicationNotification", None
    )

    while True:
        connected = find_keyboard_path() is not None

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

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

        # Pump run loop — notifications fire here and send immediately;
        # 2s is enough for connect/disconnect detection
        NSRunLoop.currentRunLoop().runUntilDate_(
            NSDate.dateWithTimeIntervalSinceNow_(2.0)
        )

if __name__ == "__main__":
    main()