// Copyright 2026 rootiest
// SPDX-License-Identifier: GPL-3.0-or-later

//! Active application / window monitor — **reserved, not yet implemented**.
//!
//! When implemented this module will detect the active window on a KDE6
//! Wayland desktop and send `CMD_ACTIVE_APP` (0x43) packets containing the
//! application name (null-terminated UTF-8, max 28 bytes) to all connected
//! keyboards.
//!
//! # Implementation notes for KDE6 / Wayland
//!
//! Candidate approaches (to evaluate during the brainstorming phase):
//!
//! 1. **KWin D-Bus interface** — `org.kde.KWin` exposes `activeWindow()` on
//!    the scripting API.  The window object has `resourceName` / `caption`
//!    properties.  Can subscribe to `windowActivated` signal.
//!    → easiest; requires D-Bus session access.
//!
//! 2. **KWin Script** — inject a tiny `.kwinscript` that emits a custom
//!    D-Bus signal or writes to a FIFO on `windowActivated`.
//!    → portable across KWin versions; slightly invasive.
//!
//! 3. **`xdg-foreign` / `wlr-foreign-toplevel`** — Wayland protocols for
//!    enumerating toplevels.  KWin supports `ext-foreign-toplevel-list-v1`.
//!    → protocol-level, no D-Bus, but requires a Wayland client loop.
//!
//! 4. **`qdbus6` / `busctl` polling** — parse output of
//!    `busctl call org.kde.KWin /KWin org.kde.KWin activeWindow`
//!    in a poll loop.  Simple but coarse.
//!
//! The chosen approach will be implemented here once the brainstorming is
//! complete.  The `Packet::active_app()` constructor in `protocol.rs` is
//! already in place.

use log::info;

use crate::keyboard::Keyboard;

/// Monitor the active application and notify keyboards.
/// Currently a no-op stub — safe to call, does nothing.
pub fn monitor(_keyboards: Vec<Keyboard>) {
    info!("Active-application monitor: not yet implemented (stub)");
    // Future: block here in an event loop and send Packet::active_app()
    // packets to keyboards whenever the active window changes.
}