Underlay/src/linux/mod.rs

use std::sync::{atomic::AtomicPtr, Arc, Mutex};

use x11rb::{
    connect,
    connection::Connection,
    protocol::{
        xproto::{
            self, Atom, AtomEnum, ChangeWindowAttributesAux, ClientMessageData, ClientMessageEvent,
            ConnectionExt, EventMask, Window,
        },
        Event,
    },
    rust_connection::RustConnection,
};

use crate::{Bounds, UnderlayEvent};

const WM_NAME_BUFSIZE: u32 = 512;

static TARGET: AtomicPtr<Arc<Mutex<Window>>> = AtomicPtr::new(std::ptr::null_mut());

struct Target {
    title: String,
    wid: Window,
    is_focused: bool,
    is_destroyed: bool,
    is_fullscreen: bool,
}

struct AtomCollection {
    net_active_window: Atom,
    net_wm_name: Atom,
    utf8_string: Atom,
    net_wm_state: Atom,
    net_wm_state_fullscreen: Atom,
    // net_wm_state_skip_taskbar: Atom,
    // net_wm_state_skip_pager: Atom,
}
impl AtomCollection {
    fn new(conn: &RustConnection) -> Option<Self> {
        Some(Self {
            net_active_window: get_atom(conn, "_NET_ACTIVE_WINDOW")?,
            net_wm_name: get_atom(conn, "_NET_WM_NAME")?,
            utf8_string: get_atom(conn, "UTF8_STRING")?,
            net_wm_state: get_atom(conn, "_NET_WM_STATE")?,
            net_wm_state_fullscreen: get_atom(conn, "_NET_WM_STATE_FULLSCREEN")?,
            // net_wm_state_skip_taskbar: Self::_get(conn, "_NET_WM_STATE_SKIP_TASKBAR")?,
            // net_wm_state_skip_pager: Self::_get(conn, "_NET_WM_STATE_SKIP_PAGER")?,
        })
    }
}

fn get_atom<T: Into<String>>(conn: &RustConnection, name: T) -> Option<Atom> {
    Some(
        conn.intern_atom(false, name.into().as_bytes())
            .ok()?
            .reply()
            .ok()?
            .atom,
    )
}

//Not very pretty and a bit wasteful making a new connection and getting the atom every time..
pub fn focus_target() {
    unsafe {
        if let Ok(target) = (*TARGET.load(std::sync::atomic::Ordering::SeqCst)).lock() {
            if *target != x11rb::NONE {
                if let Ok((conn, _screen_num)) = connect(None) {
                    let net_active_window = get_atom(&conn, "_NET_ACTIVE_WINDOW").unwrap();

                    let event = ClientMessageEvent {
                        response_type: xproto::CLIENT_MESSAGE_EVENT,
                        format: 32,
                        sequence: 0,
                        window: *target,
                        type_: net_active_window,
                        data: ClientMessageData::from([1, x11rb::CURRENT_TIME, 0, 0, 0]),
                    };

                    if let Ok(cookie) = conn.send_event(
                        false,
                        conn.setup().roots[_screen_num].root,
                        EventMask::SUBSTRUCTURE_NOTIFY | EventMask::SUBSTRUCTURE_REDIRECT,
                        event,
                    ) {
                        if let Err(e) = cookie.check() {
                            log::error!("Error focusing target: {e:?}");
                        }
                    }

                    conn.flush().ok();
                }
            }
        }
    }
}

struct Runtime {
    conn: RustConnection,
    root: Window,
    target: Target,
    atoms: AtomCollection,
    underlay_tx: std::sync::mpsc::Sender<UnderlayEvent>,
    active: Window,
}

impl Runtime {
    fn get_active_window(&self) -> Option<Window> {
        let cookie = self
            .conn
            .get_property(
                false,
                self.root,
                self.atoms.net_active_window,
                AtomEnum::WINDOW,
                0,
                1,
            )
            .ok()?;

        let reply = cookie.reply().ok()?;

        let mut value32_iter = reply.value32()?;

        value32_iter.next()
    }

    ///Using this instead to allow setting the globally accessible target too for focus_target.
    fn set_target(&mut self, wid: Window) {
        self.target.wid = wid;
        unsafe {
            if let Ok(mut target) = (*TARGET.load(std::sync::atomic::Ordering::Relaxed)).lock() {
                *target = wid;
            }
        }
    }

    fn get_title(&self, wid: Window) -> Option<String> {
        if wid == x11rb::NONE {
            return None;
        }

        let cookie = self
            .conn
            .get_property(
                false,
                wid,
                self.atoms.net_wm_name,
                self.atoms.utf8_string,
                0,
                WM_NAME_BUFSIZE,
            )
            .ok()?;

        let reply = cookie.reply().ok()?;

        let data = reply.value8()?.collect();

        String::from_utf8(data).ok()
    }

    fn get_content_bounds(&self, wid: Window) -> Option<Bounds> {
        let geometry_cookie = self.conn.get_geometry(wid).ok()?;
        let geometry_reply = geometry_cookie.reply().ok()?;

        let translation_cookie = self.conn.translate_coordinates(wid, self.root, 0, 0).ok()?;
        let translation_reply = translation_cookie.reply().ok()?;

        Some(Bounds {
            x: translation_reply.dst_x as i32,
            y: translation_reply.dst_y as i32,
            width: geometry_reply.width as i32,
            height: geometry_reply.height as i32,
        })
    }

    fn is_fullscreen_window(&self, wid: Window) -> Option<bool> {
        let cookie = self
            .conn
            .get_property(false, wid, self.atoms.net_wm_state, AtomEnum::ATOM, 0, 0)
            .ok()?;
        let reply = cookie.reply().ok()?;

        let len = reply.value32()?.count();

        let cookie = self
            .conn
            .get_property(
                false,
                wid,
                self.atoms.net_wm_state,
                AtomEnum::ATOM,
                0,
                len as u32,
            )
            .ok()?;
        let reply = cookie.reply().ok()?;

        let mut is_fullscreen = false;

        for state in reply.value32()? {
            is_fullscreen = state == self.atoms.net_wm_state_fullscreen;
        }

        Some(is_fullscreen)
    }

    fn handle_moveresize_xevent(&self) {
        if let Some(bounds) = self.get_content_bounds(self.target.wid) {
            self.underlay_tx
                .send(UnderlayEvent::MoveResize(bounds))
                .ok();
        }
    }

    fn handle_fullscreen_xevent(&mut self) {
        if let Some(is_fullscreen) = self.is_fullscreen_window(self.target.wid) {
            if self.target.is_fullscreen != is_fullscreen {
                self.target.is_fullscreen = is_fullscreen;
                self.underlay_tx
                    .send(UnderlayEvent::X11FullscreenEvent { is_fullscreen })
                    .ok();
            }
        }
    }

    fn check_and_handle_window(&mut self, wid: Window) {
        if self.target.wid != x11rb::NONE {
            if self.target.wid == wid {
                if !self.target.is_focused {
                    self.target.is_focused = true;
                    self.underlay_tx.send(UnderlayEvent::Focus).ok();
                }
                return;
            }

            if self.target.is_focused {
                self.target.is_focused = false;
                self.underlay_tx.send(UnderlayEvent::Blur).ok();
            }

            if self.target.is_destroyed {
                self.set_target(x11rb::NONE);

                self.target.is_destroyed = false;
                self.underlay_tx.send(UnderlayEvent::Detach).ok();
            }
        }
        log::trace!(
            "got title: {}",
            self.get_title(wid).unwrap_or("ERROR".into())
        );
        match self.get_title(wid) {
            Some(title) => {
                if title != self.target.title {
                    return;
                }
            }
            _ => return,
        }

        log::trace!("Found target!");

        if self.target.wid != x11rb::NONE {
            self.conn
                .change_window_attributes(
                    self.target.wid,
                    &ChangeWindowAttributesAux::new().event_mask(EventMask::NO_EVENT),
                )
                .ok();
        }

        self.set_target(wid);

        self.conn
            .change_window_attributes(
                wid,
                &ChangeWindowAttributesAux::new()
                    .event_mask(EventMask::PROPERTY_CHANGE | EventMask::STRUCTURE_NOTIFY),
            )
            .ok();
        if let Some(is_fullscreen) = self.is_fullscreen_window(self.target.wid) {
            if let Some(bounds) = self.get_content_bounds(self.target.wid) {
                if is_fullscreen != self.target.is_fullscreen {
                    self.target.is_fullscreen = is_fullscreen;
                }
                self.underlay_tx
                    .send(UnderlayEvent::Attach {
                        bounds,
                        has_access: None,
                        is_fullscreen: Some(is_fullscreen),
                    })
                    .ok();

                self.target.is_focused = true;
                self.underlay_tx.send(UnderlayEvent::Focus).ok();
                //Early return to not unset target wid
                return;
            }
        }

        self.set_target(x11rb::NONE);
    }

    fn handle_event(&mut self, event: Event) {
        match event {
            Event::DestroyNotify(event) => {
                log::trace!("Got DestroyNotify: {event:?}");
                if event.window == self.target.wid {
                    self.target.is_destroyed = true;
                    self.check_and_handle_window(x11rb::NONE);
                }
            }
            Event::ConfigureNotify(event) => {
                log::trace!("Got ConfigureNotify: {event:?}");
                if event.window == self.target.wid {
                    self.handle_moveresize_xevent();
                }
            }
            Event::PropertyNotify(event) => {
                log::trace!("Got PropertyNotify: {event:?}");
                if event.window == self.root && event.atom == self.atoms.net_active_window {
                    let old = self.active;
                    self.active = self.get_active_window().unwrap_or(x11rb::NONE);

                    if old != self.target.wid {
                        self.conn
                            .change_window_attributes(
                                old,
                                &ChangeWindowAttributesAux::new().event_mask(EventMask::NO_EVENT),
                            )
                            .ok();
                    }

                    if self.active != x11rb::NONE && self.active != self.target.wid {
                        self.conn
                            .change_window_attributes(
                                self.active,
                                &ChangeWindowAttributesAux::new()
                                    .event_mask(EventMask::PROPERTY_CHANGE),
                            )
                            .ok();
                    }
                    self.check_and_handle_window(self.active);
                } else if event.window == self.target.wid && event.atom == self.atoms.net_wm_state {
                    self.handle_fullscreen_xevent();
                } else if event.window == self.active && event.atom == self.atoms.net_wm_name {
                    self.check_and_handle_window(self.active);
                }
            }
            _ => (),
        }
    }
}

pub fn init(
    window_title: String,
    tx: std::sync::mpsc::Sender<crate::UnderlayEvent>,
) -> Result<(), String> {
    std::thread::spawn(move || {
        let (conn, screen_num) = match connect(None) {
            Ok(conn) => conn,
            Err(_) => {
                log::error!("Could not connect");
                return;
            }
        };

        let root = conn.setup().roots[screen_num].root;
        let atoms = match AtomCollection::new(&conn) {
            Some(atoms) => atoms,
            None => {
                log::error!("Could not initialize atoms");
                return;
            }
        };

        conn.change_window_attributes(
            root,
            &ChangeWindowAttributesAux::new().event_mask(EventMask::PROPERTY_CHANGE),
        )
        .ok();

        let mut runtime = Runtime {
            conn,
            root,
            target: Target {
                title: window_title,
                wid: x11rb::NONE,
                is_focused: false,
                is_destroyed: false,
                is_fullscreen: false,
            },
            atoms,
            underlay_tx: tx,
            active: x11rb::NONE,
        };

        runtime.active = runtime.get_active_window().unwrap_or(x11rb::NONE);
        if runtime.active != x11rb::NONE {
            runtime
                .conn
                .change_window_attributes(
                    runtime.active,
                    &ChangeWindowAttributesAux::new().event_mask(EventMask::PROPERTY_CHANGE),
                )
                .ok();
            runtime.check_and_handle_window(runtime.active);
        }

        runtime.conn.flush().ok();

        TARGET.store(
            Box::into_raw(Box::new(Arc::new(Mutex::new(x11rb::NONE)))),
            std::sync::atomic::Ordering::Relaxed,
        );

        log::trace!("Initialized, listning for events");
        while let Ok(event) = runtime.conn.wait_for_event() {
            log::trace!("Got event");
            runtime.handle_event(event);
            runtime.conn.flush().ok();
        }
    });

    Ok(())
}