{
    const EYE_RECORD_FPS: u32 = 20;
    const EYE_RECORD_FRAME_INTERVAL_MS: u64 = 1000 / EYE_RECORD_FPS as u64;

    #[derive(Default)]
    struct EyeRecordState {
        save_dir_override: Option<PathBuf>,
        timer: Option<glib::SourceId>,
        frame_dir: Option<PathBuf>,
        output_path: Option<PathBuf>,
        next_frame_index: u32,
        captured_frames: u32,
    }

    fn eye_slug(title: &str) -> &'static str {
        if title.to_ascii_lowercase().contains("left") {
            "left-eye"
        } else {
            "right-eye"
        }
    }

    fn timestamp_slug() -> String {
        let now = SystemTime::now()
            .duration_since(UNIX_EPOCH)
            .unwrap_or_default();
        format!("{}-{:03}", now.as_secs(), now.subsec_millis())
    }

    fn expand_home_token(raw: &str) -> PathBuf {
        if raw.contains("$HOME") {
            if let Some(home) = std::env::var_os("HOME") {
                return PathBuf::from(raw.replace("$HOME", &home.to_string_lossy()));
            }
        }
        if let Some(rest) = raw.strip_prefix("~/")
            && let Some(home) = std::env::var_os("HOME")
        {
            return PathBuf::from(home).join(rest);
        }
        PathBuf::from(raw)
    }

    fn default_eye_capture_root() -> PathBuf {
        if let Some(raw) = std::env::var_os("XDG_PICTURES_DIR") {
            let path = expand_home_token(&raw.to_string_lossy());
            if !path.as_os_str().is_empty() {
                return path.join("Lesavka");
            }
        }
        if let Some(home) = std::env::var_os("HOME") {
            return PathBuf::from(home).join("Pictures").join("Lesavka");
        }
        if let Some(profile) = std::env::var_os("USERPROFILE") {
            return PathBuf::from(profile).join("Pictures").join("Lesavka");
        }
        std::env::current_dir()
            .unwrap_or_else(|_| PathBuf::from("."))
            .join("Lesavka")
    }

    fn ensure_eye_capture_root(override_dir: Option<&PathBuf>) -> Result<PathBuf, String> {
        let root = override_dir
            .cloned()
            .unwrap_or_else(default_eye_capture_root);
        std::fs::create_dir_all(&root)
            .map_err(|err| format!("could not create {}: {err}", root.display()))?;
        Ok(root)
    }

    fn unique_capture_path(root: &PathBuf, stem: &str, ext: &str) -> PathBuf {
        let mut candidate = root.join(format!("{stem}.{ext}"));
        if !candidate.exists() {
            return candidate;
        }
        for idx in 1..1000 {
            candidate = root.join(format!("{stem}-{idx}.{ext}"));
            if !candidate.exists() {
                break;
            }
        }
        candidate
    }

    fn current_eye_texture(picture: &gtk::Picture) -> Result<gtk::gdk::Texture, String> {
        let paintable = picture
            .paintable()
            .ok_or_else(|| "no live frame is available yet".to_string())?;
        paintable
            .downcast::<gtk::gdk::Texture>()
            .map_err(|_| "the current frame is not directly exportable".to_string())
    }

    fn save_texture_png(texture: &gtk::gdk::Texture, output_path: &PathBuf) -> Result<(), String> {
        texture
            .save_to_png(output_path)
            .map_err(|err| format!("could not write {}: {err}", output_path.display()))
    }

    fn write_record_frame(state: &mut EyeRecordState, picture: &gtk::Picture) -> Result<(), String> {
        let frame_dir = state
            .frame_dir
            .as_ref()
            .ok_or_else(|| "recording session is not initialized".to_string())?
            .clone();
        let texture = current_eye_texture(picture)?;
        let frame_path = frame_dir.join(format!("frame-{:06}.png", state.next_frame_index));
        save_texture_png(&texture, &frame_path)?;
        state.next_frame_index = state.next_frame_index.saturating_add(1);
        state.captured_frames = state.captured_frames.saturating_add(1);
        Ok(())
    }

    fn finalize_recording(state: &mut EyeRecordState) -> Result<PathBuf, String> {
        let frame_dir = state
            .frame_dir
            .take()
            .ok_or_else(|| "recording frames were not initialized".to_string())?;
        let output_path = state
            .output_path
            .take()
            .ok_or_else(|| "recording output path was not initialized".to_string())?;
        let captured_frames = state.captured_frames;
        state.captured_frames = 0;
        state.next_frame_index = 0;

        if captured_frames < 2 {
            let _ = std::fs::remove_dir_all(&frame_dir);
            return Err("need at least two captured frames to build a recording".to_string());
        }

        let frame_pattern = frame_dir.join("frame-%06d.png");
        let encode = Command::new("ffmpeg")
            .args([
                "-hide_banner",
                "-loglevel",
                "error",
                "-y",
                "-framerate",
                &EYE_RECORD_FPS.to_string(),
                "-i",
                &frame_pattern.to_string_lossy(),
                "-c:v",
                "libx264",
                "-pix_fmt",
                "yuv420p",
                &output_path.to_string_lossy(),
            ])
            .status()
            .map_err(|err| format!("ffmpeg is unavailable: {err}"))?;

        if !encode.success() {
            return Err(format!(
                "ffmpeg failed while encoding {}; frame data is still in {}",
                output_path.display(),
                frame_dir.display()
            ));
        }

        let _ = std::fs::remove_dir_all(&frame_dir);
        Ok(output_path)
    }

    {
        let child_proc = Rc::clone(&child_proc);
        let widgets = widgets.clone();
        let server_entry = server_entry.clone();
        let server_addr_fallback = Rc::clone(&server_addr);
        let clipboard_tx = clipboard_tx.clone();
        widgets.clipboard_button.connect_clicked(move |_| {
            if child_proc.borrow().is_none() {
                widgets
                    .status_label
                    .set_text("Start the relay before sending clipboard text.");
                return;
            }
            let server_addr = selected_server_addr(&server_entry, server_addr_fallback.as_ref());
            let Some(display) = gtk::gdk::Display::default() else {
                widgets
                    .status_label
                    .set_text("No desktop clipboard is available in this session.");
                return;
            };
            widgets
                .status_label
                .set_text("Reading the local clipboard and preparing remote paste...");
            let clipboard = display.clipboard();
            let clipboard_tx = clipboard_tx.clone();
            clipboard.read_text_async(None::<&gtk::gio::Cancellable>, move |result| match result {
                Ok(Some(text)) => {
                    let text = text.trim_end_matches(['\r', '\n']).to_string();
                    if text.is_empty() {
                        let _ = clipboard_tx
                            .send(ClipboardMessage::Finished(Err("clipboard is empty".to_string())));
                        return;
                    }
                    let clipboard_tx = clipboard_tx.clone();
                    std::thread::spawn(move || {
                        let result = send_clipboard_text_to_remote(&server_addr, &text)
                            .map_err(|err| err.to_string());
                        let _ = clipboard_tx.send(ClipboardMessage::Finished(result));
                    });
                }
                Ok(None) => {
                    let _ = clipboard_tx
                        .send(ClipboardMessage::Finished(Err("clipboard is empty".to_string())));
                }
                Err(err) => {
                    let _ = clipboard_tx.send(ClipboardMessage::Finished(Err(format!(
                        "clipboard read failed: {err}"
                    ))));
                }
            });
        });
    }

    for monitor_id in 0..2 {
        let pane = widgets.display_panes[monitor_id].clone();
        let widgets_for_ui = widgets.clone();
        let save_state = Rc::new(RefCell::new(EyeRecordState::default()));

        {
            let pane = pane.clone();
            let widgets = widgets_for_ui.clone();
            let save_state = Rc::clone(&save_state);
            let window_for_save = window.clone();
            pane.save_button.connect_clicked(move |_| {
                let chooser = gtk::FileChooserNative::new(
                    Some("Choose Eye Capture Folder"),
                    Some(&window_for_save),
                    gtk::FileChooserAction::SelectFolder,
                    Some("Select"),
                    Some("Cancel"),
                );
                chooser.set_modal(true);
                let save_state = Rc::clone(&save_state);
                let widgets = widgets.clone();
                let eye_name = pane.title.clone();
                chooser.connect_response(move |dialog, response| {
                    if response == gtk::ResponseType::Accept {
                        if let Some(folder) = dialog.file().and_then(|file| file.path()) {
                            save_state.borrow_mut().save_dir_override = Some(folder.clone());
                            widgets.status_label.set_text(&format!(
                                "{} saves now go to {}.",
                                eye_name,
                                folder.display()
                            ));
                        } else {
                            widgets.status_label.set_text(
                                "Capture folder selection did not return a filesystem path.",
                            );
                        }
                    }
                    dialog.destroy();
                });
                chooser.show();
            });
        }

        {
            let pane = pane.clone();
            let widgets = widgets_for_ui.clone();
            let save_state = Rc::clone(&save_state);
            pane.clip_button.connect_clicked(move |_| {
                let root = {
                    let borrowed = save_state.borrow();
                    match ensure_eye_capture_root(borrowed.save_dir_override.as_ref()) {
                        Ok(path) => path,
                        Err(err) => {
                            widgets
                                .status_label
                                .set_text(&format!("Could not prepare capture folder: {err}"));
                            return;
                        }
                    }
                };

                let stem = format!("{}-clip-{}", eye_slug(&pane.title), timestamp_slug());
                let clip_path = unique_capture_path(&root, &stem, "png");
                match current_eye_texture(&pane.picture)
                    .and_then(|texture| save_texture_png(&texture, &clip_path))
                {
                    Ok(()) => {
                        widgets.status_label.set_text(&format!(
                            "{} clip saved to {}.",
                            pane.title,
                            clip_path.display()
                        ));
                    }
                    Err(err) => {
                        widgets
                            .status_label
                            .set_text(&format!("{} clip failed: {err}", pane.title));
                    }
                }
            });
        }

        {
            let pane = pane.clone();
            let widgets = widgets_for_ui.clone();
            let save_state = Rc::clone(&save_state);
            let record_button = pane.record_button.clone();
            record_button.connect_clicked(move |button| {
                if save_state.borrow().timer.is_some() {
                    let mut state = save_state.borrow_mut();
                    if let Some(timer) = state.timer.take() {
                        timer.remove();
                    }
                    drop(state);

                    let mut state = save_state.borrow_mut();
                    match finalize_recording(&mut state) {
                        Ok(output) => {
                            button.set_label("Record");
                            widgets.status_label.set_text(&format!(
                                "{} recording saved to {}.",
                                pane.title,
                                output.display()
                            ));
                        }
                        Err(err) => {
                            button.set_label("Record");
                            widgets.status_label.set_text(&format!(
                                "{} recording stop failed: {err}",
                                pane.title,
                            ));
                        }
                    }
                    return;
                }

                let root = {
                    let borrowed = save_state.borrow();
                    match ensure_eye_capture_root(borrowed.save_dir_override.as_ref()) {
                        Ok(path) => path,
                        Err(err) => {
                            widgets
                                .status_label
                                .set_text(&format!("Could not prepare capture folder: {err}"));
                            return;
                        }
                    }
                };

                let recording_stem = format!("{}-record-{}", eye_slug(&pane.title), timestamp_slug());
                let output_path = unique_capture_path(&root, &recording_stem, "mp4");
                let frame_dir = root.join(format!("{}.frames", recording_stem));
                if let Err(err) = std::fs::create_dir_all(&frame_dir) {
                    widgets.status_label.set_text(&format!(
                        "{} record failed creating frame cache {}: {err}",
                        pane.title,
                        frame_dir.display()
                    ));
                    return;
                }

                {
                    let mut state = save_state.borrow_mut();
                    state.frame_dir = Some(frame_dir);
                    state.output_path = Some(output_path.clone());
                    state.next_frame_index = 0;
                    state.captured_frames = 0;
                }

                let pane_for_tick = pane.clone();
                let widgets_for_tick = widgets.clone();
                let save_state_for_tick = Rc::clone(&save_state);
                let timer = glib::timeout_add_local(
                    Duration::from_millis(EYE_RECORD_FRAME_INTERVAL_MS),
                    move || {
                        let mut state = save_state_for_tick.borrow_mut();
                        if state.frame_dir.is_none() {
                            return glib::ControlFlow::Break;
                        }
                        if let Err(err) = write_record_frame(&mut state, &pane_for_tick.picture) {
                            widgets_for_tick.status_label.set_text(&format!(
                                "{} recording frame skipped: {err}",
                                pane_for_tick.title
                            ));
                        }
                        glib::ControlFlow::Continue
                    },
                );
                save_state.borrow_mut().timer = Some(timer);
                button.set_label("Stop");
                widgets.status_label.set_text(&format!(
                    "Recording {}... press Stop to finish.",
                    pane.title
                ));
            });
        }
    }

    {
        let widgets = widgets.clone();
        let server_entry = server_entry.clone();
        let server_addr_fallback = Rc::clone(&server_addr);
        let widgets_for_click = widgets.clone();
        widgets.usb_recover_button.connect_clicked(move |_| {
            let server_addr = selected_server_addr(&server_entry, server_addr_fallback.as_ref());
            widgets_for_click.status_label.set_text(
                "Requesting a forced USB gadget re-enumeration on the relay host...",
            );
            let (tx, rx) = std::sync::mpsc::channel();
            std::thread::spawn(move || {
                let result = reset_usb_gadget(&server_addr).map_err(|err| format!("{err:#}"));
                let _ = tx.send(result);
            });
            let widgets = widgets_for_click.clone();
            glib::timeout_add_local(Duration::from_millis(100), move || match rx.try_recv() {
                Ok(Ok(())) => {
                    widgets.status_label.set_text(
                        "USB gadget recovery requested. Give the host a few seconds to re-enumerate keyboard, mouse, webcam, and audio.",
                    );
                    glib::ControlFlow::Break
                }
                Ok(Err(err)) => {
                    widgets
                        .status_label
                        .set_text(&format!("USB gadget recovery failed: {err}"));
                    glib::ControlFlow::Break
                }
                Err(std::sync::mpsc::TryRecvError::Empty) => glib::ControlFlow::Continue,
                Err(std::sync::mpsc::TryRecvError::Disconnected) => {
                    widgets.status_label.set_text(
                        "USB gadget recovery ended unexpectedly before the relay answered.",
                    );
                    glib::ControlFlow::Break
                }
            });
        });
    }

    {
        let widgets = widgets.clone();
        let server_entry = server_entry.clone();
        let server_addr_fallback = Rc::clone(&server_addr);
        let widgets_for_click = widgets.clone();
        widgets.uac_recover_button.connect_clicked(move |_| {
            let server_addr = selected_server_addr(&server_entry, server_addr_fallback.as_ref());
            widgets_for_click
                .status_label
                .set_text("Requesting UAC recovery (USB gadget rebuild) on the relay host...");
            let (tx, rx) = std::sync::mpsc::channel();
            std::thread::spawn(move || {
                let result = reset_usb_gadget(&server_addr).map_err(|err| format!("{err:#}"));
                let _ = tx.send(result);
            });
            let widgets = widgets_for_click.clone();
            glib::timeout_add_local(Duration::from_millis(100), move || match rx.try_recv() {
                Ok(Ok(())) => {
                    widgets.status_label.set_text(
                        "UAC recovery requested via USB gadget rebuild. Give the host a few seconds to re-enumerate audio.",
                    );
                    glib::ControlFlow::Break
                }
                Ok(Err(err)) => {
                    widgets
                        .status_label
                        .set_text(&format!("UAC recovery failed: {err}"));
                    glib::ControlFlow::Break
                }
                Err(std::sync::mpsc::TryRecvError::Empty) => glib::ControlFlow::Continue,
                Err(std::sync::mpsc::TryRecvError::Disconnected) => {
                    widgets.status_label.set_text(
                        "UAC recovery ended unexpectedly before the relay answered.",
                    );
                    glib::ControlFlow::Break
                }
            });
        });
    }

    {
        let widgets = widgets.clone();
        let server_entry = server_entry.clone();
        let server_addr_fallback = Rc::clone(&server_addr);
        let widgets_for_click = widgets.clone();
        widgets.uvc_recover_button.connect_clicked(move |_| {
            let server_addr = selected_server_addr(&server_entry, server_addr_fallback.as_ref());
            widgets_for_click
                .status_label
                .set_text("Requesting UVC recovery (USB gadget rebuild) on the relay host...");
            let (tx, rx) = std::sync::mpsc::channel();
            std::thread::spawn(move || {
                let result = reset_usb_gadget(&server_addr).map_err(|err| format!("{err:#}"));
                let _ = tx.send(result);
            });
            let widgets = widgets_for_click.clone();
            glib::timeout_add_local(Duration::from_millis(100), move || match rx.try_recv() {
                Ok(Ok(())) => {
                    widgets.status_label.set_text(
                        "UVC recovery requested via USB gadget rebuild. Give the host a few seconds to re-enumerate webcam video.",
                    );
                    glib::ControlFlow::Break
                }
                Ok(Err(err)) => {
                    widgets
                        .status_label
                        .set_text(&format!("UVC recovery failed: {err}"));
                    glib::ControlFlow::Break
                }
                Err(std::sync::mpsc::TryRecvError::Empty) => glib::ControlFlow::Continue,
                Err(std::sync::mpsc::TryRecvError::Disconnected) => {
                    widgets.status_label.set_text(
                        "UVC recovery ended unexpectedly before the relay answered.",
                    );
                    glib::ControlFlow::Break
                }
            });
        });
    }

    {
        let widgets = widgets.clone();
        widgets.diagnostics_copy_button.connect_clicked(move |_| {
            if let Err(err) = copy_plain_text(&widgets.diagnostics_rendered_text.borrow()) {
                widgets
                    .status_label
                    .set_text(&format!("Could not copy the diagnostics report: {err}"));
            } else {
                widgets
                    .status_label
                    .set_text("Diagnostics report copied to the local clipboard.");
            }
        });
    }

    {
        let app = app.clone();
        let widgets = widgets.clone();
        let diagnostics_popout = Rc::clone(&diagnostics_popout);
        widgets.diagnostics_popout_button.connect_clicked(move |_| {
            open_diagnostics_popout(
                &app,
                &diagnostics_popout,
                &widgets.diagnostics_popout_label,
                &widgets.diagnostics_popout_scroll,
                &widgets.diagnostics_rendered_text,
            );
            widgets
                .status_label
                .set_text("Diagnostics report moved into its own window.");
        });
    }

    {
        let widgets = widgets.clone();
        widgets.console_level_combo.connect_changed(move |combo| {
            let level = combo
                .active_id()
                .as_deref()
                .and_then(ConsoleLogLevel::from_id)
                .unwrap_or_default();
            *widgets.session_log_level.borrow_mut() = level;
            widgets.status_label.set_text(&format!(
                "Console now shows {} relay logs and higher.",
                level.label()
            ));
        });
    }

    {
        let widgets = widgets.clone();
        widgets.console_copy_button.connect_clicked(move |_| {
            if let Err(err) = copy_session_log(&widgets.session_log_buffer) {
                widgets
                    .status_label
                    .set_text(&format!("Could not copy the session log: {err}"));
            } else {
                widgets
                    .status_label
                    .set_text("Session log copied to the local clipboard.");
            }
        });
    }

    {
        let app = app.clone();
        let widgets = widgets.clone();
        let log_popout = Rc::clone(&log_popout);
        widgets.console_popout_button.connect_clicked(move |_| {
            open_session_log_popout(&app, &log_popout, &widgets.session_log_buffer);
            widgets
                .status_label
                .set_text("Session log moved into its own window.");
        });
    }
}