homelab/dotfiles/quickshell/hyprchrome/widgets/HyprChromeShell.qml

pragma ComponentBehavior: Bound

import Quickshell
import Quickshell.Hyprland
import Quickshell.Wayland
import qs.hyprchrome.widgets

// The hyprchrome shell: owns everything the rail's surfaces have to agree on,
// and instantiates them.
//
// State lives here rather than in any one surface because more than one of them
// reads it, and a second reader is what turns a local property into shared
// state. Three things qualify so far:
//
//   * which monitor the shell lives on — every surface has to pick the same one
//   * the density — the whole rail expands and collapses as one, so the toggle
//     and the shortcut that drives it belong to the shell, not to the bar
//   * the layer PAIR — the backdrop must sit exactly one layer below the bar in
//     both densities. Two surfaces on the same layer stack by creation order,
//     which is not something to rely on; one layer apart is a guarantee. Split
//     across two files those two assignments drifted apart and the scrim ended
//     up over the bar, so they are derived together here and passed down.
//
// A future widget joins by taking `targetScreen` and `expanded` the same way.
Scope {
    id: shell

    // Monitor the rail lives on. Falls back to the FIRST connected screen when
    // the name matches nothing, so the bar still appears on a single-monitor
    // session or after a cable swap (DebugWindow falls back to the last one
    // instead — it wants the secondary).
    property string screenName: "DP-2"

    // Quickshell.screens is a QML list, not a JS array — no .find() on it.
    readonly property var targetScreen: {
        const screens = Quickshell.screens;
        if (screens.length === 0)
            return null;
        for (let i = 0; i < screens.length; i++) {
            if (screens[i].name === shell.screenName)
                return screens[i];
        }
        return screens[0];
    }

    // Density is a property of the SHELL: every panel follows it, so the whole
    // rail expands and collapses as one. Panels keep their own animation; only
    // the decision is centralised here.
    property bool expanded: false

    function toggle() {
        shell.expanded = !shell.expanded;
    }

    // Expanded the rail is over everything; collapsed it drops below ordinary
    // windows. BOTTOM rather than BACKGROUND for the collapsed bar: it is the
    // lowest level that still leaves a layer underneath for the backdrop, and
    // it keeps the rail off the wallpaper's own level.
    readonly property int barLayer: shell.expanded ? WlrLayer.Overlay : WlrLayer.Bottom
    readonly property int backdropLayer: shell.expanded ? WlrLayer.Top : WlrLayer.Background

    // SUPER A — see hosts/terra/home/hyprland.nix.
    GlobalShortcut {
        name: "chrome"
        description: "Expand or collapse the hyprchrome bar"
        onPressed: shell.toggle()
    }

    // Backdrop first: it is a layer below the bar, so stacking does not depend
    // on creation order, but keeping the declaration order the same as the
    // visual order costs nothing.
    ChromeBackdrop {
        screen: shell.targetScreen
        active: shell.expanded
        wlrLayer: shell.backdropLayer

        // Collapsed, the scrim only backs the rail, so it needs the band the
        // rail occupies. contentHeight is the SETTLED height for the current
        // state — it jumps once per toggle rather than tracking the panels
        // frame by frame, so the backdrop animates the change itself instead of
        // chasing a value that is already being animated.
        barHeight: bar.contentHeight
    }

    HyprChromeBar {
        id: bar

        screen: shell.targetScreen
        // Set here, not from the window's own `screen`: reading that inside
        // `visible` is circular — a hidden window has no screen to report.
        visible: shell.targetScreen !== null
        expanded: shell.expanded
        wlrLayer: shell.barLayer
    }
}