feat: stage the wallpaper on homepage and notify on completion

bin/udt-homepage replaces install.sh's inline scp. It stages custom.css
and the current wallpaper, keeping the wallpaper's own extension, then
raises a desktop notification with the root commands that install both
and point settings.yaml at the new background. Plain root commands, not
sudo: the login user on that host has no sudo rights.

udt-accent starts it detached on every run, so it follows a wallpaper
change (wallp) as well as a scheme switch (install.sh) without holding
either up when the host is unreachable.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

2 files changed, 59 insertions, 0 deletions

diff --git a/bin/udt-accent b/bin/udt-accent
index 6462aae..c0b6529 100755
--- a/bin/udt-accent
+++ b/bin/udt-accent
@@ -463,6 +463,12 @@ def main(image):
     # Hyprland only rereads its config on request, and may not be running.
     subprocess.run(["hyprctl", "reload"], capture_output=True, check=False)
 
+    # The dashboard host. Detached, because wallp runs this synchronously and
+    # an unreachable host would hold the wallpaper change for the scp timeout.
+    subprocess.Popen([Path(__file__).resolve().parent / "udt-homepage"],
+                     stdin=subprocess.DEVNULL, stdout=subprocess.DEVNULL,
+                     stderr=subprocess.DEVNULL, start_new_session=True)
+
     before, after = hue_neighbours(name)
     print(f"{name} {ACCENTS[name]} (border: {before} .. {name} .. {after})")
 
diff --git a/bin/udt-homepage b/bin/udt-homepage
new file mode 100755
index 0000000..7be5d16
--- /dev/null
+++ b/bin/udt-homepage
@@ -0,0 +1,53 @@
+#!/bin/bash
+# udt-homepage: stage the homepage stylesheet and wallpaper on the dashboard host.
+# Copyright (C) 2026 Danilo M. <danix@danix.xyz>
+# Licensed under the GNU General Public License v2 only.
+#
+# Staged, not installed: /opt/homepage is root-owned and this script does not
+# hold root there, so it copies into ~/hp-stage/ and a notification carries
+# the command that finishes the job.
+#
+# udt-accent starts this detached on every run, which covers both a wallpaper
+# change (wallp) and a scheme switch (install.sh). Never slow and never loud
+# when the host is away: a laptop off that network gets a short connect
+# timeout and no notification, since there is nothing for the user to do.
+
+repo="$(dirname "$(readlink -f "$0")")/.."
+css="$repo/templates/homepage/custom.css"
+wall="$HOME/.cache/udt/wpaper"
+opts=(-q -o ConnectTimeout=5 -o BatchMode=yes)
+
+[ -f "$css" ] && [ -e "$wall" ] || exit 0
+
+# The wallpaper keeps its own extension, so settings.yaml has to follow it: the
+# finish command rewrites its background.image line to match. The extension
+# ends up in a command the user runs as root, so only known image types pass.
+real="$(readlink -f "$wall")"
+ext="${real##*.}"
+ext="${ext,,}"
+case "$ext" in
+    png|jpg|jpeg|webp|gif|avif) ;;
+    *) echo "homepage: $real is not a known image type, skipped" >&2; exit 1 ;;
+esac
+bg="background.$ext"
+
+scp "${opts[@]}" "$css" homepage:hp-stage/custom.css &&
+    scp "${opts[@]}" "$real" "homepage:hp-stage/$bg" || {
+    echo "homepage: unreachable, skipped" >&2
+    exit 1
+}
+
+# Root commands, not sudo: the login user there has no sudo rights. Root's ~
+# is not the staging directory, so it is named through the ssh login user,
+# which ssh -G resolves from the config without connecting.
+stage="~$(ssh -G homepage 2>/dev/null | awk '/^user /{print $2}')/hp-stage"
+finish="cp $stage/custom.css /opt/homepage/config/
+cp $stage/$bg /opt/homepage/public/images/
+sed -i 's|/images/background\.[a-z]*|/images/$bg|' /opt/homepage/config/settings.yaml
+systemctl restart homepage"
+echo "homepage: staged, finish as root on homepage:"
+echo "$finish"
+command -v notify-send >/dev/null 2>&1 &&
+    notify-send -a udt "homepage: theme staged" "As root on homepage:
+$finish"
+exit 0