From ed2fc8301bece4ead0c2133c57124a1b2815f5c7 Mon Sep 17 00:00:00 2001
From: Marco Allegretti <mightymarco4@gmail.com>
Date: Tue, 5 May 2026 09:06:46 +0200
Subject: [PATCH] Seed lockscreen wallpaper defaults at startup

When kscreenlockerrc has no greeter wallpaper configured, or still
points at the legacy Next wallpaper, the lockscreen falls back to KDE
default imagery. Seed the greeter wallpaper settings from the installed
SHIFT wallpaper package during Plasma Mobile startup so the lockscreen
uses the fork default consistently.

Link ConfigCore for the startup module so it can read and update
kscreenlockerrc.
---
 kded/start/CMakeLists.txt |  1 +
 kded/start/start.cpp      | 60 +++++++++++++++++++++++++++++++++++++++
 2 files changed, 61 insertions(+)

diff --git a/kded/start/CMakeLists.txt b/kded/start/CMakeLists.txt
index 2f4d9b92..37d09c35 100644
--- a/kded/start/CMakeLists.txt
+++ b/kded/start/CMakeLists.txt
@@ -10,6 +10,7 @@ kcoreaddons_add_plugin(kded_plasma_mobile_start SOURCES ${kded_plasma_mobile_sta
 target_link_libraries(kded_plasma_mobile_start PRIVATE
     Qt::Core
     KF6::DBusAddons
+    KF6::ConfigCore
     KF6::KIOGui
     KF6::JobWidgets
     KF6::Package
diff --git a/kded/start/start.cpp b/kded/start/start.cpp
index ef9c68dd..ba6d3eb9 100644
--- a/kded/start/start.cpp
+++ b/kded/start/start.cpp
@@ -1,17 +1,77 @@
 // SPDX-FileCopyrightText: 2023 Devin Lin <devin@kde.org>
 // SPDX-License-Identifier: GPL-2.0-or-later
 
+#include <QFileInfo>
+#include <QStandardPaths>
+#include <QUrl>
+
+#include <KConfigGroup>
 #include <KIO/CommandLauncherJob>
 #include <KNotificationJobUiDelegate>
 #include <KPluginFactory>
+#include <KSharedConfig>
 
 #include "start.h"
 
+namespace
+{
+bool isLegacyNextWallpaperPath(const QString &path)
+{
+    return path == QStringLiteral("Next") || path.startsWith(QStringLiteral("/usr/share/wallpapers/Next/"))
+        || path.startsWith(QStringLiteral("file:///usr/share/wallpapers/Next/"));
+}
+
+QString shiftWallpaperPackageUrl()
+{
+    const QString metadataPath = QStandardPaths::locate(QStandardPaths::GenericDataLocation, QStringLiteral("wallpapers/SHIFT/metadata.json"));
+    if (metadataPath.isEmpty()) {
+        return QString();
+    }
+
+    QString packageUrl = QUrl::fromLocalFile(QFileInfo(metadataPath).absolutePath()).toString();
+    if (!packageUrl.endsWith(QLatin1Char('/'))) {
+        packageUrl += QLatin1Char('/');
+    }
+    return packageUrl;
+}
+
+void ensureLockscreenWallpaperDefaults()
+{
+    auto config = KSharedConfig::openConfig(QStringLiteral("kscreenlockerrc"));
+    auto greeterGroup = config->group(QStringLiteral("Greeter"));
+
+    const QString wallpaperPlugin = greeterGroup.readEntry(QStringLiteral("WallpaperPlugin"), QString());
+    const QString wallpaperPath =
+        greeterGroup.group(QStringLiteral("Wallpaper")).group(wallpaperPlugin).group(QStringLiteral("General")).readEntry(QStringLiteral("Image"), QString());
+
+    const bool wallpaperUnset = wallpaperPlugin.isEmpty() || wallpaperPath.isEmpty();
+    const bool wallpaperLegacyNext = wallpaperPlugin == QStringLiteral("org.kde.image") && isLegacyNextWallpaperPath(wallpaperPath);
+    if (!wallpaperUnset && !wallpaperLegacyNext) {
+        return;
+    }
+
+    const QString defaultWallpaperUrl = shiftWallpaperPackageUrl();
+    if (defaultWallpaperUrl.isEmpty()) {
+        qWarning() << "Could not locate SHIFT wallpaper package for lockscreen defaults";
+        return;
+    }
+
+    greeterGroup.group(QStringLiteral("Wallpaper"))
+        .group(QStringLiteral("org.kde.image"))
+        .group(QStringLiteral("General"))
+        .writeEntry(QStringLiteral("Image"), defaultWallpaperUrl, KConfigGroup::Notify);
+    greeterGroup.writeEntry(QStringLiteral("WallpaperPlugin"), QStringLiteral("org.kde.image"), KConfigGroup::Notify);
+    config->sync();
+}
+}
+
 K_PLUGIN_FACTORY_WITH_JSON(StartFactory, "kded_plasma_mobile_start.json", registerPlugin<Start>();)
 
 Start::Start(QObject *parent, const QList<QVariant> &)
     : KDEDModule{parent}
 {
+    ensureLockscreenWallpaperDefaults();
+
     auto *envmanagerJob = new KIO::CommandLauncherJob(QStringLiteral("plasma-mobile-envmanager --apply-settings"), {});
     envmanagerJob->setUiDelegate(new KNotificationJobUiDelegate(KJobUiDelegate::AutoErrorHandlingEnabled));
     envmanagerJob->setDesktopName(QStringLiteral("org.kde.plasma-mobile-envmanager"));