prefs: the wallpaper engine's settings, lists and homes

The engine needs on/off, an interval, per-screen lists and a home per
screen to survive restarts. They live in prefs rather than list files
because the lists can be empty, and an empty FileView write writes nothing.

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

1 files changed, 22 insertions, 1 deletions

diff --git a/desktop/Prefs.qml b/desktop/Prefs.qml
index 0ed6ee9..9a9b0b7 100644
--- a/desktop/Prefs.qml
+++ b/desktop/Prefs.qml
@@ -50,6 +50,18 @@ Singleton {
     readonly property int sidebarMax: 420
     property int settingsSidebar: 200
 
+    // The wallpaper engine (modules/appearance/WallEngine.qml): on or off,
+    // the interval, a list of paths per screen, and each screen's home, the
+    // wallpaper switching off returns to. In here rather than in list files:
+    // the lists can be empty, and an empty FileView write writes nothing.
+    readonly property var wallEngineDefaults: ({ on: false, minutes: 30, h: [], v: [], homeH: "", homeV: "" })
+    property var wallEngine: wallEngineDefaults
+    function setWallEngine(changes) {
+        const w = Object.assign({}, root.wallEngine, changes);
+        root.wallEngine = w;
+        root.write(Object.assign({}, root.doc, { wallEngine: w }));
+    }
+
     // The whole parsed object, so a write keeps keys this version does not
     // know about.
     property var doc: ({})
@@ -103,6 +115,15 @@ Singleton {
         const w = parsed.settings ? parsed.settings.sidebar : undefined;
         root.settingsSidebar = typeof w === "number" && w >= root.sidebarMin && w <= root.sidebarMax
             ? Math.round(w) : 200;
+        const we = parsed.wallEngine && typeof parsed.wallEngine === "object" ? parsed.wallEngine : {};
+        const paths = a => Array.isArray(a) ? a.filter(s => typeof s === "string" && s !== "") : [];
+        const str = s => typeof s === "string" ? s : "";
+        root.wallEngine = {
+            on: we.on === true,
+            minutes: Number.isInteger(we.minutes) && we.minutes >= 1 ? we.minutes : 30,
+            h: paths(we.h), v: paths(we.v),
+            homeH: str(we.homeH), homeV: str(we.homeV),
+        };
     }
 
     FileView {
@@ -117,6 +138,6 @@ Singleton {
         onFileChanged: reload()
         onLoaded: root.reparse()
         // Missing file: the defaults, and nothing written.
-        onLoadFailed: { root.doc = {}; root.pinnedIp = ""; root.presets = null; root.settingsSidebar = 200; root.assistantModel = ""; }
+        onLoadFailed: { root.doc = {}; root.pinnedIp = ""; root.presets = null; root.settingsSidebar = 200; root.assistantModel = ""; root.wallEngine = root.wallEngineDefaults; }
     }
 }