fix: preserve markers when deleting final space

Issue: #244
User-Visible: yes

src/houseplan-card.ts

@@ -14460,11 +14460,15 @@ class HouseplanCard extends LitElement {
   private async _deleteSpace(): Promise<void> {
     const d = this._spaceDialog;
     if (!d || d.mode !== 'edit') return;
-    const sp = this._serverCfg!.spaces.find((x: any) => x.id === d.spaceId);
+    const serverCfg = this._serverCfg;
+    if (!serverCfg) return;
+    const sp = serverCfg.spaces.find((x: any) => x.id === d.spaceId);
     const dependencies = collectSpaceMarkerDependencies(
-      this._serverCfg, this._layout || {}, d.spaceId || '',
+      serverCfg, this._layout || {}, d.spaceId || '',
     );
-    if (dependencies.count) {
+    const deletingLastSpace = serverCfg.spaces.length === 1
+      && serverCfg.spaces[0]?.id === d.spaceId;
+    if (dependencies.count && !deletingLastSpace) {
       this._spaceDialog = { ...d, deleteBlockers: dependencies.count };
       return;
     }
@@ -14496,11 +14500,18 @@ class HouseplanCard extends LitElement {
       if (e?.code === 'conflict' || e?.code === 'space_in_use') {
         await Promise.all([this._reloadConfigOnly(true), this._reloadLayoutOnly()]);
       }
-      if (this._spaceDialog) {
+      const refreshedConfig = this._serverCfg;
+      if (this._spaceDialog && refreshedConfig) {
         const refreshed = collectSpaceMarkerDependencies(
-          this._serverCfg, this._layout || {}, d.spaceId || '',
+          refreshedConfig, this._layout || {}, d.spaceId || '',
         );
-        this._spaceDialog = { ...this._spaceDialog, busy: false, deleteBlockers: refreshed.count };
+        const stillLastSpace = refreshedConfig.spaces.length === 1
+          && refreshedConfig.spaces[0]?.id === d.spaceId;
+        this._spaceDialog = {
+          ...this._spaceDialog,
+          busy: false,
+          deleteBlockers: stillLastSpace ? 0 : refreshed.count,
+        };
       }
       this._showToast(this._t('toast.delete_failed', { err: this._errText(e) }));
     }

src/space-deletion.ts

@@ -34,7 +34,9 @@ export function createSpaceDeletionCandidate(
   const dependencies = collectSpaceMarkerDependencies(configIn, layoutIn, spaceId);
   const config = clone(configIn);
   const layout = clone(layoutIn || {});
-  if (dependencies.count) return { config, layout, dependencies };
+  const spaces = config.spaces || [];
+  const deletingLastSpace = spaces.length === 1 && spaces[0]?.id === spaceId;
+  if (dependencies.count && !deletingLastSpace) return { config, layout, dependencies };
 
   const space = (config.spaces || []).find((item: any) => item?.id === spaceId);
   const roomIds = new Set(
@@ -42,6 +44,16 @@ export function createSpaceDeletionCandidate(
   );
   config.spaces = (config.spaces || []).filter((item: any) => item?.id !== spaceId);
   for (const marker of config.markers || []) {
+    const markerOwnsPosition = typeof marker?.id === 'string'
+      && layout?.[marker.id]?.s === spaceId;
+    const referencesDeletedSpace = marker?.space === spaceId
+      || (typeof marker?.room_id === 'string' && roomIds.has(marker.room_id))
+      || markerOwnsPosition;
+    if (deletingLastSpace && referencesDeletedSpace) {
+      delete marker.space;
+      delete marker.room_id;
+      continue;
+    }
     if (marker?.removed !== true) continue;
     if (marker.space === spaceId) delete marker.space;
     if (typeof marker.room_id === 'string' && roomIds.has(marker.room_id)) delete marker.room_id;