fix issue where construction sites could not be selected

src/ui/SelectedBuildingPanel.cpp

@@ -168,7 +168,43 @@ void SelectedBuildingPanel::buildSingle(EntityId id)
     const Building* b = m_sim->buildings().findBuilding(id);
     if (!b)
     {
-        buildEmpty();
+        const ConstructionSite* s = m_sim->buildings().findSite(id);
+        if (!s)
+        {
+            buildEmpty();
+            return;
+        }
+
+        QString progress;
+        if (s->completesAt == 0)
+        {
+            progress = "Queued";
+        }
+        else
+        {
+            const BuildingDef* def = nullptr;
+            for (const BuildingDef& d : m_config->buildings.buildings)
+            {
+                if (d.type == s->type) { def = &d; break; }
+            }
+            if (def && def->constructionTimeSeconds > 0)
+            {
+                const Tick duration = secondsToTicks(def->constructionTimeSeconds);
+                const Tick elapsed  = m_sim->currentTick() - (s->completesAt - duration);
+                const int pct = static_cast<int>(
+                    std::max(Tick(0), std::min(duration, elapsed)) * 100 / duration);
+                progress = QString::number(pct) + "% complete";
+            }
+            else
+            {
+                progress = "Building...";
+            }
+        }
+
+        m_titleLabel->setText("(Building) " + buildingTypeName(s->type));
+        m_titleLabel->show();
+        m_buffersLabel->setText(progress);
+        m_buffersLabel->show();
         return;
     }
 
@@ -367,12 +403,27 @@ void SelectedBuildingPanel::onStateUpdated(Tick /*tick*/, int /*blocks*/, double
 {
     if (m_singleId == kInvalidEntityId) { return; }
     const Building* b = m_sim->buildings().findBuilding(m_singleId);
-    if (!b)
+    if (b)
     {
-        buildEmpty();
+        // If the panel was last showing this id as a construction site, the
+        // full building UI (recipe combo, ports, etc.) hasn't been built yet.
+        if (m_titleLabel->text().startsWith("(Building) "))
+        {
+            rebuild();
+        }
+        else
+        {
+            refreshBuffers(b);
+        }
         return;
     }
-    refreshBuffers(b);
+    const ConstructionSite* s = m_sim->buildings().findSite(m_singleId);
+    if (s)
+    {
+        rebuild();
+        return;
+    }
+    buildEmpty();
 }
 
 void SelectedBuildingPanel::buildMulti(const std::vector<EntityId>& ids)
@@ -393,6 +444,12 @@ void SelectedBuildingPanel::buildMulti(const std::vector<EntityId>& ids)
         if (b)
         {
             counts[b->type]++;
+            continue;
+        }
+        const ConstructionSite* s = m_sim->buildings().findSite(id);
+        if (s)
+        {
+            counts[s->type]++;
         }
     }