split the selection panel into one card per kind of selection

src/ui/selection/ProductionSection.cpp

@@ -0,0 +1,53 @@
+#include "ProductionSection.h"
+
+#include <algorithm>
+
+#include <QLabel>
+#include <QVBoxLayout>
+
+#include "Building.h"
+
+ProductionSection::ProductionSection(QWidget* parent)
+    : QWidget(parent)
+{
+    QVBoxLayout* layout = new QVBoxLayout(this);
+    layout->setContentsMargins(0, 0, 0, 0);
+    layout->setSpacing(0);
+
+    m_label = new QLabel(this);
+    layout->addWidget(m_label);
+}
+
+void ProductionSection::setProduction(bool runsProduction, const Building& building,
+                                      double durationSeconds, Tick currentTick)
+{
+    // Nothing selected to produce means neither a cycle time nor a progress indicator
+    // (REQ-UI-PRODUCTION-PROGRESS).
+    if (!runsProduction)
+    {
+        hide();
+        return;
+    }
+
+    QString text;
+    if (durationSeconds > 0.0)
+    {
+        text = tr("Cycle: %1 s\n").arg(durationSeconds, 0, 'f', 1);
+    }
+    if (durationSeconds > 0.0 && building.production.has_value())
+    {
+        const Tick cycleTicks = secondsToTicks(durationSeconds);
+        const Tick elapsed =
+            currentTick - (building.production->completesAt - cycleTicks);
+        const int percent = static_cast<int>(
+            std::max(Tick(0), std::min(cycleTicks, elapsed)) * 100 / cycleTicks);
+        text += tr("Progress: %1%").arg(percent);
+    }
+    else
+    {
+        text += tr("Progress: idle");
+    }
+
+    m_label->setText(text);
+    show();
+}