show recipes visually instead of describing them in text

src/ui/selection/ItemChip.h

@@ -1,28 +1,51 @@
 #pragma once
 
+#include <string>
+
 #include <QPixmap>
 #include <QString>
 #include <QWidget>
 
+#include "SelectionContext.h"
+
+class ItemTooltip;
+class QEvent;
 class QLabel;
+class QTimer;
 
 // One buffered item: its icon, its count in a larger type, and a sub-line beneath the
 // count (REQ-UI-SINGLE-SELECTION). Boxed so a row of them reads as separate quantities
 // rather than as a run of text.
+//
+// Hovering it explains where its item comes from (REQ-UI-ITEM-TOOLTIP).
 class ItemChip : public QWidget
 {
     Q_OBJECT
 
 public:
     // An empty icon leaves the icon off and the chip laid out around the text alone.
-    ItemChip(const QPixmap& icon, QWidget* parent = nullptr);
+    ItemChip(const SelectionContext& context, const std::string& itemId,
+             const QPixmap& icon, QWidget* parent = nullptr);
 
     void setCount(const QString& count);
     // Left empty for an item with nothing to say beneath its count.
     void setSubLine(const QString& subLine);
 
+protected:
+    void enterEvent(QEvent* event) override;
+    void leaveEvent(QEvent* event) override;
+
 private:
-    QLabel* m_iconLabel;
-    QLabel* m_countLabel;
-    QLabel* m_subLineLabel;
+    void showTooltip();
+
+    SelectionContext m_context;
+    std::string      m_itemId;
+    QLabel*          m_iconLabel;
+    QLabel*          m_countLabel;
+    QLabel*          m_subLineLabel;
+    // Held back so a cursor crossing the chip on its way elsewhere does not flash the
+    // tooltip, the way an ordinary tooltip is.
+    QTimer*          m_hoverTimer;
+    // Built on the first hover, because most chips are never hovered at all.
+    ItemTooltip*     m_tooltip = nullptr;
 };