Clamp selected_ on list resize for Radiobox/Menu/Toggle (#298)

fix: https://github.com/ArthurSonzogni/FTXUI/issues/296#issue-1092343846

When the list in Radiobox/Menu/Toggle is resized, clamp the |selected_| values so that it stays within bounds.
Clamping is executed in Render() and in OnEvent()

Co-authored-by: ArthurSonzogni <sonzogniarthur@gmail.com>

src/ftxui/component/toggle.cpp

@@ -1,5 +1,4 @@
-#include <stddef.h>    // for size_t
-#include <algorithm>   // for max, min
+#include <algorithm>   // for clamp, max
 #include <functional>  // for function
 #include <memory>      // for shared_ptr, allocator_traits<>::value_type
 #include <utility>     // for move
@@ -13,7 +12,7 @@
 #include "ftxui/component/mouse.hpp"  // for Mouse, Mouse::Left, Mouse::Pressed
 #include "ftxui/dom/elements.hpp"  // for operator|, Element, Elements, hbox, reflect, separator, text, focus, nothing, select
 #include "ftxui/screen/box.hpp"    // for Box
-#include "ftxui/util/ref.hpp"      // for ConstStringListRef, Ref
+#include "ftxui/util/ref.hpp"      // for Ref, ConstStringListRef
 
 namespace ftxui {
 
@@ -30,16 +29,16 @@ class ToggleBase : public ComponentBase {
 
  private:
   Element Render() override {
+    Clamp();
     Elements children;
     bool is_toggle_focused = Focused();
-    boxes_.resize(entries_.size());
-    for (size_t i = 0; i < entries_.size(); ++i) {
+    for (int i = 0; i < size(); ++i) {
       // Separator.
       if (i != 0)
         children.push_back(separator());
 
-      bool is_focused = (focused_entry() == int(i)) && is_toggle_focused;
-      bool is_selected = (*selected_ == int(i));
+      bool is_focused = (focused_entry() == i) && is_toggle_focused;
+      bool is_selected = (*selected_ == i);
 
       auto style = is_selected ? (is_focused ? option_->style_selected_focused
                                              : option_->style_selected)
@@ -55,6 +54,7 @@ class ToggleBase : public ComponentBase {
   }
 
   bool OnEvent(Event event) override {
+    Clamp();
     if (event.is_mouse())
       return OnMouseEvent(event);
 
@@ -63,12 +63,12 @@ class ToggleBase : public ComponentBase {
       (*selected_)--;
     if (event == Event::ArrowRight || event == Event::Character('l'))
       (*selected_)++;
-    if (event == Event::Tab && entries_.size())
-      *selected_ = (*selected_ + 1) % entries_.size();
-    if (event == Event::TabReverse && entries_.size())
-      *selected_ = (*selected_ + entries_.size() - 1) % entries_.size();
+    if (event == Event::Tab && size())
+      *selected_ = (*selected_ + 1) % size();
+    if (event == Event::TabReverse && size())
+      *selected_ = (*selected_ + size() - 1) % size();
 
-    *selected_ = std::max(0, std::min(int(entries_.size()) - 1, *selected_));
+    *selected_ = std::clamp(*selected_, 0, size() - 1);
 
     if (old_selected != *selected_) {
       focused_entry() = *selected_;
@@ -87,7 +87,7 @@ class ToggleBase : public ComponentBase {
   bool OnMouseEvent(Event event) {
     if (!CaptureMouse(event))
       return false;
-    for (int i = 0; i < int(boxes_.size()); ++i) {
+    for (int i = 0; i < size(); ++i) {
       if (!boxes_[i].Contain(event.mouse().x, event.mouse().y))
         continue;
 
@@ -106,8 +106,15 @@ class ToggleBase : public ComponentBase {
     return false;
   }
 
-  bool Focusable() const final { return entries_.size(); }
+  void Clamp() {
+    boxes_.resize(size());
+    *selected_ = std::clamp(*selected_, 0, size() - 1);
+    focused_entry() = std::clamp(focused_entry(), 0, size() - 1);
+  }
+
+  bool Focusable() const final { return size(); }
   int& focused_entry() { return option_->focused_entry(); }
+  int size() const { return entries_.size(); }
 
   ConstStringListRef entries_;
   int* selected_ = 0;