Add the sidebar's "Advances to" tooltip to the recruit/recall dialogs

Fixes #4135

This commit:
- Moves creation of the tooltip text to a helper function.
- Converts the dialog's label to a styled_widget to allow setting a
  tooltip.

src/gui/widgets/unit_preview_pane.cpp

@@ -77,7 +77,7 @@ void unit_preview_pane::finalize_setup()
 
 	// Labels
 	label_name_             = find_widget<label>(this, "type_name", false, false);
-	label_level_            = find_widget<label>(this, "type_level", false, false);
+	label_level_            = find_widget<styled_widget>(this, "type_level", false, false);
 	label_race_             = find_widget<label>(this, "type_race_label", false, false);
 	label_details_          = find_widget<styled_widget>(this, "type_details_minimal", false, false);
 
@@ -292,7 +292,11 @@ void unit_preview_pane::set_displayed_type(const unit_type& type)
 	if(label_level_) {
 		std::string l_str = VGETTEXT("Lvl $lvl", {{"lvl", std::to_string(type.level())}});
 
-		label_level_->set_label("<b>" + l_str + "</b>");
+		label_level_->set_members({
+			{ "label", "<b>" + l_str + "</b>" },
+			{ "tooltip", unit_helper::unit_level_tooltip(type) }
+		});
+
 		label_level_->set_use_markup(true);
 	}
 
@@ -443,7 +447,11 @@ void unit_preview_pane::set_displayed_unit(const unit& u)
 	if(label_level_) {
 		std::string l_str = VGETTEXT("Lvl $lvl", {{"lvl", std::to_string(u.level())}});
 
-		label_level_->set_label("<b>" + l_str + "</b>");
+		label_level_->set_members({
+			{ "label", "<b>" + l_str + "</b>" },
+			{ "tooltip", unit_helper::unit_level_tooltip(u) }
+		});
+
 		label_level_->set_use_markup(true);
 	}
 

src/gui/widgets/unit_preview_pane.hpp

@@ -81,7 +81,7 @@ class unit_preview_pane : public container_base
 	image* icon_alignment_;
 
 	label* label_name_;
-	label* label_level_;
+	styled_widget* label_level_;
 	label* label_race_;
 
 	styled_widget* label_details_;

src/reports.cpp

@@ -263,27 +263,7 @@ static config unit_level(const unit* u)
 	if (!u) return config();
 	std::ostringstream str, tooltip;
 	str << u->level();
-	tooltip << _("Level: ") << "<b>" << u->level() << "</b>\n";
-	const std::vector<std::string> &adv_to_types = u->advances_to_translated();
-	const std::vector<config> &adv_to_mods = u->get_modification_advances();
-	const bool has_advancements = !adv_to_types.empty() || !adv_to_mods.empty();
-	if(has_advancements) {
-		tooltip << _("Advancements:") << "\n<b>\t";
-		if(!adv_to_types.empty())
-			tooltip << utils::join(adv_to_types, "\n\t");
-		if(!adv_to_mods.empty()) {
-			if(!adv_to_types.empty())
-				tooltip << "\n\t";
-			std::vector<std::string> descriptions;
-			for(const config& adv : adv_to_mods)
-				descriptions.push_back(adv["description"].str());
-			tooltip << utils::join(descriptions, "\n\t");
-		}
-		tooltip << "</b>";
-	} else {
-		tooltip << _("No advancement");
-	}
-	return text_report(str.str(), tooltip.str());
+	return text_report(str.str(), unit_helper::unit_level_tooltip(*u));
 }
 REPORT_GENERATOR(unit_level, rc)
 {

src/units/helper.cpp

@@ -46,4 +46,41 @@ std::string resistance_color(const int resistance)
 	return std::string("#00FF00");
 }
 
+std::string unit_level_tooltip(const int level, const std::vector<std::string> &adv_to_types, const std::vector<config> &adv_to_mods)
+{
+	std::ostringstream tooltip;
+	tooltip << _("Level: ") << "<b>" << level << "</b>\n";
+	const bool has_advancements = !adv_to_types.empty() || !adv_to_mods.empty();
+	if(has_advancements) {
+		tooltip << _("Advancements:") << "\n<b>\t";
+		if(!adv_to_types.empty())
+			tooltip << utils::join(adv_to_types, "\n\t");
+		if(!adv_to_mods.empty()) {
+			if(!adv_to_types.empty())
+				tooltip << "\n\t";
+			std::vector<std::string> descriptions;
+			for(const config& adv : adv_to_mods)
+				descriptions.push_back(adv["description"].str());
+			tooltip << utils::join(descriptions, "\n\t");
+		}
+		tooltip << "</b>";
+	} else {
+		tooltip << _("No advancement");
+	}
+	return tooltip.str();
+}
+
+std::string unit_level_tooltip(const unit &u)
+{
+	return unit_level_tooltip(u.level(), u.advances_to_translated(), u.get_modification_advances());
+}
+
+std::string unit_level_tooltip(const unit_type &type)
+{
+	const auto mod_adv_iters = type.modification_advancements();
+	const std::vector<config> mod_advancements(mod_adv_iters.begin(), mod_adv_iters.end());
+
+	return unit_level_tooltip(type.level(), type.advances_to(), mod_advancements);
+}
+
 }

src/units/helper.hpp

@@ -40,4 +40,14 @@ int number_of_possible_advances(const unit &unit);
  */
 std::string resistance_color(const int resistance);
 
+/**
+ * @return the tooltip text showing a unit's level and what it can advance to.
+ */
+std::string unit_level_tooltip(const unit &u);
+
+/**
+ * @return the tooltip text showing a unit type's level and what it can
+ * advance to.
+ */
+std::string unit_level_tooltip(const unit_type &u);
 }