DEV: Add property value validation to ThemeSettingsObjectValidator (#25718)

Why this change?

This change adds property value validation to `ThemeSettingsObjectValidator`
for the following types: "string", "integer", "float", "boolean", "enum". Note
that this class is not being used anywhere yet and is still in
development.

lib/theme_settings_object_validator.rb

@@ -9,7 +9,7 @@ class ThemeSettingsObjectValidator
   end
 
   def validate
-    validate_required_properties
+    validate_properties
 
     @properties.each do |property_name, property_attributes|
       if property_attributes[:type] == "objects"
@@ -28,12 +28,56 @@ class ThemeSettingsObjectValidator
 
   private
 
-  def validate_required_properties
+  def validate_properties
     @properties.each do |property_name, property_attributes|
-      if property_attributes[:required] && @object[property_name].nil?
-        @errors[property_name] ||= []
-        @errors[property_name] << I18n.t("themes.settings_errors.objects.required")
-      end
+      next if property_attributes[:required] && validate_required_property(property_name)
+      validate_property_type(property_attributes, property_name)
     end
   end
+
+  def validate_property_type(property_attributes, property_name)
+    value = @object[property_name]
+    type = property_attributes[:type]
+
+    return if (value.nil? && type != "enum")
+    return if type == "objects"
+
+    is_value_valid =
+      case type
+      when "string"
+        value.is_a?(String)
+      when "integer"
+        value.is_a?(Integer)
+      when "float"
+        value.is_a?(Float) || value.is_a?(Integer)
+      when "boolean"
+        [true, false].include?(value)
+      when "enum"
+        property_attributes[:choices].include?(value)
+      else
+        add_error(property_name, I18n.t("themes.settings_errors.objects.invalid_type", type:))
+        return
+      end
+
+    if !is_value_valid
+      add_error(
+        property_name,
+        I18n.t("themes.settings_errors.objects.not_valid_#{type}_value", property_attributes),
+      )
+    end
+  end
+
+  def validate_required_property(property_name)
+    if @object[property_name].nil?
+      add_error(property_name, I18n.t("themes.settings_errors.objects.required"))
+      true
+    else
+      false
+    end
+  end
+
+  def add_error(property_name, error)
+    @errors[property_name] ||= []
+    @errors[property_name] << error
+  end
 end