1 files changed, 87 insertions, 0 deletions
diff --git a/include/cru/ui/style/StyleRuleSet.hpp b/include/cru/ui/style/StyleRuleSet.hpp
new file mode 100644
index 00000000..e62dd2de
--- /dev/null
+++ b/include/cru/ui/style/StyleRuleSet.hpp
@@ -0,0 +1,87 @@
+#pragma once
+#include "StyleRule.hpp"
+#include "cru/common/Base.hpp"
+#include "cru/common/Event.hpp"
+
+#include <cstddef>
+
+namespace cru::ui::style {
+class StyleRuleSet : public Object {
+ public:
+  StyleRuleSet() = default;
+  explicit StyleRuleSet(StyleRuleSet* parent);
+
+  CRU_DELETE_COPY(StyleRuleSet)
+  CRU_DELETE_MOVE(StyleRuleSet)
+
+  ~StyleRuleSet() override = default;
+
+ public:
+  StyleRuleSet* GetParent() const { return parent_; }
+  void SetParent(StyleRuleSet* parent);
+
+  gsl::index GetSize() const { return static_cast<gsl::index>(rules_.size()); }
+  const std::vector<StyleRule>& GetRules() const { return rules_; }
+
+  void AddStyleRule(StyleRule rule) {
+    AddStyleRule(std::move(rule), GetSize());
+  }
+
+  void AddStyleRule(StyleRule rule, gsl::index index);
+
+  template <typename Iter>
+  void AddStyleRuleRange(Iter start, Iter end, gsl::index index) {
+    Expects(index >= 0 && index <= GetSize());
+    rules_.insert(rules_.cbegin() + index, std::move(start), std::move(end));
+    UpdateChangeListener();
+    UpdateStyle();
+  }
+
+  void RemoveStyleRule(gsl::index index, gsl::index count = 1);
+
+  void Clear() { RemoveStyleRule(0, GetSize()); }
+
+  void Set(const StyleRuleSet& other, bool set_parent = false);
+
+  const StyleRule& operator[](gsl::index index) const { return rules_[index]; }
+
+  // Triggered whenever a change happened to this (rule add or remove, parent
+  // change ...). Subscribe to this and update style change listeners and style.
+  IEvent<std::nullptr_t>* ChangeEvent() { return &change_event_; }
+
+ private:
+  void RaiseChangeEvent() { change_event_.Raise(nullptr); }
+
+ private:
+  Event<std::nullptr_t> change_event_;
+
+  StyleRuleSet* parent_ = nullptr;
+  EventRevokerGuard parent_change_event_guard_;
+
+  std::vector<StyleRule> rules_;
+};
+
+class StyleRuleSetBind {
+ public:
+  StyleRuleSetBind(controls::Control* control, StyleRuleSet* ruleset);
+
+  CRU_DELETE_COPY(StyleRuleSetBind)
+  CRU_DELETE_MOVE(StyleRuleSetBind)
+
+  ~StyleRuleSetBind() = default;
+
+ private:
+  void UpdateRuleSetChainCache();
+  void UpdateChangeListener();
+  void UpdateStyle();
+
+ private:
+  controls::Control* control_;
+  StyleRuleSet* ruleset_;
+
+  // child first, parent last.
+  std::vector<StyleRuleSet*> ruleset_chain_cache_;
+
+  EventRevokerListGuard guard_;
+};
+}  // namespace cru::ui::style