1 files changed, 97 insertions, 0 deletions
diff --git a/src/ui/style/StyleRuleSet.cpp b/src/ui/style/StyleRuleSet.cpp
new file mode 100644
index 00000000..537d1956
--- /dev/null
+++ b/src/ui/style/StyleRuleSet.cpp
@@ -0,0 +1,97 @@
+#include "cru/ui/style/StyleRuleSet.hpp"
+#include "cru/common/Event.hpp"
+#include "cru/ui/controls/Control.hpp"
+#include "gsl/gsl_assert"
+
+#include <unordered_set>
+
+namespace cru::ui::style {
+StyleRuleSet::StyleRuleSet(StyleRuleSet* parent) { SetParent(parent); }
+
+void StyleRuleSet::SetParent(StyleRuleSet* parent) {
+  if (parent == parent_) return;
+  parent_change_event_guard_.Reset();
+  parent_ = parent;
+  if (parent != nullptr) {
+    parent_change_event_guard_.Reset(parent->ChangeEvent()->AddSpyOnlyHandler(
+        [this] { this->RaiseChangeEvent(); }));
+  }
+  RaiseChangeEvent();
+}
+
+void StyleRuleSet::AddStyleRule(StyleRule rule, gsl::index index) {
+  Expects(index >= 0 && index <= GetSize());
+
+  rules_.insert(rules_.cbegin() + index, std::move(rule));
+
+  RaiseChangeEvent();
+}
+
+void StyleRuleSet::RemoveStyleRule(gsl::index index, gsl::index count) {
+  Expects(index >= 0);
+  Expects(count >= 0 && index + count <= GetSize());
+
+  rules_.erase(rules_.cbegin() + index, rules_.cbegin() + index + count);
+
+  RaiseChangeEvent();
+}
+
+void StyleRuleSet::Set(const StyleRuleSet& other, bool set_parent) {
+  rules_ = other.rules_;
+  if (set_parent) parent_ = other.parent_;
+
+  RaiseChangeEvent();
+}
+
+StyleRuleSetBind::StyleRuleSetBind(controls::Control* control,
+                                   StyleRuleSet* ruleset)
+    : control_(control), ruleset_(ruleset) {
+  Expects(control);
+  Expects(ruleset);
+
+  ruleset->ChangeEvent()->AddSpyOnlyHandler([this] {
+    UpdateRuleSetChainCache();
+    UpdateChangeListener();
+    UpdateStyle();
+  });
+}
+
+void StyleRuleSetBind::UpdateRuleSetChainCache() {
+  ruleset_chain_cache_.clear();
+  auto parent = ruleset_;
+  while (parent != nullptr) {
+    ruleset_chain_cache_.push_back(parent);
+    parent = parent->GetParent();
+  }
+}
+
+void StyleRuleSetBind::UpdateChangeListener() {
+  guard_.Clear();
+
+  std::unordered_set<IBaseEvent*> events;
+
+  // ruleset order does not matter
+  for (auto ruleset : ruleset_chain_cache_) {
+    for (const auto& rule : ruleset->GetRules()) {
+      auto e = rule.GetCondition()->ChangeOn(control_);
+      events.insert(e.cbegin(), e.cend());
+    }
+  }
+
+  for (auto e : events) {
+    guard_ += e->AddSpyOnlyHandler([this] { this->UpdateStyle(); });
+  }
+}
+
+void StyleRuleSetBind::UpdateStyle() {
+  // cache is parent last, but when calculate style, parent first, so iterate
+  // reverse.
+  for (auto iter = ruleset_chain_cache_.crbegin();
+       iter != ruleset_chain_cache_.crend(); ++iter) {
+    for (const auto& rule : (*iter)->GetRules())
+      if (rule.GetCondition()->Judge(control_)) {
+        rule.GetStyler()->Apply(control_);
+      }
+  }
+}
+}  // namespace cru::ui::style