4 files changed, 227 insertions, 0 deletions
diff --git a/src/ui/style/Condition.cpp b/src/ui/style/Condition.cpp
new file mode 100644
index 00000000..f4866c04
--- /dev/null
+++ b/src/ui/style/Condition.cpp
@@ -0,0 +1,84 @@
+#include "cru/ui/style/Condition.hpp"
+#include <memory>
+
+#include "cru/common/ClonablePtr.hpp"
+#include "cru/common/Event.hpp"
+#include "cru/ui/controls/Control.hpp"
+#include "cru/ui/controls/IClickableControl.hpp"
+#include "cru/ui/helper/ClickDetector.hpp"
+
+namespace cru::ui::style {
+CompoundCondition::CompoundCondition(
+    std::vector<ClonablePtr<Condition>> conditions)
+    : conditions_(std::move(conditions)) {}
+
+std::vector<IBaseEvent*> CompoundCondition::ChangeOn(
+    controls::Control* control) const {
+  std::vector<IBaseEvent*> result;
+
+  for (auto condition : conditions_) {
+    for (auto e : condition->ChangeOn(control)) {
+      result.push_back(e);
+    }
+  }
+
+  return result;
+}
+
+bool AndCondition::Judge(controls::Control* control) const {
+  for (auto condition : conditions_) {
+    if (!condition->Judge(control)) return false;
+  }
+  return true;
+}
+
+bool OrCondition::Judge(controls::Control* control) const {
+  for (auto condition : conditions_) {
+    if (condition->Judge(control)) return true;
+  }
+  return false;
+}
+
+FocusCondition::FocusCondition(bool has_focus) : has_focus_(has_focus) {}
+
+std::vector<IBaseEvent*> FocusCondition::ChangeOn(
+    controls::Control* control) const {
+  return {control->GainFocusEvent()->Direct(),
+          control->LoseFocusEvent()->Direct()};
+}
+
+bool FocusCondition::Judge(controls::Control* control) const {
+  return control->HasFocus() == has_focus_;
+}
+
+std::vector<IBaseEvent*> HoverCondition::ChangeOn(
+    controls::Control* control) const {
+  return {control->MouseEnterEvent()->Direct(),
+          control->MouseLeaveEvent()->Direct()};
+}
+
+bool HoverCondition::Judge(controls::Control* control) const {
+  return control->IsMouseOver() == hover_;
+}
+
+ClickStateCondition::ClickStateCondition(helper::ClickState click_state)
+    : click_state_(click_state) {}
+
+std::vector<IBaseEvent*> ClickStateCondition::ChangeOn(
+    controls::Control* control) const {
+  auto clickable_control = dynamic_cast<controls::IClickableControl*>(control);
+  if (clickable_control) {
+    return {clickable_control->ClickStateChangeEvent()};
+  } else {
+    return {};
+  }
+}
+
+bool ClickStateCondition::Judge(controls::Control* control) const {
+  auto clickable_control = dynamic_cast<controls::IClickableControl*>(control);
+  if (clickable_control) {
+    return clickable_control->GetClickState() == click_state_;
+  }
+  return false;
+}
+}  // namespace cru::ui::style
diff --git a/src/ui/style/StyleRule.cpp b/src/ui/style/StyleRule.cpp
new file mode 100644
index 00000000..1a72a970
--- /dev/null
+++ b/src/ui/style/StyleRule.cpp
@@ -0,0 +1,17 @@
+#include "cru/ui/style/StyleRule.hpp"
+
+namespace cru::ui::style {
+StyleRule::StyleRule(ClonablePtr<Condition> condition,
+                     ClonablePtr<Styler> styler, std::u16string name)
+    : condition_(std::move(condition)),
+      styler_(std::move(styler)),
+      name_(std::move(name)) {}
+
+bool StyleRule::CheckAndApply(controls::Control *control) const {
+  auto active = condition_->Judge(control);
+  if (active) {
+    styler_->Apply(control);
+  }
+  return active;
+}
+}  // namespace cru::ui::style
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
diff --git a/src/ui/style/Styler.cpp b/src/ui/style/Styler.cpp
new file mode 100644
index 00000000..da3a2247
--- /dev/null
+++ b/src/ui/style/Styler.cpp
@@ -0,0 +1,29 @@
+#include "cru/ui/style/Styler.hpp"
+
+#include "../Helper.hpp"
+#include "cru/common/ClonablePtr.hpp"
+#include "cru/platform/gui/Cursor.hpp"
+#include "cru/platform/gui/UiApplication.hpp"
+#include "cru/ui/controls/Control.hpp"
+#include "cru/ui/controls/IBorderControl.hpp"
+#include "cru/ui/style/ApplyBorderStyleInfo.hpp"
+
+namespace cru::ui::style {
+BorderStyler::BorderStyler(ApplyBorderStyleInfo style)
+    : style_(std::move(style)) {}
+
+void BorderStyler::Apply(controls::Control *control) const {
+  if (auto border_control = dynamic_cast<controls::IBorderControl *>(control)) {
+    border_control->ApplyBorderStyle(style_);
+  }
+}
+
+ClonablePtr<CursorStyler> CursorStyler::Create(
+    platform::gui::SystemCursorType type) {
+  return Create(GetUiApplication()->GetCursorManager()->GetSystemCursor(type));
+}
+
+void CursorStyler::Apply(controls::Control *control) const {
+  control->SetCursor(cursor_);
+}
+}  // namespace cru::ui::style