Add XCUI runtime screen stack helper

engine/src/UI/Runtime/UIScreenStackController.cpp

@@ -0,0 +1,148 @@
+#include <XCEngine/UI/Runtime/UIScreenStackController.h>
+
+#include <utility>
+
+namespace XCEngine {
+namespace UI {
+namespace Runtime {
+
+namespace {
+
+std::string ResolveDebugName(
+    const UIScreenAsset& asset,
+    const std::string& fallbackName,
+    const std::string& explicitName) {
+    if (!explicitName.empty()) {
+        return explicitName;
+    }
+    if (!asset.screenId.empty()) {
+        return asset.screenId;
+    }
+    return fallbackName;
+}
+
+} // namespace
+
+UIScreenStackController::UIScreenStackController(UISystem& system)
+    : m_system(&system) {
+}
+
+UIScreenLayerId UIScreenStackController::PushScreen(
+    const UIScreenAsset& asset,
+    const UIScreenLayerOptions& options) {
+    const UIScreenLayerId layerId = m_system != nullptr
+        ? m_system->PushScreen(asset, options)
+        : 0;
+    if (layerId == 0) {
+        return 0;
+    }
+
+    UIScreenStackEntry entry = {};
+    entry.layerId = layerId;
+    entry.asset = asset;
+    entry.options = options;
+    m_entries.push_back(std::move(entry));
+    return layerId;
+}
+
+UIScreenLayerId UIScreenStackController::PushMenu(
+    const UIScreenAsset& asset,
+    const std::string& debugName) {
+    UIScreenLayerOptions options = {};
+    options.debugName = ResolveDebugName(asset, "Menu", debugName);
+    options.acceptsInput = true;
+    options.blocksLayersBelow = true;
+    return PushScreen(asset, options);
+}
+
+UIScreenLayerId UIScreenStackController::PushModal(
+    const UIScreenAsset& asset,
+    const std::string& debugName) {
+    UIScreenLayerOptions options = {};
+    options.debugName = ResolveDebugName(asset, "Modal", debugName);
+    options.acceptsInput = true;
+    options.blocksLayersBelow = true;
+    return PushScreen(asset, options);
+}
+
+UIScreenLayerId UIScreenStackController::PushHud(
+    const UIScreenAsset& asset,
+    const std::string& debugName) {
+    UIScreenLayerOptions options = {};
+    options.debugName = ResolveDebugName(asset, "HUD", debugName);
+    options.acceptsInput = false;
+    options.blocksLayersBelow = false;
+    return PushScreen(asset, options);
+}
+
+bool UIScreenStackController::ReplaceTop(
+    const UIScreenAsset& asset,
+    const UIScreenLayerOptions& options) {
+    if (m_entries.empty()) {
+        return PushScreen(asset, options) != 0;
+    }
+
+    if (!Pop()) {
+        return false;
+    }
+
+    return PushScreen(asset, options) != 0;
+}
+
+bool UIScreenStackController::Pop() {
+    if (m_system == nullptr || m_entries.empty()) {
+        return false;
+    }
+
+    const UIScreenLayerId layerId = m_entries.back().layerId;
+    if (!m_system->RemoveLayer(layerId)) {
+        return false;
+    }
+
+    m_entries.pop_back();
+    return true;
+}
+
+bool UIScreenStackController::Remove(UIScreenLayerId layerId) {
+    if (m_system == nullptr) {
+        return false;
+    }
+
+    for (std::size_t index = 0; index < m_entries.size(); ++index) {
+        if (m_entries[index].layerId != layerId) {
+            continue;
+        }
+
+        if (!m_system->RemoveLayer(layerId)) {
+            return false;
+        }
+
+        m_entries.erase(m_entries.begin() + static_cast<std::ptrdiff_t>(index));
+        return true;
+    }
+
+    return false;
+}
+
+void UIScreenStackController::Clear() {
+    if (m_system != nullptr) {
+        m_system->DestroyAllPlayers();
+    }
+    m_entries.clear();
+}
+
+std::size_t UIScreenStackController::GetEntryCount() const {
+    return m_entries.size();
+}
+
+const UIScreenStackEntry* UIScreenStackController::GetTop() const {
+    return m_entries.empty() ? nullptr : &m_entries.back();
+}
+
+const std::vector<UIScreenStackEntry>& UIScreenStackController::GetEntries() const {
+    return m_entries;
+}
+
+} // namespace Runtime
+} // namespace UI
+} // namespace XCEngine