Refactor new editor boundaries and test ownership

new_editor/app/Platform/Win32/WindowManager/TabDragDropTarget.cpp

@@ -0,0 +1,116 @@
+#include "Platform/Win32/WindowManager/TabDragDropTarget.h"
+
+#include <algorithm>
+
+namespace XCEngine::UI::Editor::App::Internal {
+
+namespace {
+
+using ::XCEngine::UI::UIPoint;
+using ::XCEngine::UI::UIRect;
+
+bool IsPointInsideRect(const UIRect& rect, const UIPoint& point) {
+    return point.x >= rect.x &&
+        point.x <= rect.x + rect.width &&
+        point.y >= rect.y &&
+        point.y <= rect.y + rect.height;
+}
+
+std::size_t ResolveDropInsertionIndex(
+    const Widgets::UIEditorDockHostTabStackLayout& tabStack,
+    const UIPoint& point) {
+    if (!IsPointInsideRect(tabStack.tabStripLayout.headerRect, point)) {
+        return Widgets::UIEditorTabStripInvalidIndex;
+    }
+
+    std::size_t insertionIndex = 0u;
+    for (const UIRect& rect : tabStack.tabStripLayout.tabHeaderRects) {
+        const float midpoint = rect.x + rect.width * 0.5f;
+        if (point.x > midpoint) {
+            ++insertionIndex;
+        }
+    }
+    return insertionIndex;
+}
+
+UIEditorWorkspaceDockPlacement ResolveDropPlacement(
+    const Widgets::UIEditorDockHostTabStackLayout& tabStack,
+    const UIPoint& point) {
+    if (IsPointInsideRect(tabStack.tabStripLayout.headerRect, point)) {
+        return UIEditorWorkspaceDockPlacement::Center;
+    }
+
+    const float leftDistance = point.x - tabStack.bounds.x;
+    const float rightDistance = tabStack.bounds.x + tabStack.bounds.width - point.x;
+    const float topDistance = point.y - tabStack.bounds.y;
+    const float bottomDistance = tabStack.bounds.y + tabStack.bounds.height - point.y;
+    const float minHorizontalThreshold = tabStack.bounds.width * 0.25f;
+    const float minVerticalThreshold = tabStack.bounds.height * 0.25f;
+    const float nearestEdge = (std::min)(
+        (std::min)(leftDistance, rightDistance),
+        (std::min)(topDistance, bottomDistance));
+
+    if (nearestEdge == leftDistance && leftDistance <= minHorizontalThreshold) {
+        return UIEditorWorkspaceDockPlacement::Left;
+    }
+    if (nearestEdge == rightDistance && rightDistance <= minHorizontalThreshold) {
+        return UIEditorWorkspaceDockPlacement::Right;
+    }
+    if (nearestEdge == topDistance && topDistance <= minVerticalThreshold) {
+        return UIEditorWorkspaceDockPlacement::Top;
+    }
+    if (nearestEdge == bottomDistance && bottomDistance <= minVerticalThreshold) {
+        return UIEditorWorkspaceDockPlacement::Bottom;
+    }
+
+    return UIEditorWorkspaceDockPlacement::Center;
+}
+
+} // namespace
+
+EditorWindowTabDragDropTarget ResolveEditorWindowTabDragDropTarget(
+    const Widgets::UIEditorDockHostLayout& layout,
+    const UIPoint& point) {
+    EditorWindowTabDragDropTarget result = {};
+    if (!IsPointInsideRect(layout.bounds, point)) {
+        return result;
+    }
+
+    const Widgets::UIEditorDockHostHitTarget hitTarget =
+        Widgets::HitTestUIEditorDockHost(layout, point);
+    for (const Widgets::UIEditorDockHostTabStackLayout& tabStack : layout.tabStacks) {
+        if ((!hitTarget.nodeId.empty() && tabStack.nodeId != hitTarget.nodeId) ||
+            !IsPointInsideRect(tabStack.bounds, point)) {
+            continue;
+        }
+
+        result.valid = true;
+        result.nodeId = tabStack.nodeId;
+        result.placement = ResolveDropPlacement(tabStack, point);
+        if (result.placement == UIEditorWorkspaceDockPlacement::Center) {
+            result.insertionIndex = ResolveDropInsertionIndex(tabStack, point);
+            if (result.insertionIndex == Widgets::UIEditorTabStripInvalidIndex) {
+                result.insertionIndex = tabStack.items.size();
+            }
+        }
+        return result;
+    }
+
+    for (const Widgets::UIEditorDockHostTabStackLayout& tabStack : layout.tabStacks) {
+        if (!IsPointInsideRect(tabStack.bounds, point)) {
+            continue;
+        }
+
+        result.valid = true;
+        result.nodeId = tabStack.nodeId;
+        result.placement = ResolveDropPlacement(tabStack, point);
+        if (result.placement == UIEditorWorkspaceDockPlacement::Center) {
+            result.insertionIndex = tabStack.items.size();
+        }
+        return result;
+    }
+
+    return result;
+}
+
+} // namespace XCEngine::UI::Editor::App::Internal