Extract XCUI text input controller to common layer

tests/Core/UI/CMakeLists.txt

@@ -7,6 +7,7 @@ set(UI_TEST_SOURCES
     test_layout_engine.cpp
     test_ui_runtime.cpp
     test_ui_text_editing.cpp
+    test_ui_text_input_controller.cpp
 )
 
 add_executable(core_ui_tests ${UI_TEST_SOURCES})

tests/Core/UI/test_ui_text_input_controller.cpp

@@ -0,0 +1,115 @@
+#include <gtest/gtest.h>
+
+#include <XCEngine/Input/InputTypes.h>
+#include <XCEngine/UI/Text/UITextInputController.h>
+
+namespace {
+
+namespace UIText = XCEngine::UI::Text;
+using XCEngine::Input::KeyCode;
+
+TEST(UITextInputControllerTest, InsertCharacterTracksUtf8CaretMovement) {
+    UIText::UITextInputState state = {};
+
+    EXPECT_TRUE(UIText::InsertCharacter(state, 'A'));
+    EXPECT_TRUE(UIText::InsertCharacter(state, 0x4F60u));
+    EXPECT_EQ(state.value, std::string("A") + "\xE4\xBD\xA0");
+    EXPECT_EQ(state.caret, state.value.size());
+}
+
+TEST(UITextInputControllerTest, BackspaceAndArrowKeysUseUtf8Boundaries) {
+    UIText::UITextInputState state = {};
+    state.value = std::string("A") + "\xE4\xBD\xA0" + "B";
+    state.caret = state.value.size();
+
+    const auto moveLeft = UIText::HandleKeyDown(
+        state,
+        static_cast<std::int32_t>(KeyCode::Left),
+        {},
+        {});
+    EXPECT_TRUE(moveLeft.handled);
+    EXPECT_EQ(state.caret, 4u);
+
+    const auto backspace = UIText::HandleKeyDown(
+        state,
+        static_cast<std::int32_t>(KeyCode::Backspace),
+        {},
+        {});
+    EXPECT_TRUE(backspace.handled);
+    EXPECT_TRUE(backspace.valueChanged);
+    EXPECT_EQ(state.value, "AB");
+    EXPECT_EQ(state.caret, 1u);
+}
+
+TEST(UITextInputControllerTest, SingleLineEnterRequestsSubmitWithoutMutatingValue) {
+    UIText::UITextInputState state = {};
+    state.value = "prompt";
+    state.caret = state.value.size();
+
+    const auto result = UIText::HandleKeyDown(
+        state,
+        static_cast<std::int32_t>(KeyCode::Enter),
+        {},
+        {});
+    EXPECT_TRUE(result.handled);
+    EXPECT_FALSE(result.valueChanged);
+    EXPECT_TRUE(result.submitRequested);
+    EXPECT_EQ(state.value, "prompt");
+}
+
+TEST(UITextInputControllerTest, MultilineEnterAndVerticalMovementStayInController) {
+    UIText::UITextInputState state = {};
+    state.value = std::string("A") + "\xE4\xBD\xA0" + "Z\nBC";
+    state.caret = 4u;
+
+    const UIText::UITextInputOptions options = { true, 4u };
+
+    const auto moveDown = UIText::HandleKeyDown(
+        state,
+        static_cast<std::int32_t>(KeyCode::Down),
+        {},
+        options);
+    EXPECT_TRUE(moveDown.handled);
+    EXPECT_EQ(state.caret, 8u);
+
+    const auto enter = UIText::HandleKeyDown(
+        state,
+        static_cast<std::int32_t>(KeyCode::Enter),
+        {},
+        options);
+    EXPECT_TRUE(enter.handled);
+    EXPECT_TRUE(enter.valueChanged);
+    EXPECT_EQ(state.value, std::string("A") + "\xE4\xBD\xA0" + "Z\nBC\n");
+}
+
+TEST(UITextInputControllerTest, MultilineTabAndShiftTabIndentAndOutdentCurrentLine) {
+    UIText::UITextInputState state = {};
+    state.value = "root\nnode";
+    state.caret = 5u;
+
+    const UIText::UITextInputOptions options = { true, 4u };
+
+    const auto indent = UIText::HandleKeyDown(
+        state,
+        static_cast<std::int32_t>(KeyCode::Tab),
+        {},
+        options);
+    EXPECT_TRUE(indent.handled);
+    EXPECT_TRUE(indent.valueChanged);
+    EXPECT_EQ(state.value, "root\n    node");
+    EXPECT_EQ(state.caret, 9u);
+
+    XCEngine::UI::UIInputModifiers modifiers = {};
+    modifiers.shift = true;
+    const auto outdent = UIText::HandleKeyDown(
+        state,
+        static_cast<std::int32_t>(KeyCode::Tab),
+        modifiers,
+        options);
+    EXPECT_TRUE(outdent.handled);
+    EXPECT_TRUE(outdent.valueChanged);
+    EXPECT_EQ(state.value, "root\nnode");
+    EXPECT_EQ(state.caret, 5u);
+}
+
+} // namespace