StellarX-kaifa/include/StellarX/InputEvents.h

/*******************************************************************************
 * StellarX native keyboard, text, IME, and activation event model.
 * Stage 1 only captures, normalizes, queues, and observes these events.
 * Focus, routing, and control behavior are intentionally out of scope.
 ******************************************************************************/
#pragma once

#include <windows.h>

#include <cstdint>
#include <string>
#include <variant>

namespace StellarX
{
	enum class KeyAction : std::uint8_t
	{
		Down,
		Up
	};

	// Snapshot modifiers in WndProc; delayed consumers must not reread global state.
	struct KeyModifiers
	{
		bool leftControl = false;
		bool rightControl = false;
		bool leftShift = false;
		bool rightShift = false;
		bool leftAlt = false;
		bool rightAlt = false;

		bool control() const noexcept { return leftControl || rightControl; }
		bool shift() const noexcept { return leftShift || rightShift; }
		bool alt() const noexcept { return leftAlt || rightAlt; }
	};

	struct KeyEvent
	{
		KeyAction action = KeyAction::Down;

		UINT virtualKey = 0;          // Raw WndProc VK; VK_PROCESSKEY is never rewritten.
		UINT physicalVirtualKey = 0;  // Left/right-normalized modifier VK.
		UINT scanCode = 0;

		std::uint16_t repeatCount = 0;
		bool extended = false;
		bool wasDown = false;
		bool altContext = false; // Raw lParam bit 29; modifiers.alt() is the semantic snapshot.
		bool systemKey = false;

		// Snapshot of the standard IME lifecycle axis at capture time.
		// It never overrides the per-key ownership expressed by VK_PROCESSKEY.
		bool imeComposingAtCapture = false;

		KeyModifiers modifiers{};

		bool isAutoRepeat() const noexcept
		{
			return action == KeyAction::Down && wasDown;
		}

		bool isImeOwnedAtCapture() const noexcept
		{
			// Per-key ownership and IME lifecycle are intentionally independent axes.
			// A normal key captured during a standard composition remains a normal key;
			// routing may suppress it because of the lifecycle snapshot, but must not
			// rewrite its ownership.
			return virtualKey == VK_PROCESSKEY;
		}
	};

	enum class TextSource : std::uint8_t
	{
		ImeResult,
		UnicodeChar,
		UnicodeScalar,
		AnsiCharFallback,
		Clipboard
	};

	struct TextInputEvent
	{
		std::wstring text;
		TextSource source = TextSource::UnicodeChar;
		std::uint64_t compositionId = 0; // Zero for non-IME input.
	};

	enum class CompositionStage : std::uint8_t
	{
		Start,
		Update,
		Commit,
		Cancel,
		End
	};

	struct CompositionEvent
	{
		CompositionStage stage = CompositionStage::Start;
		std::uint64_t compositionId = 0;
		std::wstring compositionText;
		std::uint32_t caretOffset = 0;
	};

	struct WindowActivationEvent
	{
		bool keyboardFocusActive = false;
		HWND otherWindow = nullptr;
	};

	using NativeInputPayload = std::variant<
		KeyEvent,
		TextInputEvent,
		CompositionEvent,
		WindowActivationEvent>;

	struct NativeInputEvent
	{
		std::uint64_t sequence = 0;
		DWORD messageTime = 0;
		HWND hwnd = nullptr;
		NativeInputPayload payload{};
	};
}