#include "WindowMessageDispatcher.h"

#include "Platform/Win32/EditorWindow.h"
#include "WindowMessageHost.h"

#include <utility>

namespace XCEngine::UI::Editor::Host {

namespace {

constexpr UINT kMessageNcUaDrawCaption = 0x00AEu;
constexpr UINT kMessageNcUaDrawFrame = 0x00AFu;

} // namespace

struct WindowMessageDispatcher::DispatchContext {
    HWND hwnd = nullptr;
    WindowMessageHost& windowHost;
    App::EditorWindow& window;
};

void WindowMessageDispatcher::RenderAndValidateWindow(const DispatchContext& context) {
    if (!context.window.IsRenderReady()) {
        return;
    }

    App::EditorWindowFrameTransferRequests transferRequests = context.window.RenderFrame(
        context.windowHost.GetEditorContext(),
        context.windowHost.IsGlobalTabDragActive());
    if (transferRequests.HasPendingRequests()) {
        context.windowHost.HandleWindowFrameTransferRequests(
            context.window,
            std::move(transferRequests));
    }
    if (context.hwnd != nullptr && IsWindow(context.hwnd)) {
        ValidateRect(context.hwnd, nullptr);
    }
}

bool WindowMessageDispatcher::EnsureTrackingMouseLeave(const DispatchContext& context) {
    if (context.window.IsTrackingMouseLeave()) {
        return true;
    }

    TRACKMOUSEEVENT trackMouseEvent = {};
    trackMouseEvent.cbSize = sizeof(trackMouseEvent);
    trackMouseEvent.dwFlags = TME_LEAVE;
    trackMouseEvent.hwndTrack = context.hwnd;
    if (!TrackMouseEvent(&trackMouseEvent)) {
        return false;
    }

    context.window.SetTrackingMouseLeave(true);
    return true;
}

bool WindowMessageDispatcher::TryHandleChromeHoverConsumption(
    const DispatchContext& context,
    LPARAM lParam,
    LRESULT& outResult) {
    const bool resizeHoverChanged = context.window.UpdateBorderlessWindowResizeHover(lParam);
    if (context.window.UpdateBorderlessWindowChromeHover(lParam)) {
        context.window.InvalidateHostWindow();
    }
    if (resizeHoverChanged) {
        context.window.InvalidateHostWindow();
    }

    EnsureTrackingMouseLeave(context);
    if (context.window.HasHoveredBorderlessResizeEdge()) {
        outResult = 0;
        return true;
    }

    const BorderlessWindowChromeHitTarget chromeHitTarget =
        context.window.HitTestBorderlessWindowChrome(lParam);
    if (chromeHitTarget == BorderlessWindowChromeHitTarget::MinimizeButton ||
        chromeHitTarget == BorderlessWindowChromeHitTarget::MaximizeRestoreButton ||
        chromeHitTarget == BorderlessWindowChromeHitTarget::CloseButton) {
        outResult = 0;
        return true;
    }

    return false;
}

bool WindowMessageDispatcher::TryDispatchWindowPointerMessage(
    const DispatchContext& context,
    UINT message,
    WPARAM wParam,
    LPARAM lParam,
    LRESULT& outResult) {
    switch (message) {
    case WM_MOUSEMOVE:
        if (context.windowHost.HandleGlobalTabDragPointerMove(context.hwnd)) {
            outResult = 0;
            return true;
        }
        if (context.window.HandleBorderlessWindowResizePointerMove(
                context.windowHost.GetEditorContext(),
                context.windowHost.IsGlobalTabDragActive())) {
            outResult = 0;
            return true;
        }
        if (context.window.HandleBorderlessWindowChromeDragRestorePointerMove(
                context.windowHost.GetEditorContext(),
                context.windowHost.IsGlobalTabDragActive())) {
            outResult = 0;
            return true;
        }
        if (TryHandleChromeHoverConsumption(context, lParam, outResult)) {
            return true;
        }

        context.window.QueuePointerEvent(
            ::XCEngine::UI::UIInputEventType::PointerMove,
            ::XCEngine::UI::UIPointerButton::None,
            wParam,
            lParam);
        outResult = 0;
        return true;
    case WM_MOUSELEAVE:
        context.window.SetTrackingMouseLeave(false);
        context.window.ClearBorderlessWindowResizeState();
        context.window.ClearBorderlessWindowChromeDragRestoreState();
        context.window.ClearBorderlessWindowChromeState();
        context.window.QueuePointerLeaveEvent();
        outResult = 0;
        return true;
    case WM_LBUTTONDOWN:
        if (context.window.HandleBorderlessWindowResizeButtonDown(lParam)) {
            outResult = 0;
            return true;
        }
        if (context.window.HandleBorderlessWindowChromeButtonDown(lParam)) {
            outResult = 0;
            return true;
        }
        SetFocus(context.hwnd);
        context.window.QueuePointerEvent(
            ::XCEngine::UI::UIInputEventType::PointerButtonDown,
            ::XCEngine::UI::UIPointerButton::Left,
            wParam,
            lParam);
        outResult = 0;
        return true;
    case WM_LBUTTONUP:
        if (context.windowHost.HandleGlobalTabDragPointerButtonUp(context.hwnd)) {
            outResult = 0;
            return true;
        }
        if (context.window.HandleBorderlessWindowResizeButtonUp()) {
            outResult = 0;
            return true;
        }
        if (context.window.HandleBorderlessWindowChromeButtonUp(
                context.windowHost.GetEditorContext(),
                context.windowHost.IsGlobalTabDragActive(),
                lParam)) {
            outResult = 0;
            return true;
        }
        context.window.QueuePointerEvent(
            ::XCEngine::UI::UIInputEventType::PointerButtonUp,
            ::XCEngine::UI::UIPointerButton::Left,
            wParam,
            lParam);
        outResult = 0;
        return true;
    case WM_LBUTTONDBLCLK:
        if (context.window.HandleBorderlessWindowChromeDoubleClick(
                context.windowHost.GetEditorContext(),
                context.windowHost.IsGlobalTabDragActive(),
                lParam)) {
            outResult = 0;
            return true;
        }
        return false;
    case WM_MOUSEWHEEL:
        context.window.QueuePointerWheelEvent(GET_WHEEL_DELTA_WPARAM(wParam), wParam, lParam);
        outResult = 0;
        return true;
    default:
        return false;
    }
}

bool WindowMessageDispatcher::TryDispatchWindowInputMessage(
    const DispatchContext& context,
    UINT message,
    WPARAM wParam,
    LPARAM lParam,
    LRESULT& outResult) {
    if (TryDispatchWindowPointerMessage(context, message, wParam, lParam, outResult)) {
        return true;
    }

    switch (message) {
    case WM_SETFOCUS:
        context.window.SyncInputModifiersFromSystemState();
        context.window.QueueWindowFocusEvent(::XCEngine::UI::UIInputEventType::FocusGained);
        outResult = 0;
        return true;
    case WM_KILLFOCUS:
        context.window.ResetInputModifiers();
        context.window.QueueWindowFocusEvent(::XCEngine::UI::UIInputEventType::FocusLost);
        outResult = 0;
        return true;
    case WM_CAPTURECHANGED:
        if (context.windowHost.OwnsActiveGlobalTabDrag(context.window.GetWindowId()) &&
            reinterpret_cast<HWND>(lParam) != context.hwnd) {
            context.windowHost.EndGlobalTabDragSession();
            outResult = 0;
            return true;
        }
        if (reinterpret_cast<HWND>(lParam) != context.hwnd &&
            context.window.HasInteractiveCaptureState()) {
            context.window.QueueWindowFocusEvent(::XCEngine::UI::UIInputEventType::FocusLost);
            context.window.ForceClearBorderlessWindowResizeState();
            context.window.ClearBorderlessWindowChromeDragRestoreState();
            context.window.ClearBorderlessWindowChromeState();
            outResult = 0;
            return true;
        }
        if (reinterpret_cast<HWND>(lParam) != context.hwnd) {
            context.window.ForceClearBorderlessWindowResizeState();
            context.window.ClearBorderlessWindowChromeDragRestoreState();
            context.window.ClearBorderlessWindowChromeState();
        }
        return false;
    case WM_KEYDOWN:
    case WM_SYSKEYDOWN:
        if (wParam == VK_F12) {
            context.window.RequestManualScreenshot();
        }
        context.window.QueueKeyEvent(::XCEngine::UI::UIInputEventType::KeyDown, wParam, lParam);
        outResult = 0;
        return true;
    case WM_KEYUP:
    case WM_SYSKEYUP:
        context.window.QueueKeyEvent(::XCEngine::UI::UIInputEventType::KeyUp, wParam, lParam);
        outResult = 0;
        return true;
    case WM_CHAR:
        context.window.QueueCharacterEvent(wParam, lParam);
        outResult = 0;
        return true;
    default:
        return false;
    }
}

bool WindowMessageDispatcher::TryDispatchWindowLifecycleMessage(
    const DispatchContext& context,
    UINT message,
    WPARAM wParam,
    LPARAM lParam,
    LRESULT& outResult) {
    switch (message) {
    case WM_DPICHANGED:
        if (lParam == 0) {
            return false;
        }
        context.window.OnDpiChanged(
            static_cast<UINT>(LOWORD(wParam)),
            *reinterpret_cast<const RECT*>(lParam));
        RenderAndValidateWindow(context);
        outResult = 0;
        return true;
    case WM_ENTERSIZEMOVE:
        context.window.OnEnterSizeMove();
        outResult = 0;
        return true;
    case WM_EXITSIZEMOVE:
        context.window.OnExitSizeMove();
        RenderAndValidateWindow(context);
        outResult = 0;
        return true;
    case WM_SIZE:
        if (wParam != SIZE_MINIMIZED) {
            context.window.OnResize(
                static_cast<UINT>(LOWORD(lParam)),
                static_cast<UINT>(HIWORD(lParam)));
            RenderAndValidateWindow(context);
        }
        outResult = 0;
        return true;
    case WM_PAINT:
        if (App::EditorWindowFrameTransferRequests transferRequests = context.window.OnPaintMessage(
            context.windowHost.GetEditorContext(),
            context.windowHost.IsGlobalTabDragActive());
            transferRequests.HasPendingRequests()) {
            context.windowHost.HandleWindowFrameTransferRequests(
                context.window,
                std::move(transferRequests));
        }
        outResult = 0;
        return true;
    case WM_ERASEBKGND:
        outResult = 1;
        return true;
    case WM_DESTROY:
        if (context.windowHost.OwnsActiveGlobalTabDrag(context.window.GetWindowId())) {
            context.windowHost.EndGlobalTabDragSession();
        }
        context.windowHost.HandleDestroyedWindow(context.hwnd);
        outResult = 0;
        return true;
    default:
        return false;
    }
}

bool WindowMessageDispatcher::TryDispatchWindowChromeMessage(
    const DispatchContext& context,
    UINT message,
    WPARAM wParam,
    LPARAM lParam,
    LRESULT& outResult) {
    switch (message) {
    case WM_GETMINMAXINFO:
        if (context.window.IsBorderlessWindowEnabled() &&
            context.window.HandleBorderlessWindowGetMinMaxInfo(lParam)) {
            outResult = 0;
            return true;
        }
        return false;
    case WM_NCCALCSIZE:
        if (context.window.IsBorderlessWindowEnabled()) {
            outResult = context.window.HandleBorderlessWindowNcCalcSize(wParam, lParam);
            return true;
        }
        return false;
    case WM_NCACTIVATE:
        if (context.window.IsBorderlessWindowEnabled()) {
            outResult = TRUE;
            return true;
        }
        return false;
    case WM_NCHITTEST:
        if (context.window.IsBorderlessWindowEnabled()) {
            outResult = HTCLIENT;
            return true;
        }
        return false;
    case WM_NCPAINT:
    case kMessageNcUaDrawCaption:
    case kMessageNcUaDrawFrame:
        if (context.window.IsBorderlessWindowEnabled()) {
            outResult = 0;
            return true;
        }
        return false;
    case WM_SYSCOMMAND:
        if (context.window.HandleBorderlessWindowSystemCommand(
                context.windowHost.GetEditorContext(),
                context.windowHost.IsGlobalTabDragActive(),
                wParam)) {
            outResult = 0;
            return true;
        }
        return false;
    case WM_SETCURSOR:
        if (LOWORD(lParam) == HTCLIENT && context.window.ApplyCurrentCursor()) {
            outResult = TRUE;
            return true;
        }
        return false;
    default:
        return false;
    }
}

bool WindowMessageDispatcher::TryDispatch(
    HWND hwnd,
    WindowMessageHost& windowHost,
    App::EditorWindow& window,
    UINT message,
    WPARAM wParam,
    LPARAM lParam,
        LRESULT& outResult) {
    const DispatchContext context = {
        .hwnd = hwnd,
        .windowHost = windowHost,
        .window = window,
    };

    return TryDispatchWindowChromeMessage(context, message, wParam, lParam, outResult) ||
        TryDispatchWindowLifecycleMessage(context, message, wParam, lParam, outResult) ||
        TryDispatchWindowInputMessage(context, message, wParam, lParam, outResult);
}

} // namespace XCEngine::UI::Editor::Host