Crafter.Graphics/tests/PointerWin32/main.cpp

//SPDX-License-Identifier: LGPL-3.0-only
//SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®

// The Win32 backend's pointer, capture, close and teardown handling. Posts
// a real Window's HWND the messages Windows would send it, pumps them as
// StartSync does, and checks what the Window made of them:
//
//   - a move into the client area is an enter, with the entry position
//     already in currentMousePos, and a move; WM_MOUSELEAVE is one leave
//   - a position past the client area (a drag under capture) arrives
//     signed, and is a move only
//   - a press captures the mouse and its release lets go; losing the
//     capture mid-drag releases the button, and the button-up after that
//     fires nothing
//   - the wheel adds up sub-detent steps, and a leave drops them
//   - WM_CLOSE fires onClose and clears `open`, but leaves the HWND alone;
//     ~Window destroys it, what is still queued for it reaches nothing,
//     and another window can be made after it
//   - an enter listener that takes the window away stops the move that
//     would follow
//
// The window is moved off-screen first, so the real cursor stays out of
// it. Built on Linux, it runs under Wine:
//   crafter-build test --target=x86_64-w64-mingw32 PointerWin32

#include <windows.h>
#include <cstdlib>

import Crafter.Graphics;
import Crafter.Event;
import std;
using namespace Crafter;

namespace {

int failures = 0;

void Check(bool ok, std::string_view what) {
    std::println("{}  {}", ok ? "PASS" : "FAIL", what);
    if (!ok) ++failures;
}

// One pass of StartSync's pump.
void Pump() {
    MSG msg;
    while (PeekMessageW(&msg, NULL, 0, 0, PM_REMOVE)) {
        TranslateMessage(&msg);
        DispatchMessageW(&msg);
    }
}

void Post(HWND hwnd, UINT msg, WPARAM wParam = 0, LPARAM lParam = 0) {
    PostMessage(hwnd, msg, wParam, lParam);
    Pump();
}

// An event as it fired, and what the window looked like then.
struct Seen {
    std::string_view event;
    float x;
    float y;
    bool inside;
    bool operator==(const Seen&) const = default;
};

} // namespace

int main() {
    Device::Initialize();
    auto window = std::make_unique<Window>(320, 240);
    const HWND hwnd = window->hwnd;
    SetWindowPos(hwnd, nullptr, -20000, -20000, 0, 0, SWP_NOSIZE | SWP_NOZORDER | SWP_NOACTIVATE);
    // Whatever the real cursor did while the window was on screen.
    Pump();
    Post(hwnd, WM_MOUSELEAVE);

    std::vector<Seen> seen;
    auto record = [&](std::string_view event) {
        return [&seen, &window, event] {
            seen.push_back({ event, window->currentMousePos.x, window->currentMousePos.y, window->mouseInside });
        };
    };
    auto count = [&](std::string_view event) { return std::ranges::count(seen, event, &Seen::event); };
    EventListener<void> enterSub(&window->onMouseEnter, record("enter"));
    EventListener<void> moveSub(&window->onMouseMove, record("move"));
    EventListener<void> leaveSub(&window->onMouseLeave, record("leave"));

    Post(hwnd, WM_MOUSEMOVE, 0, MAKELPARAM(10, 20));
    Check(seen.size() >= 2 && seen[0] == Seen{ "enter", 10.0f, 20.0f, true } && seen[1] == Seen{ "move", 10.0f, 20.0f, true },
          "a move into the client area: an enter at the entry position, then a move");
    // Windows answers a TME_LEAVE for a window the cursor is not over with
    // a leave at once, Wine with none, so the leave posted here is the
    // second on Windows and the first on Wine: either way, one leave.
    Post(hwnd, WM_MOUSELEAVE);
    Check(count("leave") == 1 && seen.back() == Seen{ "leave", 10.0f, 20.0f, false },
          "WM_MOUSELEAVE: a leave, with mouseInside cleared");
    Post(hwnd, WM_MOUSELEAVE);
    Check(count("leave") == 1, "a second WM_MOUSELEAVE fires nothing");
    seen.clear();

    Post(hwnd, WM_MOUSEMOVE, MK_LBUTTON, MAKELPARAM(-5, -7));
    Check(seen == std::vector<Seen>{ { "move", -5.0f, -7.0f, false } },
          "a position past the client area: a move only, signed");
    seen.clear();

    int clicks = 0;
    int releases = 0;
    EventListener<void> clickSub(&window->onMouseLeftClick, [&] { ++clicks; });
    EventListener<void> releaseSub(&window->onMouseLeftRelease, [&] { ++releases; });
    Post(hwnd, WM_LBUTTONDOWN, MK_LBUTTON, MAKELPARAM(10, 20));
    Check(clicks == 1 && window->mouseLeftHeld && GetCapture() == hwnd, "a press: a click, held, and the mouse captured");
    Post(hwnd, WM_LBUTTONUP, 0, MAKELPARAM(10, 20));
    Check(releases == 1 && !window->mouseLeftHeld && GetCapture() != hwnd, "its release: a release, and the capture let go");
    Post(hwnd, WM_LBUTTONDOWN, MK_LBUTTON, MAKELPARAM(10, 20));
    // As when the capture is taken away mid-drag.
    ReleaseCapture();
    Pump();
    Check(releases == 2 && !window->mouseLeftHeld, "losing the capture mid-drag releases the button");
    Post(hwnd, WM_LBUTTONUP, 0, MAKELPARAM(10, 20));
    Check(releases == 2, "and the button-up after that fires nothing");

    std::vector<std::int32_t> scrolls;
    EventListener<std::uint32_t> scrollSub(&window->onMouseScroll, [&](std::uint32_t delta) {
        scrolls.push_back(static_cast<std::int32_t>(delta));
    });
    auto wheel = [&](int delta) { Post(hwnd, WM_MOUSEWHEEL, MAKEWPARAM(0, delta), 0); };
    wheel(-WHEEL_DELTA);
    Check(scrolls == std::vector<std::int32_t>{ 1 }, "one detent toward the user: +1");
    scrolls.clear();
    wheel(WHEEL_DELTA / 2);
    wheel(WHEEL_DELTA / 2);
    Check(scrolls == std::vector<std::int32_t>{ -1 }, "two half detents away from the user add up to -1");
    scrolls.clear();
    wheel(-WHEEL_DELTA / 2);
    Post(hwnd, WM_MOUSELEAVE);
    wheel(-WHEEL_DELTA / 2);
    Check(scrolls.empty(), "a leave drops a half detent");
    wheel(-WHEEL_DELTA / 2);
    Check(scrolls == std::vector<std::int32_t>{ 1 }, "after which two add up again");

    int closes = 0;
    EventListener<void> closeSub(&window->onClose, [&] { ++closes; });
    Post(hwnd, WM_CLOSE);
    Check(closes == 1 && !window->open && IsWindow(hwnd), "WM_CLOSE: onClose, open cleared, the HWND still there");

    // ~Window detaches the HWND before destroying it, which is how WndProc
    // tells that a listener destroyed the window before it reports the
    // move. Destroying it for real here would leave Event::Invoke reading
    // the destroyed event once the listener returns, so this listener
    // detaches the HWND itself, as ~Window does.
    seen.clear();
    {
        EventListener<void> goneSub(&window->onMouseEnter, [hwnd] { SetWindowLongPtr(hwnd, GWLP_USERDATA, 0); });
        Post(hwnd, WM_MOUSEMOVE, 0, MAKELPARAM(30, 40));
        SetWindowLongPtr(hwnd, GWLP_USERDATA, reinterpret_cast<LONG_PTR>(window.get()));
    }
    Check(seen == std::vector<Seen>{ { "enter", 30.0f, 40.0f, true } }, "no move after an enter listener takes the window away");

    PostMessage(hwnd, WM_MOUSEMOVE, 0, MAKELPARAM(50, 60));
    PostMessage(hwnd, WM_MOUSELEAVE, 0, 0);
    PostMessage(hwnd, WM_LBUTTONDOWN, MK_LBUTTON, MAKELPARAM(50, 60));
    seen.clear();
    clicks = 0;
    window.reset();
    Check(!IsWindow(hwnd), "~Window destroys the HWND");
    Pump();
    Check(seen.empty() && clicks == 0, "and what was still queued for it reaches nothing");

    // As a resident app does on every hide and show. The window class is
    // still registered from the first.
    window = std::make_unique<Window>(320, 240);
    Check(IsWindow(window->hwnd), "another window can be made after it");

    if (failures != 0) {
        std::println("{} check(s) failed", failures);
        return EXIT_FAILURE;
    }
    std::println("all checks passed");
    return EXIT_SUCCESS;
}