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

// The Win32 backend's text, through a real HWND. The library speaks UTF-8
// and Windows UTF-16, and the window class decides what a window procedure
// hears: one registered with RegisterClassA gets text in the process code
// page, which is CP1252 on a Western system.
//
//   - the title given to the constructor is the window's: SetTitle had no
//     Win32 body, so every Win32 window was untitled
//   - SetTitle replaces it, and characters outside the code page survive.
//     On an ANSI class they would not: WM_SETTEXT would reach
//     DefWindowProcA in the code page, and 日本 would come back as ??
//   - SetTitle takes only the view's bytes, though the string goes on past
//     them, and an empty title clears the old one
//   - StartSync's loop delivers WM_CHAR as UTF-16 code units, as the handler
//     always assumed. On the ANSI class € arrived as CP1252's 0x80, taken
//     for U+0080, and 日 and both halves of a surrogate pair as ?. A loop
//     that pumped with PeekMessageA would still turn 日 and the surrogates
//     into ?, whatever the class
//
// The window is disabled, so no real keystroke reaches the WM_CHAR check,
// while the messages posted to it still arrive. Needs a Vulkan device, for
// the Window's swapchain. Built on Linux, it runs under Wine:
//   crafter-build test --target=x86_64-w64-mingw32 TextWin32

#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;
}

// A string's code units in hex, for a failed check to say what it got.
template <typename Char>
std::string Units(std::basic_string_view<Char> text) {
    std::string out;
    for (const Char unit : text) {
        out += std::format(" {:0{}X}", static_cast<std::make_unsigned_t<Char>>(unit), sizeof(Char) * 2);
    }
    return out;
}

// The title as Windows has it, which is what the title bar, the taskbar
// and Alt+Tab show.
void CheckTitle(HWND hwnd, std::wstring_view expected, std::string_view what) {
    std::wstring title(static_cast<std::size_t>(GetWindowTextLengthW(hwnd)) + 1, L'\0');
    title.resize(static_cast<std::size_t>(GetWindowTextW(hwnd, title.data(), static_cast<int>(title.size()))));
    Check(title == expected, what);
    if (title != expected) std::println("      the window has [{} ]", Units(std::wstring_view(title)));
}

} // namespace

int main() {
    Device::Initialize();
    auto window = std::make_unique<Window>(320, 240, "Crafter");
    const HWND hwnd = window->hwnd;
    // Windows activates the window when it is shown, so keys typed now
    // would reach it. A disabled window gets no keyboard input, and what
    // was typed before that is dropped.
    EnableWindow(hwnd, FALSE);
    MSG msg;
    while (PeekMessageW(&msg, hwnd, WM_KEYFIRST, WM_KEYLAST, PM_REMOVE)) {}

    CheckTitle(hwnd, L"Crafter", "the constructor's title");

    // é and € are in CP1252, 日本 and 😀 in no Western code page.
    window->SetTitle("café € 日本 \U0001F600");
    CheckTitle(hwnd, L"café € 日本 \U0001F600", "SetTitle, with characters outside the code page");

    const std::string longer = "Crafter.Graphics";
    window->SetTitle(std::string_view(longer).substr(0, 7));
    CheckTitle(hwnd, L"Crafter", "SetTitle takes the view's bytes, not the string's up to its NUL");

    window->SetTitle("");
    CheckTitle(hwnd, L"", "an empty title clears the old one");

    std::vector<std::string> typed;
    EventListener<const std::string_view> textSub(&window->onTextInput, [&](const std::string_view text) {
        typed.emplace_back(text);
    });
    // As TranslateMessage posts them, a UTF-16 code unit each: é is 0xE9 in
    // CP1252 and Unicode alike, € is 0x80 in CP1252, 日 is in no Western
    // code page, and 😀 is a surrogate pair. StartSync's own loop delivers
    // them, and returns once the WM_CLOSE after them has cleared `open`.
    for (const wchar_t unit : std::wstring_view(L"é€日\U0001F600")) {
        PostMessageW(hwnd, WM_CHAR, unit, 1);
    }
    PostMessageW(hwnd, WM_CLOSE, 0, 0);
    window->StartSync();
    const std::vector<std::string> expected{ "é", "€", "日", "\U0001F600" };
    Check(typed == expected, "WM_CHAR through StartSync: each character as itself in UTF-8, the surrogate pair as one");
    if (typed != expected) {
        for (const std::string& text : typed) std::println("      onTextInput had [{} ]", Units(std::string_view(text)));
    }

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