// SPDX-FileCopyrightText: 2002-2023 PCSX2 Dev Team
// SPDX-License-Identifier: LGPL-3.0+

#include <cstdint>

#define WIN32_LEAN_AND_MEAN
#include <Windows.h>
#include <shellapi.h>
#include <winver.h>

#include <fmt/format.h>

// Minimum version is 14.38.33135.0.
static constexpr uint64_t MIN_VERSION_V0 = 14;
static constexpr uint64_t MIN_VERSION_V1 = 38;
static constexpr uint64_t MIN_VERSION_V2 = 33135;
static constexpr uint64_t MIN_VERSION_V3 = 0;
static constexpr uint64_t MIN_VERSION = (MIN_VERSION_V0 << 48) | (MIN_VERSION_V1 << 32) | (MIN_VERSION_V2 << 16) | MIN_VERSION_V3;
static constexpr const char *DOWNLOAD_URL = "https://aka.ms/vs/17/release/vc_redist.x64.exe";

struct VCRuntimeCheckObject {
    VCRuntimeCheckObject() {
        const HMODULE crt_handle = GetModuleHandleW(L"msvcp140.dll");
        if (!crt_handle)
            return;

        const HANDLE heap = GetProcessHeap();
        DWORD filename_length = MAX_PATH;
        LPWSTR filename = static_cast<LPWSTR>(HeapAlloc(heap, 0, filename_length * sizeof(*filename)));
        if (!filename)
            return;

        for (;;) {
            DWORD len = GetModuleFileNameW(crt_handle, filename, filename_length);
            if (len == filename_length && GetLastError() == ERROR_INSUFFICIENT_BUFFER) {
                filename_length *= 2;
                if (filename_length >= 4 * 1024)
                    return;
                LPWSTR new_filename = static_cast<LPWSTR>(HeapReAlloc(heap, 0, filename, filename_length * sizeof(*filename)));
                if (!new_filename) {
                    HeapFree(heap, 0, filename);
                    return;
                }
                filename = new_filename;
                continue;
            }

            break;
        }

        const DWORD version_size = GetFileVersionInfoSizeExW(0, filename, nullptr);
        LPVOID version_block;
        if (version_size == 0 || !(version_block = HeapAlloc(heap, 0, version_size))) {
            HeapFree(heap, 0, filename);
            return;
        }

        VS_FIXEDFILEINFO *fi;
        UINT fi_size;
        if (!GetFileVersionInfoExW(0, filename, 0, version_size, version_block) || !VerQueryValueW(version_block, L"\\", reinterpret_cast<LPVOID *>(&fi), &fi_size)) {
            HeapFree(heap, 0, version_block);
            HeapFree(heap, 0, filename);
            return;
        }

        const DWORD v0 = (fi->dwFileVersionMS >> 16) & 0xFFFFu;
        const DWORD v1 = fi->dwFileVersionMS & 0xFFFFu;
        const DWORD v2 = (fi->dwFileVersionLS >> 16) & 0xFFFFu;
        const DWORD v3 = fi->dwFileVersionLS & 0xFFFFu;
        const uint64_t version = (static_cast<uint64_t>(fi->dwFileVersionMS) << 32) | fi->dwFileVersionLS;

        HeapFree(heap, 0, version_block);
        HeapFree(heap, 0, filename);

        if (version >= MIN_VERSION)
            return;

        // fmt is self-contained, hopefully it'll be okay.
        char message[512];
        const auto fmt_result = fmt::format_to_n(message, sizeof(message),
            "Your Microsoft Visual C++ Runtime appears to be too old for this build of Vita3K.\n\n"
            "Your version: {}.{}.{}.{}\n"
            "Required version: {}.{}.{}.{}\n\n"
            "You can download the latest version from {}.\n\n"
            "Do you want to exit and download this version now?\n"
            "If you select No, Vita3K will likely crash.",
            v0, v1, v2, v3, MIN_VERSION_V0, MIN_VERSION_V1, MIN_VERSION_V2, MIN_VERSION_V3, DOWNLOAD_URL);
        message[(fmt_result.size > (sizeof(message) - 1)) ? (sizeof(message) - 1) : fmt_result.size] = 0;

        if (MessageBoxA(NULL, message, "Old Visual C++ Runtime Detected", MB_ICONERROR | MB_YESNO) == IDNO)
            return;

        if (!ShellExecuteA(NULL, "open", DOWNLOAD_URL, nullptr, nullptr, SW_SHOWNORMAL))
            MessageBoxA(NULL, "ShellExecuteA() failed, you may need to manually open the URL.", "Error", MB_OK);

        TerminateProcess(GetCurrentProcess(), 0xFFFFFFFF);
    }
};

// We have to use a special object which gets initialized before all other global objects, because those might use the
// CRT and go kaboom. Yucky, but gets the job done.
#pragma optimize("", off)
#pragma warning(disable : 4075) // warning C4075: initializers put in unrecognized initialization area
#pragma init_seg(".CRT$XCT")
VCRuntimeCheckObject s_vcruntime_checker;
