module;
#include <Windows.h>
#include <windowsx.h>
#include <wincodec.h>
#include <iostream>
#include <chrono>
#include <thread>

module MegaEngine;

import Input;

using namespace std;
using namespace std::chrono;

void Game::Run()
{
    StartUp();

    while (PeekMsg() && !Done())
    {
        Update();
        Render();
        LaterUpdate();
    }

    CleanUp();
}

void Game::StartUp()
{
    last = steady_clock::now();

    CreateWnd();
    Graphics::Init(hwnd);

    steve.OnStartUp();

}

void Game::Update()
{
    auto now = steady_clock::now();
    delta = duration_cast<duration<float>>(now - last).count();
    last = now;
    steve.OnUpdate(delta);
}

void Game::Render()
{
    Graphics::BeginDraw();
    Graphics::Clear();

    steve.OnRender();
    
    Graphics::Present();
}

void Game::LaterUpdate()
{
    steve.OnLaterUpdate(delta);
}

void Game::CleanUp()
{
    steve.OnCleanUp();

    Graphics::Finalize();

    if (hwnd) DestroyWindow(hwnd);

    auto hInst = GetModuleHandleW(nullptr);
    UnregisterClassW(L"1mGameWnd", hInst);
}

void Game::CreateWnd()
{
    auto hInst = GetModuleHandleW(nullptr);

    WNDCLASSEXW wc =
    {
        sizeof(WNDCLASSEXW),
        CS_CLASSDC,
        WndProcSetUp,
        0,
        0,
        hInst,
        LoadIconW(nullptr, IDI_APPLICATION),
        LoadCursorW(nullptr, IDC_ARROW),
        CreateSolidBrush(0x808080),
        nullptr,
        wndClassName,
        nullptr
    };

    wc.lpszClassName = L"1mGameWnd";

    RegisterClassExW(&wc);

    auto wnd_style = WS_OVERLAPPEDWINDOW & ~WS_THICKFRAME;//WS_CAPTION | WS_SYSMENU;

    RECT client_rect{ 0, 0, wndWidth, wndHeight };
    AdjustWindowRectEx(&client_rect, wnd_style, FALSE, 0u);

    hwnd = CreateWindowExW
    (
        0L,
        L"1mGameWnd",
        L"1mGame",
        wnd_style,
        CW_USEDEFAULT,
        CW_USEDEFAULT,
        client_rect.right - client_rect.left,
        client_rect.bottom - client_rect.top,
        nullptr, nullptr, hInst, (LPVOID)this
    );

    ShowWindow(hwnd, SW_SHOW);
    UpdateWindow(hwnd);
}

bool Game::PeekMsg()
{
    MSG msg;
    while (PeekMessageW(&msg, nullptr, 0, 0, PM_REMOVE))
    {
        if (msg.message == WM_QUIT) return false;
        DispatchMessageW(&msg);
    }
    return true;
}

bool Game::Done()
{
    return done;
}

LRESULT CALLBACK Game::WndProcSetUp(HWND hWnd, UINT msg, WPARAM wParam, LPARAM lParam)
{
    if (msg == WM_NCCREATE)
    {
        ImmDisableIME(GetCurrentThreadId());
        auto CreateData = reinterpret_cast<CREATESTRUCTW*>(lParam);
        auto wnd_ptr = reinterpret_cast<Game*>(CreateData->lpCreateParams);

        SetWindowLongPtrW(hWnd, GWLP_WNDPROC, reinterpret_cast<LONG_PTR>(&Game::WndProcThunk));
        SetWindowLongPtrW(hWnd, GWLP_USERDATA, reinterpret_cast<LONG_PTR>(wnd_ptr));

        return wnd_ptr->WndProc(hWnd, msg, wParam, lParam);
    }

    return DefWindowProcW(hWnd, msg, wParam, lParam);
}

LRESULT CALLBACK Game::WndProcThunk(HWND hWnd, UINT msg, WPARAM wParam, LPARAM lParam)
{
    auto wnd_ptr = reinterpret_cast<Game*>(GetWindowLongPtrW(hWnd, GWLP_USERDATA));
    return wnd_ptr->WndProc(hWnd, msg, wParam, lParam);
}

LRESULT Game::WndProc(HWND hWnd, UINT msg, WPARAM wParam, LPARAM lParam)
{
    switch (msg)
    {
    case WM_KEYDOWN:
        KeyBoard::Update((char)wParam, true);
        break;
    case WM_KEYUP:
        KeyBoard::Update((char)wParam, false);
        break;
    case WM_CLOSE:
        done = true;
        DestroyWindow(hwnd);
        hwnd = nullptr;
        break;
    case WM_DESTROY:
        PostQuitMessage(0);
        break;
    default:
        return DefWindowProcW(hWnd, msg, wParam, lParam);
    }
    return 0;
}