#include "Window.h"

// https://learn.microsoft.com/en-us/windows/win32/learnwin32/creating-a-window

INT Window::init(HINSTANCE hInstance, UINT width, UINT height)
{
    // 1. describe window class
    WNDCLASS wc = {};
    wc.hInstance = hInstance;
    wc.lpszClassName = TEXT("D3D9"); // class name
    wc.lpfnWndProc = WindowProc; // callback function for windows to communicate with our application
    wc.hbrBackground = CreateSolidBrush(RGB(0, 255, 0));
    wc.hCursor = LoadCursor(nullptr, IDC_ARROW);
    wc.hIcon = LoadIcon(nullptr, IDI_APPLICATION);
    wc.style = CS_HREDRAW | CS_VREDRAW | CS_OWNDC; // technical behaviour
    
    // 2. register window class
    if (!RegisterClass(&wc)) return 100;
    
    // 3. adjust window size (optional)
    DWORD style = {};
    style = WS_OVERLAPPEDWINDOW; // window with border & title
    //style = WS_POPUP; // window without any border or title

    RECT rect = { 100, 100, width + 100, height + 100 }; // left top right bottom
    AdjustWindowRect(&rect, style, FALSE);
    
    // 4. create window instance
    _hWnd = CreateWindow(
        wc.lpszClassName, // class name of window class to be instantiated
        wc.lpszClassName, // window title
        style, // visual style
        rect.left, rect.top, // window position (left-top corner)
        rect.right - rect.left, rect.bottom - rect.top, // window size
        nullptr, // handle to parent window
        nullptr, // handle to menu instance
        hInstance,
        nullptr // pointer to optional parameter
    );
    if (_hWnd == nullptr) return 110;
    
    // 5. show window
    ShowWindow(_hWnd, SW_SHOW);
    SetFocus(_hWnd);
    
    return 0;
}

BOOL Window::run()
{
    // 6. run window
    // GetMessage - syncronous call which holds until a new message arrived
    // PeekMessage - get last message from message queue or nothing if there is no message
    // TranslateMessage - translates keyboard input
    // DispatchMessage - send message to WindowProcedure

    MSG msg = {};
    if (PeekMessage(&msg, nullptr, 0, UINT_MAX, PM_REMOVE))
    {
        TranslateMessage(&msg);
        DispatchMessage(&msg);
    }
    
    return msg.message != WM_QUIT;
}

void Window::deInit()
{
}

LRESULT WindowProc(HWND hWnd, UINT msg, WPARAM wParam, LPARAM lParam)
{
    switch (msg)
    {
    case WM_CLOSE:
        DestroyWindow(hWnd);
        return 0;

    case WM_DESTROY:
        PostQuitMessage(0);
        return 0;

    case WM_KEYDOWN:
        if (wParam == VK_ESCAPE) DestroyWindow(hWnd);
        break;
    }

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