#include "Window.h"

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 decorations

	RECT rect = { 100, 100, 100 + width, 100 + height }; // left-top corner, right-bottom corner
	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 a parent window
		nullptr, // handle to a 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 - synchronous call which holds until a new message arrives
	// PeekMessage - get last message from message queue or nothing if no one is available
	// TranslateMessage - translates keyboard input
	// DispatchMessage - send message to WindowProc

	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);
		return 0;

	default:
		break;
	}
	return DefWindowProc(hWnd, msg, wParam, lParam);
}