#include <windows.h>
#include <string.h>
#include <stdio.h>
#include <math.h>


// Global variable
HINSTANCE hInst;
UINT  MessageCount = 0;
UINT  Count = 0;
int posX = 0;
int posY = 0;

// Function prototypes.
int WINAPI WinMain(HINSTANCE, HINSTANCE, LPSTR, int);
LRESULT CALLBACK MainWndProc(HWND, UINT, WPARAM, LPARAM);
void paintObject(HWND hWnd, HDC hDC, PAINTSTRUCT ps, int posX, int posY, POINT cursorPosition);
void paintPosition(HWND hWnd, HDC hDC, PAINTSTRUCT ps, POINT cursorPosition);
void drawLine(HDC hDC, HWND hWnd, PAINTSTRUCT ps, int posX, int posY);

HWND TextBox;
// Application entry point. This is the same as main() in standart C.
int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nCmdShow)
{
	MSG msg;
	BOOL bRet;
	WNDCLASS wcx;          // register class
	HWND hWnd;

	hInst = hInstance;     // Save the application-instance handle.
		// Fill in the window class structure with parameters that describe the main window.

	wcx.style = CS_HREDRAW | CS_VREDRAW;              // redraw if size changes
	wcx.lpfnWndProc = (WNDPROC)MainWndProc;          // points to window procedure
	wcx.cbClsExtra = 0;                               // no extra class memory
	wcx.cbWndExtra = 0;                               // no extra window memory
	wcx.hInstance = hInstance;                        // handle to instance
	wcx.hIcon = LoadIcon(NULL, IDI_APPLICATION);      // predefined app. icon
	wcx.hCursor = LoadCursor(NULL, IDC_ARROW);        // predefined arrow
	//wcx.hbrBackground  und = GetStockObject(WHITE_BRUSH);   white background brush
	wcx.hbrBackground = (HBRUSH) COLOR_BACKGROUND;
	wcx.lpszMenuName = (LPCSTR)"MainMenu";          // name of menu resource
	wcx.lpszClassName = (LPCSTR)"MainWClass";        // name of window class

	// Register the window class.

	if (!RegisterClass(&wcx)) return FALSE;

	// create window of registered class

	hWnd = CreateWindow(
		"MainWClass",        // name of window class
		"ITU",               // title-bar string
		WS_OVERLAPPEDWINDOW, // top-level window
		200,                  // default horizontal position
		25,                 // default vertical positionv
		1000,                // default width
		700,                 // default height
		(HWND)NULL,         // no owner window
		(HMENU)NULL,        // use class menu
		hInstance,           // handle to application instance
		(LPVOID)NULL);      // no window-creation data
	if (!hWnd) return FALSE;

	// Show the window and send a WM_PAINT message to the window procedure.
	// Record the current cursor position.

	ShowWindow(hWnd, nCmdShow);
	UpdateWindow(hWnd);

	// loop of message processing
	while ((bRet = GetMessage(&msg, NULL, 0, 0)) != 0)
	{
		if (bRet == -1)
		{
			// handle the error and possibly exit
		}
		else
		{
			TranslateMessage(&msg);
			DispatchMessage(&msg);
		}
	}
	return (int)msg.wParam;
}


LRESULT CALLBACK MainWndProc(
	HWND hWnd,        // handle to window
	UINT uMsg,        // message identifier
	WPARAM wParam,    // first message parameter
	LPARAM lParam)    // second message parameter
{
	HDC         hDC;
	PAINTSTRUCT ps;
	POINT cursorPosition;


	// init cursor position
	GetCursorPos(&cursorPosition);
	ScreenToClient(hWnd, &cursorPosition);
	switch (uMsg)
	{
	case WM_CREATE:



        /*CreateWindow("BUTTON","Go", WS_VISIBLE | WS_CHILD | WS_BORDER,
                     420,10,70, 20,
                     hWnd, (HMENU) 1, NULL, NULL);*/
		break;

	// character input
	case WM_CHAR:
		switch (wParam) {
		case 0x08:  // backspace
		case 0x0A:  // linefeed
		case 0x1B:  // escape
		    TextBox = CreateWindow("EDIT",
                            "U pressed escape button",
                            WS_BORDER | WS_CHILD | WS_VISIBLE,
                            10, 10, 400, 20,
                            hWnd, NULL, NULL, NULL);
			break;

		case 0x09:  // tab
            if (GetCursorPos(&cursorPosition))
            {
                //cursor position now in p.x and p.y
                if (ScreenToClient(hWnd, &cursorPosition))
                {
                ::MessageBeep(1);
                //p.x and p.y are now relative to hwnd's client area
                paintPosition(hWnd, hDC, ps, cursorPosition);
                ::MessageBox(hWnd, "Button was clicked", "Button was clicked", MB_OK);
                }
            }
			break;

		default:
			break;
		}
		break;

	// key input
	case WM_KEYDOWN:
		switch (wParam) {
	        // update posX and posY in order to move object
		case VK_LEFT: // left arrow
			break;
		case VK_RIGHT: // right arrow
			break;
		case VK_UP: // up arrow
			break;
		case VK_DOWN: // down arrow
			break;

		// react on the other pressed keys
		case VK_SPACE: // space
			break;
		case VK_BACK: // backspace
			break;
		case VK_TAB: // tab
			break;
	        // more virtual codes can be found here: https://docs.microsoft.com/en-us/windows/win32/inputdev/virtual-key-codes
		}
		break;

	// get cursor position
	case WM_MOUSEMOVE:
		break;

	// react on mouse clicks
	case WM_LBUTTONDOWN:
        //hDC = BeginPaint(hWnd, &ps);
		//paintObject(hWnd, hDC, ps, 100, 600, cursorPosition);

		paintPosition(hWnd, hDC, ps, cursorPosition);
		//paint other objects
		//paintObject2(hWnd, hDC, ps, 150, 250, cursorPosition);
		//paintObject3(hWnd, hDC, ps, 200, 300, cursorPosition);
		//drawLine(hDC, hWnd, ps, 100, 100);
		//EndPaint(hWnd, &ps);
		//DeleteDC(hDC);
		break;
	case WM_LBUTTONUP:
		break;

	// paint objects
	case WM_PAINT:
        hDC = BeginPaint(hWnd, &ps);
        paintPosition(hWnd, hDC, ps, cursorPosition);
        paintObject(hWnd, hDC, ps, 100, 100, cursorPosition);
		//paintObject(hWnd, hDC, ps, 100, 600, cursorPosition);
		//paintPosition(hWnd, hDC, ps);
		//paint other objects
		//paintObject2(hWnd, hDC, ps, 150, 250, cursorPosition);
		//paintObject3(hWnd, hDC, ps, 200, 300, cursorPosition);
		drawLine(hDC, hWnd, ps, 500, 500);
		paintPosition(hWnd, hDC, ps, cursorPosition);
		EndPaint(hWnd, &ps);
		DeleteDC(hDC);


		break;

		//
		// Process other messages.
		//

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

}

void drawLine(HDC hDC, HWND hWnd, PAINTSTRUCT ps, int posX, int posY){
        HPEN hPenOld;
        HPEN hLinePen;
        COLORREF qLineColor;

        qLineColor = RGB (255, 0, 0);
        hLinePen = CreatePen(PS_SOLID, 7, qLineColor);
        hPenOld = (HPEN)SelectObject(hDC, hLinePen);

        MoveToEx(hDC, posX, posX, NULL);
        LineTo(hDC, posY, posY);
        return;
}


void paintObject(HWND hWnd, HDC hDC, PAINTSTRUCT ps, int posX, int posY, POINT cursorPosition)
{
	// Paint rectangles, ellipses, polygons, lines etc.
        HPEN hPenOld;
        HPEN hLinePen;
        COLORREF qLineColor;

        qLineColor = RGB (200, 0, 0);
        hLinePen = CreatePen(PS_SOLID, 7, qLineColor);
        hPenOld = (HPEN)SelectObject(hDC, hLinePen);

        MoveToEx(hDC, posX, posY, NULL);
        //LineTo(hDC, cursorPosition.x, cursorPosition.y);
        LineTo(hDC, 100, 110);
        LineTo(hDC, 110, 110);
        LineTo(hDC, 110, 100);
        LineTo(hDC, 100, 100);
        LineTo(hDC, cursorPosition.x, cursorPosition.y);
        //SelectObject(hDC, hPenOld);
        //DeleteObject(hLinePen);
        //EndPaint(hWnd, &ps);
	return;
}

void paintPosition(HWND hWnd, HDC hDC, PAINTSTRUCT ps, POINT cursorPosition)
{
	char        text[40];          // buffer to store an output text
	HFONT       font;              // new large font
	HFONT       oldFont;           // saves the previous font

	font = CreateFont(25, 0, 0, 0, 0, FALSE, FALSE, FALSE, ANSI_CHARSET, OUT_DEFAULT_PRECIS, CLIP_DEFAULT_PRECIS, DEFAULT_QUALITY, FF_DONTCARE, 0);
	oldFont = (HFONT)SelectObject(hDC, font);
	sprintf(text, "Position -- x:%d, y:%d", cursorPosition.x, cursorPosition.y);
	TextOut(hDC, 50, 600, text, (int)strlen(text));
	SelectObject(hDC, oldFont);
	DeleteObject(font);
}