module app;

import win32.api;


class MyFrame: public Frame
{
	
	Panel panel;	
	
	this()
	{
		super();
		this.position(200,200);
				
		panel = new Panel(1,this);	
		panel.position(10,10);
		panel.size(400,300);
		panel.keyDown = &onKeyDown;		
	}
	
	void onKeyDown(WPARAM wParam)
	{
		// implementation of event	
	}
}



void main()
{
	MyFrame frm = new MyFrame();
	frm.run();
}

//--------------------------------------------------------------------------------------------------------


class Frame
{
	
	int width = 640;							// main window width
	int height = 480;							// main window height
	int x = 0;									// main window initial position
	int y = 0;
	HWND		hWnd;							// Holds Our Window Handle
	HINSTANCE	hInst;							// Holds The Instance Of The Application		
	DWORD		dwStyle;						// Window Style	


	
	this()
	{		
		createWindow();
	}

	
	void createWindow()
	{
		WNDCLASS wc;			
	
		hInst = GetModuleHandleA(null);
	
		wc.lpszClassName = "DWndProc";
		wc.style = CS_OWNDC | CS_HREDRAW | CS_VREDRAW;
		wc.lpfnWndProc = &WindowProc;
		wc.hInstance = hInst;
		wc.hIcon = LoadIconA(null, IDI_APPLICATION);
		wc.hCursor = LoadCursorA(null, IDC_ARROW);
		wc.hbrBackground = GetStockObject(GRAY_BRUSH); ;
		wc.lpszMenuName = null;
		wc.cbClsExtra = wc.cbWndExtra = 0;
		assert(RegisterClassA(&wc));							// register parent

		
		dwStyle=WS_OVERLAPPEDWINDOW;							// Windows Style		
																// get window handle
		hWnd = CreateWindowA(cast(LPCSTR)"DWndProc",cast(LPCSTR)"Window", 			
		dwStyle | WS_CLIPSIBLINGS |WS_CLIPCHILDREN|WS_THICKFRAME |WS_MAXIMIZEBOX | WS_MINIMIZEBOX | 
		WS_SYSMENU | WS_VISIBLE ,x,y,width, height, null, null, hInst, null);
	    assert(hWnd);
	    	 
    }
       

	public void position(int x,int y)
	{
		this.x = x;
		this.y = y;
		MoveWindow(hWnd,x,y,width,height,true);
	}
	
	public void size(int width,int height)
	{
		this.width = width;
		this.height = height;
		MoveWindow(hWnd,x,y,width,height,true);
	}	    
	
	
	void run()
	{		
		MSG msg;
		bit done = false;
		while (!done)
		{
			if (PeekMessageA(&msg,null,0,0,PM_REMOVE))	// Is There A Message Waiting?
			{
				if (msg.message==WM_QUIT)				// Have We Received A Quit Message?
				{
					done=true;							// If So done=TRUE
				}
				else									// If Not, Deal With Window Messages
				{
					TranslateMessage(&msg);				// Translate The Message
					DispatchMessageA(&msg);				// Dispatch The Message
				}
			}		

		}		
				
	}	   	


		
	extern(Windows)
	static int WindowProc(HWND hWnd, uint uMsg, WPARAM wParam, LPARAM lParam)
	{
		switch (uMsg)
		{
	
	   	 	case WM_DESTROY:
	    	{
				PostQuitMessage(0);
				break;
			}		
	
							
			default:
				break;
		}
		return DefWindowProcA(hWnd, uMsg, wParam, lParam);
	}	
}

//----------------------------------------------------------------------------------------------------


class Panel
{
	Frame parent;								// child's parent
	HMENU childID;								
	int width = 100 ;							// child width
	int height = 100 ;							// child height
	int x = 0;									// child position within parent
	int y = 0;	
	HWND		hWnd;							// Holds Our Window Handle	
	void delegate(WPARAM) keyDown;				// to hold pointer to method that implements message handler

		
	
	this(int childID, Frame parent)
	{
		 
		this.childID = cast(HMENU) childID;
		this.parent = parent;		
		createWindow();			
	}

	
	void createWindow()
	{
		WNDCLASS wc;		
	
		wc.lpszClassName = "Panel";				
		wc.lpfnWndProc = &WndProc;								// window procedure		
		wc.hIcon = null;		
		wc.cbWndExtra = 8;
		wc.hbrBackground = GetStockObject(LTGRAY_BRUSH);
		assert(RegisterClassA(&wc));							// register child
																// create child window
		hWnd = CreateWindowA(cast(LPCSTR)"Panel",cast(LPCSTR)"Window", 
		WS_CHILDWINDOW | WS_VISIBLE ,x,y,width,height, parent.hWnd, childID, parent.hInst, null);
	    assert(hWnd);
	    SetWindowLong(hWnd,GWL_USERDATA,cast(LONG)cast(void*) this);   // remember this for Panel class	 
    }  
	  	
		
	extern(Windows)
	static int WndProc(HWND hWnd, uint uMsg, WPARAM wParam, LPARAM lParam)
	{
		Panel objectPtr = cast(Panel)cast(void*) GetWindowLong(hWnd,GWL_USERDATA);
		assert(objectPtr);
		objectPtr.messageHandler(hWnd, uMsg, wParam, lParam);		
		return DefWindowProcA(hWnd, uMsg, wParam, lParam);								
    }
    
    
    void messageHandler(HWND hWnd, uint uMsg, WPARAM wParam, LPARAM lParam)
    {
		switch(uMsg)
		{
		    case WM_PAINT:
	    	{
				static char[] text = "D does Windows";
				PAINTSTRUCT ps;
				HDC dc = BeginPaint(hWnd, &ps);		
				RECT r;
				GetClientRect(hWnd, &r);
				HFONT font = CreateFontA(80, 0, 0, 0, FW_EXTRABOLD, FALSE, FALSE,
					FALSE, ANSI_CHARSET, OUT_DEFAULT_PRECIS, CLIP_DEFAULT_PRECIS,
					DEFAULT_QUALITY, DEFAULT_PITCH | FF_DONTCARE, "Arial");
				HGDIOBJ old = SelectObject(dc, cast(HGDIOBJ) font);
				SetTextAlign(dc, TA_CENTER | TA_BASELINE);
				TextOutA(dc, r.right / 2, r.bottom / 2, text, text.length);
				SelectObject(dc, old);
				EndPaint(hWnd, &ps);
				break;
			}

			case WM_KEYDOWN:
			{				
				keyDown(wParam);												
				break;
			}
									
			default:
				break;
		}	        
    }	
	
	public void position(int x,int y)
	{
		this.x = x;
		this.y = y;
		MoveWindow(hWnd,x,y,width,height,true);
	}
	
	public void size(int width,int height)
	{
		this.width = width;
		this.height = height;
		MoveWindow(hWnd,x,y,width,height,true);
	}	
}