#Include "windows.bi"
#Include "resource.bi"

Const As String g_szClassName = "myWindowClass"

Dim Shared As HMODULE hInstance
Dim Shared As ZString Ptr lpCmdLine

Dim Shared As HBITMAP g_hbmBall = NULL

Function WndProc(hwnd As HWND, msg As UINT, wParam As WPARAM, lParam As LPARAM) As LRESULT
	Select Case msg
		Case WM_CREATE
			g_hbmBall = LoadBitmap(GetModuleHandle(NULL), MAKEINTRESOURCE(IDB_BALL))
			If g_hbmBall = NULL Then
				MessageBox(hwnd, "Could not load IDB_BALL!", "Error", MB_OK Or MB_ICONEXCLAMATION)
			EndIf
		
		Case WM_CLOSE
			DestroyWindow(hwnd)
		
		Case WM_PAINT
			' Just a note, never use a MessageBox from inside WM_PAINT
			' The box will cause more WM_PAINT messages and you'll probably end up
			' stuck in a loop

			Dim As BITMAP bm
			Dim As PAINTSTRUCT ps

			Dim As HDC hdc = BeginPaint(hwnd, @ps)

			Dim As HDC hdcMem = CreateCompatibleDC(hdc)
			Dim As HBITMAP hbmOld = Cast(HBITMAP, SelectObject(hdcMem, g_hbmBall))

			GetObject(g_hbmBall, SizeOf(bm), @bm)

			BitBlt(hdc, 0, 0, bm.bmWidth, bm.bmHeight, hdcMem, 0, 0, SRCCOPY)

			SelectObject(hdcMem, hbmOld)
			DeleteDC(hdcMem)

			EndPaint(hwnd, @ps)
		
		Case WM_DESTROY
			DeleteObject(g_hbmBall)
			PostQuitMessage(0)
		
		Case Else
			Return DefWindowProc(hwnd, msg, wParam, lParam)
	End Select
	Return 0
End Function

Function WinMain(hInstance As HINSTANCE, hPrevInstance As HINSTANCE, lpCmdLine As ZString Ptr, nCmdShow As Long) As Long
	Dim As WNDCLASSEX wc
	Dim As HWND hwnd
	Dim As MSG Msg

	wc.cbSize		     = SizeOf(WNDCLASSEX)
	wc.style		     = 0
	wc.lpfnWndProc	 = @WndProc
	wc.cbClsExtra	   = 0
	wc.cbWndExtra	   = 0
	wc.hInstance	   = hInstance
	wc.hIcon		     = LoadIcon(NULL, IDI_APPLICATION)
	wc.hCursor		   = LoadCursor(NULL, IDC_ARROW)
	wc.hbrBackground = Cast(HBRUSH, COLOR_WINDOW + 1)
	wc.lpszMenuName  = NULL
	wc.lpszClassName = @g_szClassName
	wc.hIconSm	  	 = LoadIcon(NULL, IDI_APPLICATION)

	If RegisterClassEx(@wc) = 0 Then
		MessageBox(NULL, "Window Registration Failed!", "Error!", MB_ICONEXCLAMATION Or MB_OK)
		Return 0
	EndIf

	hwnd = CreateWindowEx(WS_EX_CLIENTEDGE, _
		                    g_szClassName, _
		                    "A Bitmap Program", _
		                    WS_OVERLAPPEDWINDOW, _
		                    CW_USEDEFAULT, CW_USEDEFAULT, 240, 120, _
		                    NULL, NULL, hInstance, NULL)

	If hwnd = NULL Then
		MessageBox(NULL, "Window Creation Failed!", "Error!", MB_ICONEXCLAMATION Or MB_OK)
		Return 0
	EndIf

	ShowWindow(hwnd, nCmdShow)
	UpdateWindow(hwnd)

	Do While GetMessage(@msg,NULL,0,0)
		TranslateMessage(@msg)
		DispatchMessage(@msg)
	Loop
	Return msg.wParam
End Function

' Program start
hInstance = GetModuleHandle(NULL)
lpCmdLine = GetCommandLine
WinMain(hInstance, NULL, lpCmdLine, SW_SHOWDEFAULT)
ExitProcess(0)