LRESULT CALLBACK WndProc(HWND hwnd, UINT msg, WPARAM wparam, LPARAM lparam)
{
	static int charWidth, charHeight, capsWidth, maxWidth;
	static int clientWidth, clientHeight;
	static int verticalScrollPos, horizontalScrollPos;

	switch(msg)
	{
	case WM_CREATE:
		{
			HDC hdc = GetDC(hwnd);
			TEXTMETRIC tm;
			GetTextMetrics(hdc, &tm);

			charWidth = tm.tmAveCharWidth;
			capsWidth = (tm.tmPitchAndFamily & 1 ? 3 : 2) * charWidth / 2;
			charHeight = tm.tmHeight + tm.tmExternalLeading;

			ReleaseDC(hwnd, hdc);

			maxWidth = 40 * charWidth + 22 * capsWidth;
			return 0;
		}

	case WM_SIZE:
		{
			clientWidth = LOWORD(lparam);
			clientHeight = HIWORD(lparam);

			SCROLLINFO si;
			si.cbSize = sizeof(si);
			si.fMask = SIF_RANGE | SIF_PAGE;
			si.nMin = 0;
			si.nMax = NUMLINES - 1;
			si.nPage = clientHeight / charHeight;
			SetScrollInfo(hwnd, SB_VERT, &si, true);

			si.cbSize = sizeof(si);
			si.fMask = SIF_RANGE | SIF_PAGE;
			si.nMin = 0;
			si.nMax = 2 + maxWidth / charWidth;
			si.nPage = clientWidth / charWidth;
			SetScrollInfo(hwnd, SB_HORZ, &si, true);
			return 0;
		}

	case WM_HSCROLL:
		{
			SCROLLINFO si;
			si.cbSize = sizeof(si);
			si.fMask = SIF_ALL;
			GetScrollInfo(hwnd, SB_HORZ, &si);
			horizontalScrollPos = si.nPos;

			switch(LOWORD(wparam))
			{
				case SB_LINELEFT:
					si.nPos -= 1;
					break;

				case SB_LINERIGHT:
					si.nPos += 1;
					break;

				case SB_PAGELEFT:
					si.nPos -= si.nPage;
					break;

				case SB_PAGERIGHT:
					si.nPos += si.nPage;
					break;

				case SB_THUMBPOSITION:
					si.nPos = si.nTrackPos;
					break;

				default:
					break;
			}

			si.fMask = SIF_POS;
			SetScrollInfo(hwnd, SB_HORZ, &si, true);
			GetScrollInfo(hwnd, SB_HORZ, &si);
			if(si.nPos != horizontalScrollPos)
			{
				ScrollWindow(hwnd, 0, charWidth * (horizontalScrollPos - si.nPos), 
							 0, 0);
			}
			return 0;
		}

	case WM_PAINT:
		{
			PAINTSTRUCT ps;
			HDC hdc = BeginPaint(hwnd, &ps);

			SCROLLINFO si;
			si.cbSize = sizeof(si);
			si.fMask = SIF_POS;

			GetScrollInfo(hwnd, SB_VERT, &si);
			verticalScrollPos = si.nPos;

			GetScrollInfo(hwnd, SB_HORZ, &si);
			horizontalScrollPos = si.nPos;

			int paintBegin = max(0, verticalScrollPos + ps.rcPaint.top / charHeight);
			int paintEnd = min(NUMLINES - 1, 
							   verticalScrollPos + ps.rcPaint.bottom / charHeight);
			
			for(int i = paintBegin; i <= paintEnd; ++i)
			{
				const Sysmetrics& sm = sysmetrics;
				int x = charWidth * (1 - horizontalScrollPos);
				int y = charHeight * (i - verticalScrollPos);

				TextOut(hdc, x, y, sm.label, strlen(sm.label));
				TextOut(hdc, x + 22 * capsWidth, y, 
						sm.desc, strlen(sm.desc));

				SetTextAlign(hdc, TA_RIGHT | TA_TOP);
				string text = str(format("%1%") % GetSystemMetrics(sm.index));

				TextOut(hdc, x + 22 * capsWidth + 40 * charWidth, y,
						text.c_str(), text.size());

				SetTextAlign(hdc, TA_LEFT | TA_TOP);
			}

			EndPaint(hwnd, &ps);
			return 0;
		}

	case WM_DESTROY:
		PostQuitMessage(0);
		return 0;
	}
	return DefWindowProc(hwnd, msg, wparam, lparam);
}