/* scroll.c implements the Scroll library. See the header, scroll.h, for the app
   interface. The Scroll library provides a simple tty interface to a Windows app. 
   This app is similar to a console app except that it runs as a Windows program 
   and has the full Windows API available to it.
 */

/* I, Eric Prud'hommeaux, grant unlimited use of this code to the WWW consortium.
   I retain the copyright ownership and expect to be contacted for licencing if 
   the Scroll library or the library interface are used in any commercial products 
   or ventures.

   Also, please contact me if for a CURSES version of this.
   eric@apocalypse.org
 */

#include <windows.h>
#include <string.h>
#include "lib.h"
#include "scroll.h"

//private functions
int scroll_MoveCursor(ScrollInfo_t* pScroll)
	{
	if (pScroll->cursorState & Scroll_cursorShow)
		SetCaretPos((pScroll->nColumn * pScroll->xChar) - pScroll->xOffset,
							  (pScroll->nRow * pScroll->yChar) - pScroll->yOffset);
	return ( TRUE ) ;
	}

//public functions
int Scroll_SetupInfo(ScrollInfo_t* pScroll, int maxRows, int maxCols)
	{
	pScroll->xSize			= 0;
	pScroll->ySize			= 0;
	pScroll->xScroll		 = 0;
	pScroll->yScroll		 = 0;
	pScroll->xOffset		 = 0;
	pScroll->yOffset		 = 0;
	pScroll->nColumn		  = 0;
	pScroll->nRow			  = 0;
	pScroll->maxRows = maxRows;
	pScroll->maxCols = maxCols;
	pScroll->cursorState	= Scroll_cursorHide;
	pScroll->maxTrackSize.x = (int)0x0;
	pScroll->maxTrackSize.y = (int)0x0;
	// clear screen space
	// GPF here means no memory was allocated by caller
	_fmemset(pScroll->screenBuf, ' ', pScroll->maxRows * pScroll->maxCols);
	return (0);
	}

void Scroll_DestroyInfo(ScrollInfo_t* pScroll)
	{
	return;
	}

int Scroll_WriteControl(ScrollInfo_t* pScroll, HWND hWnd, Scroll_control2_t control, int x, int y)
	{
	switch (control)
		{
		case Scroll_control_null:
			return (0);
		case Scroll_control_CR:
			pScroll->nColumn = 0;
			scroll_MoveCursor(pScroll);
			return (0);
		case Scroll_control_LF:
			if (pScroll->nRow++ == pScroll->maxRows - 1)
				{
				memmove(pScroll->screenBuf, pScroll->screenBuf + pScroll->maxCols, (pScroll->maxRows - 1) * pScroll->maxCols);
				memset(pScroll->screenBuf + (pScroll->maxRows - 1) * pScroll->maxCols, ' ', pScroll->maxCols);
				InvalidateRect(hWnd, 0, FALSE);
				pScroll->nRow--;
				}
			scroll_MoveCursor(pScroll);
			return (0);
		case Scroll_control_BS:
			if (pScroll->nColumn > 0)
				pScroll->nColumn--;
            if (pScroll->control | Scroll_control_BSbegetsSpace)
                {
        		*(pScroll->screenBuf + pScroll->nRow * pScroll->maxCols + pScroll->nColumn) = ' ';
				InvalidateRect(hWnd, 0, FALSE);
                }
			scroll_MoveCursor(pScroll);
			return (0);
		case Scroll_control_Bell:
			MessageBeep(0);
			return (0);
		case Scroll_control_Tab:
			{
			int curTab;
			curTab = pScroll->nColumn/8;
			curTab++;
			pScroll->nColumn = curTab * 8;
			if (pScroll->nColumn >= pScroll->maxCols)
				{
				Scroll_WriteControl(pScroll, hWnd, Scroll_control_CR, 0, 0);
				Scroll_WriteControl(pScroll, hWnd, Scroll_control_LF ,0 ,0);
				}
			else
				scroll_MoveCursor(pScroll);
			}
			return (0);
		case Scroll_control_clearEol:
			memset(pScroll->screenBuf + (pScroll->nRow)*pScroll->maxCols + pScroll->nColumn, ' ', pScroll->maxCols - pScroll->nColumn);
			InvalidateRect(hWnd, 0, FALSE);
			return (0);
		case Scroll_control_goto:
			pScroll->nColumn = x;
			pScroll->nRow = y;
			scroll_MoveCursor(pScroll);
			return (0);
		case Scroll_control_normal:
			return (0);
		case Scroll_control_bold:
			return (0);
		case Scroll_control_inverse:
			return (0);
		default:	//undefined request
			return (1);
		}
	}

int Scroll_writeLiteral(ScrollInfo_t* pScroll, HWND hWnd, LPSTR lpBlock, int nLength)
	{
	int		  i ;
	RECT		 rect ;
int Scroll_writeInterpreted(ScrollInfo_t* pScroll, HWND hWnd, LPSTR lpBlock, int nLength);

	for (i = 0 ; i < nLength; i++)
		{
		*(pScroll->screenBuf + pScroll->nRow * pScroll->maxCols + pScroll->nColumn) = lpBlock[i];
		rect.left = (pScroll->nColumn * pScroll->xChar) -	pScroll->xOffset;
		rect.right = rect.left + pScroll->xChar;
		rect.top = (pScroll->nRow * pScroll->yChar) -	pScroll->yOffset;
		rect.bottom = rect.top + pScroll->yChar;
		InvalidateRect(hWnd, &rect, FALSE);
		// Line wrap
		if (pScroll->nColumn < pScroll->maxCols - 1)
			pScroll->nColumn++;
		else if (pScroll->control & Scroll_control_autoWrap)
			{
			if (pScroll->control  & Scroll_control_crBegetsLf)
				Scroll_writeInterpreted(pScroll, hWnd, "\r", 1);
			else
				Scroll_writeInterpreted(pScroll, hWnd, "\r\n", 2);
			}
		}
	return (TRUE);
	}

// interpretable keycodes
#define SCROLL_BELL      0x07
#define SCROLL_BS        0x08
#define SCROLL_TAB       0x09
#define SCROLL_LF        0x0A
#define SCROLL_CR        0x0D

int Scroll_writeInterpreted(ScrollInfo_t* pScroll, HWND hWnd, LPSTR lpBlock, int nLength)
	{
	int		  i ;

	for (i = 0 ; i < nLength; i++)
		{
		switch (lpBlock[i])
			{
			case SCROLL_BELL:
				Scroll_WriteControl(pScroll, hWnd, Scroll_control_Bell, 0, 0);
				break ;

			case SCROLL_BS:
				Scroll_WriteControl(pScroll, hWnd, Scroll_control_BS, 0, 0);
				break;

			case SCROLL_TAB:
				Scroll_WriteControl(pScroll, hWnd, Scroll_control_Tab, 0, 0);
				break;

			case SCROLL_CR:
				Scroll_WriteControl(pScroll, hWnd, Scroll_control_CR, 0, 0);
				if (pScroll->control  & Scroll_control_crBegetsLf)
					Scroll_WriteControl(pScroll, hWnd, Scroll_control_LF, 0, 0);
				break;

			case SCROLL_LF:
				if (pScroll->control  & Scroll_control_lfBegetsCr)
					Scroll_WriteControl(pScroll, hWnd, Scroll_control_CR, 0, 0);
				Scroll_WriteControl(pScroll, hWnd, Scroll_control_LF, 0, 0);
				break ;

			default:
	 			Scroll_writeLiteral(pScroll, hWnd, lpBlock+i, 1);
				break;
			}
		}
	return (TRUE);
	} // end of Scroll_writeInterpreted()

int Scroll_WriteBlock(ScrollInfo_t* pScroll, HWND hWnd, LPSTR lpBlock, int nLength)
	{
	if (pScroll->control & Scroll_control_literal)
		return (Scroll_writeLiteral(pScroll, hWnd, lpBlock, nLength));
	else
		return (Scroll_writeInterpreted(pScroll, hWnd, lpBlock, nLength));
	}

int Scroll_SetSize(ScrollInfo_t* pScroll, HWND hWnd, WORD wVertSize, WORD wHorzSize)
	{
	int		  nScrollAmt ;

	pScroll->ySize = (int) wVertSize ;
	pScroll->yScroll = max(0, (pScroll->maxRows * pScroll->yChar) -	pScroll->ySize);
	nScrollAmt = min(pScroll->yScroll, pScroll->yOffset ) -	pScroll->yOffset;
	ScrollWindow(hWnd, 0, -nScrollAmt, 0, 0);

	pScroll->yOffset = pScroll->yOffset + nScrollAmt;
	SetScrollPos(hWnd, SB_VERT, pScroll->yOffset, FALSE);
	SetScrollRange(hWnd, SB_VERT, 0, pScroll->yScroll, TRUE);

	pScroll->xSize = (int) wHorzSize ;
	pScroll->xScroll = max(0, (pScroll->maxCols * pScroll->xChar) - pScroll->xSize);
	nScrollAmt = min(pScroll->xScroll, pScroll->xOffset) - pScroll->xOffset;
	ScrollWindow(hWnd, 0, -nScrollAmt, 0, 0);
	pScroll->xOffset = pScroll->xOffset + nScrollAmt;
	SetScrollPos(hWnd, SB_HORZ, pScroll->xOffset, FALSE);
	SetScrollRange(hWnd, SB_HORZ, 0, pScroll->xScroll, TRUE);

	InvalidateRect(hWnd, 0, TRUE);

	return (TRUE);

	} // end of Scroll_SetSize()

int Scroll_SetVert(ScrollInfo_t* pScroll, HWND hWnd, WORD wScrollCmd, WORD wScrollPos)
	{
	int		  nScrollAmt ;

	switch (wScrollCmd)
		{
		case SB_TOP:
			nScrollAmt = -pScroll->yOffset ;
			break ;

		case SB_BOTTOM:
			nScrollAmt = pScroll->yScroll - pScroll->yOffset ;
			break ;

		case SB_PAGEUP:
			nScrollAmt = -pScroll->ySize ;
			break ;

		case SB_PAGEDOWN:
			nScrollAmt = pScroll->ySize ;
			break ;

		case SB_LINEUP:
			nScrollAmt = -pScroll->yChar ;
			break ;

		case SB_LINEDOWN:
			nScrollAmt = pScroll->yChar ;
			break ;

		case SB_THUMBPOSITION:
			nScrollAmt = wScrollPos - pScroll->yOffset ;
			break ;

		default:
			return ( FALSE ) ;
		}
	if ((pScroll->yOffset + nScrollAmt) > pScroll->yScroll)
		nScrollAmt = pScroll->yScroll - pScroll->yOffset ;
	if ((pScroll->yOffset + nScrollAmt) < 0)
		nScrollAmt = -pScroll->yOffset ;
	ScrollWindow( hWnd, 0, -nScrollAmt, 0, 0 ) ;
	pScroll->yOffset = pScroll->yOffset + nScrollAmt ;
	SetScrollPos( hWnd, SB_VERT, pScroll->yOffset, TRUE ) ;

	return ( TRUE ) ;

	} // end of Scroll_SetVert()

int Scroll_SetHorz(ScrollInfo_t* pScroll, HWND hWnd, WORD wScrollCmd, WORD wScrollPos)
	{
	int		  nScrollAmt ;

	switch (wScrollCmd)
		{
		case SB_TOP:
			nScrollAmt = -pScroll->xOffset ;
			break ;

		case SB_BOTTOM:
			nScrollAmt = pScroll->xScroll - pScroll->xOffset ;
			break ;

		case SB_PAGEUP:
			nScrollAmt = -pScroll->xSize ;
			break ;

		case SB_PAGEDOWN:
			nScrollAmt = pScroll->xSize ;
			break ;

		case SB_LINEUP:
			nScrollAmt = -pScroll->xChar ;
			break ;

		case SB_LINEDOWN:
			nScrollAmt = pScroll->xChar ;
			break ;

		case SB_THUMBPOSITION:
			nScrollAmt = wScrollPos - pScroll->xOffset ;
			break ;

		default:
			return ( FALSE ) ;
		}
	if ((pScroll->xOffset + nScrollAmt) > pScroll->xScroll)
		nScrollAmt = pScroll->xScroll - pScroll->xOffset ;
	if ((pScroll->xOffset + nScrollAmt) < 0)
		nScrollAmt = -pScroll->xOffset ;
	ScrollWindow( hWnd, -nScrollAmt, 0, 0, 0 ) ;
	pScroll->xOffset = pScroll->xOffset + nScrollAmt ;
	SetScrollPos( hWnd, SB_HORZ, pScroll->xOffset, TRUE ) ;

	return ( TRUE ) ;
	} // end of Scroll_SetHorz()

int Scroll_SetFocus(HWND hWnd, ScrollInfo_t* pScroll)
	{
	if (!(pScroll->cursorState & Scroll_cursorShow))
		{
		CreateCaret(hWnd, 0, pScroll->xChar, pScroll->yChar);
		ShowCaret(hWnd);
		pScroll->cursorState |= Scroll_cursorShow;
		}
	scroll_MoveCursor(pScroll);
	return (TRUE);
	} // end of Scroll_SetFocus()

int Scroll_KillFocus(HWND hWnd, ScrollInfo_t* pScroll)
	{
	if (pScroll->cursorState & Scroll_cursorShow)
		{
		HideCaret(hWnd);
		DestroyCaret();
		pScroll->cursorState &= ~Scroll_cursorShow;
		}
	return (TRUE);
	} // end of Scroll_KillFocus()

int Scroll_Paint(ScrollInfo_t* pScroll, FontInfo_t* pFont, HWND hWnd, CursorState_t cursorState)
	{
	int			 nRow, nCol, nEndRow, nEndCol, nCount, nHorzPos, nVertPos ;
	HDC			 hDC ;
	HFONT		  hOldFont ;
	PAINTSTRUCT  ps ;
	RECT			rect ;

	hDC = BeginPaint( hWnd, &ps ) ;
	hOldFont = SelectObject( hDC, pFont->hFont ) ;
	SetTextColor( hDC, pFont->rgbFGColor ) ;
	SetBkColor( hDC, GetSysColor( COLOR_WINDOW ) ) ;
	rect = ps.rcPaint ;
	nRow = min(pScroll->maxRows - 1, max(0, (rect.top + pScroll->yOffset) / pScroll->yChar));
	nEndRow = min(pScroll->maxRows - 1, ((rect.bottom + pScroll->yOffset - 1) / pScroll->yChar));
	nCol = min(pScroll->maxCols - 1, max(0, (rect.left + pScroll->xOffset) / pScroll->xChar));
	nEndCol = min(pScroll->maxCols - 1, ((rect.right + pScroll->xOffset - 1) / pScroll->xChar));
	nCount = nEndCol - nCol + 1 ;
	for (; nRow <= nEndRow; nRow++)
		{
		nVertPos = (nRow * pScroll->yChar) - pScroll->yOffset ;
		nHorzPos = (nCol * pScroll->xChar) - pScroll->xOffset ;
		rect.top = nVertPos ;
		rect.bottom = nVertPos + pScroll->yChar ;
		rect.left = nHorzPos ;
		rect.right = nHorzPos + pScroll->xChar * nCount ;
		SetBkMode( hDC, OPAQUE ) ;
		ExtTextOut( hDC, nHorzPos, nVertPos, ETO_OPAQUE | ETO_CLIPPED, &rect,
						(LPSTR)( pScroll->screenBuf + nRow * pScroll->maxCols + nCol ),
						nCount, 0 ) ;
		}
	SelectObject( hDC, hOldFont ) ;
	EndPaint( hWnd, &ps ) ;
	if (cursorState | Scroll_cursorShow)
		scroll_MoveCursor(pScroll);
	return ( TRUE ) ;
	} // end of Scroll_Paint()

int Scroll_ResetScreen(HWND hWnd, ScrollInfo_t* pScroll, FontInfo_t* pFont)
	{
	HDC			hDC ;
	TEXTMETRIC  tm ;
	RECT rect;

	if (0 != pFont->hFont)
		DeleteObject( pFont->hFont ) ;

	pFont->hFont = CreateFontIndirect( &pFont->logFont ) ;

	hDC = GetDC(hWnd);
	SelectObject(hDC, pFont->hFont);
	GetTextMetrics(hDC, &tm);
	ReleaseDC(hWnd, hDC);

	pScroll->xChar = tm.tmAveCharWidth;
	pScroll->yChar = tm.tmHeight + tm.tmExternalLeading;
	rect.left = 0;
	rect.top = 0;
	rect.right = pScroll->xChar * pScroll->maxCols;
	rect.bottom = pScroll->yChar * pScroll->maxRows;
	AdjustWindowRect(&rect, GetWindowLong(hWnd, GWL_STYLE), TRUE);
	pScroll->maxTrackSize.x = rect.right - rect.left;
	pScroll->maxTrackSize.y = rect.bottom - rect.top;
//	pScroll->maxTrackSize.x = pScroll->xChar * pScroll->maxCols + 2*GetSystemMetrics(SM_CXFRAME) + GetSystemMetrics(SM_CXVSCROLL);
//	pScroll->maxTrackSize.y = pScroll->yChar * pScroll->maxRows + 2*GetSystemMetrics(SM_CYFRAME) + GetSystemMetrics(SM_CYHSCROLL);

	// a slimy hack to force the scroll position, region to
	// be recalculated based on the new character sizes

//	SendMessage(hWnd, WM_SIZE, SIZENORMAL, (LPARAM)MAKELONG(rcWindow.right - rcWindow.left, rcWindow.bottom - rcWindow.top));
//	Scroll_SetSize(pScroll, hWnd, (WORD)(rcWindow.bottom - rcWindow.top), (WORD)(rcWindow.right - rcWindow.left));
	Scroll_SetSize(pScroll, hWnd, (WORD)pScroll->maxTrackSize.y, (WORD)pScroll->maxTrackSize.x);
	return (TRUE);
	} // end of Scroll_ResetScreen()