/*
 *		Buffer handling.
 */

#include "def.h"
#include "kbd.h"		/* needed for modes */

static RSIZE    itor		__P((char *, int, RSIZE));
static BUFFER  *makelist	__P((void));

/*
 * Attach a buffer to a window. The values of dot and mark come
 * from the buffer if the use count is 0. Otherwise, they come
 * from some other window.  *scratch* is the default alternate
 * buffer.
 */
/* ARGSUSED */
int
usebuffer(f, n)
	int     f, n;
{
	BUFFER *bp;
	int     s;
	char    bufn[NBUFN];

	/* Get buffer to use from user */
	if ((curbp->b_altb == NULL)
	    && ((curbp->b_altb = bfind("*scratch*", TRUE)) == NULL))
		s = eread("Switch to buffer: ", bufn, NBUFN, EFNEW | EFBUF);
	else
		s = eread("Switch to buffer: (default %s) ", bufn, NBUFN,
			  EFNEW | EFBUF, curbp->b_altb->b_bname);

	if (s == ABORT)
		return s;
	if (s == FALSE && curbp->b_altb != NULL)
		bp = curbp->b_altb;
	else if ((bp = bfind(bufn, TRUE)) == NULL)
		return FALSE;

	/* and put it in current window */
	curbp = bp;
	return showbuffer(bp, curwp, WFFORCE | WFHARD);
}

/*
 * pop to buffer asked for by the user.
 */
/* ARGSUSED */
int
poptobuffer(f, n)
	int     f, n;
{
	BUFFER *bp;
	MGWIN  *wp;
	int     s;
	char    bufn[NBUFN];

	/* Get buffer to use from user */
	if ((curbp->b_altb == NULL)
	    && ((curbp->b_altb = bfind("*scratch*", TRUE)) == NULL))
		s = eread("Switch to buffer in other window: ", bufn, NBUFN,
			  EFNEW | EFBUF);
	else
		s = eread("Switch to buffer in other window: (default %s) ",
			bufn, NBUFN, EFNEW | EFBUF, curbp->b_altb->b_bname);
	if (s == ABORT)
		return s;
	if (s == FALSE && curbp->b_altb != NULL)
		bp = curbp->b_altb;
	else if ((bp = bfind(bufn, TRUE)) == NULL)
		return FALSE;

	/* and put it in a new window */
	if ((wp = popbuf(bp)) == NULL)
		return FALSE;
	curbp = bp;
	curwp = wp;
	return TRUE;
}

/*
 * Dispose of a buffer, by name.
 * Ask for the name. Look it up (don't get too
 * upset if it isn't there at all!). Clear the buffer (ask
 * if the buffer has been changed). Then free the header
 * line and the buffer header. Bound to "C-X K".
 */
/* ARGSUSED */
int
killbuffer(f, n)
	int     f, n;
{
	BUFFER *bp;
	BUFFER *bp1;
	BUFFER *bp2;
	MGWIN  *wp;
	int     s;
	char    bufn[NBUFN];

	if ((s = eread("Kill buffer: (default %s) ", bufn, NBUFN, EFNEW | EFBUF,
		       curbp->b_bname)) == ABORT)
		return (s);
	else if (s == FALSE)
		bp = curbp;
	else if ((bp = bfind(bufn, FALSE)) == NULL)
		return FALSE;

	/*
	 * Find some other buffer to display. try the alternate buffer,
	 * then the first different buffer in the buffer list.  If there's
	 * only one buffer, create buffer *scratch* and make it the alternate
	 * buffer.  Return if *scratch* is only buffer...
	 */
	if ((bp1 = bp->b_altb) == NULL) {
		bp1 = (bp == bheadp) ? bp->b_bufp : bheadp;
		if (bp1 == NULL) {
			/* only one buffer. see if it's *scratch* */
			if (bp == bfind("*scratch*", FALSE))
				return FALSE;
			/* create *scratch* for alternate buffer */
			if ((bp1 = bfind("*scratch*", TRUE)) == NULL)
				return FALSE;
		}
	}
	if (bclear(bp) != TRUE)
		return TRUE;
	for (wp = wheadp; bp->b_nwnd > 0; wp = wp->w_wndp) {
		if (wp->w_bufp == bp) {
			bp2 = bp1->b_altb;	/* save alternate buffer */
			if (showbuffer(bp1, wp, WFMODE | WFFORCE | WFHARD))
				bp1->b_altb = bp2;
			else
				bp1 = bp2;
		}
	}
	if (bp == curbp)
		curbp = bp1;
	free(bp->b_linep);			/* Release header line.  */
	bp2 = NULL;				/* Find the header.	 */
	bp1 = bheadp;
	while (bp1 != bp) {
		if (bp1->b_altb == bp)
			bp1->b_altb = (bp->b_altb == bp1) ? NULL : bp->b_altb;
		bp2 = bp1;
		bp1 = bp1->b_bufp;
	}
	bp1 = bp1->b_bufp;			/* Next one in chain.	 */
	if (bp2 == NULL)			/* Unlink it.		 */
		bheadp = bp1;
	else
		bp2->b_bufp = bp1;
	while (bp1 != NULL) {			/* Finish with altb's	 */
		if (bp1->b_altb == bp)
			bp1->b_altb = (bp->b_altb == bp1) ? NULL : bp->b_altb;
		bp1 = bp1->b_bufp;
	}
	free(bp->b_bname);			/* Release name block	 */
	free(bp);				/* Release buffer block */
	return TRUE;
}

/*
 * Save some buffers - just call anycb with the arg flag.
 */
/* ARGSUSED */
int
savebuffers(f, n)
	int f, n;
{
	if (anycb(f) == ABORT)
		return ABORT;
	return TRUE;
}

/*
 * Display the buffer list. This is done
 * in two parts. The "makelist" routine figures out
 * the text, and puts it in a buffer. "popbuf"
 * then pops the data onto the screen. Bound to
 * "C-X C-B".
 */
/* ARGSUSED */
int
listbuffers(f, n)
	int f, n;
{
	BUFFER *bp;
	MGWIN  *wp;

	if ((bp = makelist()) == NULL || (wp = popbuf(bp)) == NULL)
		return FALSE;
	wp->w_dotp = bp->b_dotp;/* fix up if window already on screen */
	wp->w_doto = bp->b_doto;
	return TRUE;
}

/*
 * This routine rebuilds the text for the
 * list buffers command. Return TRUE if
 * everything works. Return FALSE if there
 * is an error (if there is no memory).
 */
static BUFFER *
makelist()
{
	char   *cp1;
	char   *cp2;
	int     c;
	BUFFER *bp;
	LINE   *lp;
	RSIZE   nbytes;
	BUFFER *blp;
	char    b[6 + 1];
	char    line[128];

	if ((blp = bfind("*Buffer List*", TRUE)) == NULL)
		return NULL;
	if (bclear(blp) != TRUE)
		return NULL;
	blp->b_flag &= ~BFCHG;		/* Blow away old.	 */

	(VOID) strcpy(line, " MR Buffer");
	cp1 = line + 10;
	while (cp1 < line + 4 + NBUFN + 1)
		*cp1++ = ' ';
	(VOID) strcpy(cp1, "Size   File");
	if (addline(blp, line) == FALSE)
		return NULL;
	(VOID) strcpy(line, " -- ------");
	cp1 = line + 10;
	while (cp1 < line + 4 + NBUFN + 1)
		*cp1++ = ' ';
	(VOID) strcpy(cp1, "----   ----");
	if (addline(blp, line) == FALSE)
		return NULL;
	bp = bheadp;				/* For all buffers	 */
	while (bp != NULL) {
		cp1 = &line[0];			/* Start at left edge	 */
		*cp1++ = (bp == curbp) ? '.' : ' ';
		*cp1++ = ((bp->b_flag & BFCHG) != 0) ? '*' : ' ';
		*cp1++ = ' ';			/* Gap.			 */
		*cp1++ = ' ';
		cp2 = &bp->b_bname[0];		/* Buffer name		 */
		while ((c = *cp2++) != 0)
			*cp1++ = c;
		while (cp1 < &line[4 + NBUFN + 1])
			*cp1++ = ' ';
		nbytes = 0;			/* Count bytes in buf.	 */
		if (bp != blp) {
			lp = lforw(bp->b_linep);
			while (lp != bp->b_linep) {
				nbytes += llength(lp) + 1;
				lp = lforw(lp);
			}
			if (nbytes)
				nbytes--;	/* no bonus newline	 */
		}
		(VOID) itor(b, 6, nbytes);	/* 6 digit buffer size. */
		cp2 = &b[0];
		while ((c = *cp2++) != 0)
			*cp1++ = c;
		*cp1++ = ' ';			/* Gap..		 */
		cp2 = &bp->b_fname[0];		/* File name		 */
		if (*cp2 != 0) {
			while ((c = *cp2++) != 0) {
				if (cp1 < &line[128 - 1])
					*cp1++ = c;
			}
		}
		*cp1 = 0;	/* Add to the buffer.	 */
		if (addline(blp, line) == FALSE)
			return NULL;
		bp = bp->b_bufp;
	}
	blp->b_dotp = lforw(blp->b_linep);	/* put dot at beginning of
						 * buffer */
	blp->b_doto = 0;
	return blp;				/* All done		 */
}

/*
 * Used above.
 */
static RSIZE 
itor(buf, width, num)
	char  *buf;
	int    width;
	RSIZE  num;
{
	RSIZE  r;

	if (num / 10 == 0) {
		buf[0] = (num % 10) + '0';
		for (r = 1; r < width; buf[r++] = ' ');
		buf[width] = '\0';
		return 1;
	} else {
		buf[r = itor(buf, width, num / (RSIZE) 10)] =
			(num % (RSIZE) 10) + '0';
		return r + 1;
	}
	/* NOTREACHED */
}

/*
 * The argument "text" points to a string.  Append this line to the
 * buffer. Handcraft the EOL on the end.  Return TRUE if it worked and
 * FALSE if you ran out of room.
 */
int
addline(bp, text)
	BUFFER *bp;
	char   *text;
{
	LINE  *lp;
	int    i;
	int    ntext;

	ntext = strlen(text);
	if ((lp = lalloc(ntext)) == NULL)
		return FALSE;
	for (i = 0; i < ntext; ++i)
		lputc(lp, i, text[i]);
	bp->b_linep->l_bp->l_fp = lp;		/* Hook onto the end	 */
	lp->l_bp = bp->b_linep->l_bp;
	bp->b_linep->l_bp = lp;
	lp->l_fp = bp->b_linep;
#ifdef CANTHAPPEN
	if (bp->b_dotp == bp->b_linep)		/* If "." is at the end	 */
		bp->b_dotp = lp;		/* move it to new line	 */
	if (bp->b_markp == bp->b_linep)		/* ditto for mark	 */
		bp->b_markp = lp;
#endif
	return TRUE;
}

/*
 * Look through the list of buffers, giving the user a chance to save them.
 * Return TRUE if there are any changed buffers afterwards.  Buffers that
 * don't have an associated file don't count.  Return FALSE if there are
 * no changed buffers.
 */
int
anycb(f)
	int     f;
{
	BUFFER *bp;
	int     s = FALSE, save = FALSE;
	char    prompt[NFILEN + 11];

	for (bp = bheadp; bp != NULL; bp = bp->b_bufp) {
		if (*(bp->b_fname) != '\0'
		    && (bp->b_flag & BFCHG) != 0) {
			(VOID) strcpy(prompt, "Save file ");
			(VOID) strcpy(prompt + 10, bp->b_fname);
			if ((f == TRUE || (save = eyorn(prompt)) == TRUE)
			    && buffsave(bp) == TRUE) {
				bp->b_flag &= ~BFCHG;
				upmodes(bp);
			} else
				s = TRUE;
			if (save == ABORT)
				return (save);
			save = TRUE;
		}
	}
	if (save == FALSE /* && kbdmop == NULL */ )	/* experimental */
		ewprintf("(No files need saving)");
	return s;
}

/*
 * Search for a buffer, by name.
 * If not found, and the "cflag" is TRUE,
 * create a buffer and put it in the list of
 * all buffers. Return pointer to the BUFFER
 * block for the buffer.
 */
BUFFER *
bfind(bname, cflag)
	char *bname;
	int   cflag;
{
	BUFFER	*bp;
	LINE	*lp;
	int	 i; 

	bp = bheadp;
	while (bp != NULL) {
		if (fncmp(bname, bp->b_bname) == 0)
			return bp;
		bp = bp->b_bufp;
	}
	if (cflag != TRUE)
		return NULL;
	/* NOSTRICT */
	if ((bp = (BUFFER *) malloc(sizeof(BUFFER))) == NULL) {
		ewprintf("Can't get %d bytes", sizeof(BUFFER));
		return NULL;
	}
	if ((bp->b_bname = malloc((strlen(bname) + 1))) == NULL) {
		ewprintf("Can't get %d bytes", strlen(bname) + 1);
		free((char *) bp);
		return NULL;
	}
	if ((lp = lalloc(0)) == NULL) {
		free(bp->b_bname);
		free((char *) bp);
		return NULL;
	}
	bp->b_altb = bp->b_bufp = NULL;
	bp->b_dotp = lp;
	bp->b_doto = 0;
	bp->b_markp = NULL;
	bp->b_marko = 0;
	bp->b_flag = defb_flag;
	bp->b_nwnd = 0;
	bp->b_linep = lp;
	bp->b_nmodes = defb_nmodes;
	i = 0;
	do {
		bp->b_modes[i] = defb_modes[i];
	} while (i++ < defb_nmodes);
	bp->b_fname[0] = '\0';
	bzero(&bp->b_fi, sizeof(bp->b_fi));
	(VOID) strcpy(bp->b_bname, bname);
	lp->l_fp = lp;
	lp->l_bp = lp;
	bp->b_bufp = bheadp;
	bheadp = bp;
	return bp;
}

/*
 * This routine blows away all of the text
 * in a buffer. If the buffer is marked as changed
 * then we ask if it is ok to blow it away; this is
 * to save the user the grief of losing text. The
 * window chain is nearly always wrong if this gets
 * called; the caller must arrange for the updates
 * that are required. Return TRUE if everything
 * looks good.
 */
int
bclear(bp)
	BUFFER *bp;
{
	LINE  *lp;
	int    s;

	if ((bp->b_flag & BFCHG) != 0	/* Changed.		 */
	    && (s = eyesno("Buffer modified; kill anyway")) != TRUE)
		return (s);
	bp->b_flag &= ~BFCHG;	/* Not changed		 */
	while ((lp = lforw(bp->b_linep)) != bp->b_linep)
		lfree(lp);
	bp->b_dotp = bp->b_linep;	/* Fix "."		 */
	bp->b_doto = 0;
	bp->b_markp = NULL;	/* Invalidate "mark"	 */
	bp->b_marko = 0;
	return TRUE;
}

/*
 * Display the given buffer in the given window. Flags indicated
 * action on redisplay.
 */
int
showbuffer(bp, wp, flags)
	BUFFER *bp;
	MGWIN  *wp;
	int     flags;
{
	BUFFER *obp;
	MGWIN  *owp;

	if (wp->w_bufp == bp) {	/* Easy case!	 */
		wp->w_flag |= flags;
		return TRUE;
	}
	/* First, dettach the old buffer from the window */
	if ((bp->b_altb = obp = wp->w_bufp) != NULL) {
		if (--obp->b_nwnd == 0) {
			obp->b_dotp = wp->w_dotp;
			obp->b_doto = wp->w_doto;
			obp->b_markp = wp->w_markp;
			obp->b_marko = wp->w_marko;
		}
	}
	/* Now, attach the new buffer to the window */
	wp->w_bufp = bp;

	if (bp->b_nwnd++ == 0) {	/* First use.		 */
		wp->w_dotp = bp->b_dotp;
		wp->w_doto = bp->b_doto;
		wp->w_markp = bp->b_markp;
		wp->w_marko = bp->b_marko;
	} else
		/* already on screen, steal values from other window */
		for (owp = wheadp; owp != NULL; owp = wp->w_wndp)
			if (wp->w_bufp == bp && owp != wp) {
				wp->w_dotp = owp->w_dotp;
				wp->w_doto = owp->w_doto;
				wp->w_markp = owp->w_markp;
				wp->w_marko = owp->w_marko;
				break;
			}
	wp->w_flag |= WFMODE | flags;
	return TRUE;
}

/*
 * Pop the buffer we got passed onto the screen.
 * Returns a status.
 */
MGWIN *
popbuf(bp)
	BUFFER *bp;
{
	MGWIN  *wp;

	if (bp->b_nwnd == 0) {	/* Not on screen yet.	 */
		if ((wp = wpopup()) == NULL)
			return NULL;
	} else
		for (wp = wheadp; wp != NULL; wp = wp->w_wndp)
			if (wp->w_bufp == bp) {
				wp->w_flag |= WFHARD | WFFORCE;
				return wp;
			}
	if (showbuffer(bp, wp, WFHARD) != TRUE)
		return NULL;
	return wp;
}

/*
 * Insert another buffer at dot.  Very useful.
 */
/* ARGSUSED */
int
bufferinsert(f, n)
{
	BUFFER *bp;
	LINE   *clp;
	int     clo;
	int     nline;
	int     s;
	char    bufn[NBUFN];

	/* Get buffer to use from user */
	if (curbp->b_altb != NULL)
		s = eread("Insert buffer: (default %s) ", bufn, NBUFN,
			  EFNEW | EFBUF, &(curbp->b_altb->b_bname),
			  (char *) NULL);
	else
		s = eread("Insert buffer: ", bufn, NBUFN, EFNEW | EFBUF,
			  (char *) NULL);
	if (s == ABORT)
		return (s);
	if (s == FALSE && curbp->b_altb != NULL)
		bp = curbp->b_altb;
	else if ((bp = bfind(bufn, FALSE)) == NULL)
		return FALSE;

	if (bp == curbp) {
		ewprintf("Cannot insert buffer into self");
		return FALSE;
	}
	/* insert the buffer */
	nline = 0;
	clp = lforw(bp->b_linep);
	for (;;) {
		for (clo = 0; clo < llength(clp); clo++)
			if (linsert(1, lgetc(clp, clo)) == FALSE)
				return FALSE;
		if ((clp = lforw(clp)) == bp->b_linep)
			break;
		if (newline(FFRAND, 1) == FALSE)	/* fake newline */
			return FALSE;
		nline++;
	}
	if (nline == 1)
		ewprintf("[Inserted 1 line]");
	else
		ewprintf("[Inserted %d lines]", nline);

	clp = curwp->w_linep;	/* cosmetic adjustment */
	if (curwp->w_dotp == clp) {	/* for offscreen insert */
		while (nline-- && lback(clp) != curbp->b_linep)
			clp = lback(clp);
		curwp->w_linep = clp;	/* adjust framing.	 */
		curwp->w_flag |= WFHARD;
	}
	return (TRUE);
}

/*
 * Turn off the dirty bit on this buffer.
 */
/* ARGSUSED */
int
notmodified(f, n)
{
	MGWIN *wp;

	curbp->b_flag &= ~BFCHG;
	wp = wheadp;		/* Update mode lines.	 */
	while (wp != NULL) {
		if (wp->w_bufp == curbp)
			wp->w_flag |= WFMODE;
		wp = wp->w_wndp;
	}
	ewprintf("Modification-flag cleared");
	return TRUE;
}

#ifndef NO_HELP
/*
 * Popbuf and set all windows to top of buffer.	 Currently only used by
 * help functions.
 */
int
popbuftop(bp)
	BUFFER *bp;
{
	MGWIN *wp;

	bp->b_dotp = lforw(bp->b_linep);
	bp->b_doto = 0;
	if (bp->b_nwnd != 0) {
		for (wp = wheadp; wp != NULL; wp = wp->w_wndp)
			if (wp->w_bufp == bp) {
				wp->w_dotp = bp->b_dotp;
				wp->w_doto = 0;
				wp->w_flag |= WFHARD;
			}
	}
	return popbuf(bp) != NULL;
}
#endif