/* buffer.c -- implements buffer.h */
#include "buffer.h"

/*	buffer.c
 *
 *	Buffer management.
 *	Some of the functions are internal,
 *	and some are actually attached to user
 *	keys. Like everyone else, they set hints
 *	for the display system
 *
 *	modified by Petri Kutvonen
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "defines.h"
#include "estruct.h"
#include "file.h"
#include "input.h"
#include "mlout.h"
#include "window.h"


struct buffer *curbp ;		/* Current buffer               */
struct buffer *bheadp ;		/* Head of list of buffers      */
struct buffer *blistp ;		/* Buffer for C-X C-B           */

const char *modename[] = {	/* name of modes                */
	"Wrap", "Cmode", "Exact", "View", "Over",
	"Magic",
	"Asave", "Utf-8", "Dos"
} ;

int gmode = 0 ;			/* global editor mode           */

static int makelist( int iflag) ;
static int addline( char *text) ;
static void l_to_a( char *buf, int width, long num) ;


/*
 * 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.
 */
int usebuffer( int f, int n) {
	struct buffer *bp ;
	int status ;
	char *bufn ;

/* Get buffer name */
	status = newmlarg( &bufn, "Use buffer: ", sizeof( bname_t)) ;
	if( status != TRUE)
		return status ;

/* Find buffer in list */
	bp = bfind( bufn, TRUE, 0) ;
	free( bufn) ;
	if( bp == NULL)
		return FALSE ;

/* Switch to buffer */
	return swbuffer( bp) ;
}

/*
 * switch to the next buffer in the buffer list
 *
 * int f, n;		default flag, numeric argument
 */
int nextbuffer(int f, int n)
{
	struct buffer *bp = NULL;  /* eligable buffer to switch to */
	struct buffer *bbp;        /* eligable buffer to switch to */

	/* make sure the arg is legit */
	if (f == FALSE)
		n = 1;
	if (n < 1)
		return FALSE;

	bbp = curbp;
	while (n-- > 0) {
		/* advance to the next buffer */
		bp = bbp->b_bufp;

		/* cycle through the buffers to find an eligable one */
		while (bp == NULL || bp->b_flag & BFINVS) {
			if (bp == NULL)
				bp = bheadp;
			else
				bp = bp->b_bufp;

			/* don't get caught in an infinite loop! */
			if (bp == bbp)
				return FALSE;

		}

		bbp = bp;
	}

	return swbuffer(bp);
}

/*
 * make buffer BP current
 */
int swbuffer(struct buffer *bp)
{
	struct window *wp;

	if (--curbp->b_nwnd == 0) {	/* Last use.            */
		curbp->b_dotp = curwp->w_dotp;
		curbp->b_doto = curwp->w_doto;
		curbp->b_markp = curwp->w_markp;
		curbp->b_marko = curwp->w_marko;
	}
	curbp = bp;		/* Switch.              */
	if (curbp->b_active != TRUE) {	/* buffer not active yet */
		/* read it in and activate it */
		readin(curbp->b_fname, TRUE);
		curbp->b_dotp = lforw(curbp->b_linep);
		curbp->b_doto = 0;
		curbp->b_active = TRUE;
		curbp->b_mode |= gmode;	/* P.K. */
	}
	curwp->w_bufp = bp;
	curwp->w_linep = bp->b_linep;	/* For macros, ignored. */
	curwp->w_flag |= WFMODE | WFFORCE | WFHARD;	/* Quite nasty.         */
	if (bp->b_nwnd++ == 0) {	/* First use.           */
		curwp->w_dotp = bp->b_dotp;
		curwp->w_doto = bp->b_doto;
		curwp->w_markp = bp->b_markp;
		curwp->w_marko = bp->b_marko;
		cknewwindow();
		return TRUE;
	}
	wp = wheadp;		/* Look for old.        */
	while (wp != NULL) {
		if (wp != curwp && wp->w_bufp == bp) {
			curwp->w_dotp = wp->w_dotp;
			curwp->w_doto = wp->w_doto;
			curwp->w_markp = wp->w_markp;
			curwp->w_marko = wp->w_marko;
			break;
		}
		wp = wp->w_wndp;
	}
	cknewwindow();
	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!). Get quite upset
 * if the buffer is being displayed. Clear the buffer (ask
 * if the buffer has been changed). Then free the header
 * line and the buffer header. Bound to "C-X K".
 */
int killbuffer( int f, int n) {
	struct buffer *bp ;
	int status ;
	char *bufn ;

/* Get buffer name */
	status = newmlarg( &bufn, "Kill buffer: ", sizeof( bname_t)) ;
	if( status != TRUE)
		return status ;

/* Find buffer in list */
	bp = bfind( bufn, FALSE, 0) ;
	free( bufn) ;
	if( bp == NULL)	/* Easy if unknown.	*/
		return TRUE ;

	if( bp->b_flag & BFINVS)	/* Deal with special buffers	*/
		return TRUE ;			/* by doing nothing.			*/

	return zotbuf( bp) ;
}

/*
 * kill the buffer pointed to by bp
 */
int zotbuf(struct buffer *bp)
{
	struct buffer *bp1;
	struct buffer *bp2;
	int s;

	if (bp->b_nwnd != 0) {	/* Error if on screen.  */
		mloutstr("Buffer is being displayed");
		return FALSE;
	}
	if ((s = bclear(bp)) != TRUE)	/* Blow text away.      */
		return s;
	free((char *) bp->b_linep);	/* Release header line. */
	bp1 = NULL;		/* Find the header.     */
	bp2 = bheadp;
	while (bp2 != bp) {
		bp1 = bp2;
		bp2 = bp2->b_bufp;
	}
	bp2 = bp2->b_bufp;	/* Next one in chain.   */
	if (bp1 == NULL)	/* Unlink it.           */
		bheadp = bp2;
	else
		bp1->b_bufp = bp2;
	free((char *) bp);	/* Release buffer block */
	return TRUE;
}

/*
 * Rename the current buffer
 *
 * int f, n;		default Flag & Numeric arg
 */
int namebuffer( int f, int n) {
	struct buffer *bp ;	/* pointer to scan through all buffers */
	int status ;
	char *bufn ;		/* buffer to hold buffer name */

/* prompt for and get the new buffer name */
ask:
    status = newmlarg( &bufn, "Change buffer name to: ", sizeof( bname_t)) ;
    if( status != TRUE)
		return status ;

/* and check for duplicates */
	bp = bheadp ;
	while( bp != NULL) {
		if( bp != curbp) {
		/* retry if the names are the same */
			if( strcmp( bufn, bp->b_bname) == 0) {
				free( bufn) ;
				goto ask ;	/* try again */
			}
		}

		bp = bp->b_bufp ;	/* onward */
	}

/* copy buffer name to structure */
	strncpy( curbp->b_bname, bufn, sizeof( bname_t) - 1) ;
	curbp->b_bname[ sizeof( bname_t) - 1] = '\0' ;
	free( bufn) ;
	
	curwp->w_flag |= WFMODE ;	/* make mode line replot */
	mloutstr( "") ; /* erase message line */
	return TRUE ;
}

/*
 * List all of the active buffers.  First update the special
 * buffer that holds the list.  Next make sure at least 1
 * window is displaying the buffer list, splitting the screen
 * if this is what it takes.  Lastly, repaint all of the
 * windows that are displaying the list.  Bound to "C-X C-B". 
 *
 * A numeric argument forces it to list invisible buffers as
 * well.
 */
int listbuffers(int f, int n)
{
	struct window *wp;
	int s;

	if ((s = makelist(f)) != TRUE)
		return s;
	if (blistp->b_nwnd == 0) {	/* Not on screen yet.   */
		struct buffer *bp ;

		if ((wp = wpopup()) == NULL)
			return FALSE;
		bp = wp->w_bufp;
		if (--bp->b_nwnd == 0) {
			bp->b_dotp = wp->w_dotp;
			bp->b_doto = wp->w_doto;
			bp->b_markp = wp->w_markp;
			bp->b_marko = wp->w_marko;
		}
		wp->w_bufp = blistp;
		++blistp->b_nwnd;
	}
	wp = wheadp;
	while (wp != NULL) {
		if (wp->w_bufp == blistp) {
			wp->w_linep = lforw(blistp->b_linep);
			wp->w_dotp = lforw(blistp->b_linep);
			wp->w_doto = 0;
			wp->w_markp = NULL;
			wp->w_marko = 0;
			wp->w_flag |= WFMODE | WFHARD;
		}
		wp = wp->w_wndp;
	}
	return TRUE;
}

/*
 * This routine rebuilds the
 * text in the special secret buffer
 * that holds the buffer list. It is called
 * by the list buffers command. Return TRUE
 * if everything works. Return FALSE if there
 * is an error (if there is no memory). Iflag
 * indicates wether to list hidden buffers.
 *
 * int iflag;		list hidden buffer flag
 */
/* Layout: "ACT MODES          Size Buffer          File"
            AAA MMMMMMMMMSSSSSSSSSS BBBBBBBBBBBBBBB FFF...
   FNAMSTART ---------------------------------------^
*/
#define FNAMSTART (3 + 1 + NUMMODES + 10 + 1 + (sizeof( bname_t) - 1) + 1)

static void do_layout( char *line, int mode) {
	int i ;

	/* build line to report global mode settings */
	strcpy( line, "    WCEVOMAUD           Global Modes") ;

	/* output the mode codes */
	for( i = 0 ; i < NUMMODES ; i++)
		if( 0 == (mode & (1 << i)))
			line[ 4 + i] = '.' ;
}

static int makelist( int iflag)
{
	struct buffer *bp;
	int s;
	char line[ FNAMSTART + sizeof( fname_t)] ;

	blistp->b_flag &= ~BFCHG;	/* Don't complain! Mute bclear() */
	if ((s = bclear(blistp)) != TRUE)	/* Blow old text away   */
		return s;

	blistp->b_fname[ 0] = 0 ;	/* in case of user override */

	if(		addline("ACT MODES          Size Buffer          File") == FALSE
	    ||	addline("‾‾‾ ‾‾‾‾‾          ‾‾‾‾ ‾‾‾‾‾‾          ‾‾‾‾") == FALSE)
		return FALSE;

/* report global mode settings */
	do_layout( line, gmode) ;
	if( addline( line) == FALSE)
		return FALSE ;

/* output the list of buffers */
	for( bp = bheadp ; bp != NULL ; bp = bp->b_bufp) {	/* For all buffers */
		char *cp1, *cp2 ;
		int c ;
		struct line *lp ;
		long nbytes ;		/* # of bytes in current buffer */
		long nlines ;		/* # of lines in current buffer */

	/* skip invisible buffers if iflag is false */
		if (((bp->b_flag & BFINVS) != 0) && (iflag != TRUE))
			continue;

		do_layout( line, bp->b_mode) ;
		cp1 = line ;	/* Start at left edge   */

	/* output status of ACTIVE flag ('@' when the file has been read in) */
		*cp1++ = (bp->b_active == TRUE) ? '@' : ' ' ;

	/* report if the file is truncated */
		*cp1++ = ((bp->b_flag & BFTRUNC) != 0) ? '#' : ' ' ;

	/* output status of changed flag ('*' when the buffer is changed) */
		*cp1 = ((bp->b_flag & BFCHG) != 0) ? '*' : ' ' ;

	/* Buffer size */
		nbytes = 0L;	/* Count bytes in buf.  */
		nlines = 0 ;
		for( lp = lforw( bp->b_linep) ; lp != bp->b_linep ; lp = lforw( lp)) {
			nbytes += (long) llength(lp) + 1L;
			nlines += 1 ;
		}

		if( bp->b_mode & MDDOS)
			nbytes += nlines ;

		l_to_a( &line[ 13], 10 + 1, nbytes) ;	/* "%10d" formatted numbers */
		cp1 = &line[ 23] ;
		*cp1++ = ' ' ;
		cp2 = &bp->b_bname[0];	/* Buffer name          */
		while ((c = *cp2++) != 0)
			*cp1++ = c;

		if( bp->b_fname[ 0] != 0) {
			while( cp1 < &line[ FNAMSTART])
				*cp1++ = ' ' ;

			strncpy( cp1, bp->b_fname, &line[ sizeof line - 1] - cp1) ;
			line[ sizeof line - 1] = 0 ;
		} else
			*cp1 = 0 ;					/* Terminate string */

		if( addline( line) == FALSE)	/* Add to the buffer.   */
			return FALSE ;
	}

	return TRUE ;		/* All done             */
}

static void l_to_a(char *buf, int width, long num)
{
	buf[ --width] = 0 ;		/* End of string.       */
	while (num >= 10) {	/* Conditional digits.  */
		buf[--width] = (int) (num % 10L) + '0';
		num /= 10L;
	}
	buf[--width] = (int) num + '0';	/* Always 1 digit.      */
	while( width > 0)	/* Pad with blanks.     */
		buf[--width] = ' ';
}

/*
 * The argument "text" points to
 * a string. Append this line to the
 * buffer list buffer. Handcraft the EOL
 * on the end. Return TRUE if it worked and
 * FALSE if you ran out of room.
 */
static int addline( char *text)
{
	struct 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]);
	blistp->b_linep->l_bp->l_fp = lp;	/* Hook onto the end    */
	lp->l_bp = blistp->b_linep->l_bp;
	blistp->b_linep->l_bp = lp;
	lp->l_fp = blistp->b_linep;
	if (blistp->b_dotp == blistp->b_linep)	/* If "." is at the end */
		blistp->b_dotp = lp;	/* move it to new line  */
	return TRUE;
}

/*
 * Look through the list of
 * buffers. Return TRUE if there
 * are any changed buffers. Buffers
 * that hold magic internal stuff are
 * not considered; who cares if the
 * list of buffer names is hacked.
 * Return FALSE if no buffers
 * have been changed.
 */
int anycb(void)
{
	struct buffer *bp;

	bp = bheadp;
	while (bp != NULL) {
		if ((bp->b_flag & BFINVS) == 0
		    && (bp->b_flag & BFCHG) != 0)
			return TRUE;
		bp = bp->b_bufp;
	}
	return FALSE;
}

/*
 * Find a buffer, by name. Return a pointer
 * to the buffer structure associated with it.
 * If the buffer is not found
 * and the "cflag" is TRUE, create it. The "bflag" is
 * the settings for the flags in in buffer.
 */
struct buffer *bfind( const char *bname, int cflag, int bflag)
{
	struct buffer *bp;
	struct line *lp;

	for( bp = bheadp ; bp != NULL ; bp = bp->b_bufp)
		if( strcmp( bname, bp->b_bname) == 0)
			return bp ;

	if (cflag != FALSE) {
		if ((bp = (struct buffer *)malloc(sizeof(struct buffer))) == NULL)
			return NULL;
		if ((lp = lalloc(0)) == NULL) {
			free((char *) bp);
			return NULL;
		}
		/* find the place in the list to insert this buffer */
		if (bheadp == NULL || strcmp(bheadp->b_bname, bname) > 0) {
			/* insert at the beginning */
			bp->b_bufp = bheadp;
			bheadp = bp;
		} else {
			struct buffer *sb;	/* buffer to insert after */

			for( sb = bheadp ; sb->b_bufp != NULL ; sb = sb->b_bufp)
				if( strcmp( sb->b_bufp->b_bname, bname) > 0)
					break ;

			/* and insert it */
			bp->b_bufp = sb->b_bufp ;
			sb->b_bufp = bp ;
		}

		/* and set up the other buffer fields */
		bp->b_active = TRUE;
		bp->b_dotp = lp;
		bp->b_doto = 0;
		bp->b_markp = NULL;
		bp->b_marko = 0;
		bp->b_flag = bflag;
		bp->b_mode = gmode;
		bp->b_nwnd = 0;
		bp->b_linep = lp;
		bp->b_fname[ 0] = '\0' ;
		strncpy( bp->b_bname, bname, sizeof( bname_t) - 1) ;
		bp->b_bname[ sizeof( bname_t) - 1] = '\0' ;
		lp->l_fp = lp;
		lp->l_bp = lp;
	}
	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(struct buffer *bp)
{
	struct line *lp;
	int s;

	if ((bp->b_flag & BFINVS) == 0	/* Not scratch buffer.  */
	    && (bp->b_flag & BFCHG) != 0	/* Something changed    */
	    && (s = mlyesno("Discard changes")) != 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;
}

/*
 * unmark the current buffers change flag
 *
 * int f, n;		unused command arguments
 */
int unmark(int f, int n)
{
	curbp->b_flag &= ~BFCHG;
	curwp->w_flag |= WFMODE;
	return TRUE;
}