/*
 * Copyright (c) 1988 Mark Nudleman
 * Copyright (c) 1988, 1993
 *	The Regents of the University of California.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#ifndef lint
static char sccsid[] = "@(#)prim.c	8.1 (Berkeley) 6/6/93";
#endif /* not lint */

#ifndef lint
static const char rcsid[] =
  "$FreeBSD: src/usr.bin/more/prim.c,v 1.10 2000/05/14 03:30:59 hoek Exp $";
#endif /* not lint */

/*
 * Bookmarking commands.
 */

#include <sys/param.h>
#include <sys/types.h>

#include <assert.h>
#include <ctype.h>
#include <errno.h>
#include <limits.h>
#include <regex.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>

#include "less.h"

extern int sc_width, sc_height;
extern int horiz_off;
extern int wraplines;
extern char *line;
extern int retain_below;

typedef char * ch_file;

/*
 * A mark is simply a viewing position of a file.  This structure is considered
 * opaque outside of dosetmark(), marks_bookhints(), gomark(), and initmark().
 *
 * An initialised mark pointing at nowhere has hint == file == NULL and
 * pos == 0.
 *
 * An initialised mark pointing at somwhere has all valid fields and possibly
 * a NULL hint.  The hint must be free'd before changing it.
 */
struct mark {
	int	horiz_off;  /* value of horiz_off */
	int	wraplines;  /* value of wraplines */
	off_t	pos;        /* for jump_loc() */
	ch_file	file;       /* file into which mark points */
	char	*hint;      /* hint for human user of the mark's destination */
	int	linenum;    /* optional line number to suplement hint */
};

/*
 * The table of bookmarks.
 */
#define	NMARKS		(27)		/* 26 for a-z plus one for quote */
#define	LASTMARK	(NMARKS-1)	/* For quote */
static struct mark marks[NMARKS];

/*
 * Internal function prototypes.
 */
static void dosetmark(struct mark *);
static void initmark(struct mark *);
static int badmark(int);

/*
 * Initialize the mark table to show no marks are set.
 */
void
marks_initmarks(void)
{
	int i;

	for (i = 0;  i < NMARKS;  i++)
		initmark(&marks[i]);
}

/*
 * See if a mark letter is valid (between a and z).
 */
static int
badmark(c)
	int c;
{
	if (c < 'a' || c > 'z') {
		error("Choose a letter between 'a' and 'z'");
		return (1);
	}
	return (0);
}

/*
 * Set a bookmark.
 */
setmark(c)
	int c;  /* user identifier for bookmark to set */
{
	if (badmark(c)) return;

	dosetmark(&marks[c - 'a']);
}

/*
 * This function should be called whenever the file position we are viewing
 * is changed by a significant amount.  The function will record the current
 * position and remember it for the user.
 */
lastmark()
{
	dosetmark(&marks[LASTMARK]);
}

/*
 * Initialise mark pointed at by mark_p to an empty mark.
 */
static void
initmark (mark_p)
	struct mark * mark_p;  /* mark to initialize */
{
	mark_p->pos = NULL_POSITION;
	mark_p->file = NULL;
	mark_p->hint = NULL;
}

/*
 * This function sets the mark pointed at by mark_p to the current viewing
 * position.
 */
static void
dosetmark(mark_p)
	struct mark * mark_p;  /* bookmark to set to the current position */
{
	extern char *current_file;
	extern char *line;
	off_t npos, t, maxpos;
	int maxlen;
	int i;

	mark_p->pos = position(TOP);
	mark_p->horiz_off = horiz_off;
	mark_p->wraplines = wraplines;
	if (mark_p->file) free(mark_p->file);
	asprintf(&mark_p->file, "%s", current_file);

#define NTOP 4
	/*
	 * Find the longest of the top NTOP lines and set that one to
	 * be the hint.
	 *
	 * A different algorithm would be to take the middle line shown
	 * and make that one to be the hint.  Perhaps just taking the
	 * top line always would be better.
	 *
	 * There are many places in this program where introducing the
	 * concept of a ``highlight'' line would be useful.
	 *
	 * It's also very debatable which line is the correct line to take
	 * the line number from.
	 */
	for (maxlen = i = 0, npos = mark_p->pos; i < NTOP; i++) {
		t = npos;
		npos = forw_raw_line (npos);
		if (strlen(line) >= maxlen) {
			maxlen = strlen(line);
			maxpos = t;
		}
	}
	forw_raw_line(maxpos);
	free (mark_p->hint);
	mark_p->hint = strdup(line);
	mark_p->linenum = find_linenum (mark_p->pos);
}

/*
 * Put the hints and associated bookmark keys into a temporary file
 * and run a copy of more(1) over the resulting hint file.
 *
 * If an error occurrs, returns -1 and sets the erreur and errstr.
 *
 * XXX We don't even come close to handling signals correctly here.
 */
int
marks_bookhints (void)
{
	extern int top_scroll;
	char *p;
	int i, n;
	int fname_width;
	int fd;
	FILE *out;
	char cmd[MAXPATHLEN + 20];
	char template[] = "/tmp/more.XXXXXXXXXX";

	fd = mkstemp(template);
	if (fd == -1) goto mkstemp_error;
	out = fdopen (fd, "w");
	if (out == NULL) goto fdopen_error;

	/*
	 * Find the longest filename.  We will find zero if the filenames are
	 * all the same.
	 */
	for (fname_width = i = 0; i < NMARKS; i++) {
		if (marks[i].file && strlen(marks[i].file) >= fname_width)
			fname_width = strlen(marks[i].file);
	}
	for (p = NULL, i = 0; i < NMARKS; i++) {
		if (p && marks[i].file && strcmp(marks[i].file, p))
			break;
		else if (marks[i].file)
			p = marks[i].file;
	}
	if (i == NMARKS)
		fname_width = 0;

	/*
	 * Print-out the header.
	 */
	errno = 0;
	if (fname_width) {
		n = fprintf (out, "key\t%.*s\tline#\tkeyline\n\n",
		    fname_width, "file");
	} else {
		n = fprintf (out, "key\tline#\tkeyline\n\n");
	}
	if (!n) goto fprintf_error;

	/*
	 * Print-out the actual bookmarks.
	 */
	for (i = 0; i < NMARKS; i++) 
	{
		int mchar;
		if (i == LASTMARK)
			mchar = '\'';
		else
			mchar = 'a' + i;

		if (marks[i].file) {
			if (fname_width) {
				n = fprintf (out, "%c\t%.*s\t%d\t%s\n",
			    	mchar, fname_width, marks[i].file,
				    marks[i].linenum, marks[i].hint);
			} else {
				n = fprintf (out, "%c\t%d\t%s\n",
				    mchar, marks[i].linenum, marks[i].hint);
			}
		}
		if (!n) goto fprintf_error;
	}
	fclose (out);

	/*
 	 * Run a recursive copy of more on the hints file.
	 */
	snprintf (cmd, sizeof(cmd), "-more -ec %s", template);
	lsystem(cmd);
	if (unlink(template) == -1)
		goto unlink_error;

	return 0;


mkstemp_error:
	SETERRSTR (E_SYSTEM, "mkstemp(): %s", strerror(errno));
	return -1;
fdopen_error:
	SETERRSTR (E_SYSTEM, "fdopen(): %s", strerror(errno));
	return -1;
unlink_error:
	SETERRSTR (E_SYSTEM, "unlink(): %s", strerror(errno));
	return -1;
fprintf_error:
	if (errno)
		SETERRSTR (E_SYSTEM, strerror(errno));
	else
		SETERRSTR (E_SYSTEM, "fprintf() failed");
	return -1;
}

/*
 * Go to a previously set mark.
 */
gomark(c)
	int c;
{
	off_t pos;
	char *file;
	int new_horiz_off, new_wraplines;
	extern char *current_file;

	if (c == '\'') {
		pos = marks[LASTMARK].pos;
		if (pos == NULL_POSITION)
			pos = 0;
		file = marks[LASTMARK].file;
		new_horiz_off = marks[LASTMARK].horiz_off;
		new_wraplines = marks[LASTMARK].wraplines;
	} else {
		if (badmark(c))
			return;
		pos = marks[c-'a'].pos;
		if (pos == NULL_POSITION) {
			error("mark not set");
			return;
		}
		file = marks[c-'a'].file;
		new_horiz_off = marks[c-'a'].horiz_off;
		new_wraplines = marks[c-'a'].wraplines;
	}

	/*
	 * This can only fail if gomark('\'') is called before lastmark()
	 * is called, which is in turn impossible since both edit() and
	 * jump_back() call jump_loc() which calls lastmark() to start
	 * all files.
	 */
	assert (file);

	/*
	 * This can only fail if gomark() is called before any file has
	 * been opened.  Calling gomark() before any file has been
	 * opened would be non-sensical.
	 */
	assert (current_file);

	/*
	 * XXX The edit() needs to return success or failure so that we
	 *     can abort at this point if edit() fails.
	 */
	edit(file, NO_FORCE_OPEN);

	/* Try to be nice about changing the horizontal scroll and wrapping */
	if (new_horiz_off > horiz_off + sc_width / 3 ||
	    new_horiz_off < horiz_off - sc_width / 3 ||
	    wraplines != new_wraplines || strcmp(file, current_file)) {
		/*
		 * We should change horiz_off: if we don't change horiz_off
		 * the bookmarked location won't be readily visible.
		 */

		/*
		 * A prepaint() doesn't call lastmark() (jump_loc() does),
		 * but we need to call repaint() somewhere since we've
		 * changed the horizontal offset.  We don't want to call
		 * jump_loc() followed by repaint() since that represents
		 * more unnecessary screen redrawing than I'm comfortable
		 * with.  Manually calling lastmark() here means, however,
		 * that lastmark() is always called even if we scroll only
		 * a few lines --- unlike letting jump_loc() call lastmark()
		 * where lastmark() is only called for jumps of more than
		 * a screenful.  A better interface is needed.
		 */
		lastmark();

		horiz_off = new_horiz_off;
		wraplines = new_wraplines;
		prepaint(pos);
	} else {
		/*
		 * We can honour the bookmark request without doing any
		 * horizontal scrolling.
		 */
		jump_loc(pos);
	}
}