/* unslist.c: Functions to manage the list of unsolvable levels.
 *
 * Copyright (C) 2001-2006 by Brian Raiter, under the GNU General Public
 * License. No warranty. See COPYING for details.
 */

#include	<stdio.h>
#include	<stdlib.h>
#include	<string.h>
#include	<ctype.h>
#include	"defs.h"
#include	"err.h"
#include	"fileio.h"
#include	"res.h"
#include	"solution.h"
#include	"unslist.h"

/* The information comprising one entry in the list of unsolvable
 * levels.
 */
typedef	struct unslistentry {
    int			setid;		/* the ID of the level set's name */
    int			levelnum;	/* the level's number */
    int			size;		/* the levels data's compressed size */
    unsigned long	hashval;	/* the levels data's hash value */
    int			note;		/* the entry's annotation ID, if any */
} unslistentry;

/* The pool of strings. In here are stored the level set names and the
 * annotations. The string IDs are simple offsets from the strings
 * pointer.
 */
static int		stringsused = 0;
static int		stringsallocated = 0;
static char	       *strings = NULL;

/* The list of level set names for which unsolvable levels appear on
 * the list. This list allows the program to quickly find the level
 * set name's string ID.
 */
static int		namescount = 0;
static int		namesallocated = 0;
static int	       *names = NULL;

/* The list of unsolvable levels proper.
 */
static int		listcount = 0;
static int		listallocated = 0;
static unslistentry    *unslist = NULL;

/*
 * Managing the pool of strings.
 */

/* Turn a string ID back into a string pointer. (Note that a string ID
 * of zero will always return a null string, assuming that
 * storestring() has been called at least once.)
 */
#define	getstring(id)	(strings + (id))

/* Make a copy of a string and add it to the string pool. The new
 * string's ID is returned.
 */
static int storestring(char const *str)
{
    int	len;

    len = strlen(str) + 1;
    if (stringsused + len > stringsallocated) {
	stringsallocated = stringsallocated ? 2 * stringsallocated : 256;
	xalloc(strings, stringsallocated);
	if (!stringsused) {
	    *strings = '\0';
	    ++stringsused;
	}
    }
    memcpy(strings + stringsused, str, len);
    stringsused += len;
    return stringsused - len;
}

/*
 * Managing the list of set names.
 */

/* Return the string ID of the given set name. If the set name is not
 * already in the list, then if add is TRUE the set name is added to
 * the list; otherwise zero is returned.
 */
static int lookupsetname(char const *name, int add)
{
    int	i;

    for (i = 0 ; i < namescount ; ++i)
	if (!strcmp(getstring(names[i]), name))
	    return names[i];
    if (!add)
	return 0;

    if (namescount >= namesallocated) {
	namesallocated = namesallocated ? 2 * namesallocated : 8;
	xalloc(names, namesallocated * sizeof *names);
    }
    names[namescount] = storestring(name);
    return names[namescount++];
}

/*
 * Managing the list of unsolvable levels.
 */

/* Add a new entry with the given data to the list.
 */
static int addtounslist(int setid, int levelnum,
			int size, unsigned long hashval, int note)
{
    if (listcount == listallocated) {
	listallocated = listallocated ? listallocated * 2 : 16;
	xalloc(unslist, listallocated * sizeof *unslist);
    }
    unslist[listcount].setid = setid;
    unslist[listcount].levelnum = levelnum;
    unslist[listcount].size = size;
    unslist[listcount].hashval = hashval;
    unslist[listcount].note = note;
    ++listcount;
    return TRUE;
}

/* Remove all entries for the given level from the list. FALSE is
 * returned if the level was not on the list to begin with.
 */
static int removefromunslist(int setid, int levelnum)
{
    int	i, f = FALSE;

    for (i = 0 ; i < listcount ; ++i) {
	if (unslist[i].setid == setid && unslist[i].levelnum == levelnum) {
	    --listcount;
	    unslist[i] = unslist[listcount];
	    f = TRUE;
	}
    }
    return f;
}

/* Add the information in the given file to the list of unsolvable
 * levels. Errors in the file are flagged but do not prevent the
 * function from reading the rest of the file.
 */
static int readunslist(fileinfo *file)
{
    char		buf[256], token[256];
    char const	       *p;
    unsigned long	hashval;
    int			setid, size;
    int			lineno, levelnum, n;

    setid = 0;
    for (lineno = 1 ; ; ++lineno) {
	n = sizeof buf - 1;
	if (!filegetline(file, buf, &n, NULL))
	    break;
	for (p = buf ; isspace(*p) ; ++p) ;
	if (!*p || *p == '#')
	    continue;
	if (sscanf(p, "[%[^]]]", token) == 1) {
	    setid = lookupsetname(token, TRUE);
	    continue;
	}
	n = sscanf(p, "%d: %04X%08lX: %[^\n\r]",
		      &levelnum, &size, &hashval, token);
	if (n > 0 && levelnum > 0 && levelnum < 65536 && setid) {
	    if (n == 1) {
		n = sscanf(p, "%*d: %s", token);
		if (n > 0 && !strcmp(token, "ok")) {
		    removefromunslist(setid, levelnum);
		    continue;
		}
	    } else if (n >= 3) {
		addtounslist(setid, levelnum, size, hashval,
			     n == 4 ? storestring(token) : 0);
		continue;
	    }
	}
	warn("%s:%d: syntax error", file->name, lineno);
    }
    return TRUE;
}

/*
 * Exported functions.
 */

/* Return TRUE if the given level in the list of unsolvable levels. No
 * set name is supplied, so this function relies on the other three
 * data. A copy of the level's annotation is made if note is not NULL.
 */
int islevelunsolvable(gamesetup const *game, char *note)
{
    int		i;

    for (i = 0 ; i < listcount ; ++i) {
	if (unslist[i].levelnum == game->number
		      && unslist[i].size == game->levelsize
		      && unslist[i].hashval == game->levelhash) {
	    if (note)
		strcpy(note, getstring(unslist[i].note));
	    return TRUE;
	}
    }
    return FALSE;
}

/* Look up the levels that constitute the given series and find which
 * levels appear in the list. Those that do will have the unsolvable
 * field in the gamesetup structure initialized.
 */
int markunsolvablelevels(gameseries *series)
{
    int		count = 0;
    int		setid, i, j;

    for (j = 0 ; j < series->count ; ++j)
	series->games[j].unsolvable = NULL;

    setid = lookupsetname(series->name, FALSE);
    if (!setid)
	return 0;

    for (i = 0 ; i < listcount ; ++i) {
	if (unslist[i].setid != setid)
	    continue;
	for (j = 0 ; j < series->count ; ++j) {
	    if (series->games[j].number == unslist[i].levelnum
			&& series->games[j].levelsize == unslist[i].size
			&& series->games[j].levelhash == unslist[i].hashval) {
		series->games[j].unsolvable = getstring(unslist[i].note);
		++count;
		break;
	    }
	}
    }
    return count;
}

/* Read the list of unsolvable levels from the given filename. If the
 * filename does not contain a path, then the function looks for the
 * file in the resource directory and the user's save directory.
 */
int loadunslistfromfile(char const *filename)
{
    fileinfo	file;

    memset(&file, 0, sizeof file);
    if (openfileindir(&file, resdir, filename, "r", NULL)) {
	readunslist(&file);
	fileclose(&file, NULL);
    }
    if (!haspathname(filename)) {
	memset(&file, 0, sizeof file);
	if (openfileindir(&file, savedir, filename, "r", NULL)) {
	    readunslist(&file);
	    fileclose(&file, NULL);
	}
    }
    return TRUE;
}

/* Free all memory associated with the list of unsolvable levels.
 */
void clearunslist(void)
{
    free(unslist);
    listcount = 0;
    listallocated = 0;
    unslist = NULL;

    free(names);
    namescount = 0;
    namesallocated = 0;
    names = NULL;

    free(strings);
    stringsused = 0;
    stringsallocated = 0;
    strings = NULL;
}