/* GLIB - Library of useful routines for C programming
 * Copyright (C) 1995-1997  Peter Mattis, Spencer Kimball and Josh MacDonald
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public
 * License along with this library; if not, write to the
 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA 02111-1307, USA.
 */

#include "glib.h"
#include <string.h>

static void completion_check_cache (GCompletion* cmp, gchar** new_prefix);

GCompletion* 
g_completion_new (GCompletionFunc func) {
	GCompletion* gcomp;

	gcomp = g_new(GCompletion, 1);
	gcomp->items = NULL;
	gcomp->cache = NULL;
	gcomp->prefix = NULL;
	if ( func )
		gcomp->func = func;
	else
		gcomp->func = NULL;
	return gcomp;
}

void 
g_completion_add_items (GCompletion* cmp, GList* items) {
	GList* it;

	g_return_if_fail( cmp != NULL);
	g_return_if_fail( items != NULL);

	/* optimize adding to cache? */
	if ( cmp->cache ) {
		g_list_free(cmp->cache);
		cmp->cache = NULL;
	}
	if ( cmp->prefix ) {
		g_free(cmp->prefix);
		cmp->prefix = NULL;
	}

	it = items;
	while ( it ) {
		cmp->items = g_list_prepend(cmp->items, it->data);
		it = it->next;
	}
}

void 
g_completion_remove_items (GCompletion* cmp, GList* items) {
	GList* it;
	
	g_return_if_fail( cmp != NULL);
	g_return_if_fail( items != NULL);

	it = items;
	while ( cmp->items && it ) {
		cmp->items = g_list_remove(cmp->items, it->data);
		it = it->next;
	}
	it = items;
	while ( cmp->cache && it ) {
		cmp->cache = g_list_remove(cmp->cache, it->data);
		it = it->next;
	}
}

void 
g_completion_clear_items  (GCompletion* cmp) {
	g_return_if_fail(cmp != NULL);

	g_list_free(cmp->items);
	cmp->items = NULL;
	g_list_free(cmp->cache);
	cmp->cache = NULL;
	g_free(cmp->prefix);
	cmp->prefix = NULL;
}

static void   
completion_check_cache (GCompletion* cmp, gchar** new_prefix) {
	register GList* list;
	register gint len;
	register gint i;
	register gint plen;
	gchar* postfix=NULL;
	gchar* s;

	if ( !new_prefix )
		return;
	if ( !cmp->cache ) {
		*new_prefix = NULL;
		return;
	}

	len = strlen(cmp->prefix);
	list = cmp->cache;
	s = cmp->func?(*cmp->func)(list->data):(gchar*)list->data;
	postfix = s + len;
	plen = strlen(postfix);
	list = list->next;

	while (list && plen) {
		s = cmp->func?(*cmp->func)(list->data):(gchar*)list->data;
		s += len;
		for (i=0; i < plen; ++i) {
			if ( postfix[i] != s[i] ) 
				break;
		}
		plen = i;
		list = list->next;
	}

	*new_prefix = g_new0(gchar, len+plen+1);
	strncpy(*new_prefix, cmp->prefix, len);
	strncpy(*new_prefix+len, postfix, plen);
}

GList* 
g_completion_complete (GCompletion* cmp, gchar* prefix, gchar** new_prefix) {
	gint plen, len;
	gint done=0;
	GList* list;
	
	g_return_val_if_fail(cmp != NULL, NULL);
	g_return_val_if_fail(prefix != NULL, NULL);

	len = strlen(prefix);
	if ( cmp->prefix && cmp->cache ) {
		plen = strlen(cmp->prefix);
		if ( plen <= len && !strncmp(prefix, cmp->prefix, plen) ) { 
			/* use the cache */
			list = cmp->cache;
			while ( list ) {
				if ( strncmp(prefix, cmp->func?(*cmp->func)(list->data):(gchar*)list->data, len) ) {
					list = g_list_remove_link(cmp->cache, list);
					if ( list != cmp->cache )
						cmp->cache = list;
				} else
					list = list->next;
			}
			done = 1;
		}
	}

	if (!done) { /* normal code */
		g_list_free(cmp->cache);
		cmp->cache = NULL;
		list = cmp->items;
		while (*prefix && list) {
			if ( !strncmp(prefix, cmp->func?(*cmp->func)(list->data):(gchar*)list->data, len) )
				cmp->cache = g_list_prepend(cmp->cache, list->data);
			list = list->next;
		}
	}
	if ( cmp->prefix ) {
		g_free(cmp->prefix);
		cmp->prefix = NULL;
	}
	if ( cmp->cache )
		cmp->prefix = g_strdup(prefix);
	completion_check_cache(cmp, new_prefix);
	return *prefix?cmp->cache:cmp->items;

}

void 
g_completion_free (GCompletion* cmp) {
	g_return_if_fail(cmp != NULL);

	g_completion_clear_items(cmp);
	g_free(cmp);
}

#ifdef TEST_COMPLETION

#include <stdio.h>

int main (int argc, char* argv[]) {

	FILE * file;
	gchar buf[1024];
	GList *list;
	GList *result;
	GList *tmp;
	GCompletion * cmp;
	gint i;
	gchar* longp=NULL;

	if ( argc < 3 ) {
		g_warning("Usage: %s filename prefix1 [prefix2 ...]\n", argv[0]);
		return 1;
	}

	if ( !(file=fopen(argv[1], "r")) ) {
		g_warning("Cannot open %s\n", argv[1]);
		return 1;
	}

	cmp = g_completion_new(NULL);
	list = g_list_alloc();
	while (fgets(buf, 1024, file)) {
		list->data = g_strdup(buf);
		g_completion_add_items(cmp, list);
	}
	fclose(file);

	for ( i= 2; i < argc; ++i) {
		printf("COMPLETING: %s\n", argv[i]);
		result = g_completion_complete(cmp, argv[i], &longp);
		g_list_foreach(result, (GFunc)printf, NULL);
		printf("LONG MATCH: %s\n", longp);
		g_free(longp);
		longp = NULL;
	}

	g_list_foreach(cmp->items, (GFunc)g_free, NULL);
	g_completion_free(cmp);
	g_list_free(list);
	return 0;
}

#endif