/*
 * Copyright (c) 2022 Omar Polo <op@openbsd.org>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

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

#include "db.h"
#include "fts.h"
#include "tokenize.h"

struct doclist {
	uint32_t	*ids;
	size_t		 len;
};

int
fts(struct db *db, const char *query, db_hit_cb cb, void *data)
{
	struct doclist *xs = NULL;
	size_t i, len;
	char **toks, **t;
	int ret = 0;

	if ((toks = tokenize(query)) == NULL)
		return -1;

	len = 0;
	for (t = toks; *t != NULL; ++t)
		len++;

	if (len == 0)
		goto done;

	if ((xs = calloc(len, sizeof(*xs))) == NULL) {
		freetoks(toks);
		return -1;
	}

	for (i = 0; i < len; ++i) {
		xs[i].ids = db_word_docs(db, toks[i], &xs[i].len);
		if (xs[i].ids == NULL || xs[i].len == 0)
			goto done;
	}

	for (;;) {
		struct db_entry e;
		uint32_t mdoc;

		mdoc = xs[0].ids[0];
		for (i = 1; i < len; ++i) {
			if (xs[i].ids[0] > mdoc)
				goto next;
			while (xs[i].ids[0] < mdoc) {
				if (--xs[i].len == 0)
					goto done;
				xs[i].ids++;
			}

			if (xs[i].ids[0] != mdoc)
				goto next;
		}

		if (db_doc_by_id(db, mdoc, &e) == -1) {
			ret = -1;
			goto done;
		}

		if (cb(db, &e, data) == -1) {
			ret = -1;
			goto done;
		}

	next:
		if (--xs[0].len == 0)
			goto done;
		xs[0].ids++;
	}

done:
	free(xs);
	freetoks(toks);

	return ret;
}