/* Copyright (C) 2004 Timo Sirainen */

#include "lib.h"
#include "mail-index-private.h"
#include "mail-transaction-log.h"

static void mail_index_fsck_error(struct mail_index *index,
				  const char *fmt, ...) __attr_format__(2, 3);
static void mail_index_fsck_error(struct mail_index *index,
				  const char *fmt, ...)
{
	va_list va;

	va_start(va, fmt);
	mail_index_set_error(index, "Fixed index file %s: %s",
			     index->filepath, t_strdup_vprintf(fmt, va));
	va_end(va);
}

#define CHECK(field, oper) \
	if (hdr.field oper index->hdr->field) { \
		mail_index_fsck_error(index, #field" %u -> %u", \
				      index->hdr->field, hdr.field); \
	}

static int mail_index_fsck_locked(struct mail_index *index,
				  const char **error_r)
{
	struct mail_index_header hdr;
	const struct mail_index_record *rec, *end;
	uint32_t last_uid;

	*error_r = NULL;

	/* locking already does the most important sanity checks for header */
	hdr = *index->hdr;

	if (hdr.uid_validity == 0) {
		*error_r = "uid_validity = 0";
		return 0;
	}

	hdr.messages_count = 0;
	hdr.seen_messages_count = 0;
	hdr.deleted_messages_count = 0;

	hdr.first_recent_uid_lowwater = 0;
	hdr.first_unseen_uid_lowwater = 0;
	hdr.first_deleted_uid_lowwater = 0;

	end = index->map->records + index->map->records_count; last_uid = 0;
	for (rec = index->map->records; rec != end; rec++) {
		if (rec->uid <= last_uid) {
			*error_r = "Record UIDs are not ordered";
			return 0;
		}

		hdr.messages_count++;
		if ((rec->flags & MAIL_SEEN) != 0)
			hdr.seen_messages_count++;
		if ((rec->flags & MAIL_DELETED) != 0)
			hdr.deleted_messages_count++;

		if ((rec->flags & MAIL_INDEX_MAIL_FLAG_NONRECENT) == 0 &&
		    hdr.first_recent_uid_lowwater == 0)
			hdr.first_recent_uid_lowwater = rec->uid;
		if ((rec->flags & MAIL_SEEN) == 0 &&
		    hdr.first_unseen_uid_lowwater == 0)
			hdr.first_unseen_uid_lowwater = rec->uid;
		if ((rec->flags & MAIL_DELETED) != 0 &&
		    hdr.first_deleted_uid_lowwater == 0)
			hdr.first_deleted_uid_lowwater = rec->uid;

		last_uid = rec->uid;
	}

	if (hdr.next_uid <= last_uid) {
		mail_index_fsck_error(index, "next_uid %u -> %u",
				      hdr.next_uid, last_uid+1);
		hdr.next_uid = last_uid+1;
	}

	if (hdr.first_recent_uid_lowwater == 0)
                hdr.first_recent_uid_lowwater = hdr.next_uid;
	if (hdr.first_unseen_uid_lowwater == 0)
                hdr.first_unseen_uid_lowwater = hdr.next_uid;
	if (hdr.first_deleted_uid_lowwater == 0)
                hdr.first_deleted_uid_lowwater = hdr.next_uid;

        CHECK(messages_count, !=);
        CHECK(seen_messages_count, !=);
        CHECK(deleted_messages_count, !=);

        CHECK(first_recent_uid_lowwater, <);
        CHECK(first_unseen_uid_lowwater, <);
        CHECK(first_deleted_uid_lowwater, <);

	if (mail_index_write_header(index, &hdr) < 0)
		return -1;

	return 1;
}

int mail_index_fsck(struct mail_index *index)
{
	const char *error;
	unsigned int lock_id;
	uint32_t file_seq;
	uoff_t file_offset;
	int ret;

	if (mail_transaction_log_sync_lock(index->log, &file_seq,
					   &file_offset) < 0)
		return -1;
	if (mail_index_lock_exclusive(index, 0, 0, &lock_id) < 0) {
                mail_transaction_log_sync_unlock(index->log);
		return -1;
	}

	error = NULL;
	ret = mail_index_map(index, FALSE);
	if (ret >= 0)
		ret = mail_index_fsck_locked(index, &error);

	mail_index_unlock(index, lock_id);
        mail_transaction_log_sync_unlock(index->log);

	if (error != NULL) {
		mail_index_set_error(index, "Corrupted index file %s: %s",
				     index->filepath, error);
	}
	if (ret == 0)
		mail_index_reset(index);
	return ret;
}