import { GroupData } from '../types/group';
import { Item, ItemResponse } from '../types/item';
/**
 * Retrieves all groups from the database.
 * @returns {Promise<Group[]>} A promise that resolves to an array of groups.
 */
export declare function getAllGroups(): Promise<any>;
/**
 * Saves the group data to the database.
 * If a group with the same ID already exists, it updates the group's version and updatedAt fields.
 * Otherwise, it creates a new group with the provided data.
 * @param {Array<Object>} groupData - The group data to be saved.
 * @returns {Promise<void>} - A promise that resolves when the group data is saved.
 */
export declare function saveGroup(groupData: GroupData[]): Promise<void>;
/**
 * Saves Zotero items to the database.
 *
 * @param allFetchedItems - An array of fetched items.
 * @param lastModifiedVersion - The last modified version of the items.
 * @param groupId - The ID of the group.
 * @returns {Promise<void>}
 */
export declare function saveZoteroItems(allFetchedItems: ItemResponse[][], lastModifiedVersion: any, groupId: string): Promise<void>;
/**
 * Looks up items in the database based on the provided keys.
 * @param keys - The keys to lookup items for.
 * @returns A promise that resolves to an array of items matching the provided keys.
 */
export declare function lookupItems(keys: {
    keys: string[];
}): Promise<Item[]>;
/**
 * Finds empty items from the database for a given group ID.
 * @param group_id - The ID of the group to search for empty items.
 * @returns A promise that resolves to an array of empty items.
 */
export declare function FindEmptyItemsFromDatabase(group_id: string): Promise<Item[]>;