import type { FetchedMessage } from '../../../../core/email/client.ts';
declare const SORT_KINDS: readonly ["date", "from", "to", "subject"];
type SortKind = (typeof SORT_KINDS)[number];
export declare class QueryError extends Error {
}
export interface Sorter {
    kind: SortKind;
    descending: boolean;
}
export interface Query {
    criteria: string;
    sorters: Sorter[];
}
/** Parses a himalaya search query into IMAP criteria plus sorters. */
export declare function parseQuery(source: string): Query;
/**
 * Orders fetched headers by the query's sorters, applied right to left so
 * the first sorter ends up the primary key. With no sorters the order is
 * date descending, matching `envelope list`.
 */
export declare function sortHeaders(headers: FetchedMessage[], sorters: readonly Sorter[]): FetchedMessage[];
/** Takes one page of results, counting from 1. */
/**
 * How many of the newest matching UIDs to fetch headers for.
 *
 * Sorting happens client-side, so a page cannot be served without
 * holding the candidate headers. Under the default order (date
 * descending) the newest `page * pageSize` messages are the only ones
 * that can appear, so ask for exactly those. An explicit `order by` is
 * unrelated to arrival order, so the whole account window has to be
 * considered, capped by `maxMessages` either way: that is the account
 * knob for how far back mirage looks, and without it one `envelope list`
 * would fetch every message in the mailbox.
 */
export declare function uidBudget(page: number, pageSize: number, sorters: readonly Sorter[], maxMessages: number): number;
export declare function pageSlice<T>(items: readonly T[], page: number, pageSize: number): T[];
export {};
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