import type { ImapAttributeList, ParserOptions } from './types.js';
/**
 * Parses a single IMAP response line into its structural components: tag, command,
 * and attributes. Handles status responses (OK, NO, BAD, PREAUTH, BYE) with their
 * human-readable text and response codes, as well as continuation responses ("+").
 */
export declare class ParserInstance {
    input: string;
    options: ParserOptions;
    remainder: string;
    pos: number;
    tag?: string | undefined;
    command?: string | undefined;
    humanReadable?: string | undefined;
    /**
     * Creates a new ParserInstance for parsing an IMAP response line.
     *
     * @param input - The raw IMAP response line to parse.
     * @param options - Parser options passed through to the TokenParser for attribute parsing.
     * @param options.literalPlus - Whether the LITERAL+ extension is in use.
     * @param options.literals - Pre-parsed literal values from the stream.
     */
    constructor(input?: Buffer | string | null | undefined, options?: ParserOptions | undefined);
    /**
     * Extracts and returns the IMAP tag from the beginning of the response.
     * The tag is typically "*" for untagged responses, "+" for continuation requests,
     * or a client-assigned command tag like "A1".
     *
     * @returns The parsed tag string.
     * @throws {Error} If the tag contains invalid characters.
     */
    getTag(): Promise<string>;
    /**
     * Extracts and returns the IMAP command or response name from the input.
     * For continuation responses (tag "+"), returns an empty string and stores
     * the remainder as human-readable text. For status responses (OK, NO, BAD,
     * PREAUTH, BYE), separates the optional response code from the human-readable text.
     *
     * @returns The parsed command string.
     * @throws {Error} If the command contains invalid characters or input ends unexpectedly.
     */
    getCommand(): Promise<string>;
    /**
     * Extracts the next whitespace-delimited element from the input and validates it
     * against the given syntax character set. Advances the parser position past the element.
     *
     * @param syntax - A string of allowed characters for the element (as returned by imap-formal-syntax methods).
     * @returns The extracted element string.
     * @throws {Error} If the element contains characters not in the syntax set, or if input ends unexpectedly.
     */
    getElement(syntax: string): Promise<string>;
    /**
     * Consumes a single space character from the current position in the input.
     * Advances the parser position by one.
     *
     * @throws {Error} If the current character is not a space, or if input has ended unexpectedly.
     */
    getSpace(): Promise<void>;
    /**
     * Parses the remaining input as IMAP attributes using the TokenParser.
     * This handles complex structures including nested lists, literals, strings,
     * atoms, sections, sequences, and partial ranges.
     *
     * @returns A promise that resolves to an array of parsed attribute objects.
     * @throws {Error} If the input contains unexpected whitespace, invalid characters, or ends unexpectedly.
     */
    getAttributes(): Promise<ImapAttributeList>;
}