import { SentlyError } from "./errors.js";
export { computeCRAMMD5 } from "./cram-md5.js";
/** SMTP command to send to the server. */
export type SMTPCommand = {
    type: "EHLO";
    domain: string;
} | {
    type: "STARTTLS";
} | {
    type: "AUTH_LOGIN";
    user: string;
    pass: string;
} | {
    type: "AUTH_PLAIN";
    user: string;
    pass: string;
} | {
    type: "AUTH_CRAM_MD5_INIT";
} | {
    type: "AUTH_CRAM_MD5_RESPONSE";
    response: string;
} | {
    type: "AUTH_XOAUTH2";
    xoauth2String: string;
} | {
    type: "MAIL_FROM";
    address: string;
} | {
    type: "RCPT_TO";
    address: string;
} | {
    type: "DATA";
} | {
    type: "DATA_BODY";
    content: Uint8Array;
} | {
    type: "QUIT";
} | {
    type: "RSET";
} | {
    type: "NOOP";
};
/** Parsed SMTP server response. */
export interface SMTPResponse {
    /** Three-digit SMTP status code. */
    code: number;
    /** Human-readable response text after the status code. */
    message: string;
    /** True when the code is in the 2xx success range. */
    isSuccess: boolean;
    /** True when the code is 354 (ready for message data). */
    isReady: boolean;
    /** True when the code is 4xx or 5xx. */
    isError: boolean;
}
/** SMTP protocol error with server response details. */
export declare class SMTPError extends SentlyError {
    readonly command: string;
    readonly response: string;
    /** Creates an SMTP protocol error. */
    constructor(message: string, smtpCode: number, command: string, response: string);
}
/**
 * Encode an SMTPCommand into a Uint8Array for sending over the socket.
 */
export declare function encodeCommand(cmd: SMTPCommand): Uint8Array;
/**
 * Parse raw bytes from the server into an SMTPResponse.
 */
export declare function parseResponse(data: Uint8Array): SMTPResponse;
/**
 * Accumulate byte chunks until a complete SMTP response is received.
 */
export declare function accumulateResponse(chunks: Uint8Array[]): Uint8Array | null;
/**
 * Select the best AUTH method from EHLO capability lines.
 * Priority: XOAUTH2 > CRAM-MD5 > LOGIN > PLAIN.
 */
export declare function selectAuthMethod(capabilities: string[]): "LOGIN" | "PLAIN" | "CRAM-MD5" | "OAUTH2";
/**
 * Parse an EHLO multi-line response and extract capability keywords.
 */
export declare function parseEHLO(response: SMTPResponse): string[];
/**
 * Assert that an SMTPResponse code is within the expected set.
 */
export declare function assertResponse(response: SMTPResponse, expectedCodes: number[], command: string): void;
/** Encode AUTH LOGIN password step (second base64 chunk). */
export declare function encodeAuthLoginPass(pass: string): Uint8Array;
/** Encode AUTH LOGIN user step when sent separately after 334. */
export declare function encodeAuthLoginUser(user: string): Uint8Array;
/** Encode CRAM-MD5 response after challenge. */
export declare function encodeAuthCramResponse(response: string): Uint8Array;
/** Encode raw SMTP line with CRLF. */
export declare function encodeLine(line: string): Uint8Array;