import { Email } from '../core/classes.email.js';
import type { EmailProcessingMode } from './interfaces.js';
/**
 * SMTP client connection options
 */
export type ISmtpClientOptions = {
    /**
     * Hostname of the SMTP server
     */
    host: string;
    /**
     * Port to connect to
     */
    port: number;
    /**
     * Whether to use TLS for the connection
     */
    secure?: boolean;
    /**
     * Connection timeout in milliseconds
     */
    connectionTimeout?: number;
    /**
     * Socket timeout in milliseconds
     */
    socketTimeout?: number;
    /**
     * Command timeout in milliseconds
     */
    commandTimeout?: number;
    /**
     * TLS options
     */
    tls?: {
        /**
         * Whether to verify certificates
         */
        rejectUnauthorized?: boolean;
        /**
         * Minimum TLS version
         */
        minVersion?: string;
        /**
         * CA certificate path
         */
        ca?: string;
    };
    /**
     * Authentication options
     */
    auth?: {
        /**
         * Authentication user
         */
        user: string;
        /**
         * Authentication password
         */
        pass: string;
        /**
         * Authentication method
         */
        method?: 'PLAIN' | 'LOGIN' | 'OAUTH2';
    };
    /**
     * Domain name for EHLO
     */
    domain?: string;
    /**
     * DKIM options for signing outgoing emails
     */
    dkim?: {
        /**
         * Whether to sign emails with DKIM
         */
        enabled: boolean;
        /**
         * Domain name for DKIM
         */
        domain: string;
        /**
         * Selector for DKIM
         */
        selector: string;
        /**
         * Private key for DKIM signing
         */
        privateKey: string;
        /**
         * Headers to sign
         */
        headers?: string[];
    };
};
/**
 * SMTP delivery result
 */
export type ISmtpDeliveryResult = {
    /**
     * Whether the delivery was successful
     */
    success: boolean;
    /**
     * Message ID if successful
     */
    messageId?: string;
    /**
     * Error message if failed
     */
    error?: string;
    /**
     * SMTP response code
     */
    responseCode?: string;
    /**
     * Recipients successfully delivered to
     */
    acceptedRecipients: string[];
    /**
     * Recipients rejected during delivery
     */
    rejectedRecipients: string[];
    /**
     * Server response
     */
    response?: string;
    /**
     * Timestamp of the delivery attempt
     */
    timestamp: number;
    /**
     * Whether DKIM signing was applied
     */
    dkimSigned?: boolean;
    /**
     * Whether this was a TLS secured delivery
     */
    secure?: boolean;
    /**
     * Whether authentication was used
     */
    authenticated?: boolean;
};
/**
 * SMTP client for sending emails to remote mail servers
 */
export declare class SmtpClient {
    private options;
    private connected;
    private socket?;
    private supportedExtensions;
    /**
     * Create a new SMTP client instance
     * @param options SMTP client connection options
     */
    constructor(options: ISmtpClientOptions);
    /**
     * Connect to the SMTP server
     */
    connect(): Promise<void>;
    /**
     * Send EHLO command to the server
     */
    private sendEhlo;
    /**
     * Start TLS negotiation
     */
    private startTls;
    /**
     * Upgrade socket to TLS
     * @param socket Original socket
     */
    private upgradeTls;
    /**
     * Authenticate with the server
     */
    private authenticate;
    /**
     * Authenticate using PLAIN method
     * @param user Username
     * @param pass Password
     */
    private authPlain;
    /**
     * Authenticate using LOGIN method
     * @param user Username
     * @param pass Password
     */
    private authLogin;
    /**
     * Authenticate using OAuth2 method
     * @param user Username
     * @param token OAuth2 token
     */
    private authOAuth2;
    /**
     * Send an email through the SMTP client
     * @param email Email to send
     * @param processingMode Optional processing mode
     */
    sendMail(email: Email, processingMode?: EmailProcessingMode): Promise<ISmtpDeliveryResult>;
    /**
     * Apply DKIM signature to email
     * @param email Email to sign
     */
    private applyDkimSignature;
    /**
     * Format email for SMTP transmission
     * @param email Email to format
     */
    private getFormattedEmail;
    /**
     * Get size of email in bytes
     * @param email Email to measure
     */
    private getEmailSize;
    /**
     * Send SMTP command and wait for response
     * @param command SMTP command to send
     */
    private commandQueue;
    private processingCommands;
    private supportsPipelining;
    /**
     * Send an SMTP command and wait for response
     * @param command SMTP command to send
     * @param allowPipelining Whether this command can be pipelined
     */
    private sendCommand;
    /**
     * Process the command queue - either one by one or pipelined if supported
     */
    private processCommandQueue;
    /**
     * Process the next command in the queue (non-pipelined mode)
     */
    private processNextCommand;
    /**
     * Process responses for pipelined commands
     */
    private processResponses;
    /**
     * Read response from the server
     */
    private readResponse;
    /**
     * Check if the response is complete
     * @param response Response to check
     */
    private isCompleteResponse;
    /**
     * Check if the response is an error
     * @param response Response to check
     */
    private isErrorResponse;
    /**
     * Create appropriate error from response
     * @param response Error response
     * @param code SMTP status code
     */
    private createErrorFromResponse;
    /**
     * Close the connection to the server
     */
    close(): Promise<void>;
    /**
     * Checks if the connection is active
     */
    isConnected(): boolean;
    /**
     * Update SMTP client options
     * @param options New options
     */
    updateOptions(options: Partial<ISmtpClientOptions>): void;
}