export interface IntegrationStrategy {
    sendMessage(to: string, message: string, config: any): Promise<IntegrationResult>;
    validateConfig(config: any): boolean;
    createUserSpecificConfig?(baseConfig: any, userIntegrationData?: any): any;
}
export interface IntegrationResult {
    success: boolean;
    messageId?: string;
    provider: string;
    service: string;
    error?: string;
    timestamp: Date;
    refreshedToken?: string;
    message?: string;
}
export interface EmailAttachment {
    filename: string;
    content: string;
    contentType: string;
    disposition?: 'attachment' | 'inline';
    contentId?: string;
}
export interface MessageTemplate {
    subject?: string;
    body: string;
    attachments?: EmailAttachment[];
}
export declare class EmailAttachmentValidator {
    static validate(attachments: EmailAttachment[], maxSizeBytes: number, providerName: string): void;
    private static isValidBase64;
}