export interface EmailConfig {
  provider: EmailProvider;
  apiKey?: string;
  from: string;
  replyTo?: string;
  onSent?: (result: EmailResult) => Promise<void>;
  onError?: (error: EmailError) => void;
  footer?: EmailFooterConfig;
}

export type EmailProvider = 'resend' | 'sendgrid' | 'ses' | 'postmark' | 'smtp';

export interface SendEmailOptions<T = Record<string, any>> {
  to: string | string[];
  template: string | EmailTemplate<T>;
  data?: T;
  from?: string;
  replyTo?: string;
  cc?: string | string[];
  bcc?: string | string[];
  attachments?: Attachment[];
  schedule?: Date;
  priority?: 'high' | 'normal' | 'low';
  tags?: string[];
  metadata?: Record<string, any>;
}

export interface Attachment {
  filename: string;
  content: string | Buffer;
  contentType?: string;
  encoding?: string;
}

export interface EmailResult {
  id: string;
  provider: EmailProvider;
  to: string[];
  template?: string;
  sentAt: Date;
  status: 'sent' | 'queued' | 'scheduled' | 'failed';
  error?: string;
}

export interface EmailError {
  code: string;
  message: string;
  provider: EmailProvider;
  originalError?: any;
}

export interface BatchEmailOptions<T = Record<string, any>> {
  template: string | EmailTemplate<T>;
  recipients: Array<{
    to: string;
    data?: T;
    metadata?: Record<string, any>;
  }>;
  from?: string;
  replyTo?: string;
  schedule?: Date;
}

export interface BatchEmailResult {
  batchId: string;
  total: number;
  successful: number;
  failed: number;
  results: EmailResult[];
}

export interface EmailTemplate<T = Record<string, any>> {
  id: string;
  name: string;
  subject: string | ((data: T) => string);
  preview?: string | ((data: T) => string);
  body: {
    html: string | ((data: T) => string);
    text?: string | ((data: T) => string);
  };
  metadata?: {
    category?: string;
    tags?: string[];
    version?: number;
  };
  includeFooter?: boolean; // Allow templates to opt out of footer
}

export interface EmailFooterConfig {
  html?: string | (() => string);
  text?: string | (() => string);
  unsubscribe?: {
    enabled: boolean;
    url?: string;
    text?: string;
  };
  privacy?: {
    enabled: boolean;
    url?: string;
    text?: string;
  };
  disclaimer?: {
    enabled: boolean;
    text: string;
  };
  company?: {
    name: string;
    address?: string;
    website?: string;
  };
}