import {
  SmtpConfig,
  SendGridConfig,
  SesConfig,
  EmailProviderConfig,
  EmailProviderType,
} from '../interfaces/email-options.interface';

export const DEFAULT_RETRY_ATTEMPTS = 3;
export const DEFAULT_RETRY_DELAY = 1000; // 1 second
export const DEFAULT_TIMEOUT = 10000; // 10 seconds

export const DEFAULT_SMTP_CONFIG: SmtpConfig = {
  host: 'smtp.example.com',
  port: 587,
  secure: false,
  auth: {
    user: '',
    pass: '',
  },
  tls: {
    rejectUnauthorized: true,
  },
};

export const DEFAULT_SENDGRID_CONFIG: SendGridConfig = {
  apiKey: '',
};

/**
 * Default AWS SES Configuration
 */
export const DEFAULT_SES_CONFIG: SesConfig = {
  region: 'us-west-2',
  apiVersion: '2010-12-01',
  maxRetries: 3,
  httpOptions: {
    timeout: 10000,
    connectTimeout: 5000,
  },
};

export class EmailConfigBuilder {
  private config: EmailProviderConfig;
  private retryAttempts: number = DEFAULT_RETRY_ATTEMPTS;
  private retryDelay: number = DEFAULT_RETRY_DELAY;
  private timeout: number = DEFAULT_TIMEOUT;

  constructor(providerType: EmailProviderType = EmailProviderType.SMTP) {
    let defaultConfig: SmtpConfig | SendGridConfig | SesConfig;
    
    switch (providerType) {
      case EmailProviderType.SMTP:
        defaultConfig = { ...DEFAULT_SMTP_CONFIG };
        break;
      case EmailProviderType.SENDGRID:
        defaultConfig = { ...DEFAULT_SENDGRID_CONFIG };
        break;
      case EmailProviderType.SES:
        // AWS SES Configuration
        defaultConfig = { ...DEFAULT_SES_CONFIG };
        break;
      default:
        defaultConfig = { ...DEFAULT_SMTP_CONFIG };
    }

    this.config = {
      type: providerType,
      config: defaultConfig,
    };
  }

  withSmtpConfig(config: Partial<SmtpConfig>): this {
    if (this.config.type !== EmailProviderType.SMTP) {
      throw new Error('Cannot set SMTP config for non-SMTP provider');
    }
    this.config.config = { ...this.config.config, ...config } as SmtpConfig;
    return this;
  }

  withSendGridConfig(config: Partial<SendGridConfig>): this {
    if (this.config.type !== EmailProviderType.SENDGRID) {
      throw new Error('Cannot set SendGrid config for non-SendGrid provider');
    }
    this.config.config = { ...this.config.config, ...config } as SendGridConfig;
    return this;
  }

  /**
   * Configure AWS SES settings
   */
  withSesConfig(config: Partial<SesConfig>): this {
    if (this.config.type !== EmailProviderType.SES) {
      throw new Error('Cannot set SES config for non-SES provider');
    }
    this.config.config = { ...this.config.config, ...config } as SesConfig;
    return this;
  }

  withRetryAttempts(attempts: number): this {
    this.retryAttempts = attempts;
    return this;
  }

  withRetryDelay(delay: number): this {
    this.retryDelay = delay;
    return this;
  }

  withTimeout(timeout: number): this {
    this.timeout = timeout;
    return this;
  }

  build(): EmailProviderConfig & {
    retryAttempts: number;
    retryDelay: number;
    timeout: number;
  } {
    return {
      ...this.config,
      retryAttempts: this.retryAttempts,
      retryDelay: this.retryDelay,
      timeout: this.timeout,
    };
  }
}