SAMLProvider.ts

/**
 * SAML 2.0 Provider Implementation for Enterprise SSO
 */
export interface SAMLConfig {
  entryPoint: string;
  issuer: string;
  callbackUrl: string;
  cert: string; // Identity Provider Public Certificate
}

export class SAMLProvider {
  constructor(private config: SAMLConfig) {}

  /**
   * Generates the SAML AuthnRequest URL for redirection
   */
  async getAuthorizeUrl(): Promise<string> {
    // Implementation would typically use a library like passport-saml or samlify
    // to construct the XML request, sign it, and encode it
    const state = { 
      timestamp: Date.now(), 
      issuer: this.config.issuer 
    };
    const relayState = Buffer.from(JSON.stringify(state)).toString('base64');
    const samlRequest = Buffer.from('<samlp:AuthnRequest ... />').toString('base64');
    return `${this.config.entryPoint}?SAMLRequest=${encodeURIComponent(samlRequest)}&RelayState=${encodeURIComponent(relayState)}`;
  }

  /**
   * Validates the SAML Response from the Identity Provider
   */
  async validateResponse(samlResponse: string): Promise<any> {
    try {
      // 1. Decode base64 SAML response
      // 2. Verify XML signature using config.cert
      // 3. Check NotBefore and NotOnOrAfter constraints
      // 4. Extract Attributes (NameID, Email, Groups)
      
      // Mock implementation of profile extraction
      return {
        nameID: 'user@enterprise.com',
        email: 'user@enterprise.com',
        attributes: {
          firstName: 'Enterprise',
          lastName: 'User',
          groups: ['Engineering', 'Staff']
        }
      };
    } catch (error) {
      throw new Error('SAML Response validation failed');
    }
  }

  getMetadata(): string {
    return `<EntityDescriptor ... issuer="${this.config.issuer}" ... />`;
  }
}