import { RevocationStatusListFactory } from './revocationStatusListFactory.js';
import { RevocationStatusList } from './revocationStatusList.js';
import { StatusListDecoder } from './statusListDecoderFactory.js';
import { StatusListCredentialResponse } from '../resolvers/statusListCredentialFetcher.js';
import { decodeJwt } from 'jose';

export type StatusListCredentialSubject = {
  id?: string;
  type: string;
  encodedList: string;
  statusPurpose?: string;
  statusListIndex?: string;
  statusListCredential?: string;
};

export class CredentialStatusListDecoder implements StatusListDecoder {
  getEncodedList(
    data: string | StatusListCredentialResponse,
  ): RevocationStatusList {
    const credentialSubject = this.extractCredentialSubject(data);

    if (typeof credentialSubject.encodedList !== 'string') {
      throw new Error('Invalid or missing encodedList');
    }

    if (typeof credentialSubject.type !== 'string') {
      throw new Error('Invalid or missing type');
    }

    return RevocationStatusListFactory.fromEncoded(
      credentialSubject.encodedList,
      credentialSubject.type,
    );
  }

  private extractCredentialSubject(
    data: string | StatusListCredentialResponse,
  ): StatusListCredentialSubject {
    if (typeof data === 'string') {
      const payload = decodeJwt(data);
      if (!payload['vc']) {
        throw new Error(
          'Expected a JWT with a vc payload for CredentialStatus types',
        );
      }
      const vc = payload['vc'] as StatusListCredentialResponse;
      if (!vc.credentialSubject) {
        throw new Error('Missing credentialSubject in vc payload');
      }
      return vc.credentialSubject as StatusListCredentialSubject;
    }

    if (!data.credentialSubject) {
      throw new Error('Missing credentialSubject');
    }

    return data.credentialSubject as StatusListCredentialSubject;
  }
}