import OpenTimestamps from 'opentimestamps-javascript'; // Atualizar import
import { createHash } from 'crypto';
import * as fs from 'fs/promises';
import * as path from 'path';

export class BlockchainService {
  private readonly storageDir: string;

  constructor() {
    this.storageDir = path.join(process.cwd(), 'storage', 'timestamps');
    this.ensureStorageDir();
  }

  private async ensureStorageDir() {
    try {
      await fs.mkdir(this.storageDir, { recursive: true });
    } catch (error) {
      console.error('Erro ao criar diretório de timestamps:', error);
    }
  }

  async createTimestamp(buffer: Buffer) {
    try {
      // 1. Criar hash do arquivo
      const fileHash = createHash('sha256').update(buffer).digest();

      // 2. Criar timestamp
      const timestamp = await OpenTimestamps.stamp(fileHash);

      // 3. Salvar arquivo .ots
      const otsPath = path.join(this.storageDir, `${fileHash.toString('hex')}.ots`);
      await fs.writeFile(otsPath, Buffer.from(timestamp));

      return {
        hash: fileHash.toString('hex'),
        timestamp,
        otsPath
      };
    } catch (error) {
      console.error('Erro ao criar timestamp:', error);
      throw new Error('Falha ao criar timestamp na blockchain');
    }
  }

  async verifyTimestamp(hash: string, timestamp: Buffer) {
    try {
      // Usar a API correta do OpenTimestamps
      const result = await OpenTimestamps.verify(
        Buffer.from(timestamp),
        Buffer.from(hash, 'hex')
      );
      
      if (!result) {
        return { 
          verified: false, 
          message: 'Timestamp ainda não confirmado na blockchain' 
        };
      }

      return {
        verified: true,
        timestamp: new Date(result * 1000),
        message: 'Timestamp verificado na blockchain do Bitcoin'
      };
    } catch (error) {
      console.error('Erro ao verificar timestamp:', error);
      return { 
        verified: false, 
        message: 'Erro ao verificar timestamp' 
      };
    }
  }
}