Dart BR Code PIX Estático

main.dart

import 'dart:convert';
import 'package:crclib/catalog.dart';

// const test_pix = '00020126360014BR.GOV.BCB.PIX0114+55119647714305204000053039865406986.005802BR5913Fulano de Tal6008BRASILIA62070503***63047E91';
// const test_pix2 = '00020126360014BR.GOV.BCB.PIX0114+55119647714305204000053039865406100.005802BR5907Enrique6009Sao Paulo62070503***630402D3';

class Data {
  const Data({
    required this.amout,
    required this.pixKey,
    required this.merchantName,
    this.merchantCity = '',
  });

  final String pixKey;
  final double amout;
  final String merchantName;
  final String merchantCity;
}

class BRCodeValue {
  const BRCodeValue(this.id, this.value);

  final int id;
  final String value;
  String get formattedId => id.toString().padLeft(2, "0");
  String get formattedLength => value.length.toString().padLeft(2, "0");

  @override
  toString() {
    return '$formattedId$formattedLength$value';
  }
}

class BRCode {
  BRCode(this.data);

  final Data data;

  final _crc = Crc16CcittFalse();
  final _crcLength = 4;
  final _crcId = 63;

  String generate() {
    final result = _buildValues({
      00: "01",
      26: _buildValues({
        00: "br.gov.bcb.pix".toUpperCase(),
        01: data.pixKey,
      }),
      52: "0000",
      53: "986",
      54: data.amout.toStringAsFixed(2),
      58: "BR",
      59: data.merchantName,
      60: data.merchantCity,
      62: _buildValues({05: "***"}),
    });

    return '$result${_buildCrcValue(result)}';
  }

  String _buildValues(Map<int, String> map) {
    final values = List.from(
      map.entries.map(
        (e) => BRCodeValue(e.key, e.value).toString(),
      ),
    );

    return values.join("");
  }

  String _buildCrcValue(String value) {
    final length = _crcLength.toString().padLeft(2, "0");

    return BRCodeValue(_crcId, _toCrc('$value$_crcId$length')).toString();
  }

  String _toCrc(String result) {
    return _crc
        .convert(utf8.encode(result))
        .toRadixString(16)
        .padLeft(_crcLength, '0')
        .toUpperCase();
  }
}