getBalance static method

String? getBalance(dynamic message, [ BalanceKeywordType keyWordType = BalanceKeywordType.available ])

Gets balance from the message

Implementation

static String? getBalance(
  dynamic message, [
  BalanceKeywordType keyWordType = BalanceKeywordType.available,
]) {
  final processedMessage = MessageProcessor.getProcessedMessage(message);
  final messageString = processedMessage.join(' ');
  int indexOfKeyword = -1;
  String balance = '';

  final balanceKeywords = keyWordType == BalanceKeywordType.available
      ? availableBalanceKeywords
      : outstandingBalanceKeywords;

  for (final word in balanceKeywords) {
    indexOfKeyword = messageString.indexOf(word);

    if (indexOfKeyword != -1) {
      indexOfKeyword += word.length;
      break;
    }
  }

  // Found the index of keyword, moving on to finding 'rs.' occurring after indexOfKeyword
  int index = indexOfKeyword;
  int indexOfRs = -1;

  // If keyword not found or not enough space for 'rs.', check non-standard
  if (indexOfKeyword == -1 || index + 3 > messageString.length) {
    balance = _findNonStandardBalance(messageString, keyWordType) ?? '';
    return balance.isNotEmpty
        ? MessageProcessor.padCurrencyValue(balance)
        : null;
  }

  String nextThreeChars = messageString.substring(index, index + 3);
  index += 3;

  while (index < messageString.length) {
    // Discard first char and add the current char at the end
    nextThreeChars = nextThreeChars.substring(1) + messageString[index];

    if (nextThreeChars == 'rs.') {
      indexOfRs = index + 2;
      break;
    }

    index += 1;
  }

  // No occurrence of 'rs.'
  if (indexOfRs == -1) {
    // Check for non-standard balance
    balance = _findNonStandardBalance(messageString, keyWordType) ?? '';
    return balance.isNotEmpty
        ? MessageProcessor.padCurrencyValue(balance)
        : null;
  }

  balance = _extractBalance(indexOfRs, messageString, messageString.length);

  return balance.isNotEmpty
      ? MessageProcessor.padCurrencyValue(balance)
      : null;
}