import 'dart:math';

import 'package:intl/intl.dart';

extension Abbreviation on num {
  /// adds "k" for thousand, "m" for
  /// million, "b" for billion, "t"
  /// for trillion
  String toAbbreviatedString() {
    final zerothPowerToSuffix = {
      15: 'qd',
      12: 't',
      9: 'b',
      6: 'm',
      3: 'k',
    };
    for (int i = 0; i < zerothPowerToSuffix.length; i++) {
      final pair = zerothPowerToSuffix.entries.elementAt(i);
      final threshold = pow(10, pair.key);
      if (abs() > threshold) {
        final n = this / threshold;
        final nWithDecimal = n.toStringAsFixed(2);
        final nonDecimalPart = nWithDecimal.split('.')[0];
        final decimalPart = nWithDecimal.split('.')[1];
        final end = decimalPart == '00'
            ? ''
            : decimalPart[1] == '0'
                ? decimalPart[0]
                : decimalPart;
        final nWithRationalizedDecimals =
            nonDecimalPart + (end.isEmpty ? '' : '.$end');
        final suffix = pair.value.toUpperCase();
        return nWithRationalizedDecimals + suffix;
      }
    }
    return toStringAsFixed(2);
  }

  String toStringWithCommas({
    bool hideDecimals = false,
    int? abbreviateIfAbove10powN,
  }) {
    if (abbreviateIfAbove10powN != null) {
      final comparator = pow(10, abbreviateIfAbove10powN);
      if (this > comparator) return toAbbreviatedString();
    }
    final formatter = NumberFormat(
      hideDecimals ? '#,###' : '#,##0.##',
    );
    return formatter.format(this);
  }

  double pctDifferenceFrom(num n) => 100 * (n - this) / this;
  double asPctOf(num n) => 100 * this / n;
}