feat: add very large amount support

lib/src/currency.dart

@@ -4,8 +4,6 @@
  * Written by Brett Sutton <[email protected]>, Jan 2022
  */
 
-import 'dart:math';
-
 import 'package:meta/meta.dart';
 
 import '../money2.dart';
@@ -167,7 +165,7 @@ class Currency {
       throw ArgumentError.value(
           precision, 'precision', 'Must be a non-negative value.');
     }
-    return BigInt.from(pow(10, precision));
+    return BigInt.from(10).pow(precision);
   }
 
   /// Takes a [majorUnits] and a [minorUnits] and returns

lib/src/money.dart

@@ -367,10 +367,7 @@ class Money implements Comparable<Money> {
   /// The JSON representation follows the same format generated by the
   /// [toJson] method.
   factory Money.fromJson(Map<String, dynamic> json) => Money.fromFixed(
-        Fixed.parse(
-          '${json['integerPart']}.${json['decimalPart']}',
-          scale: json['decimals'] as int,
-        ),
+        Fixed.fromJson(json['amount'] as Map<String, dynamic>),
         isoCode: json['isoCode'] as String,
       );
 
@@ -488,7 +485,8 @@ class Money implements Comparable<Money> {
   /// > $AUD11
   /// ```
   ///
-  String format(String pattern) => encodedBy(PatternEncoder(this, pattern));
+  String format([String? pattern]) =>
+      encodedBy(PatternEncoder(this, pattern ?? currency.pattern));
 
   @override
   String toString() => encodedBy(PatternEncoder(this, currency.pattern));
@@ -498,9 +496,7 @@ class Money implements Comparable<Money> {
   /// The JSON representation can be used to recreate this [Money] instance
   /// using the [Money.fromJson] factory.
   Map<String, dynamic> toJson() => {
-        'integerPart': amount.integerPart.toInt(),
-        'decimalPart': amount.decimalPart.toInt(),
-        'decimals': amount.scale,
+        'amount': amount.toJson(),
         'isoCode': currency.isoCode,
       };
 

lib/src/pattern_encoder.dart

@@ -78,10 +78,9 @@ class PatternEncoder implements MoneyEncoder<String> {
     final moneyPattern = _getMoneyPattern(majorPattern);
     _checkZeros(moneyPattern, patternGroupSeparator, minor: false);
 
-    final integerPart = data.integerPart;
-
-    final formattedMajorUnits =
-        _getFormattedMajorUnits(data, moneyPattern, integerPart);
+    final formattedMajorUnits = data.amount
+        .format(moneyPattern)
+        .replaceAll(patternGroupSeparator, data.currency.groupSeparator);
 
     // replace the the money components with a single #
     var compressedMajorPattern = _compressMoney(majorPattern);
@@ -118,22 +117,6 @@ class PatternEncoder implements MoneyEncoder<String> {
     return formatted;
   }
 
-  ///
-  String _getFormattedMajorUnits(
-      MoneyData data, String moneyPattern, BigInt majorUnits) {
-    // format the no. into that pattern.
-    var formattedMajorUnits =
-        NumberFormat(moneyPattern).format(majorUnits.toInt());
-
-    if (!majorUnits.isNegative && data.amount.isNegative) {
-      formattedMajorUnits = '-$formattedMajorUnits';
-    }
-
-    // Convert to the MoneyData's preferred group separator
-    return formattedMajorUnits.replaceAll(
-        patternGroupSeparator, data.currency.groupSeparator);
-  }
-
   /// returns the currency isoCode from [data] using the
   /// supplied [pattern] to find the isoCode.
   String _getIsoCode(MoneyData data, String pattern) {

test/src/money_format_test.dart

@@ -84,7 +84,7 @@ void main() {
           decimalSeparator: '/',
           groupSeparator: ' ',
           symbol: '€',
-          pattern: '###,###.##S');
+          pattern: '#,###,###.##S');
 
       final amount =
           Money.fromIntWithCurrency(1234567890, euroCurrency, decimalDigits: 3);

test/src/money_json_test.dart

@@ -11,9 +11,10 @@ import 'package:test/test.dart';
 void main() {
   final money = Money.fromInt(1025, isoCode: 'USD');
   final expectedJson = <String, dynamic>{
-    'integerPart': 10,
-    'decimalPart': 25,
-    'decimals': 2,
+    'amount': {
+      'minorUnits': '1025',
+      'scale': 2,
+    },
     'isoCode': 'USD',
   };
 

test/src/money_large_json_test.dart

@@ -0,0 +1,19 @@
+import 'package:money2/money2.dart';
+import 'package:test/test.dart';
+
+void main() {
+  final amount = '${'9' * 100}.${'9' * 100}';
+  final minorUnits = '9' * 200;
+
+  test('Money serialization', () {
+    final c = Currency.create('c100', 100, symbol: '=100=');
+    Currencies().register(c);
+    final m0 = Money.parseWithCurrency(amount, c);
+    final json = m0.toJson();
+    final m1 = Money.fromJson(json);
+    expect(m0.integerPart, m1.integerPart);
+    expect(m0.decimalPart, m1.decimalPart);
+    expect(m1.compareTo(m0), 0);
+    expect(m1.minorUnits, BigInt.parse(minorUnits));
+  });
+}

test/src/money_large_test.dart

@@ -0,0 +1,148 @@
+import 'package:money2/money2.dart';
+import 'package:test/test.dart';
+
+void main() {
+  const maxScale = 100;
+  const maxInts = 100;
+
+  setUp(() {
+    for (var scale = 0; scale <= maxScale; scale++) {
+      final c = Currency.create('C$scale', scale, symbol: '=$scale=');
+      Currencies().register(c);
+    }
+  });
+
+  test('test default currency formatting', () {
+    final roflWithDefaultFormatting =
+        Currency.create('ROFL', 9, symbol: 'ROFL');
+    expect(
+      Money.parseWithCurrency('2.0', roflWithDefaultFormatting).format(),
+      'ROFL2.00',
+      reason: 'Failed default formatting',
+    );
+  });
+
+  test('test custom currency formatting', () {
+    final roflWithDefaultFormatting =
+        Currency.create('ROFL', 9, symbol: 'ROFL', pattern: '0.000000000 S');
+    expect(
+      Money.parseWithCurrency('2.0', roflWithDefaultFormatting).format(),
+      '2.000000000 ROFL',
+      reason: 'Failed custom formatting',
+    );
+  });
+
+  test('test custom currency formatting 2', () {
+    final roflWithDefaultFormatting =
+        Currency.create('ROFL', 9, symbol: 'ROFL', pattern: '0.000000000 S');
+    expect(
+      Money.parseWithCurrency('2.01', roflWithDefaultFormatting).format(),
+      '2.010000000 ROFL',
+      reason: 'Failed custom formatting',
+    );
+  });
+
+  test('test custom currency formatting 3 (trim zeros)', () {
+    final roflWithDefaultFormatting =
+        Currency.create('ROFL', 9, symbol: 'ROFL', pattern: '0.######### S');
+    expect(
+      Money.parseWithCurrency('2.01', roflWithDefaultFormatting).format(),
+      '2.01 ROFL',
+      reason: 'Failed custom formatting',
+    );
+  });
+
+  test('test custom explicit formatting', () {
+    final roflWithDefaultFormatting =
+        Currency.create('ROFL', 9, symbol: 'ROFL', pattern: '0.######### S');
+    expect(
+      Money.parseWithCurrency('2.01', roflWithDefaultFormatting)
+          .format('S 0.#########'),
+      'ROFL 2.01',
+      reason: 'Failed custom formatting',
+    );
+  });
+
+  test('scale 0-$maxScale test', () {
+    for (var scale = 0; scale <= maxScale; scale++) {
+      final c = Currencies().find('C$scale');
+      expect(c, isNotNull);
+      final str = scale == 0 ? '0' : '0.${'0' * (scale - 1)}1';
+      final fmt = scale == 0 ? '0' : '0.${'#' * scale}';
+      expect(
+        Money.parseWithCurrency(str, c!).format(fmt),
+        str,
+        reason: 'Failed with $scale scale',
+      );
+    }
+  });
+
+  test('integers 0-$maxInts test', () {
+    for (var ints = 0; ints <= maxInts; ints++) {
+      final c = Currencies().find('C0');
+      expect(c, isNotNull);
+      final str = ints == 0 ? '0' : '9' * ints;
+      const fmt = '0';
+      expect(
+        Money.parseWithCurrency(str, c!).format(fmt),
+        str,
+        reason: 'Failed with $ints ints',
+      );
+    }
+  });
+
+  test('scale 0-$maxScale and integers 0-$maxInts test', () {
+    for (var scale = 19; scale <= maxScale; scale++) {
+      for (var ints = 1; ints <= maxInts; ints++) {
+        final c = Currencies().find('C$scale');
+        expect(c, isNotNull);
+        final intsStr = ints == 0 ? '0' : '9' * ints;
+        final str = scale == 0 ? intsStr : '$intsStr.${'0' * (scale - 1)}1';
+        final fmt = scale == 0 ? '0' : '0.${'0' * scale}';
+
+        expect(
+          Money.parseWithCurrency(str, c!).format(fmt),
+          str,
+          reason: 'Failed with $scale scale, $ints ints',
+        );
+      }
+    }
+  });
+
+  test(
+      'scale 0-$maxScale and integers 0-$maxInts addition and subtraction test',
+      () {
+    for (var scale = 0; scale <= maxScale; scale++) {
+      for (var ints = 0; ints <= maxInts; ints++) {
+        final c = Currencies().find('C$scale');
+        expect(c, isNotNull);
+        final intsStr = ints == 0 ? '1' : '9' * ints;
+        const str0 = '1';
+        final str1 =
+            scale == 0 ? '${intsStr}1' : '${intsStr}1.${'0' * (scale - 1)}1';
+        final str2 =
+            scale == 0 ? '${intsStr}2' : '${intsStr}2.${'0' * (scale - 1)}1';
+
+        final m0 =
+            Money.fromFixedWithCurrency(Fixed.parse(str0, scale: scale), c!);
+        final m1 =
+            Money.fromFixedWithCurrency(Fixed.parse(str1, scale: scale), c);
+        final m2 =
+            Money.fromFixedWithCurrency(Fixed.parse(str2, scale: scale), c);
+        final mDiff = m2 - m1;
+        final mSum = m1 + m0;
+
+        expect(
+          mDiff.amount,
+          Fixed.one,
+          reason: 'Failed with $scale scale, $ints ints',
+        );
+        expect(
+          mSum.amount,
+          m2.amount,
+          reason: 'Failed with $scale scale, $ints ints',
+        );
+      }
+    }
+  });
+}

test/src/money_parse_test.dart

@@ -253,7 +253,7 @@ void main() {
           decimalSeparator: '/',
           groupSeparator: ' ',
           symbol: '€',
-          pattern: '###,###.##S');
+          pattern: '#,###,###.##S');
 
       final amount = Money.parseWithCurrency('1 234 567/89€', euroCurrency);
       final formatted = amount.toString();