stack_wallet/lib/utilities/amount.dart
2023-03-24 15:30:29 -06:00

80 lines
2.6 KiB
Dart

import 'dart:convert';
import 'package:decimal/decimal.dart';
import 'package:equatable/equatable.dart';
final _ten = BigInt.from(10);
class Amount implements Equatable {
Amount({
required BigInt rawValue,
required this.fractionDigits,
}) : assert(fractionDigits >= 0),
_value = rawValue;
/// truncate double value to [fractionDigits] places
Amount.fromDouble(double amount, {required this.fractionDigits})
: assert(fractionDigits >= 0),
_value =
Decimal.parse(amount.toString()).shift(fractionDigits).toBigInt();
/// truncate decimal value to [fractionDigits] places
Amount.fromDecimal(Decimal amount, {required this.fractionDigits})
: assert(fractionDigits >= 0),
_value = amount.shift(fractionDigits).toBigInt();
// ===========================================================================
// ======= Instance properties ===============================================
final int fractionDigits;
final BigInt _value;
// ===========================================================================
// ======= Getters ===========================================================
/// raw base value
BigInt get raw => _value;
/// actual decimal vale represented
Decimal get decimal =>
(Decimal.fromBigInt(_value) / _ten.pow(fractionDigits).toDecimal())
.toDecimal(scaleOnInfinitePrecision: fractionDigits);
/// convenience getter
@Deprecated("provided for convenience only. Use fractionDigits instead.")
int get decimals => fractionDigits;
Map<String, dynamic> toMap() {
// ===========================================================================
// ======= Serialization =====================================================
return {"raw": raw.toString(), "fractionDigits": fractionDigits};
}
String toJsonString() {
return jsonEncode(toMap());
}
// ===========================================================================
// ======= Deserialization ===================================================
static Amount fromSerializedJsonString(String json) {
final map = jsonDecode(json) as Map;
return Amount(
rawValue: BigInt.parse(map["raw"] as String),
fractionDigits: map["fractionDigits"] as int,
);
}
// ===========================================================================
// ======= Overrides =========================================================
@override
String toString() => "Amount($raw, $fractionDigits)";
@override
List<Object?> get props => [fractionDigits, _value];
@override
bool? get stringify => false;
}