1import 'package:health_data_store/health_data_store.dart';
 2
 3/// A unit [Weight] can be in.
 4enum WeightUnit {
 5  /// Kilograms, SI unit
 6  kg,
 7
 8  /// Pounds, Defined by the Units of Measurement Regulations 1994
 9  lbs,
10
11  /// Stone, the imperial unit of mass
12  st;
13
14  /// Restore from [serialized].
15  static WeightUnit? deserialize(int? value) => switch(value) {
16    0 => WeightUnit.kg,
17    1 => WeightUnit.lbs,
18    2 => WeightUnit.st,
19    _ => null,
20  };
21
22  /// Create a [WeightUnit.deserialize]able number.
23  int get serialized => switch(this) {
24    WeightUnit.kg => 0,
25    WeightUnit.lbs => 1,
26    WeightUnit.st => 2,
27  };
28
29  /// Create a [Weight] from a double in this unit.
30  Weight store(double value) => switch(this) {
31    WeightUnit.kg => Weight.kg(value),
32    WeightUnit.lbs => Weight.kg(value * 2.2046226218488),
33    WeightUnit.st => Weight.kg(value * 6.350),
34  };
35
36  /// Extract a weight to the preferred unit.
37  double extract(Weight w) => switch(this) {
38    WeightUnit.kg => w.kg,
39    WeightUnit.lbs => w.kg / 2.2046226218488,
40    WeightUnit.st => w.kg / 6.350,
41  };
42}