namespace Mr.BrickAdventures.Progression;

/// <summary>
/// Lives remaining in a Playthrough. Never negative.
/// </summary>
/// <remarks>
/// Decrementing at zero floors rather than failing — unlike <see cref="Coins"/>, where a shortfall
/// is a game rule the caller must handle. Flooring here is purely defensive; the invariant that one
/// death costs exactly one life is enforced by the Attempt's outcome, not by this type.
/// </remarks>
public readonly struct Lives
{
    public int Value { get; }

    private Lives(int value) => Value = value;

    public static Lives Of(int value) => value < 0
        ? throw new ArgumentOutOfRangeException(nameof(value), value, "Lives cannot be negative.")
        : new Lives(value);

    public bool IsExhausted => Value == 0;

    public Lives Decrement() => new(Value == 0 ? 0 : Value - 1);
}