namespace Mr.BrickAdventures.Progression;

/// <summary>
/// Stable identity of a Level. Never a position in a list — Playthroughs and Best Times both
/// reference Levels, so ids must survive inserting and reordering.
/// </summary>
public readonly struct LevelId : IEquatable<LevelId>
{
    public string Value { get; }

    private LevelId(string value) => Value = value;

    public static LevelId Of(string value) => string.IsNullOrWhiteSpace(value)
        ? throw new ArgumentException("A level id cannot be blank.", nameof(value))
        : new LevelId(value);

    public bool Equals(LevelId other) => string.Equals(Value, other.Value, StringComparison.Ordinal);
    public override bool Equals(object? obj) => obj is LevelId other && Equals(other);
    public override int GetHashCode() => StringComparer.Ordinal.GetHashCode(Value ?? string.Empty);
    public override string ToString() => Value;
}