Role.cs

using System;

namespace JSONstat.Models;

/// <summary>
/// Optional object assigning special roles to dimensions.
/// Source: <c>../wiki/dataset-structure.md</c>.
/// </summary>
public sealed class Role
{
    /// <summary>Dimension ids with the time role.</summary>
    public string[]? Time { get; set; }

    /// <summary>Dimension ids with the geo role.</summary>
    public string[]? Geo { get; set; }

    /// <summary>Dimension ids with the metric role.</summary>
    public string[]? Metric { get; set; }

    /// <summary>True when no role is assigned.</summary>
    public bool IsEmpty =>
        (Time is null || Time.Length == 0) &&
        (Geo is null || Geo.Length == 0) &&
        (Metric is null || Metric.Length == 0);

    /// <summary>Resolves the role of a dimension id, or null when unroled.</summary>
    internal DimensionRole? RoleOf(string id)
    {
        if (Contains(Time, id)) return DimensionRole.Time;
        if (Contains(Geo, id)) return DimensionRole.Geo;
        if (Contains(Metric, id)) return DimensionRole.Metric;
        return null;
    }

    private static bool Contains(string[]? arr, string id) =>
        arr != null && Array.IndexOf(arr, id) >= 0;
}