namespace DeepDrftModels.Enums;

/// <summary>
/// The allowed track-count range for a <see cref="ReleaseMedium"/>, expressed as an inclusive
/// [Min, Max] band. <c>Max == int.MaxValue</c> denotes an unbounded (many-track) medium.
/// </summary>
public readonly record struct MediumCardinality(int Min, int Max)
{
    /// <summary>True when <paramref name="trackCount"/> falls within the inclusive band.</summary>
    public bool Allows(int trackCount) => trackCount >= Min && trackCount <= Max;

    /// <summary>True when the medium permits exactly one track (Max capped at 1).</summary>
    public bool IsSingleTrack => Max == 1;
}

/// <summary>
/// Single source of truth for per-medium structural rules. Today it declares track cardinality;
/// the same table is read by the upload service (to reject over-limit track-adds) and the CMS
/// batch forms (to decide whether to collapse the master list to one row), so the two cannot
/// drift. A future medium declares its cardinality here — and only here — and every consumer
/// honours it automatically. Pure declaration, no dependencies.
/// </summary>
public static class MediumRules
{
    private static readonly IReadOnlyDictionary<ReleaseMedium, MediumCardinality> Cardinalities =
        new Dictionary<ReleaseMedium, MediumCardinality>
        {
            [ReleaseMedium.Cut] = new(1, int.MaxValue),
            [ReleaseMedium.Session] = new(1, 1),
            [ReleaseMedium.Mix] = new(1, 1),
        };

    /// <summary>The declared track-count band for <paramref name="medium"/>.</summary>
    public static MediumCardinality CardinalityOf(ReleaseMedium medium) => Cardinalities[medium];
}