PKHeX/PKHeX.Core/Legality/Encounters/EncounterSlot/IMagnetStatic.cs

namespace PKHeX.Core;

/// <summary>
/// Contains information about the RNG restrictions for the slot, and any mutated RNG values.
/// </summary>
/// <remarks>
/// When encountering a Wild Pokémon with a lead that has an ability of <see cref="Ability.Static"/> or <see cref="Ability.MagnetPull"/>,
/// the game picks encounters from the <seealso cref="EncounterArea"/> that match the type.
/// The values in this interface change the <seealso cref="INumberedSlot"/> to allow different values for slot yielding.
/// </remarks>
public interface IMagnetStatic
{
    /// <summary> <see cref="INumberedSlot.SlotNumber"/> if the lead is <see cref="Ability.Static"/> </summary>
    byte StaticIndex { get; }
    /// <summary> <see cref="INumberedSlot.SlotNumber"/> if the lead is <see cref="Ability.MagnetPull"/> </summary>
    byte MagnetPullIndex { get; }

    /// <summary> Count of slots in the parent area that can be yielded by <see cref="Ability.Static"/> </summary>
    byte StaticCount { get; }
    /// <summary> Count of slots in the parent area that can be yielded by <see cref="Ability.MagnetPull"/> </summary>
    byte MagnetPullCount { get; }
}

public static class MagnetStaticExtensions
{
    private const byte NotMagnetStaticSlot = byte.MaxValue;
    public static bool IsStaticSlot(this IMagnetStatic slot) => slot.StaticCount != 0 && slot.StaticIndex != NotMagnetStaticSlot;
    public static bool IsMagnetSlot(this IMagnetStatic slot) => slot.MagnetPullCount != 0 && slot.MagnetPullIndex != NotMagnetStaticSlot;

    public static bool IsMatchStatic(this IMagnetStatic slot,  int index, int count) => index == slot.StaticIndex && count == slot.StaticCount;
    public static bool IsMatchMagnet(this IMagnetStatic slot,  int index, int count) => index == slot.MagnetPullIndex && count == slot.MagnetPullCount;
}