PKHeX/PKHeX.Core/Legality/Encounters/EncounterStatic/EncounterStatic8ND.cs

using static PKHeX.Core.Encounters8Nest;

namespace PKHeX.Core;

/// <summary>
/// Generation 8 Nest Encounter (Distributed Data)
/// </summary>
/// <inheritdoc cref="EncounterStatic8Nest{T}"/>
public sealed record EncounterStatic8ND : EncounterStatic8Nest<EncounterStatic8ND>
{
    /// <summary>
    /// Distribution raid index for <see cref="GameVersion.SWSH"/>
    /// </summary>
    public byte Index { get; init; }

    public EncounterStatic8ND(byte lvl, byte dyna, byte flawless, GameVersion game = GameVersion.SWSH) : base(game)
    {
        Level = lvl;
        DynamaxLevel = dyna;
        FlawlessIVCount = flawless;
    }

    protected override bool IsMatchLevel(PKM pk, EvoCriteria evo)
    {
        var lvl = pk.Met_Level;

        if (lvl <= 25) // 1 or 2 stars
        {
            var met = pk.Met_Location;
            if (met <= byte.MaxValue && InaccessibleRank12DistributionLocations.Contains((byte)met))
                return false;
        }

        if (lvl == Level)
            return true;

        // Check downleveled (20-55)
        if (lvl > Level)
            return false;
        if (lvl is < 20 or > 55)
            return false;

        if (lvl % 5 != 0)
            return false;

        // shared nests can be down-leveled to any
        if (pk.Met_Location == SharedNest)
            return true;

        // native down-levels: only allow 1 rank down (1 badge 2star -> 25), (3badge 3star -> 35)
        var badges = (lvl - 20) / 5;
        return badges is 1 or 3 && !pk.IsShiny;
    }

    protected override bool IsMatchLocation(PKM pk)
    {
        var loc = pk.Met_Location;
        return loc is SharedNest || Index switch
        {
            >= 40 => EncounterArea8.IsWildArea(loc),
            >= 25 => EncounterArea8.IsWildArea8(loc) || EncounterArea8.IsWildArea8Armor(loc),
            _ => EncounterArea8.IsWildArea8(loc),
        };
    }

    public override bool IsMatchExact(PKM pk, EvoCriteria evo)
    {
        if (pk.FlawlessIVCount < FlawlessIVCount)
            return false;

        return base.IsMatchExact(pk, evo);
    }
}