PKHeX/PKHeX.Core/Legality/Encounters/EncounterStatic/EncounterStatic4.cs

using System;
using System.Linq;
using static PKHeX.Core.GroundTileAllowed;

namespace PKHeX.Core;

/// <summary>
/// Generation 4 Static Encounter
/// </summary>
/// <inheritdoc cref="EncounterStatic"/>
public sealed record EncounterStatic4(GameVersion Version) : EncounterStatic(Version), IGroundTypeTile
{
    public override int Generation => 4;
    public override EntityContext Context => EntityContext.Gen4;

    /// <summary> Indicates if the encounter is a Roamer (variable met location) </summary>
    public bool Roaming { get; init; }

    /// <summary> <see cref="PK4.GroundTile"/> values permitted for the encounter. </summary>
    public GroundTileAllowed GroundTile { get; init; } = None;

    protected override bool IsMatchLocation(PKM pk)
    {
        if (!Roaming)
            return base.IsMatchLocation(pk);

        // Met location is lost on transfer
        if (pk is not G4PKM pk4)
            return true;

        var locs = GetRoamLocations(Species, pk4.GroundTile);
        return locs.Contains(pk4.Met_Location);
    }

    protected override bool IsMatchEggLocation(PKM pk)
    {
        if (!EggEncounter)
            return base.IsMatchEggLocation(pk);

        var eggloc = pk.Egg_Location;
        // Transferring 4->5 clears Pt/HG/SS location value and keeps Faraway Place
        if (pk is not G4PKM pk4)
        {
            if (eggloc == Locations.LinkTrade4)
                return true;
            var cmp = Locations.IsPtHGSSLocationEgg(EggLocation) ? Locations.Faraway4 : EggLocation;
            return eggloc == cmp;
        }

        if (!pk4.IsEgg) // hatched
            return eggloc == EggLocation || eggloc == Locations.LinkTrade4;

        // Unhatched:
        if (eggloc != EggLocation)
            return false;
        if (pk4.Met_Location is not (0 or Locations.LinkTrade4))
            return false;
        return true;
    }

    protected override void ApplyDetails(ITrainerInfo tr, EncounterCriteria criteria, PKM pk)
    {
        base.ApplyDetails(tr, criteria, pk);
        SanityCheckVersion(pk);
    }

    private void SanityCheckVersion(PKM pk)
    {
        // Unavailable encounters in DP, morph them to Pt so they're legal.
        switch (Species)
        {
            case (int)Core.Species.Darkrai when Location == 079: // DP Darkrai
            case (int)Core.Species.Shaymin when Location == 063: // DP Shaymin
                pk.Version = (int)GameVersion.Pt;
                return;
        }
    }

    protected override bool IsMatchLevel(PKM pk, EvoCriteria evo)
    {
        if (pk.Format != 4) // Met Level lost on PK4=>PK5
            return Level <= evo.LevelMax;

        return pk.Met_Level == (EggEncounter ? 0 : Level);
    }

    protected override bool IsMatchPartial(PKM pk)
    {
        if (Gift && pk.Ball != Ball)
            return true;
        return base.IsMatchPartial(pk);
    }

    protected override void SetMetData(PKM pk, int level, DateTime today)
    {
        var pk4 = (PK4)pk;
        var type = pk4.GroundTile = GroundTile.GetIndex();
        pk.Met_Location = Roaming ? GetRoamLocations(Species, type)[0] : Location;
        pk.Met_Level = level;
        pk.MetDate = today;
    }

    private static int[] GetRoamLocations(int species, GroundTileType type) => species switch
    {
        481 or 488 or 144 or 145 or 146 => type == GroundTileType.Grass ? Roaming_MetLocation_DPPt_Grass : Roaming_MetLocation_DPPt_Surf,
        243 or 244 => type == GroundTileType.Grass ? Roaming_MetLocation_HGSS_Johto_Grass : Roaming_MetLocation_HGSS_Johto_Surf,
        380 or 381 => type == GroundTileType.Grass ? Roaming_MetLocation_HGSS_Kanto_Grass : Roaming_MetLocation_HGSS_Kanto_Surf,
        _ => throw new ArgumentOutOfRangeException(nameof(species)),
    };

    private static readonly int[] Roaming_MetLocation_DPPt_Grass =
    {
        // Routes 201-218, 221-222 can be encountered in grass
        16, 17, 18, 19, 20, 21, 22, 23, 24, 25,
        26, 27, 28, 29, 30, 31, 32, 33, 36, 37,
        47,     // Valley Windworks
        49,     // Fuego Ironworks
    };

    private static readonly int[] Roaming_MetLocation_DPPt_Surf =
    {
        // Routes 203-205, 208-210, 212-214, 218-222 can be encountered in water
        18, 19, 20, 23, 24, 25, 27, 28, 29, 33,
        34, 35, 36, 37,
        47,     // Valley Windworks
        49,     // Fuego Ironworks
    };

    // Grass 29-39, 42-46, 47, 48
    // Surf 30-32 34-35, 40-45, 47
    // Route 45 inaccessible surf
    private static readonly int[] Roaming_MetLocation_HGSS_Johto_Grass =
    {
        // Routes 29-48 can be encountered in grass
        // Won't go to routes 40,41,47,48
        177, 178, 179, 180, 181, 182, 183, 184, 185, 186,
        187,                     190, 191, 192, 193, 194,
    };

    private static readonly int[] Roaming_MetLocation_HGSS_Johto_Surf =
    {
        // Routes 30-32,34-35,40-45 and 47 can be encountered in water
        // Won't go to routes 40,41,47,48
        178, 179, 180, 182, 183, 190, 191, 192, 193,
    };

    private static readonly int[] Roaming_MetLocation_HGSS_Kanto_Grass =
    {
        // Route 01-18,21,22,24,26 and 28 can be encountered in grass
        // Won't go to route 23 25 27
        149, 150, 151, 152, 153, 154, 155, 156, 157, 158,
        159, 160, 161, 162, 163, 164, 165, 166,
        169, 170,      172,      174,      176,
    };

    private static readonly int[] Roaming_MetLocation_HGSS_Kanto_Surf =
    {
        // Route 4,6,9,10,12,13,19-22,24,26 and 28 can be encountered in water
        // Won't go to route 23 25 27
        152, 154, 157, 158, 160, 161, 167, 168, 169, 170,
        172,      174,      176,
    };
}