pk3DS/pk3DS.Core/Randomizers/SpeciesRandomizer.cs

using System.Collections.Generic;
using System.Linq;

using pk3DS.Core.Structures.PersonalInfo;

namespace pk3DS.Core.Randomizers;

public class SpeciesRandomizer
{
    //private readonly GameConfig Game;
    private readonly PersonalInfo[] SpeciesStat;
    private readonly int MaxSpeciesID;

    public SpeciesRandomizer(GameConfig config)
    {
        var Game = config;
        MaxSpeciesID = Game.Info.MaxSpeciesID;
        SpeciesStat = Game.Personal.Table;
    }

    /// <summary>
    /// To be called after the allowed species are provided.
    /// </summary>
    public void Initialize()
    {
        var list = InitializeSpeciesList();
        RandSpec = new GenericRandomizer(list);
    }

    #region Randomizer Settings
    public bool G1 = true;
    public bool G2 = true;
    public bool G3 = true;
    public bool G4 = true;
    public bool G5 = true;
    public bool G6 = true;
    public bool G7 = false;
    public bool L = false;
    public bool E = false;
    public bool Shedinja = false;
    public bool rEXP = false;
    public bool rBST = true;
    public bool rType = false;
    #endregion

    #region Random Species Filtering Parameters
    private GenericRandomizer RandSpec;
    private int loopctr;
    private const int l = 10; // tweakable scalars
    private const int h = 11;
    #endregion

    internal int GetRandomSpecies(int oldSpecies, int bannedSpecies)
    {
        // Get a new random species
        PersonalInfo oldpkm = SpeciesStat[oldSpecies];

        loopctr = 0; // altering calculations to prevent infinite loops
        int newSpecies;
        while (!GetNewSpecies(bannedSpecies, oldpkm, out newSpecies))
            loopctr++;
        return newSpecies;
    }

    public int GetRandomSpeciesType(int oldSpecies, int type)
    {
        // Get a new random species
        PersonalInfo oldpkm = SpeciesStat[oldSpecies];

        loopctr = 0; // altering calculations to prevent infinite loops
        int newSpecies;
        while (!GetNewSpecies(oldSpecies, oldpkm, out newSpecies) || !GetIsTypeMatch(newSpecies, type))
            loopctr++;
        return newSpecies;
    }

    private bool GetIsTypeMatch(int newSpecies, int type) => type == -1 || SpeciesStat[newSpecies].Types.Any(z => z == type) || loopctr > 9000;

    public int GetRandomSpecies(int oldSpecies)
    {
        // Get a new random species
        PersonalInfo oldpkm = SpeciesStat[oldSpecies];

        loopctr = 0; // altering calculations to prevent infinite loops
        int newSpecies;
        while (!GetNewSpecies(oldSpecies, oldpkm, out newSpecies))
        {
            if (loopctr > 0x0001_0000)
            {
                PersonalInfo pkm = SpeciesStat[newSpecies];
                if (IsSpeciesBSTBad(oldpkm, pkm) && loopctr > 0x0001_1000) // keep trying for at minimum BST
                    continue;
                return newSpecies; // failed to find any match based on criteria, return random species that may or may not match criteria
            }
            loopctr++;
        }
        return newSpecies;
    }

    private bool IsSpeciesReplacementBad(int newSpecies, int currentSpecies)
    {
        return newSpecies == currentSpecies && loopctr < MaxSpeciesID * 10;
    }

    private bool IsSpeciesEXPRateBad(PersonalInfo oldpkm, PersonalInfo pkm)
    {
        if (!rEXP)
            return false;
        // Experience Growth Rate matches
        return oldpkm.EXPGrowth != pkm.EXPGrowth;
    }

    private bool IsSpeciesTypeBad(PersonalInfo oldpkm, PersonalInfo pkm)
    {
        if (!rType)
            return false;
        // Type has to be somewhat similar
        return !oldpkm.Types.Any(z => pkm.Types.Contains(z));
    }

    private bool IsSpeciesBSTBad(PersonalInfo oldpkm, PersonalInfo pkm)
    {
        if (!rBST)
            return false;
        // Base stat total has to be close to original BST
        int expand = loopctr / MaxSpeciesID;
        int lo = oldpkm.BST * l / (h + expand);
        int hi = oldpkm.BST * (h + expand) / l;
        return lo > pkm.BST || pkm.BST > hi;
    }

    private int[] InitializeSpeciesList()
    {
        var list = new List<int>();
        if (G1) AddGen1Species(list);
        if (G2) AddGen2Species(list);
        if (G3) AddGen3Species(list);
        if (G4) AddGen4Species(list);
        if (G5) AddGen5Species(list);
        if (G6) AddGen6Species(list);
        if (G7) AddGen7Species(list);

        return list.Count == 0 ? RandomSpeciesList : [.. list];
    }

    private void AddGen1Species(List<int> list)
    {
        list.AddRange(Enumerable.Range(1, 143)); // Bulbasaur - Snorlax
        list.AddRange(Enumerable.Range(147, 3)); // Dratini - Dragonite

        if (L)
        {
            list.AddRange(Enumerable.Range(144, 3)); // Birds
            list.Add(150); // Mewtwo
        }
        if (E) list.Add(151); // Mew
    }

    private void AddGen2Species(List<int> list)
    {
        list.AddRange(Enumerable.Range(152, 91)); // Chikorita - Blissey
        list.AddRange(Enumerable.Range(246, 3)); // Larvitar - Tyranitar

        if (L)
        {
            list.AddRange(Enumerable.Range(243, 3)); // Raikou, Entei, Suicune
            list.AddRange(Enumerable.Range(249, 2)); // Lugia & Ho-Oh
        }
        if (E) list.Add(251); // Celebi
    }

    private void AddGen3Species(List<int> list)
    {
        list.AddRange(Enumerable.Range(252, 40)); // Treecko - Ninjask
        list.AddRange(Enumerable.Range(293, 84)); // Whismur - Metagross
        if (Shedinja) list.Add(292); // Shedinja
        if (L) list.AddRange(Enumerable.Range(377, 8)); // Regi, Lati, Mascot
        if (E) list.AddRange(Enumerable.Range(385, 2)); // Jirachi/Deoxys
    }

    private void AddGen4Species(List<int> list)
    {
        list.AddRange(Enumerable.Range(387, 93)); // Turtwig - Rotom
        if (L) list.AddRange(Enumerable.Range(480, 9)); // Sinnoh Legends
        if (E) list.AddRange(Enumerable.Range(489, 5)); // Phione, Manaphy, Darkrai, Shaymin, Arceus
    }

    private void AddGen5Species(List<int> list)
    {
        list.AddRange(Enumerable.Range(495, 143)); // Snivy - Volcarona
        if (L) list.AddRange(Enumerable.Range(638, 9)); // Unova Legends
        if (E) list.Add(494); list.AddRange(Enumerable.Range(647, 3)); // Victini, Keldeo, Meloetta, Genesect
    }

    private void AddGen6Species(List<int> list)
    {
        list.AddRange(Enumerable.Range(650, 66)); // Chespin - Noivern
        if (L) list.AddRange(Enumerable.Range(716, 3)); // Kalos Legends
        if (E) list.AddRange(Enumerable.Range(719, 3)); // Diancie, Hoopa, Volcanion
    }

    private void AddGen7Species(List<int> list)
    {
        list.AddRange(Enumerable.Range(722, 50)); // Rowlet - Pyukumuku
        list.AddRange(Enumerable.Range(774, 11)); // Minior - Kommo-o

        if (L)
        {
            list.AddRange(Enumerable.Range(772, 2)); // Type: Null, Silvally
            list.AddRange(Enumerable.Range(785, 16)); // Tapus, Legends, UBs
        }
        if (E) list.AddRange(Enumerable.Range(801, 2)); // Magearna, Marshadow

        if (MaxSpeciesID == 807) // USUM
        {
            if (L) list.AddRange(Enumerable.Range(803, 4)); // Poipole, Naganadel, Stakataka, Blacephalon
            if (E) list.Add(807); // Zeraora
        }
    }

    public int[] RandomSpeciesList => Enumerable.Range(1, MaxSpeciesID).ToArray();

    private bool GetNewSpecies(int currentSpecies, PersonalInfo oldpkm, out int newSpecies)
    {
        newSpecies = RandSpec.Next();
        PersonalInfo pkm = SpeciesStat[newSpecies];

        // Verify it meets specifications
        if (IsSpeciesReplacementBad(newSpecies, currentSpecies)) // no A->A randomization
            return false;
        if (IsSpeciesEXPRateBad(oldpkm, pkm))
            return false;
        if (IsSpeciesTypeBad(oldpkm, pkm))
            return false;
        if (IsSpeciesBSTBad(oldpkm, pkm))
            return false;
        return true;
    }
}