using System.Collections.Generic;

namespace PKHeX.Core;

public interface IGigantamaxReadOnly
{
    /// <summary>
    /// Indicates if the Pokémon is capable of Gigantamax as opposed to regular Dynamax.
    /// </summary>
    bool CanGigantamax { get; }
}

public static class GigantamaxExtensions
{
    /// <summary>
    /// Checks if either of the input Species can consume the Gigantamax soup, toggling the <see cref="IGigantamax.CanGigantamax"/> flag.
    /// </summary>
    /// <param name="_">Unnecessary, just needed for extension method usage.</param>
    /// <param name="currentSpecies">The current species</param>
    /// <param name="currentForm">The current form of the species</param>
    /// <param name="originSpecies">The original species (what species it was encountered as)</param>
    /// <param name="originForm">The original form of the original species</param>
    /// <returns>True if either species can toggle Gigantamax potential</returns>
    public static bool CanToggleGigantamax(this IGigantamaxReadOnly _, ushort currentSpecies, byte currentForm, ushort originSpecies, byte originForm)
    {
        if (currentSpecies is (int)Species.Meowth or (int)Species.Pikachu)
            return currentForm == 0;

        var soup = CanEatMaxSoup;
        return soup.Contains(currentSpecies) || (currentSpecies != originSpecies && soup.Contains(originSpecies));
    }

    /// <summary>
    /// Don't use this method. Use the other overload with multi-species input.
    /// </summary>
    /// <param name="_">Unnecessary, just needed for extension method usage.</param>
    /// <param name="currentSpecies">The current species</param>
    /// <param name="currentForm">The current form of the species</param>
    /// <returns>True if the species can toggle Gigantamax potential</returns>
    public static bool CanToggleGigantamax(this IGigantamaxReadOnly _, ushort currentSpecies, byte currentForm)
    {
        if (currentSpecies is (int)Species.Meowth or (int)Species.Pikachu)
            return currentForm == 0;
        var soup = CanEatMaxSoup;
        return soup.Contains(currentSpecies);
    }

    private static readonly HashSet<ushort> CanEatMaxSoup = new()
    {
        (int)Species.Venusaur,
        (int)Species.Charizard,
        (int)Species.Blastoise,
        (int)Species.Butterfree,
        (int)Species.Pikachu,
        (int)Species.Meowth,
        (int)Species.Machamp,
        (int)Species.Gengar,
        (int)Species.Lapras,
        (int)Species.Eevee,
        (int)Species.Snorlax,
        (int)Species.Garbodor,
        (int)Species.Rillaboom,
        (int)Species.Cinderace,
        (int)Species.Inteleon,
        (int)Species.Drednaw,
        (int)Species.Corviknight,
        (int)Species.Toxtricity,
        (int)Species.Alcremie,
        (int)Species.Duraludon,
        (int)Species.Orbeetle,
        (int)Species.Coalossal,
        (int)Species.Sandaconda,
        (int)Species.Grimmsnarl,
        (int)Species.Flapple,
        (int)Species.Appletun,
        (int)Species.Hatterene,
        (int)Species.Copperajah,
        (int)Species.Kingler,
        (int)Species.Centiskorch,
        (int)Species.Urshifu,
    };
}