PKHeX/PKHeX.Core/PKM/Shared/PokeSize.cs

namespace PKHeX.Core
{
    public enum PokeSize
    {
        XS,
        S,
        AV,
        L,
        XL,
    }

    public static class PokeSizeUtil
    {
        /// <summary>
        /// Compares the sizing scalar to different thresholds to determine the size rating.
        /// </summary>
        /// <param name="scalar">Sizing scalar (0-255)</param>
        /// <returns>0-4 rating</returns>
        public static PokeSize GetSizeRating(int scalar)
        {
            if (scalar < 0x10)
                return PokeSize.XS; // 1/16 = XS
            if (scalar < 0x30u)
                return PokeSize.S; // 2/16 = S
            if (scalar < 0xD0u)
                return PokeSize.AV; // average (10/16)
            if (scalar < 0xF0u)
                return PokeSize.L; // 2/16 = L
            return PokeSize.XL; // 1/16 = XL
        }

        public static int GetRandomScalar(this PokeSize size)
        {
            return size switch
            {
                PokeSize.XS =>  (Util.Rand.Next(0x10) + 0x00),
                PokeSize.S =>   (Util.Rand.Next(0x20) + 0x10),
                PokeSize.AV =>  (Util.Rand.Next(0xA0) + 0x30),
                PokeSize.L =>   (Util.Rand.Next(0x20) + 0xD0),
                PokeSize.XL =>  (Util.Rand.Next(0x10) + 0xF0),
                _ => GetRandomScalar()
            };
        }

        /// <summary>
        /// Gets a random size scalar with a triangular distribution (copying official implementation).
        /// </summary>
        public static int GetRandomScalar()
        {
            var rnd = Util.Rand;
            return rnd.Next(0x81) + rnd.Next(0x80);
        }
    }
}