geekbot/Geekbot.net/Lib/Levels/LevelCalc.cs

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

namespace Geekbot.net.Lib.Levels
{
    public class LevelCalc : ILevelCalc
    {
        private readonly int[] _levels;

        public LevelCalc()
        {
            var levels = new List<int>();
            double total = 0;
            for (var i = 1; i < 120; i++)
            {
                total += Math.Floor(i + 300 * Math.Pow(2, i / 7.0));
                levels.Add((int) Math.Floor(total / 16));
            }
            _levels = levels.ToArray();
        }

        public int GetLevel(int? messages)
        {
            return 1 + _levels.TakeWhile(level => !(level > messages)).Count();
        }
    }
}