using System;
using System.Collections.Generic;
using System.Linq;
using zero.Core.Entities;

namespace zero.Core.Extensions
{
  public static class NumberExtensions
  {
    static Dictionary<FileSizeNotation, string[]> FileSizeUnits = new()
    {
      { FileSizeNotation.SI, new string[] { "B", "kB", "MB", "GB", "TB", "PB", "EB", "ZB", "YB" } },
      { FileSizeNotation.IEC, new string[] { "B", "KiB", "MiB", "GiB", "TiB", "PiB", "EiB", "ZiB", "YiB" } },
      { FileSizeNotation.JEDEC, new string[] { "B", "KB", "MB", "GB" } }
    };

    public static int Limit(this int input, int min, int max)
    {
      if (input < min)
      {
        return min;
      }
      if (input > max)
      {
        return max;
      }
      return input;
    }


    public static string GetFileSize(this long sizeInBytes, FileSizeNotation notation = FileSizeNotation.JEDEC)
    {
      if (!FileSizeUnits.ContainsKey(notation))
      {
        throw new NotImplementedException($"The notation {notation} has no implementation for generating human-readable file sizes");
      }

      int power = notation == FileSizeNotation.SI ? 1000 : 1024;

      string[] units = FileSizeUnits[notation];

      int order = 0;

      while (sizeInBytes >= power && order + 1 < units.Length)
      {
        order++;
        sizeInBytes = sizeInBytes / power;
      }

      return String.Format("{0:0.##} {1}", sizeInBytes, units[order]);
    }
  }
}