﻿#region Copyright
// 
// DotNetNuke® - http://www.dotnetnuke.com
// Copyright (c) 2002-2018
// by DotNetNuke Corporation
// 
// Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated 
// documentation files (the "Software"), to deal in the Software without restriction, including without limitation 
// the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and 
// to permit persons to whom the Software is furnished to do so, subject to the following conditions:
// 
// The above copyright notice and this permission notice shall be included in all copies or substantial portions 
// of the Software.
// 
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED 
// TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL 
// THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF 
// CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER 
// DEALINGS IN THE SOFTWARE.
#endregion

using System;

namespace DotNetNuke.Services.FileSystem
{
    public class FileSizeFormatProvider : IFormatProvider, ICustomFormatter
    {
        private const string FileSizeFormat = "fs";
        private const decimal OneKiloByte = 1024;
        private const decimal OneMegaByte = OneKiloByte * 1024;
        private const decimal OneGigaByte = OneMegaByte * 1024;

        public object GetFormat(Type formatType)
        {
            return formatType == typeof(ICustomFormatter) ? this : null;
        }

        public string Format(string format, object arg, IFormatProvider formatProvider)
        {
            if (format == null || !format.StartsWith(FileSizeFormat))
            {
                return DefaultFormat(format, arg, formatProvider);
            }

            if (arg is string)
            {
                return DefaultFormat(format, arg, formatProvider);
            }

            decimal size;

            try
            {
                size = Convert.ToDecimal(arg);
            }
            catch (InvalidCastException)
            {
                return DefaultFormat(format, arg, formatProvider);
            }

            string suffix;
            if (size >= OneGigaByte)
            {
                size /= OneGigaByte;
                suffix = Localization.Localization.GetString("SizeGb");
            }
            else if (size >= OneMegaByte)
            {
                size /= OneMegaByte;
                suffix = Localization.Localization.GetString("SizeMb");
            }
            else if (size >= OneKiloByte)
            {
                size /= OneKiloByte;
                suffix = Localization.Localization.GetString("SizeKb");
            }
            else
            {
                suffix = Localization.Localization.GetString("SizeB");
            }

            return string.Format("{0:N1} {1}", size, suffix);
        }

        private static string DefaultFormat(string format, object arg, IFormatProvider formatProvider)
        {
            var formattableArg = arg as IFormattable;
            if (formattableArg != null)
            {
                return formattableArg.ToString(format, formatProvider);
            }

            return arg.ToString();
        }
    }
}
