//   SparkleShare, a collaboration and sharing tool.
//   Copyright (C) 2010  Hylke Bons <hylkebons@gmail.com>
//
//   This program is free software: you can redistribute it and/or modify
//   it under the terms of the GNU Lesser General Public License as 
//   published by the Free Software Foundation, either version 3 of the 
//   License, or (at your option) any later version.
//
//   This program is distributed in the hope that it will be useful,
//   but WITHOUT ANY WARRANTY; without even the implied warranty of
//   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
//   GNU General Public License for more details.
//
//   You should have received a copy of the GNU General Public License
//   along with this program. If not, see <http://www.gnu.org/licenses/>.


using System;
using System.IO;
using System.Security.Cryptography;
using System.Text;

namespace SparkleLib {

    public static class Extensions {

        public static string Combine (this string [] parts)
        {
            string new_path = "";

            foreach (string part in parts)
                new_path = Path.Combine (new_path, part);

            return new_path;
        }

        
        public static string SHA1 (this string s)
        {
            SHA1 sha1          = new SHA1CryptoServiceProvider ();
            byte [] bytes      = ASCIIEncoding.Default.GetBytes (s);
            byte [] sha1_bytes = sha1.ComputeHash (bytes);

            return BitConverter.ToString (sha1_bytes).ToLower ().Replace ("-", "");
        }


        public static string MD5 (this string s)
        {
            MD5 md5           = new MD5CryptoServiceProvider ();
            byte [] bytes     = ASCIIEncoding.Default.GetBytes (s);
            byte [] md5_bytes = md5.ComputeHash (bytes);

            return BitConverter.ToString (md5_bytes).ToLower ().Replace ("-", "");
        }


        // Format a file size nicely with small caps.
        // Example: 1048576 becomes "1 ᴍʙ"
        public static string ToSize (this double byte_count)
        {
            if (byte_count >= 1099511627776)
                return String.Format ("{0:##.##} ᴛʙ", Math.Round (byte_count / 1099511627776, 2));
            else if (byte_count >= 1073741824)
                return String.Format ("{0:##.##} ɢʙ", Math.Round (byte_count / 1073741824, 1));
            else if (byte_count >= 1048576)
                return String.Format ("{0:##.##} ᴍʙ", Math.Round (byte_count / 1048576, 1));
            else if (byte_count >= 1024)
                return String.Format ("{0:##.##} ᴋʙ", Math.Round (byte_count / 1024, 0));
            else
                return byte_count.ToString () + " ʙ";
        }


        public static bool IsSymlink (this FileSystemInfo file)
        {
            return ((file.Attributes & FileAttributes.ReparsePoint) == FileAttributes.ReparsePoint);
        }


        public static string ToPrettyDate (this DateTime timestamp)
        {
            TimeSpan time_diff = DateTime.Now.Subtract(timestamp);
            int day_diff       = (int) time_diff.TotalDays;                
                
            if (day_diff == 0) {
                return "at " + timestamp.ToString ("HH:mm");

            } else if (day_diff == 1) {
                return "yesterday at " + timestamp.ToString ("HH:mm");
            
            } else if (day_diff < 7) {
                return timestamp.ToString ("dddd");                     
            
            } else if (day_diff < 31) {
                if (day_diff < 14)
                    return "last week";
                else
                    return string.Format ("{0} weeks ago", Math.Ceiling ((double) day_diff / 7));

            } else if (day_diff < 62) {
                return "last month";

            } else { 
                return string.Format ("{0} months ago", Math.Ceiling ((double) day_diff / 31));
            }
        }
    }
}