using System;
using System.Collections.Generic;
using System.Text;
using System.Linq;
using System.IO;
using System.Security.Cryptography;

namespace Saviour_Backup_System
{
    class tools
    {
        public static string Trim(string value, int maxLength)
        {
            if (value.Length > maxLength)
            {
                return value.Substring(0, maxLength - 3) + "...";
            }
            return value;
        }

        public static string hash(string input)
        {
            // step 1, calculate MD5 hash from input
            MD5 md5 = MD5.Create();
            byte[] inputBytes = System.Text.Encoding.ASCII.GetBytes(input);
            byte[] hash = md5.ComputeHash(inputBytes);

            // step 2, convert byte array to hex string
            StringBuilder sb = new StringBuilder();
            for (int i = 0; i < hash.Length; i++)
            {
                sb.Append(hash[i].ToString("X2"));
            }
            return sb.ToString();
        }
        public static Int64 getUnixTimeStamp() { return (Int64)(DateTime.UtcNow.Subtract(new DateTime(1970, 1, 1))).TotalSeconds; }

        public static string hashDirectory(string path)
        {
            // assuming you want to include nested folders
            var files = Directory.GetFiles(path, "*.*", SearchOption.AllDirectories)
                                 .OrderBy(p => p).ToList();

            MD5 md5 = MD5.Create();

            for (int i = 0; i < files.Count; i++)
            {
                string file = files[i];

                // hash path
                string relativePath = file.Substring(path.Length + 1);
                byte[] pathBytes = Encoding.UTF8.GetBytes(relativePath.ToLower());
                md5.TransformBlock(pathBytes, 0, pathBytes.Length, pathBytes, 0);

                // hash contents
                byte[] contentBytes = File.ReadAllBytes(file);
                if (i == files.Count - 1)
                    md5.TransformFinalBlock(contentBytes, 0, contentBytes.Length);
                else
                    md5.TransformBlock(contentBytes, 0, contentBytes.Length, contentBytes, 0);
            }

            return BitConverter.ToString(md5.Hash).Replace("-", "").ToLower();
        }

        public static DateTime unixDateTime(long unixTimeStamp)
        {
            // Unix timestamp is seconds past epoch
            System.DateTime dtDateTime = new DateTime(1970, 1, 1, 0, 0, 0, 0, System.DateTimeKind.Utc);
            dtDateTime = dtDateTime.AddSeconds(unixTimeStamp).ToLocalTime();
            return dtDateTime;
        }
    }
}