using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Globalization;
using System.IO;
using System.Linq;
using System.Net;
using System.Net.Sockets;
using System.Reflection;
using System.Text;
using System.Text.RegularExpressions;
using System.Threading;
using System.Threading.Tasks;
//using Windows.Networking;
//using Windows.Networking.Sockets;

namespace SharpCifs.Util.Sharpen
{


    public static class Extensions
    {
        private static readonly long EpochTicks;

        static Extensions()
        {
            DateTime time = new DateTime(1970, 1, 1, 0, 0, 0, DateTimeKind.Utc);
            EpochTicks = time.Ticks;
        }

        public static void Add<T>(this IList<T> list, int index, T item)
        {
            list.Insert(index, item);
        }

        public static void AddFirst<T>(this IList<T> list, T item)
        {
            list.Insert(0, item);
        }

        public static void AddLast<T>(this IList<T> list, T item)
        {
            list.Add(item);
        }

        public static void RemoveLast<T>(this IList<T> list)
        {
            if (list.Count > 0)
                list.Remove(list.Count - 1);
        }

        public static StringBuilder AppendRange(this StringBuilder sb, string str, int start, int end)
        {
            return sb.Append(str, start, end - start);
        }

        public static StringBuilder Delete(this StringBuilder sb, int start, int end)
        {
            return sb.Remove(start, end - start);
        }

        public static void SetCharAt(this StringBuilder sb, int index, char c)
        {
            sb[index] = c;
        }

        public static int IndexOf(this StringBuilder sb, string str)
        {
            return sb.ToString().IndexOf(str);
        }

        public static int BitCount(int val)
        {
            uint num = (uint)val;
            int count = 0;
            for (int i = 0; i < 32; i++)
            {
                if ((num & 1) != 0)
                {
                    count++;
                }
                num >>= 1;
            }
            return count;
        }

        public static IndexOutOfRangeException CreateIndexOutOfRangeException(int index)
        {
            return new IndexOutOfRangeException("Index: " + index);
        }

        public static string Decode(this Encoding e, byte[] chars, int start, int len)
        {
            try
            {
                byte[] bom = e.GetPreamble();
                if (bom != null && bom.Length > 0)
                {
                    if (len >= bom.Length)
                    {
                        int pos = start;
                        bool hasBom = true;
                        for (int n = 0; n < bom.Length && hasBom; n++)
                        {
                            if (bom[n] != chars[pos++])
                                hasBom = false;
                        }
                        if (hasBom)
                        {
                            len -= pos - start;
                            start = pos;
                        }
                    }
                }
                return e.GetString(chars, start, len);
            }
            catch (DecoderFallbackException)
            {
                throw new CharacterCodingException();
            }
        }



        public static Encoding GetEncoding(string name)
        {
            //			Encoding e = Encoding.GetEncoding (name, EncoderFallback.ExceptionFallback, DecoderFallback.ExceptionFallback);
            try
            {

                Encoding e = Encoding.GetEncoding(name.Replace('_', '-'));
                if (e is UTF8Encoding)
                    return new UTF8Encoding(false, true);

                return e;
            }
            catch (ArgumentException)
            {
                throw new UnsupportedCharsetException(name);
            }
        }

        public static ICollection<KeyValuePair<T, TU>> EntrySet<T, TU>(this IDictionary<T, TU> s)
        {
            return s;
        }


        public static bool AddItem<T>(this IList<T> list, T item)
        {
            list.Add(item);
            return true;
        }

        public static bool AddItem<T>(this ICollection<T> list, T item)
        {
            list.Add(item);
            return true;
        }

        public static TU Get<T, TU>(this IDictionary<T, TU> d, T key)
        {
            TU val;
            d.TryGetValue(key, out val);
            return val;
        }


        public static TU Put<T, TU>(this IDictionary<T, TU> d, T key, TU value)
        {
            TU old;
            d.TryGetValue(key, out old);
            d[key] = value;
            return old;
        }

        public static void PutAll<T, TU>(this IDictionary<T, TU> d, IDictionary<T, TU> values)
        {
            foreach (KeyValuePair<T, TU> val in values)
                d[val.Key] = val.Value;
        }


        public static CultureInfo GetEnglishCulture()
        {
            return new CultureInfo("en-US");
        }

        public static T GetFirst<T>(this IList<T> list)
        {
            return ((list.Count == 0) ? default(T) : list[0]);
        }

        public static CultureInfo GetGermanCulture()
        {
            CultureInfo r = new CultureInfo("de-DE");
            return r;
        }

        public static T GetLast<T>(this IList<T> list)
        {
            return ((list.Count == 0) ? default(T) : list[list.Count - 1]);
        }

        public static int GetOffset(this TimeZoneInfo tzone, long date)
        {
            return (int)tzone.GetUtcOffset(MillisToDateTimeOffset(date, 0).DateTime).TotalMilliseconds;
        }

        public static InputStream GetResourceAsStream(this Type type, string name)
        {
            //Type.`Assembly` property deleted
            //string str2 = type.Assembly.GetName().Name + ".resources";
            string str2 = type.GetTypeInfo().Assembly.GetName().Name + ".resources";
            string[] textArray1 = { str2, ".", type.Namespace, ".", name };
            string str = string.Concat(textArray1);
            
            //Type.`Assembly` property deleted
            //Stream manifestResourceStream = type.Assembly.GetManifestResourceStream(str);
            Stream manifestResourceStream = type.GetTypeInfo().Assembly.GetManifestResourceStream(str);
            if (manifestResourceStream == null)
            {
                return null;
            }
            return InputStream.Wrap(manifestResourceStream);
        }

        public static long GetTime(this DateTime dateTime)
        {
            return new DateTimeOffset(DateTime.SpecifyKind(dateTime, DateTimeKind.Utc), TimeSpan.Zero).ToMillisecondsSinceEpoch();
        }

        public static void InitCause(this Exception ex, Exception cause)
        {
            Console.WriteLine(cause);
        }

        public static bool IsEmpty<T>(this ICollection<T> col)
        {
            return (col.Count == 0);
        }

        public static bool IsEmpty<T>(this Stack<T> col)
        {
            return (col.Count == 0);
        }

        public static bool IsLower(this char c)
        {
            return char.IsLower(c);
        }

        public static bool IsUpper(this char c)
        {
            return char.IsUpper(c);
        }

        public static Iterator<T> Iterator<T>(this ICollection<T> col)
        {
            return new EnumeratorWrapper<T>(col, col.GetEnumerator());
        }

        public static Iterator<T> Iterator<T>(this IEnumerable<T> col)
        {
            return new EnumeratorWrapper<T>(col, col.GetEnumerator());
        } 

        public static T Last<T>(this ICollection<T> col)
        {
            IList<T> list = col as IList<T>;
            if (list != null)
            {
                return list[list.Count - 1];
            }
            return col.Last();
        }

        public static int LowestOneBit(int val)
        {
            return (1 << NumberOfTrailingZeros(val));
        }

        public static bool Matches(this string str, string regex)
        {
            Regex regex2 = new Regex(regex);
            return regex2.IsMatch(str);
        }

        public static DateTime CreateDate(long milliSecondsSinceEpoch)
        {
            long num = EpochTicks + (milliSecondsSinceEpoch * 10000);
            return new DateTime(num);
        }

        public static DateTime CreateDateFromUTC(long milliSecondsSinceEpoch)
        {
            long num = EpochTicks + (milliSecondsSinceEpoch * 10000);
            return new DateTime(num, DateTimeKind.Utc);
        }


        public static DateTimeOffset MillisToDateTimeOffset(long milliSecondsSinceEpoch, long offsetMinutes)
        {
            TimeSpan offset = TimeSpan.FromMinutes(offsetMinutes);
            long num = EpochTicks + (milliSecondsSinceEpoch * 10000);
            return new DateTimeOffset(num + offset.Ticks, offset);
        }

        public static int NumberOfLeadingZeros(int val)
        {
            uint num = (uint)val;
            int count = 0;
            while ((num & 0x80000000) == 0)
            {
                num = num << 1;
                count++;
            }
            return count;
        }

        public static int NumberOfTrailingZeros(int val)
        {
            uint num = (uint)val;
            int count = 0;
            while ((num & 1) == 0)
            {
                num = num >> 1;
                count++;
            }
            return count;
        }

        public static int Read(this StreamReader reader, char[] data)
        {
            return reader.Read(data, 0, data.Length);
        }

        public static T Remove<T>(this IList<T> list, T item)
        {
            int index = list.IndexOf(item);
            if (index == -1)
            {
                return default(T);
            }
            T local = list[index];
            list.RemoveAt(index);
            return local;
        }

        public static T Remove<T>(this IList<T> list, int i)
        {
            T old;
            try
            {
                old = list[i];
                list.RemoveAt(i);
            }
            catch (IndexOutOfRangeException)
            {
                throw new NoSuchElementException();
            }
            return old;
        }

        public static T RemoveFirst<T>(this IList<T> list)
        {
            return list.Remove(0);
        }

        public static string ReplaceAll(this string str, string regex, string replacement)
        {
            Regex rgx = new Regex(regex);

            if (replacement.IndexOfAny(new[] { '\\', '$' }) != -1)
            {
                // Back references not yet supported
                StringBuilder sb = new StringBuilder();
                for (int n = 0; n < replacement.Length; n++)
                {
                    char c = replacement[n];
                    if (c == '$')
                        throw new NotSupportedException("Back references not supported");
                    if (c == '\\')
                        c = replacement[++n];
                    sb.Append(c);
                }
                replacement = sb.ToString();
            }

            return rgx.Replace(str, replacement);
        }

        public static bool RegionMatches(this string str, bool ignoreCase, int toOffset, string other, int ooffset, int len)
        {
            if (toOffset < 0 || ooffset < 0 || toOffset + len > str.Length || ooffset + len > other.Length)
                return false;
            return string.Compare(str, toOffset, other, ooffset, len) == 0;
        }

        public static T Set<T>(this IList<T> list, int index, T item)
        {
            T old = list[index];
            list[index] = item;
            return old;
        }

        public static int Signum(long val)
        {
            if (val < 0)
            {
                return -1;
            }
            if (val > 0)
            {
                return 1;
            }
            return 0;
        }

        public static void RemoveAll<T, TU>(this ICollection<T> col, ICollection<TU> items) where TU : T
        {
            foreach (var u in items)
                col.Remove(u);
        }

        public static bool ContainsAll<T, TU>(this ICollection<T> col, ICollection<TU> items) where TU : T
        {
            foreach (var u in items)
                if (!col.Any(n => (ReferenceEquals(n, u)) || n.Equals(u)))
                    return false;
            return true;
        }

        public static bool Contains<T>(this ICollection<T> col, object item)
        {
            if (!(item is T))
                return false;
            return col.Any(n => (ReferenceEquals(n, item)) || n.Equals(item));
        }

        public static void Sort<T>(this IList<T> list)
        {
            List<T> sorted = new List<T>(list);
            sorted.Sort();
            for (int i = 0; i < list.Count; i++)
            {
                list[i] = sorted[i];
            }
        }

        public static void Sort<T>(this IList<T> list, IComparer<T> comparer)
        {
            List<T> sorted = new List<T>(list);
            sorted.Sort(comparer);
            for (int i = 0; i < list.Count; i++)
            {
                list[i] = sorted[i];
            }
        }

        public static string[] Split(this string str, string regex)
        {
            return str.Split(regex, 0);
        }

        public static string[] Split(this string str, string regex, int limit)
        {
            Regex rgx = new Regex(regex);
            List<string> list = new List<string>();
            int startIndex = 0;
            if (limit != 1)
            {
                int nm = 1;
                foreach (Match match in rgx.Matches(str))
                {
                    list.Add(str.Substring(startIndex, match.Index - startIndex));
                    startIndex = match.Index + match.Length;
                    if (limit > 0 && ++nm == limit)
                        break;
                }
            }
            if (startIndex < str.Length)
            {
                list.Add(str.Substring(startIndex));
            }
            if (limit >= 0)
            {
                int count = list.Count - 1;
                while ((count >= 0) && (list[count].Length == 0))
                {
                    count--;
                }
                list.RemoveRange(count + 1, (list.Count - count) - 1);
            }
            return list.ToArray();
        }

        public static IList<T> SubList<T>(this IList<T> list, int start, int len)
        {
            List<T> sublist = new List<T>(len);
            for (int i = start; i < (start + len); i++)
            {
                sublist.Add(list[i]);
            }
            return sublist;
        }

        public static char[] ToCharArray(this string str)
        {
            char[] destination = new char[str.Length];
            str.CopyTo(0, destination, 0, str.Length);
            return destination;
        }

        public static long ToMillisecondsSinceEpoch(this DateTime dateTime)
        {
            if (dateTime.Kind != DateTimeKind.Utc)
            {
                throw new ArgumentException("dateTime is expected to be expressed as a UTC DateTime", "dateTime");
            }
            return new DateTimeOffset(DateTime.SpecifyKind(dateTime, DateTimeKind.Utc), TimeSpan.Zero).ToMillisecondsSinceEpoch();
        }

        public static long ToMillisecondsSinceEpoch(this DateTimeOffset dateTimeOffset)
        {
            return (((dateTimeOffset.Ticks - dateTimeOffset.Offset.Ticks) - EpochTicks) / TimeSpan.TicksPerMillisecond);
        }

        public static string ToOctalString(int val)
        {
            return Convert.ToString(val, 8);
        }

        public static string ToHexString(int val)
        {
            return Convert.ToString(val, 16);
        }

        public static string ToString(object val)
        {
            return val.ToString();
        }

        public static string ToString(int val, int bas)
        {
            return Convert.ToString(val, bas);
        }

        public static IList<TU> UpcastTo<T, TU>(this IList<T> s) where T : TU
        {
            List<TU> list = new List<TU>(s.Count);
            for (int i = 0; i < s.Count; i++)
            {
                list.Add(s[i]);
            }
            return list;
        }

        public static ICollection<TU> UpcastTo<T, TU>(this ICollection<T> s) where T : TU
        {
            List<TU> list = new List<TU>(s.Count);
            foreach (var v in s)
            {
                list.Add(v);
            }
            return list;
        }

        public static T ValueOf<T>(T val)
        {
            return val;
        }


        //use? for NUnit-testing?
        //public static string GetTestName(object obj)
        //{
        //    return GetTestName();
        //}

        //public static string GetTestName()
        //{
        //    MethodBase met;
        //    int n = 0;
        //    do
        //    {
        //        met = new StackFrame(n).GetMethod();
        //        if (met != null)
        //        {
        //            foreach (Attribute at in met.GetCustomAttributes(true))
        //            {
        //                if (at.GetType().FullName == "NUnit.Framework.TestAttribute")
        //                {
        //                    // Convert back to camel case
        //                    string name = met.Name;
        //                    if (char.IsUpper(name[0]))
        //                        name = char.ToLower(name[0]) + name.Substring(1);
        //                    return name;
        //                }
        //            }
        //        }
        //        n++;
        //    } while (met != null);
        //    return "";
        //}

        public static string GetHostAddress(this IPAddress addr)
        {
            return addr.ToString();
        }


        public static IPAddress GetAddressByName(string host)
        {
            if (host == "0.0.0.0")
            {
                return IPAddress.Any;
            }                
            
            try
            {
                return IPAddress.Parse(host);
            }
            catch (Exception ex)
            {
                return null;
            }            
        }

        public static IPAddress[] GetAddressesByName(string host)
        {
            //IReadOnlyList<EndpointPair> data = null;

            //try
            //{
            //    Task.Run(async () =>
            //    {
            //        data = await DatagramSocket.GetEndpointPairsAsync(new HostName(host), "0");
            //    }).Wait();
            //}
            //catch (Exception ex)
            //{
            //    return null;
            //}

            //return data != null
            //    ? data.Where(i => i.RemoteHostName.Type == HostNameType.Ipv4)
            //          .GroupBy(i => i.RemoteHostName.DisplayName)
            //          .Select(i => IPAddress.Parse(i.First().RemoteHostName.DisplayName))
            //          .ToArray() 
            //    : null;

            //get v4-address only
            var entry = Task.Run(() => System.Net.Dns.GetHostEntryAsync(host))
                            .GetAwaiter()
                            .GetResult();
            return entry.AddressList
                        .Where(addr => addr.AddressFamily == AddressFamily.InterNetwork)
                        .ToArray();

        }

        public static string GetImplementationVersion(this Assembly asm)
        {
            return asm.GetName().Version.ToString();
        }

        public static string GetHost(this Uri uri)
        {
            return string.IsNullOrEmpty(uri.Host) ? "" : uri.Host;
        }

        public static string GetUserInfo(this Uri uri)
        {
            return string.IsNullOrEmpty(uri.UserInfo) ? null : uri.UserInfo;
        }

        public static string GetQuery(this Uri uri)
        {
            return string.IsNullOrEmpty(uri.Query) ? null : uri.Query;
        }

        public static int GetLocalPort(this Socket socket)
        {
            return ((IPEndPoint)socket.LocalEndPoint).Port;
        }

        public static int GetPort(this Socket socket)
        {
            return ((IPEndPoint)socket.RemoteEndPoint).Port;
        }

        public static IPAddress GetInetAddress(this Socket socket)
        {
            return ((IPEndPoint)socket.RemoteEndPoint).Address;
        }


        /*public static bool RemoveElement(this ArrayList list, object elem)
        {
            int i = list.IndexOf(elem);
            if (i == -1)
                return false;
            list.RemoveAt(i);
            return true;
        }*/

        public static Semaphore CreateSemaphore(int count)
        {
            return new Semaphore(count, int.MaxValue);
        }

    }
}