using System;
using System.Security.Cryptography;
using System.Collections.Generic;
using System.Text;
using libsecondlife;
using libsecondlife.Packets;

namespace OpenSim.Framework.Utilities
{
    public class Util
    {
        private static Random randomClass = new Random();
        private static uint nextXferID = 5000;
        private static object XferLock = new object();

        public static ulong UIntsToLong(uint X, uint Y)
        {
            return Helpers.UIntsToLong(X, Y);
        }

        public static Random RandomClass
        {
            get
            {
                return randomClass;
            }
        }

        public static uint GetNextXferID()
        {
            uint id = 0;
            lock(XferLock)
            {
                id = nextXferID;
                nextXferID++;
            }
            return id;
        }

        public static int UnixTimeSinceEpoch()
        {
            TimeSpan t = (DateTime.UtcNow - new DateTime(1970, 1, 1));
            int timestamp = (int)t.TotalSeconds;
            return timestamp;
        }

        public static string Md5Hash(string pass)
        {
            MD5 md5 = MD5CryptoServiceProvider.Create();
            byte[] dataMd5 = md5.ComputeHash(Encoding.Default.GetBytes(pass));
            StringBuilder sb = new StringBuilder();
            for (int i = 0; i < dataMd5.Length; i++)
                sb.AppendFormat("{0:x2}", dataMd5[i]);
            return sb.ToString();
        }

        //public static int fast_distance2d(int x, int y)
        //{
        //    x = System.Math.Abs(x);
        //    y = System.Math.Abs(y);

        //    int min = System.Math.Min(x, y);

        //    return (x + y - (min >> 1) - (min >> 2) + (min >> 4));
        //}

        public static string FieldToString(byte[] bytes)
        {
            return FieldToString(bytes, String.Empty);
        }

        /// <summary>
        /// Convert a variable length field (byte array) to a string, with a
        /// field name prepended to each line of the output
        /// </summary>
        /// <remarks>If the byte array has unprintable characters in it, a 
        /// hex dump will be put in the string instead</remarks>
        /// <param name="bytes">The byte array to convert to a string</param>
        /// <param name="fieldName">A field name to prepend to each line of output</param>
        /// <returns>An ASCII string or a string containing a hex dump, minus 
        /// the null terminator</returns>
        public static string FieldToString(byte[] bytes, string fieldName)
        {
            // Check for a common case
            if (bytes.Length == 0) return String.Empty;

            StringBuilder output = new StringBuilder();
            bool printable = true;

            for (int i = 0; i < bytes.Length; ++i)
            {
                // Check if there are any unprintable characters in the array
                if ((bytes[i] < 0x20 || bytes[i] > 0x7E) && bytes[i] != 0x09
                    && bytes[i] != 0x0D && bytes[i] != 0x0A && bytes[i] != 0x00)
                {
                    printable = false;
                    break;
                }
            }

            if (printable)
            {
                if (fieldName.Length > 0)
                {
                    output.Append(fieldName);
                    output.Append(": ");
                }

                if (bytes[bytes.Length - 1] == 0x00)
                    output.Append(UTF8Encoding.UTF8.GetString(bytes, 0, bytes.Length - 1));
                else
                    output.Append(UTF8Encoding.UTF8.GetString(bytes));
            }
            else
            {
                for (int i = 0; i < bytes.Length; i += 16)
                {
                    if (i != 0)
                        output.Append(Environment.NewLine);
                    if (fieldName.Length > 0)
                    {
                        output.Append(fieldName);
                        output.Append(": ");
                    }

                    for (int j = 0; j < 16; j++)
                    {
                        if ((i + j) < bytes.Length)
                            output.Append(String.Format("{0:X2} ", bytes[i + j]));
                        else
                            output.Append("   ");
                    }

                    for (int j = 0; j < 16 && (i + j) < bytes.Length; j++)
                    {
                        if (bytes[i + j] >= 0x20 && bytes[i + j] < 0x7E)
                            output.Append((char)bytes[i + j]);
                        else
                            output.Append(".");
                    }
                }
            }

            return output.ToString();
        }
        public Util()
        {

        }
    }
}