using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using Esiur.Data;
using Esiur.Misc;

namespace Esiur.Net
{
    public class NetworkBuffer
    {
        byte[] data;

        uint neededDataLength = 0;
        //bool trim;

        public NetworkBuffer()
        {
            data = new byte[0];
        }

        public bool Protected
        {
            get
            {
                return neededDataLength > data.Length;
            }
        }

        public uint Available
        {
            get
            {
                return (uint)data.Length;
            }
        }


        //public void HoldForAtLeast(byte[] src, uint offset, uint size, uint needed)
        //{
        //    HoldFor(src, offset, size, needed);
        //    //trim = false;
        //}

        //public void HoldForAtLeast(byte[] src, uint needed)
        //{
        //    HoldForAtLeast(src, 0, (uint)src.Length, needed);
        //}

        public void HoldForNextWrite(byte[] src)
        {
            //HoldForAtLeast(src, (uint)src.Length + 1);
            HoldFor(src, (uint)src.Length + 1);
        }

        public void HoldForNextWrite(byte[] src, uint offset, uint size)
        {
            //HoldForAtLeast(src, offset, size, size + 1);
            HoldFor(src, offset, size, size + 1);
        }


        public void HoldFor(byte[] src, uint offset, uint size, uint needed)
        {
            if (size >= needed)
                throw new Exception("Size >= Needed !");

            //trim = true;
            data = DC.Combine(src, offset, size, data, 0, (uint)data.Length);
            neededDataLength = needed;

            // Console.WriteLine("Hold StackTrace: '{0}'", Environment.StackTrace);

            Console.WriteLine("Holded {0} {1} {2} {3} - {4}", offset, size, needed, data.Length, GetHashCode());
        }

        public void HoldFor(byte[] src, uint needed)
        {
            HoldFor(src, 0, (uint)src.Length, needed);
        }

        public bool Protect(byte[] data, uint offset, uint needed)//, bool exact = false)
        {
            uint dataLength = (uint)data.Length - offset;

            // protection
            if (dataLength < needed)
            {
                //if (exact)
                //    HoldFor(data, offset, dataLength, needed);
                //else
                //HoldForAtLeast(data, offset, dataLength, needed);
                HoldFor(data, offset, dataLength, needed);
                return true;
            }
            else
                return false;
        }

        public void Write(byte[] src)
        {
            Write(src, 0, (uint)src.Length);
        }

        public void Write(byte[] src, uint offset, uint length)
        {
            DC.Append(ref data, src, offset, length);
        }

        public bool CanRead
        {
            get
            {
                if (data.Length == 0)
                    return false;
                if (data.Length < neededDataLength)
                    return false;

                return true;
            }
        }

        public byte[] Read()
        {
            if (data.Length == 0)
                return null;

            byte[] rt = null;

            if (neededDataLength == 0)
            {
                rt = data;
                data = new byte[0];
            }
            else
            {
                //Console.WriteLine("P STATE:" + data.Length + " " + neededDataLength);

                if (data.Length >= neededDataLength)
                {
                    //Console.WriteLine("data.Length >= neededDataLength " + data.Length + " >= " + neededDataLength + " " + trim);

                    //if (trim)
                    //{
                    //  rt = DC.Clip(data, 0, neededDataLength);
                    //  data = DC.Clip(data, neededDataLength, (uint)data.Length - neededDataLength);
                    //}
                    //else
                    //{
                    // return all data
                    rt = data;
                    data = new byte[0];
                    //}

                    neededDataLength = 0;
                    return rt;
                }
                else
                {
                    return null;
                }
            }

            return rt;
        }
    }
}