using System;
using System.Collections.Generic;
using log4net;

namespace TBF.BenchControl.Network.Camera
{
    /// <summary>
    /// Implements RFC2435
    /// </summary>
    public class JpegFrame : RtpFrame
    {
		static readonly ILog log = LogManager.GetLogger(typeof(TBF.UI.MainWnd));
 
        #region Statics
 
        static byte[] CreateStartOfInformation()
        {
            return new byte[] { 0xff, 0xd8 };
        }
 
        static byte[] CreateJFIFHeader(uint type, uint width, uint height, ArraySegment<byte> tables, uint dri)
        {
            List<byte> result = new List<byte>();
            result.AddRange(CreateStartOfInformation());
 
            result.Add(0xff);
            result.Add(0xe0);//AppFirst
            result.Add(0x00);
            result.Add(0x10);//length
            result.Add((byte)'J');
            result.Add((byte)'F');
            result.Add((byte)'I');
            result.Add((byte)'F');
            result.Add(0x00);
 
            result.Add(0x01);//Version Major
            result.Add(0x01);//Version Minor
 
            result.Add(0x00);//Units
 
            result.Add(0x00);//Horizontal
            result.Add(0x01);
 
            result.Add(0x00);//Vertical
            result.Add(0x01);
 
            result.Add(0x00);//No thumb
            result.Add(0x00);
 
            if (dri > 0)
            {
                result.AddRange(CreateDataRestartIntervalMarker(dri));
            }
 
            result.AddRange(CreateQuantizationTablesMarker(tables));
 
            result.Add(0xff);
            result.Add(0xc0);//SOF
            result.Add(0x00);
            result.Add(0x11);
            result.Add(0x08);
            result.Add((byte)(height >> 8));
            result.Add((byte)height);
            result.Add((byte)(width >> 8));
            result.Add((byte)width);
            
            result.Add(0x03);
            result.Add(0x01);
            result.Add((byte)(type > 0 ? 0x22 : 0x21));
            result.Add(0x00);
 
            result.Add(0x02);
            result.Add(0x11);
            result.Add(0x01);
 
            result.Add(0x03);
            result.Add(0x11);
            result.Add(0x01);
 
            //Huffman Tables
            result.AddRange(CreateHuffmanTableMarker(lum_dc_codelens, lum_dc_symbols, 0, 0));
            result.AddRange(CreateHuffmanTableMarker(lum_ac_codelens, lum_ac_symbols, 0, 1));
            result.AddRange(CreateHuffmanTableMarker(chm_dc_codelens, chm_dc_symbols, 1, 0));
            result.AddRange(CreateHuffmanTableMarker(chm_ac_codelens, chm_ac_symbols, 1, 1));
            
            result.Add(0xff);
            result.Add(0xda);//Marker SOS
            result.Add(0x00);
            result.Add(0x0c);
            result.Add(0x03);
            result.Add(0x01);
            result.Add(0x00);
            result.Add(0x02);
            result.Add(0x11);
            result.Add(0x03);
            result.Add(0x11);
            result.Add(0x00);
            result.Add(0x3f);
            result.Add(0x00);
 
            return result.ToArray();
        }
 
        // The default 'luma' and 'chroma' quantizer tables, in zigzag order:
        static byte[] defaultQuantizers = new byte[]
        {
           // luma table:
           16, 11, 12, 14, 12, 10, 16, 14,
           13, 14, 18, 17, 16, 19, 24, 40,
           26, 24, 22, 22, 24, 49, 35, 37,
           29, 40, 58, 51, 61, 60, 57, 51,
           56, 55, 64, 72, 92, 78, 64, 68,
           87, 69, 55, 56, 80, 109, 81, 87,
           95, 98, 103, 104, 103, 62, 77, 113,
           121, 112, 100, 120, 92, 101, 103, 99,
           // chroma table:
           17, 18, 18, 24, 21, 24, 47, 26,
           26, 47, 99, 66, 56, 66, 99, 99,
           99, 99, 99, 99, 99, 99, 99, 99,
           99, 99, 99, 99, 99, 99, 99, 99,
           99, 99, 99, 99, 99, 99, 99, 99,
           99, 99, 99, 99, 99, 99, 99, 99,
           99, 99, 99, 99, 99, 99, 99, 99,
           99, 99, 99, 99, 99, 99, 99, 99
        };     
 
        /// <summary>
        /// Creates a Luma and Chroma Table using the default quantizer
        /// </summary>
        /// <param name="Q">The quality</param>
        /// <returns>64 luma bytes and 64 chroma</returns>
        static byte[] CreateQuantizationTables(uint Q)
        {
            int factor = (int)Q;
            int q;
 
            if (Q < 1) factor = 1;
            else if (Q > 99) factor = 99;
 
            if (Q < 50)
            {
                q = 5000 / factor;
            }
            else
            {
                q = 200 - factor * 2;
            }
            byte[] resultTables = new byte[128];
            for (int i = 0; i < 128; ++i)
            {
                int newVal = (defaultQuantizers[i] * q + 50) / 100;
                if (newVal < 1) newVal = 1;
                else if (newVal > 255) newVal = 255;
                resultTables[i] = (byte)newVal;
            }
            return resultTables;
        }
 
        static byte[] CreateQuantizationTablesMarker(ArraySegment<byte> tables)
        {
            List<byte> result = new List<byte>();
 
            int tableSize = tables.Count / 2;
 
            //Luma
 
            result.Add(0xff);
            result.Add(0xdb);
 
            result.Add(0x00);
            result.Add((byte)(tableSize + 3));
            result.Add(0x00);
 
            for (int i = 0, e = tableSize; i < e; ++i)
            {
                result.Add(tables.Array[tables.Offset + i]);
            }
 
            //Chroma
 
            result.Add(0xff);
            result.Add(0xdb);
 
            result.Add(0x00);
            result.Add((byte)(tableSize + 3));
            result.Add(0x01);
 
            for (int i = tableSize, e = tables.Count; i < e; ++i)
            {
                result.Add(tables.Array[tables.Offset + i]);
            }
 
            return result.ToArray();
 
        }
 
        static byte[] lum_dc_codelens = { 0, 1, 5, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0 };
 
        static byte[] lum_dc_symbols = { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 };
 
        static byte[] lum_ac_codelens = { 0, 2, 1, 3, 3, 2, 4, 3, 5, 5, 4, 4, 0, 0, 1, 0x7d, };
 
        static byte[] lum_ac_symbols = {
			0x01, 0x02, 0x03, 0x00, 0x04, 0x11, 0x05, 0x12,
			0x21, 0x31, 0x41, 0x06, 0x13, 0x51, 0x61, 0x07,
			0x22, 0x71, 0x14, 0x32, 0x81, 0x91, 0xa1, 0x08,
			0x23, 0x42, 0xb1, 0xc1, 0x15, 0x52, 0xd1, 0xf0,
			0x24, 0x33, 0x62, 0x72, 0x82, 0x09, 0x0a, 0x16,
			0x17, 0x18, 0x19, 0x1a, 0x25, 0x26, 0x27, 0x28,
			0x29, 0x2a, 0x34, 0x35, 0x36, 0x37, 0x38, 0x39,
			0x3a, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48, 0x49,
			0x4a, 0x53, 0x54, 0x55, 0x56, 0x57, 0x58, 0x59,
			0x5a, 0x63, 0x64, 0x65, 0x66, 0x67, 0x68, 0x69,
			0x6a, 0x73, 0x74, 0x75, 0x76, 0x77, 0x78, 0x79,
			0x7a, 0x83, 0x84, 0x85, 0x86, 0x87, 0x88, 0x89,
			0x8a, 0x92, 0x93, 0x94, 0x95, 0x96, 0x97, 0x98,
			0x99, 0x9a, 0xa2, 0xa3, 0xa4, 0xa5, 0xa6, 0xa7,
			0xa8, 0xa9, 0xaa, 0xb2, 0xb3, 0xb4, 0xb5, 0xb6,
			0xb7, 0xb8, 0xb9, 0xba, 0xc2, 0xc3, 0xc4, 0xc5,
			0xc6, 0xc7, 0xc8, 0xc9, 0xca, 0xd2, 0xd3, 0xd4,
			0xd5, 0xd6, 0xd7, 0xd8, 0xd9, 0xda, 0xe1, 0xe2,
			0xe3, 0xe4, 0xe5, 0xe6, 0xe7, 0xe8, 0xe9, 0xea,
			0xf1, 0xf2, 0xf3, 0xf4, 0xf5, 0xf6, 0xf7, 0xf8,
			0xf9, 0xfa,
        };
 
        static byte[] chm_dc_codelens = { 0, 3, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0 };
 
        static byte[] chm_dc_symbols = { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 };
 
        static byte[] chm_ac_codelens = { 0, 2, 1, 2, 4, 4, 3, 4, 7, 5, 4, 4, 0, 1, 2, 0x77 };
 
        static byte[] chm_ac_symbols = {
			0x00, 0x01, 0x02, 0x03, 0x11, 0x04, 0x05, 0x21,
			0x31, 0x06, 0x12, 0x41, 0x51, 0x07, 0x61, 0x71,
			0x13, 0x22, 0x32, 0x81, 0x08, 0x14, 0x42, 0x91,
			0xa1, 0xb1, 0xc1, 0x09, 0x23, 0x33, 0x52, 0xf0,
			0x15, 0x62, 0x72, 0xd1, 0x0a, 0x16, 0x24, 0x34,
			0xe1, 0x25, 0xf1, 0x17, 0x18, 0x19, 0x1a, 0x26,
			0x27, 0x28, 0x29, 0x2a, 0x35, 0x36, 0x37, 0x38,
			0x39, 0x3a, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48,
			0x49, 0x4a, 0x53, 0x54, 0x55, 0x56, 0x57, 0x58,
			0x59, 0x5a, 0x63, 0x64, 0x65, 0x66, 0x67, 0x68,
			0x69, 0x6a, 0x73, 0x74, 0x75, 0x76, 0x77, 0x78,
			0x79, 0x7a, 0x82, 0x83, 0x84, 0x85, 0x86, 0x87,
			0x88, 0x89, 0x8a, 0x92, 0x93, 0x94, 0x95, 0x96,
			0x97, 0x98, 0x99, 0x9a, 0xa2, 0xa3, 0xa4, 0xa5,
			0xa6, 0xa7, 0xa8, 0xa9, 0xaa, 0xb2, 0xb3, 0xb4,
			0xb5, 0xb6, 0xb7, 0xb8, 0xb9, 0xba, 0xc2, 0xc3,
			0xc4, 0xc5, 0xc6, 0xc7, 0xc8, 0xc9, 0xca, 0xd2,
			0xd3, 0xd4, 0xd5, 0xd6, 0xd7, 0xd8, 0xd9, 0xda,
			0xe2, 0xe3, 0xe4, 0xe5, 0xe6, 0xe7, 0xe8, 0xe9,
			0xea, 0xf2, 0xf3, 0xf4, 0xf5, 0xf6, 0xf7, 0xf8,
			0xf9, 0xfa,
        };
 
        static byte[] CreateHuffmanTableMarker(byte[] codeLens, byte[] symbols, int tableNo, int tableClass)
        {
            List<byte> result = new List<byte>();
            result.Add(0xff);
            result.Add(0xc4);
            result.Add(0x00);
            result.Add((byte)(3 + codeLens.Length + symbols.Length));
            result.Add((byte)((tableClass << 4) | tableNo));
            result.AddRange(codeLens);
            result.AddRange(symbols);
            return result.ToArray();
        }
 
        static byte[] CreateDataRestartIntervalMarker(uint dri)
        {
            return new byte[] { 0xff, 0xdd, 0x00, 0x04, (byte)(dri >> 8), (byte)(dri) };
        }
 
        #endregion
 
        public JpegFrame() : base(26) { }
 
        /// <summary>
        /// //Writes the packets to a memory stream and created the default header and quantization tables if necessary.
        /// </summary>
		void ProcessPackets(System.IO.MemoryStream buffer)
        {
            ArraySegment<byte> tables = default(ArraySegment<byte>);            
            uint FragmentOffset, TypeSpecific, Type, Quality, Width, Height, DataRestartInterval = 0;

            for (int i = 0, e = this.Packets.Count, last = e - 1; i < e; ++i)
            {
                int offset = 0;
 
                RtpPacket packet = this.Packets[i];
 
                TypeSpecific = (uint)(packet.Payload[offset++]);
 
                //FragmentOffset = (uint)(packet.Payload[offset++] | packet.Payload[offset++] << 8 | packet.Payload[offset++] << 16);
                FragmentOffset = (uint)(packet.Payload[offset++] << 16 | packet.Payload[offset++] << 8 | packet.Payload[offset++]);
 
                //Ensure start packet
                if (i == 0 && FragmentOffset != 0) continue;
 
                Type = (uint)(packet.Payload[offset++]);
                Quality = (uint)packet.Payload[offset++];
                Width = (uint)(packet.Payload[offset++] * 8);
                Height = (uint)(packet.Payload[offset++] * 8);                
 
                //Only occur in the first packet
                if (FragmentOffset == 0)
                {
                    //If There is already a StartOfInformation present just copy
                    if (packet.Payload[offset] == 0xff && packet.Payload[offset + 1] == 0xd8)
                    {
                        goto WritePacket;
                    }
 
                    //Get the restart interval is present
                    if (Type > 63)
                    {
                        DataRestartInterval = (uint)(packet.Payload[offset++] << 8 | packet.Payload[offset++]);
                    }
 
                    //Get the Q Tables if present
                    if (Quality > 127)
                    {
                        uint MBZ = (uint)(packet.Payload[offset++]);//Should only proceed if MBZ > 0?
                        uint Precision = (uint)(packet.Payload[offset++]);//Wasted read
                        uint Length = (uint)(packet.Payload[offset++] << 8 | packet.Payload[offset++]);
                        if(Length > 0)
                        {
                            tables = new ArraySegment<byte>(packet.Payload, offset, (int)Length);
                            offset += (int)Length;
                        }
                        else
                        {
                            tables = new ArraySegment<byte>(CreateQuantizationTables(Quality));
                        }
                    }
 
                    //Write the header to the buffer
                    byte[] header = CreateJFIFHeader(Type, Width, Height, tables, DataRestartInterval);
                    buffer.Write(header, 0, header.Length);
 
                }
                
            WritePacket:    //Copy rest of data to buffer
                buffer.Write(packet.Payload, offset, packet.Payload.Length - offset);
 
                //Check to see if EOI is present or needs to be added on the last packet
                if (i == last && packet.Payload[packet.Payload.Length - 2] != 0xff && packet.Payload[packet.Payload.Length - 1] != 0xd9)
                {
                    buffer.WriteByte(0xff);
                    buffer.WriteByte(0xd9);
                }
 
            }
            
            //Go back to the beginning
            buffer.Seek(0, System.IO.SeekOrigin.Begin);            
        }


        /// <summary>
        /// Creates a image from the processed packets in the memory stream
        /// </summary>
        /// <returns>The image created from the packets</returns>
        public System.Drawing.Image ToImage()
        {
            try
            {
				using (System.IO.MemoryStream buffer = new System.IO.MemoryStream())
				{
					ProcessPackets(buffer);
					return System.Drawing.Image.FromStream(buffer, false, true);
				}
            }
            catch (Exception exc)
			{
				log.ErrorFormat("Exception in ToImage(): {0}", exc.Message);
				return null;
			}
        }
    }
}