/*
 * Copyright (c) Contributors, http://opensimulator.org/
 * See CONTRIBUTORS.TXT for a full list of copyright holders.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *     * Redistributions of source code must retain the above copyright
 *       notice, this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above copyright
 *       notice, this list of conditions and the following disclaimer in the
 *       documentation and/or other materials provided with the distribution.
 *     * Neither the name of the OpenSimulator Project nor the
 *       names of its contributors may be used to endorse or promote products
 *       derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE DEVELOPERS ``AS IS'' AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL THE CONTRIBUTORS BE LIABLE FOR ANY
 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

using System;
using System.Collections.Generic;
using OpenMetaverse;
using OpenMetaverse.Imaging;
using OpenSim.Framework;
using OpenSim.Region.Framework.Interfaces;
using OpenSim.Services.Interfaces;
using log4net;
using System.Reflection;

namespace OpenSim.Region.ClientStack.LindenUDP
{
    /// <summary>
    /// We use this class to store image data and associated request data and attributes
    /// </summary>
    public class J2KImage
    {
        private static readonly ILog m_log = LogManager.GetLogger(MethodBase.GetCurrentMethod().DeclaringType);

        public double m_designatedPriorityKey;
        public double m_requestedPriority = 0.0d;
        public uint m_lastSequence = 0;
        public uint m_requestedPacketNumber;
        public sbyte m_requestedDiscardLevel;
        public UUID m_requestedUUID;
        public IJ2KDecoder m_j2kDecodeModule;
        public IAssetService m_assetCache;
        public OpenJPEG.J2KLayerInfo[] Layers = new OpenJPEG.J2KLayerInfo[0];
        public AssetBase m_MissingSubstitute = null;
        public bool m_decoded = false;
        public bool m_completedSendAtCurrentDiscardLevel;

        private sbyte m_discardLevel=-1;
        private uint m_packetNumber;
        private bool m_decoderequested = false;
        public bool m_hasasset = false;
        private bool m_asset_requested = false;
        private bool m_sentinfo = false;
        private uint m_stopPacket = 0;
        private const int cImagePacketSize = 1000;
        private const int cFirstPacketSize = 600;

        private AssetBase m_asset = null;
        private int m_assetDataLength = 0;

        private LLImageManager m_image;

        public J2KImage(LLImageManager image)
        {
            m_image = image;
        }

        public uint m_pPacketNumber
        {
            get { return m_packetNumber; }
        }
        public uint m_pStopPacketNumber
        {
            get { return m_stopPacket; }
        }

        public byte[] Data
        {
            get 
            { 
                if (m_asset != null) 
                    return m_asset.Data; 
                else
                    return null;
            }
        }

        public ushort TexturePacketCount()
        {
            if (!m_decoded)
                return 0;
            try
            {
                return (ushort)(((m_assetDataLength - cFirstPacketSize + cImagePacketSize - 1) / cImagePacketSize) + 1);
            }
            catch (Exception)
            {
                // If the asset is missing/destroyed/truncated, we will land
                // here
                //
                return 0;
            }
        }

        public void DropAsset()
        {
            m_log.WarnFormat("[LLIMAGE MANAGER]: Dropping texture asset {0}", m_requestedUUID);
            m_asset = null;
            m_hasasset = false;
            m_asset_requested = false;
        }

        public void J2KDecodedCallback(UUID AssetId, OpenJPEG.J2KLayerInfo[] layers)
        {
           m_image.m_outstandingtextures++;
           Layers = layers;
           m_decoded = true;
           RunUpdate();
        }

        public void AssetDataCallback(UUID AssetID, AssetBase asset)
        {
            m_hasasset = true;
            if (asset == null || asset.Data == null)
            {
                m_asset = m_MissingSubstitute;
            }
            else
            {
                m_asset = asset; 
            }

            m_assetDataLength = m_asset.Data.Length;

            RunUpdate();
        }

        protected void AssetReceived(string id, Object sender, AssetBase asset)
        {
            UUID assetID = UUID.Zero;
            if (asset != null)
                assetID = asset.FullID;

            AssetDataCallback(assetID, asset);

        }

        private int GetPacketForBytePosition(int bytePosition)
        {
            return ((bytePosition - cFirstPacketSize + cImagePacketSize - 1) / cImagePacketSize) + 1;
        }

        public int LastPacketSize()
        {
            if (m_packetNumber == 1)
                return m_assetDataLength;
            int lastsize = (m_assetDataLength - cFirstPacketSize) % cImagePacketSize;
            //If the last packet size is zero, it's really cImagePacketSize, it sits on the boundary
            if (lastsize == 0)
            {
                lastsize = cImagePacketSize;
            }
            return lastsize;
        }
 
        public int CurrentBytePosition()
        {
            if (m_packetNumber == 0)
                return 0;
            if (m_packetNumber == 1)
                return cFirstPacketSize;

            int result = cFirstPacketSize + ((int)m_packetNumber - 2) * cImagePacketSize;
            if (result < 0)
            {
                result = cFirstPacketSize;
            }
            return result;
        }

        public bool SendFirstPacket(LLClientView client)
        {
            // this means we don't have 
            if (Data == null) 
            {
                client.SendImageNotFound(m_requestedUUID);
                m_log.WarnFormat("[TEXTURE]: Got null Data element on a asset {0}..  and the missing image Data property is al", m_requestedUUID);
                return true;
            }
            // Do we have less then 1 packet's worth of data?
            else if (m_assetDataLength <= cFirstPacketSize)
            {
                // Send only 1 packet
                client.SendImageFirstPart(1, m_requestedUUID, (uint)m_assetDataLength, m_asset.Data, 2);
                m_stopPacket = 0;
                return true;
            }
            else
            {
                byte[] firstImageData = new byte[cFirstPacketSize];
                try 
                { 
                    Buffer.BlockCopy(m_asset.Data, 0, firstImageData, 0, (int)cFirstPacketSize);
                    client.SendImageFirstPart(TexturePacketCount(), m_requestedUUID, (uint)m_assetDataLength, firstImageData, 2);                
                }
                catch (Exception)
                {
                    m_log.Error("Texture block copy failed. Possibly out of memory?");
                    return true;
                }
            }
            return false;
        }

        private bool SendPacket(LLClientView client)
        {
            bool complete = false;
            int imagePacketSize = ((int)m_packetNumber == (TexturePacketCount())) ? LastPacketSize() : cImagePacketSize;

            try
            {
                if ((CurrentBytePosition() + cImagePacketSize) > m_assetDataLength)
                {
                    imagePacketSize = LastPacketSize();
                    complete=true;
                    if ((CurrentBytePosition() + imagePacketSize) > m_assetDataLength)
                    {
                        imagePacketSize = m_assetDataLength - CurrentBytePosition();
                        complete = true;
                    }
                }

                // It's concievable that the client might request packet one
                // from a one packet image, which is really packet 0,
                // which would leave us with a negative imagePacketSize..
                if (imagePacketSize > 0)
                {
                    byte[] imageData = new byte[imagePacketSize];
                    try
                    {
                        Buffer.BlockCopy(m_asset.Data, CurrentBytePosition(), imageData, 0, imagePacketSize);
                    }
                    catch (Exception e)
                    {
                        m_log.Error("Error copying texture block. Out of memory? imagePacketSize was " + imagePacketSize.ToString() + " on packet " + m_packetNumber.ToString() + " out of " + m_stopPacket.ToString() + ". Exception: " + e.ToString());
                        return false;
                    }

                    //Send the packet
                    client.SendImageNextPart((ushort)(m_packetNumber-1), m_requestedUUID, imageData);
                }
                if (complete)
                {
                    return false;
                }
                else
                {
                    return true;
                }
            }
            catch (Exception)
            {
                return false;
            }
        }
        public bool SendPackets(LLClientView client, int maxpack)
        {

            if (!m_completedSendAtCurrentDiscardLevel)
            {
                if (m_packetNumber <= m_stopPacket)
                {
                    bool SendMore = true;
                    if (!m_sentinfo || (m_packetNumber == 0))
                    {
                        if (SendFirstPacket(client))
                        {
                            SendMore = false;
                        }
                        m_sentinfo = true;
                        m_packetNumber++;
                    }
                    // bool ignoreStop = false;
                    if (m_packetNumber < 2)
                    {
                        m_packetNumber = 2;
                    }

                    int count = 0;
                    while (SendMore && count < maxpack && m_packetNumber <= m_stopPacket)
                    {
                        count++;
                        SendMore = SendPacket(client);
                        m_packetNumber++;
                    }

                    if (m_packetNumber > m_stopPacket)
                    {
                        return true;
                    }
                }
            }
            return false;
        }

        public void RunUpdate()
        {
            //This is where we decide what we need to update
            //and assign the real discardLevel and packetNumber
            //assuming of course that the connected client might be bonkers

            if (!m_hasasset)
            {

                if (!m_asset_requested)
                {
                    m_asset_requested = true;
                    m_assetCache.Get(m_requestedUUID.ToString(), this, AssetReceived);

                }

            }
            else
            {


                if (!m_decoded)
                {
                    //We need to decode the requested image first
                    if (!m_decoderequested)
                    {
                        //Request decode
                        m_decoderequested = true;
                        // Do we have a jpeg decoder?
                        if (m_j2kDecodeModule != null)
                        {
                            if (Data == null)
                            {
                                J2KDecodedCallback(m_requestedUUID, new OpenJPEG.J2KLayerInfo[0]);
                            }
                            // Send it off to the jpeg decoder
                            m_j2kDecodeModule.decode(m_requestedUUID, Data, J2KDecodedCallback);

                        }
                        else
                        {
                            J2KDecodedCallback(m_requestedUUID, new OpenJPEG.J2KLayerInfo[0]);
                        }
                    }

                }
                else
                {
                    //discardLevel of -1 means just update the priority
                    if (m_requestedDiscardLevel != -1)
                    {
                        //Evaluate the discard level
                        //First, is it positive?
                        if (m_requestedDiscardLevel >= 0)
                        {
                            if (m_requestedDiscardLevel > Layers.Length - 1)
                            {
                                m_discardLevel = (sbyte)(Layers.Length - 1);
                            }
                            else
                            {
                                m_discardLevel = m_requestedDiscardLevel;
                            }

                            //Calculate the m_stopPacket
                            if (Layers.Length > 0)
                            {
                                m_stopPacket = (uint)GetPacketForBytePosition(Layers[(Layers.Length - 1) - m_discardLevel].End);
                                //I don't know why, but the viewer seems to expect the final packet if the file
                                //is just one packet bigger.
                                if (TexturePacketCount() == m_stopPacket + 1)
                                {
                                    m_stopPacket = TexturePacketCount();
                                }
                            }
                            else
                            {
                                m_stopPacket = TexturePacketCount();
                            }
                            //Don't reset packet number unless we're waiting or it's ahead of us
                            if (m_completedSendAtCurrentDiscardLevel || m_requestedPacketNumber>m_packetNumber)
                            {
                                m_packetNumber = m_requestedPacketNumber;
                            }

                            if (m_packetNumber <= m_stopPacket)
                            {
                                m_completedSendAtCurrentDiscardLevel = false;
                            }
                        }
                    }
                    else
                    {
                        m_packetNumber = m_stopPacket;
                    }
                }
            }
        }
    }
}