/*
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* THIS SOFTWARE IS PROVIDED BY THE DEVELOPERS ``AS IS AND ANY
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*/
using System;
using System.Collections.Generic;
using System.Net;
using System.Net.Sockets;
using System.Text;
using System.Threading;
using System.Timers;
using Axiom.Math;
using libsecondlife;
using libsecondlife.Packets;
using OpenSim.Framework;
using OpenSim.Framework.Communications.Cache;
using OpenSim.Framework.Console;
using Timer=System.Timers.Timer;

namespace OpenSim.Region.ClientStack
{
    public class PacketQueue
    {
        private BlockingQueue<QueItem> SendQueue;
        
        private Queue<QueItem> IncomingPacketQueue;
        private Queue<QueItem> OutgoingPacketQueue;
        private Queue<QueItem> ResendOutgoingPacketQueue;
        private Queue<QueItem> LandOutgoingPacketQueue;
        private Queue<QueItem> WindOutgoingPacketQueue;
        private Queue<QueItem> CloudOutgoingPacketQueue;
        private Queue<QueItem> TaskOutgoingPacketQueue;
        private Queue<QueItem> TextureOutgoingPacketQueue;
        private Queue<QueItem> AssetOutgoingPacketQueue;
        
        private Dictionary<uint, uint> PendingAcks = new Dictionary<uint, uint>();
        private Dictionary<uint, Packet> NeedAck = new Dictionary<uint, Packet>();

        // All throttle times and number of bytes are calculated by dividing by this value
        // This value also determines how many times per throttletimems the timer will run
        // If throttleimems is 1000 ms, then the timer will fire every 1000/7 milliseconds

        private int throttleTimeDivisor = 7;

        private int throttletimems = 1000;

        private PacketThrottle ResendThrottle;
        private PacketThrottle LandThrottle;
        private PacketThrottle WindThrottle;
        private PacketThrottle CloudThrottle;
        private PacketThrottle TaskThrottle;
        private PacketThrottle AssetThrottle;
        private PacketThrottle TextureThrottle;
        private PacketThrottle TotalThrottle;

        private Timer throttleTimer;

        public PacketQueue() 
        {
            // While working on this, the BlockingQueue had me fooled for a bit.
            // The Blocking queue causes the thread to stop until there's something 
            // in it to process.  it's an on-purpose threadlock though because 
            // without it, the clientloop will suck up all sim resources.
            
            SendQueue = new BlockingQueue<QueItem>();
            
            IncomingPacketQueue = new Queue<QueItem>();
            OutgoingPacketQueue = new Queue<QueItem>();
            ResendOutgoingPacketQueue = new Queue<QueItem>();
            LandOutgoingPacketQueue = new Queue<QueItem>();
            WindOutgoingPacketQueue = new Queue<QueItem>();
            CloudOutgoingPacketQueue = new Queue<QueItem>();
            TaskOutgoingPacketQueue = new Queue<QueItem>();
            TextureOutgoingPacketQueue = new Queue<QueItem>();
            AssetOutgoingPacketQueue = new Queue<QueItem>();
        

            // Set up the throttle classes (min, max, current) in bytes
            ResendThrottle = new PacketThrottle(5000, 100000, 50000);
            LandThrottle = new PacketThrottle(1000, 100000, 100000);
            WindThrottle = new PacketThrottle(1000, 100000, 10000);
            CloudThrottle = new PacketThrottle(1000, 100000, 50000);
            TaskThrottle = new PacketThrottle(1000, 800000, 100000);
            AssetThrottle = new PacketThrottle(1000, 800000, 80000);
            TextureThrottle = new PacketThrottle(1000, 800000, 100000);
            // Total Throttle trumps all
            // Number of bytes allowed to go out per second. (256kbps per client) 
            TotalThrottle = new PacketThrottle(0, 162144, 1536000);
            
            // TIMERS needed for this
            throttleTimer = new Timer((int)(throttletimems/throttleTimeDivisor));
            throttleTimer.Elapsed += new ElapsedEventHandler(throttleTimer_Elapsed);
            throttleTimer.Start();
        }

        private void ResetCounters()
        {
            ResendThrottle.Reset();
            LandThrottle.Reset();
            WindThrottle.Reset();
            CloudThrottle.Reset();
            TaskThrottle.Reset();
            AssetThrottle.Reset();
            TextureThrottle.Reset();
            TotalThrottle.Reset();
        }

        private bool PacketsWaiting()
        {
            return (ResendOutgoingPacketQueue.Count > 0 ||
                    LandOutgoingPacketQueue.Count > 0 ||
                    WindOutgoingPacketQueue.Count > 0 ||
                    CloudOutgoingPacketQueue.Count > 0 ||
                    TaskOutgoingPacketQueue.Count > 0 ||
                    AssetOutgoingPacketQueue.Count > 0 ||
                    TextureOutgoingPacketQueue.Count > 0);
        }
        
       
        private void throttleTimer_Elapsed(object sender, ElapsedEventArgs e)
        {   
            ResetCounters();
            
            // I was considering this..   Will an event fire if the thread it's on is blocked?

            // Then I figured out..  it doesn't really matter..  because this thread won't be blocked for long
            // The General overhead of the UDP protocol gets sent to the queue un-throttled by this
            // so This'll pick up about around the right time.

            int MaxThrottleLoops = 4550; // 50*7 packets can be dequeued at once.
            int throttleLoops = 0;

            // We're going to dequeue all of the saved up packets until 
            // we've hit the throttle limit or there's no more packets to send
            while (TotalThrottle.UnderLimit() && PacketsWaiting() && 
                   (throttleLoops <= MaxThrottleLoops))
            {
                throttleLoops++;
                //Now comes the fun part..   we dump all our elements into PacketQueue that we've saved up.
                if (ResendThrottle.UnderLimit() && ResendOutgoingPacketQueue.Count > 0)
                {
                    QueItem qpack = ResendOutgoingPacketQueue.Dequeue();

                    SendQueue.Enqueue(qpack);
                    TotalThrottle.Add(qpack.Packet.ToBytes().Length);
                    ResendThrottle.Add(qpack.Packet.ToBytes().Length);
                }
                if (LandThrottle.UnderLimit() && LandOutgoingPacketQueue.Count > 0)
                {
                    QueItem qpack = LandOutgoingPacketQueue.Dequeue();

                    SendQueue.Enqueue(qpack);
                    TotalThrottle.Add(qpack.Packet.ToBytes().Length);
                    LandThrottle.Add(qpack.Packet.ToBytes().Length);
                }
                if (WindThrottle.UnderLimit() && WindOutgoingPacketQueue.Count > 0)
                {
                    QueItem qpack = WindOutgoingPacketQueue.Dequeue();

                    SendQueue.Enqueue(qpack);
                    TotalThrottle.Add(qpack.Packet.ToBytes().Length);
                    WindThrottle.Add(qpack.Packet.ToBytes().Length);
                }
                if (CloudThrottle.UnderLimit() && CloudOutgoingPacketQueue.Count > 0)
                {
                    QueItem qpack = CloudOutgoingPacketQueue.Dequeue();

                    SendQueue.Enqueue(qpack);
                    TotalThrottle.Add(qpack.Packet.ToBytes().Length);
                    CloudThrottle.Add(qpack.Packet.ToBytes().Length);
                }
                if (TaskThrottle.UnderLimit() && TaskOutgoingPacketQueue.Count > 0)
                {
                    QueItem qpack = TaskOutgoingPacketQueue.Dequeue();

                    SendQueue.Enqueue(qpack);
                    TotalThrottle.Add(qpack.Packet.ToBytes().Length);
                    TaskThrottle.Add(qpack.Packet.ToBytes().Length);
                }
                if (TextureThrottle.UnderLimit() && TextureOutgoingPacketQueue.Count > 0)
                {
                    QueItem qpack = TextureOutgoingPacketQueue.Dequeue();

                    SendQueue.Enqueue(qpack);
                    TotalThrottle.Add(qpack.Packet.ToBytes().Length);
                    TextureThrottle.Add(qpack.Packet.ToBytes().Length);
                }
                if (AssetThrottle.UnderLimit() && AssetOutgoingPacketQueue.Count > 0)
                {
                    QueItem qpack = AssetOutgoingPacketQueue.Dequeue();

                    SendQueue.Enqueue(qpack);
                    TotalThrottle.Add(qpack.Packet.ToBytes().Length);
                    AssetThrottle.Add(qpack.Packet.ToBytes().Length);
                }
            }
        }

        private void ThrottleCheck(ref PacketThrottle throttle, ref Queue<QueItem> q, QueItem item)
        {
            // The idea..  is if the packet throttle queues are empty
            // and the client is under throttle for the type.  Queue
            // it up directly.  This basically short cuts having to
            // wait for the timer to fire to put things into the
            // output queue

            if((q.Count == 0) && (throttle.UnderLimit()))
            {
                throttle.Add(item.Packet.ToBytes().Length);
                TotalThrottle.Add(item.Packet.ToBytes().Length);
                SendQueue.Enqueue(item);
            }
            else
            {
                q.Enqueue(item);
            }
        }

        public void Add(QueItem item)
        {
            switch (item.throttleType)
            {
                case ThrottleOutPacketType.Resend:
                    ThrottleCheck(ref ResendThrottle, ref ResendOutgoingPacketQueue, item);
                    break;
                case ThrottleOutPacketType.Texture:
                    ThrottleCheck(ref TextureThrottle, ref TextureOutgoingPacketQueue, item);
                    break;
                case ThrottleOutPacketType.Task:
                    ThrottleCheck(ref TaskThrottle, ref TaskOutgoingPacketQueue, item);
                    break;
                case ThrottleOutPacketType.Land:
                    ThrottleCheck(ref LandThrottle, ref LandOutgoingPacketQueue, item);
                    break;
                case ThrottleOutPacketType.Asset:
                    ThrottleCheck(ref AssetThrottle, ref AssetOutgoingPacketQueue, item);
                    break;
                case ThrottleOutPacketType.Cloud:
                    ThrottleCheck(ref CloudThrottle, ref CloudOutgoingPacketQueue, item);
                    break;
                case ThrottleOutPacketType.Wind:
                    ThrottleCheck(ref WindThrottle, ref WindOutgoingPacketQueue, item);
                    break;

                default:
                    // Acknowledgements and other such stuff should go directly to the blocking Queue
                    // Throttling them may and likely 'will' be problematic
                    SendQueue.Enqueue(item); 
                    break;
            }
        }

        private int ScaleThrottle(int value, int curmax, int newmax)
        {
            return (int)(((float)value/(float)curmax) * newmax);
        }

        public void SetThrottleFromClient(Packet Pack)
        {
            AgentThrottlePacket atpack = (AgentThrottlePacket)Pack;
            
            byte[] throttle = atpack.Throttle.Throttles;
            int tResend = -1;
            int tLand = -1;
            int tWind = -1;
            int tCloud = -1;
            int tTask = -1;
            int tTexture = -1;
            int tAsset = -1;
            int tall = -1;
            int singlefloat = 4;

            //Agent Throttle Block contains 7 single floatingpoint values.
            int j = 0;

            // Some Systems may be big endian...  
            // it might be smart to do this check more often... 
            if (!BitConverter.IsLittleEndian)
                for (int i = 0; i < 7; i++)
                    Array.Reverse(throttle, j + i * singlefloat, singlefloat);
            
            // values gotten from libsecondlife.org/wiki/Throttle.  Thanks MW_
            // bytes
            // Convert to integer, since..   the full fp space isn't used.
            tResend = (int)BitConverter.ToSingle(throttle, j);
            j += singlefloat;
            tLand = (int)BitConverter.ToSingle(throttle, j);
            j += singlefloat;
            tWind = (int)BitConverter.ToSingle(throttle, j);
            j += singlefloat;
            tCloud = (int)BitConverter.ToSingle(throttle, j);
            j += singlefloat;
            tTask = (int)BitConverter.ToSingle(throttle, j);
            j += singlefloat;
            tTexture = (int)BitConverter.ToSingle(throttle, j);
            j += singlefloat;
            tAsset = (int)BitConverter.ToSingle(throttle, j);
            
            tall = tResend + tLand + tWind + tCloud + tTask + tTexture + tAsset;
            /*
              OpenSim.Framework.Console.MainLog.Instance.Verbose("CLIENT", "Client AgentThrottle - Got throttle:resendbytes=" + tResend +
              " landbytes=" + tLand +
              " windbytes=" + tWind +
              " cloudbytes=" + tCloud +
              " taskbytes=" + tTask +
              " texturebytes=" + tTexture +
              " Assetbytes=" + tAsset +
              " Allbytes=" + tall);
            */
            
            // Total Sanity
            // Make sure that the client sent sane total values.
            
            // If the client didn't send acceptable values....
            // Scale the clients values down until they are acceptable.
            
            if (tall <= TotalThrottle.Max)
            {
                ResendThrottle.Throttle = tResend;
                LandThrottle.Throttle = tLand;
                WindThrottle.Throttle = tWind;
                CloudThrottle.Throttle = tCloud;
                TaskThrottle.Throttle = tTask;
                TextureThrottle.Throttle = tTexture;
                AssetThrottle.Throttle = tAsset;
                TotalThrottle.Throttle = tall;
            } 
            else if (tall < 1)
            {
                // client is stupid, penalize him by minning everything
                ResendThrottle.Throttle = ResendThrottle.Min;
                LandThrottle.Throttle = LandThrottle.Min;
                WindThrottle.Throttle = WindThrottle.Min;
                CloudThrottle.Throttle = CloudThrottle.Min;
                TaskThrottle.Throttle = TaskThrottle.Min;
                TextureThrottle.Throttle = TextureThrottle.Min;
                AssetThrottle.Throttle = AssetThrottle.Min;
                TotalThrottle.Throttle = TotalThrottle.Min;
            }
            else
            {
                // we're over so figure out percentages and use those
                ResendThrottle.Throttle = tResend;

                LandThrottle.Throttle = ScaleThrottle(tLand, tall, TotalThrottle.Max);
                WindThrottle.Throttle = ScaleThrottle(tWind, tall, TotalThrottle.Max);
                CloudThrottle.Throttle = ScaleThrottle(tCloud, tall, TotalThrottle.Max);
                TaskThrottle.Throttle = ScaleThrottle(tTask, tall, TotalThrottle.Max);
                TextureThrottle.Throttle = ScaleThrottle(tTexture, tall, TotalThrottle.Max);
                AssetThrottle.Throttle = ScaleThrottle(tAsset, tall, TotalThrottle.Max);
                TotalThrottle.Throttle = TotalThrottle.Max;
            }
            // effectively wiggling the slider causes things reset
            ResetCounters();
        }
    }
}