using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace BCMToolbox
{
    [Serializable]
    public class WeightUpdateMessage : LocalMessage
    {
        public int[] Index = new int[] { 0, 0 };

        public WeightUpdateMessage()
            : base(WEIGHT_UPDATE)
        {
        }

        public const string WEIGHT_UPDATE = "W Update";
    }

    [Serializable]
    public class OutputUpdateMessage : LocalMessage
    {
        public int Index = 0;
        public const string OUTPUT_UPDATE = "OUT Update";

        public OutputUpdateMessage()
            : base(OUTPUT_UPDATE)
        {
        }
    }

    public abstract class SynchronousHebbian3Network : FixedTraceableNetwork
    {
        double[] __intermediaryOutputs = null;
        int[] __liveOutputs = null;
        List<LocalPipe> __outputPipes = new List<LocalPipe>();

        protected Func<double, double> __activation = MathToolbox.Sigmoid;
        protected Func<double, double> __activation_inverse = MathToolbox.InverseSigmoid;

        internal SynchronousHebbian3Network(int neuronCount, int newID, int[] liveOutputs)
            : base(neuronCount, newID)
        {
            __intermediaryOutputs = new double[neuronCount];
            __liveOutputs = liveOutputs;
            foreach (int lo in __liveOutputs)
                if (lo >= neuronCount)
                    throw new IndexOutOfRangeException();
        }

        internal void LinkPipe(LocalPipe inbound)
        {
            inbound.MessageReceive += new EventHandler<LocalMessageEventArgs>(inbound_MessageReceive);
        }        

        internal LocalPipe RegisterOtherNetwork(SynchronousHebbian3Network newNetwork)
        {
            if (newNetwork == this)
                return null;

            LocalPipe pipe = new LocalPipe();
            __outputPipes.Add(pipe);
            return pipe;
        }

        void inbound_MessageReceive(object sender, LocalMessageEventArgs e)
        {
            if (e.Message.MessageType != WeightUpdateMessage.WEIGHT_UPDATE)
                return;

            // ref message
        }

        public override string Identification
        {
            get
            {
                return String.Format("HebbM Layer #{0}", this.UID);
            }
        }

        public virtual double Inertia
        {
            get
            {
                return 0.02;
            }
        }

        public virtual double OutputDecay
        {
            get
            {
                return 0.85;
            }
        }

        protected abstract double WeightModificationKernel(double weight, double input, double output);


        public virtual bool HasNormalizedWeights
        {
            get
            {
                return false;
            }
        }

        public virtual bool HasNormalizedInputs
        {
            get
            {
                return false;
            }
        }



        public override void ApplyInputs(double[] inputs)
        {
            lock (SyncRoot)
            {
                if (inputs == null)
                    throw new ArgumentNullException();

                if (inputs.Length != this.Count)
                    throw new ArgumentException("Invalid input size. Expected: ", this.Count.ToString());

                for (int i = 0; i < this.Count; i++)
                    __potentials[i] += inputs[i];
            }

            if (HasNormalizedInputs)
                NormalizePotentials(2.0);

            base.ApplyInputs(inputs);
        }


        public override void Propagate()
        {
            // calculate outputs
            for (int i = 0; i < this.Count; i++)
            {
                __intermediaryOutputs[i] = 0.0;
                for (int j = 0; j < this.Count; j++)
                    if ((i != j) && !double.IsNaN(__weights[j, i]))
                        __intermediaryOutputs[i] += __weights[j, i] * __potentials[j];
                __intermediaryOutputs[i] = __activation(__intermediaryOutputs[i]);
            }

            if (HasNormalizedInputs)
            {
                double[] temp = __potentials;
                __potentials = __intermediaryOutputs;
                NormalizePotentials(2.0);
                __potentials = temp;
            }

            // update weights and lock outputs
            lock (SyncRoot)
            {
                for (int i = 0; i < this.Count; i++)
                    for (int j = 0; j < this.Count; j++)
                    {
                        if ((i == j) || double.IsNaN(__weights[i, j]))
                            continue;

                        __weights[i, j] = WeightModificationKernel(__weights[i, j], __potentials[i], __intermediaryOutputs[j]);


                        System.Diagnostics.Debug.Assert(!double.IsNaN(__weights[i, j]));
                        System.Diagnostics.Debug.Assert(!double.IsInfinity(__weights[i, j]));



                    }

                if (HasNormalizedWeights)
                    NormalizeWeights(2.0);

                for (int i = 0; i < this.Count; i++)
                    __potentials[i] = __intermediaryOutputs[i] * OutputDecay;
            }

            base.Propagate();
        }

        public override void Initialize(Func<int, int, double> initializerWeights, Func<int, double> initializerPotentials)
        {
            base.Initialize(initializerWeights, initializerPotentials);
            if (HasNormalizedInputs)
                NormalizePotentials(2.0);

            if (HasNormalizedWeights)
                NormalizeWeights(2.0);
        }
    }
}