#region usings
using System;
using System.ComponentModel.Composition;

using VVVV.PluginInterfaces.V1;
using VVVV.PluginInterfaces.V2;
using VVVV.Utils.VColor;
using VVVV.Utils.VMath;

using VVVV.Core.Logging;
#endregion usings

namespace VVVV.Nodes
{
    public abstract class ValueFilterNode : IPluginEvaluate
    {
        [Input("Input")]
        public ISpread<double> FInput;

        [Input("Period")]
        public ISpread<double> FPeriodIn;

        [Output("Output")]
        public ISpread<double> FOutput;

        [Import]
        protected IHDEHost FHost;
        private Spread<double> FPreviousInput = new Spread<double>(1);
        private Spread<double> FPreviousOutput = new Spread<double>(1);
        private double FTime;

        public void Evaluate(int spreadMax)
        {
            var time = FHost.FrameTime;
            var deltaTime = (time - FTime) * 2 * Math.PI;
            FTime = time;

            FOutput.SliceCount = spreadMax;
            for (int i = 0; i < spreadMax; i++)
            {
                FOutput[i] = Filter(
                    deltaTime,
                    FPeriodIn[i],
                    FInput[i],
                    FPreviousInput[i],
                    FPreviousOutput[i]
                );
            }

            FPreviousInput.AssignFrom(FInput);
            FPreviousOutput.AssignFrom(FOutput);
        }

        protected abstract double Filter(double deltaTime, double rc, double x, double oldX, double y);
    }

    [PluginInfo(Name = "HighPassFilter", Category = "Value", Credits = "http://en.wikipedia.org/wiki/High-pass_filter")]
    public class ValueHighPassFilterNode : ValueFilterNode
    {
        protected override double Filter(double deltaTime, double rc, double x, double oldX, double y)
        {
            var alpha = rc / (rc + deltaTime);
            return alpha * (y + x - oldX);
        }
    }

    [PluginInfo(Name = "LowPassFilter", Category = "Value", Credits = "http://en.wikipedia.org/wiki/Low-pass_filter")]
    public class ValueLowPassFilterNode : ValueFilterNode
    {
        protected override double Filter(double deltaTime, double rc, double x, double oldX, double y)
        {
            var alpha = deltaTime / (rc + deltaTime);
            return y + alpha * (x - y);
        }
    }
}