/*
Math.Nhtsa.Differentiation.cs

24 November 2009 - Adapted from old Dave codebase to generic DTS utility, with 
                   appropriate name change. 

$Log: Math.Nhtsa.ChannelDifferentiation.cs,v $
Revision 1.2  2007/04/20 17:40:42  Paul Hrissikopoulos
Fixed bad range checking in sample rate property set accessor.

Revision 1.1  2007/02/05 17:17:08  Paul Hrissikopoulos
Finished installing generic channel math framework + basic calculus operations.

Copyright © 2007
Diversified Technical Systems, Inc.
All Rights Reserved
*/

using System;
using System.Collections.Generic;
using System.Text;
using DTS.Common.Utilities.DotNetProgrammingConstructs;

namespace DTS.Common.Utilities.Math.Nhtsa
{
    ////////////////////////////////////////////////////////////////////////////////
    /// <summary>
    /// Representation of a NHTSA-based differentiation channel operation.
    /// </summary>
    public class Differentiation : DoubleListOperation
    {
        ////////////////////////////////////////////////////////////////////////////////
        /// <summary>
        /// Get/set the sample rate for this data to be differentiated.
        /// </summary>
        public double SampleRate
        {
            get => _SampleRate.Value;
            set => _SampleRate.Value = value;
        }
        private Property<double> _SampleRate
            = new Property<double>(
                typeof(Differentiation).FullName + ".SampleRate",
                0.0,
                false
            );
        ////////////////////////////////////////////////////////////////////////////////

        ////////////////////////////////////////////////////////////////////////////////
        /// <summary>
        /// Initialize an instance of the ChannelDifferentiation class.
        /// </summary>
        /// 
        /// <param name="domain">
        /// The System.Collections.Generic.IList of <see cref="double"/> domain for
        /// this operation.
        /// </param>
        /// 
        public Differentiation(IList<double> domain)
            : base(domain)
        {   //
            // I'd prefer to do this statically, but I don't know of any C# way to place a constraint
            // on a generic type that's already been determined by some ancestor we're inheriting from,
            // so for now we'll have to dynamically check it on object instantiation.
            //
            if (!(domain is ICloneable))
                throw new InvalidCastException("the domain type for " + typeof(Differentiation).FullName + " must be ICloneable");
        }
        ////////////////////////////////////////////////////////////////////////////////

        ////////////////////////////////////////////////////////////////////////////////
        /// <summary>
        /// Initialize an instance of the Iso.ChannelDifferentiation class.
        /// </summary>
        ///
        /// <param name="domain">
        /// The System.Collections.Generic.IList of <see cref="double"/> domain for
        /// this operation.
        /// </param>
        /// 
        /// <param name="sampleRate">
        /// The <see cref="int"/> sample rate of the channel to be differentiated.
        /// </param>
        /// 
        public Differentiation(IList<double> domain, int sampleRate)
            : this(domain)
        {
            try { SampleRate = sampleRate; }
            catch (System.Exception ex)
            {
                throw new Exception("encountered problem constructing " + GetType().FullName, ex);
            }
        }
        ////////////////////////////////////////////////////////////////////////////////

        ////////////////////////////////////////////////////////////////////////////////
        /// <summary>
        /// Get the System.Collections.Generic.IList of <see cref="double"/> result of
        /// the operation on the target domain.
        /// </summary>
        public override IList<double> Range
        {
            get
            {
                try
                {
                    if (null == Domain)
                        throw new ArgumentNullException("attempted to differentiate null channel reference");

                    else if (0 >= SampleRate)
                        throw new ArgumentOutOfRangeException("SampleRate must be greater than zero");

                    else if (!(Domain is ICloneable))
                        throw new InvalidCastException("the domain type for " + typeof(Differentiation).FullName + " must be ICloneable");

                    else
                    {
                        var IndexOfLastSample = Domain.Count - 1;
                        var deltaT = SampleRate / 2;
                        var range = ((ICloneable)Domain).Clone() as IList<double>;

                        for (var t = 1; t < IndexOfLastSample; t++)
                            range[t] = (Domain[t + 1] - Domain[t - 1]) * deltaT;

                        range[0] = (-7 * Domain[0]
                                      + 6 * Domain[1]
                                      + 3 * Domain[2]
                                      - 2 * Domain[3]) * deltaT / 3;

                        range[IndexOfLastSample] = (-7 * Domain[IndexOfLastSample]
                                                      + 6 * Domain[IndexOfLastSample - 1]
                                                      + 3 * Domain[IndexOfLastSample - 2]
                                                      - 2 * Domain[IndexOfLastSample - 3]) * deltaT / 3;
                        return range;
                    }
                }

                catch (System.Exception ex)
                {
                    throw new Exception("encountered problem doing " + GetType().FullName + " operation", ex);
                }
            }
        }
        ////////////////////////////////////////////////////////////////////////////////
    }
    ////////////////////////////////////////////////////////////////////////////////
}