using System;

namespace Science.Physics.GeneralPhysics
{
	/// <summary>
	/// In the non-relativistic limit, acceleration is defined 
	/// as the derivative of velocity, and is therefore given 
	/// by the expression. Newton's second law is a very famous 
	/// observation which expressed the force F on a body 
	/// in terms of its acceleration a and mass m. 
	/// </summary>
	public class Acceleration : Vector
	{
		private void SetDim()
		{
			this.DimensionMass = 0;
			this.DimensionLength = 1;
			this.DimensionTime = -2;
		}
		public Acceleration() 
		{	
			SetDim();
		}
        public Acceleration(Vector.FunctionOfTime func)
            : base(func)
		{
			SetDim();
		}
		public Acceleration(Velocity final, Velocity initial, Time t)
		{
			SetDim();
			this.X = (final.X - initial.X) / t.s;
			this.Y = (final.Y - initial.Y) / t.s;
			this.Z = (final.Z - initial.Z) / t.s;
		}
		public Acceleration(Mass m, TotalForce f)
		{
			SetDim();
			this.X = f.X/m.kg;
			this.Y = f.Y/m.kg;
			this.Z = f.Z/m.kg;
		}

  		private Velocity w;
		private int component;
   		public Acceleration(Velocity v, Time t) 
		{
			SetDim();
			w = v;
			double time = t.s;

            Calculus.Function<double, double> del
                = new Calculus.Function<double, double>(Func);

			component = 0;
            this.X = Calculus.Differentiation(del, time);
			component = 1;
            this.Y = Calculus.Differentiation(del, time);
			component = 2;
            this.Z = Calculus.Differentiation(del, time);
		}
		private double Func(double t)
		{
            Time time = new Time();
            time.s = t;
			w.Set(time);
			if(component==0) return w.X;
			else if(component==1) return w.Y;
			else return w.Z;
		}	

		public double mPERsSQUARE
		{
			get{return this.Norm;} 
		}

        public override string ToString()
        {
            return base.ToString() + "(m/s^2)";
        }
	}
}