using System;

namespace Science.Physics.GeneralPhysics
{
	/// <summary>
	/// Velocity
	/// </summary>
	public class Velocity : Vector
	{
		private void SetDim()
		{
			this.DimensionMass = 0;
			this.DimensionLength = 1;
			this.DimensionTime = -1;
		}
		public Velocity() 
		{
			SetDim();
		}
		public Velocity(Displacement d, Time t) 
		{
			SetDim();
			this.X = d.X/t.Interval;
			this.Y = d.Y/t.Interval;
			this.Z = d.Z/t.Interval;
		}
        public Velocity(Vector.FunctionOfTime func)
            : base(func)
	    {
		    SetDim();
	    }
		public Velocity(Mass m, KineticEnergy k)
		{
			SetDim();
			this.X = Math.Sqrt(2.0*k.J/m.kg);
		}	
		
		public Velocity(Position r, Time t) 
		{
			SetDim();

            Vector v = VectorCalculus.TimeDerivative(r, t);

            this.X = v.X;
            this.Y = v.Y;
            this.Z = v.Z;
		}	

	   	public Velocity(Time tInitial, Velocity vInitial, 
			Acceleration a, Time tFinal) 
		{
            SetDim();

			Vector v = VectorCalculus.TimeIntegral(a,tInitial,tFinal);

          	this.X = vInitial.X + v.X;
			this.Y = vInitial.Y + v.Y;
			this.Z = vInitial.Z + v.Z;
		}	
		public double mPERs
		{
			get{return this.Norm;} 
		}
        public override string ToString()
        {
            return base.ToString() + "(m/s)";
        }
	}
}