using System;

namespace Science.Physics.GeneralPhysics
{
	/// <summary>
	/// Relativity
	/// </summary>
	public class Relativity
	{
		public Relativity()
		{
		}
		private static double c = Constant.SpeedOfLightInVacuum;
		public static Time TimeDilation(Time t, Velocity v)
		{
			Time tp = new Time();
			double gamma = 1.0/Math.Sqrt(1.0-v.mPERs*v.mPERs/c/c);
			tp.s = gamma*t.s;
			return tp;
		}
		public static Length LengthContraction(Length l, Velocity v)
		{
			Length lp = new Length();
			double gamma = 1.0/Math.Sqrt(1.0-v.mPERs*v.mPERs/c/c);
			lp.m = l.m/gamma;
			return lp;
		}
		public static void LorentzTransformation(Position x, Time t, 
			Position xp, Time tp, Velocity v)
		{
			double gamma = 1.0/Math.Sqrt(1.0-v.mPERs*v.mPERs/c/c);
			xp.X = gamma*(x.X - v.X*t.s);
			xp.Y = x.Y;
			xp.Z = x.Z;
			tp.s = gamma*(t.s - v.X/c/c*x.X);
		}
		public static void LorentzTransformationForVelocity(Velocity u, 
			Velocity up, Velocity v)
		{
			double gamma = 1.0/Math.Sqrt(1.0-v.mPERs*v.mPERs/c/c);
			double denomi = 1.0 - u.X*v.X/c/c;
			up.X = (u.X - v.X)/denomi;
			up.Y = u.Y/gamma/denomi;
			up.Z = u.Z/gamma/denomi;
		}
		public static double RestEnergy(Mass m)
		{
			return m.kg*c*c;
		}
		public static Vector Momentum(Mass m, Velocity u)
		{
			double gamma = 1.0/Math.Sqrt(1.0-u.mPERs*u.mPERs/c/c);
			return gamma*m.kg*u;
		}
		public static double TotalEnergy(Mass m, Velocity u)
		{
			double gamma = 1.0/Math.Sqrt(1.0-u.mPERs*u.mPERs/c/c);
			return gamma*m.kg*c*c;
		}	
	}
}