using System;

namespace Science.Physics.GeneralPhysics
{
	/// <summary>
	/// FundamentalLaw
	/// </summary>
	public class FundamentalLaw
	{
		public FundamentalLaw()
		{
		}
		public static void AngularMomentumConservation(AngularMomentum Li, AngularMomentum Lf)
		{
			if(Li.XVariableQ) Li.X = Lf.X;
			if(Li.YVariableQ) Li.Y = Lf.Y;
			if(Li.ZVariableQ) Li.Z = Lf.Z;
			if(Lf.XVariableQ) Lf.X = Li.X;
			if(Lf.YVariableQ) Lf.Y = Li.Y;
			if(Lf.ZVariableQ) Lf.Z = Li.Z;			
		}
		public static void AngularMomentumConservation(AngularMomentum[] Li, AngularMomentum[] Lf)
		{
			double sum = 0.0;
			for(int i=0; i<Li.Length; i++)
			{
				if(!Li[i].XVariableQ) sum += Li[i].X;
			}
			for(int i=0; i<Lf.Length; i++)
			{
				if(!Lf[i].XVariableQ) sum += -Lf[i].X;
			}
			for(int i=0; i<Li.Length; i++)
			{
				if(Li[i].XVariableQ) Li[i].X = -sum;
			}
			for(int i=0; i<Lf.Length; i++)
			{
				if(Lf[i].XVariableQ) Lf[i].X = sum;
			}
			sum = 0.0;
			for(int i=0; i<Li.Length; i++)
			{
				if(!Li[i].YVariableQ) sum += Li[i].Y;
			}
			for(int i=0; i<Lf.Length; i++)
			{
				if(!Lf[i].YVariableQ) sum += -Lf[i].Y;
			}
			for(int i=0; i<Li.Length; i++)
			{
				if(Li[i].YVariableQ) Li[i].Y = -sum;
			}
			for(int i=0; i<Lf.Length; i++)
			{
				if(Lf[i].YVariableQ) Lf[i].Y = sum;
			}
			sum = 0.0;
			for(int i=0; i<Li.Length; i++)
			{
				if(!Li[i].ZVariableQ) sum += Li[i].Z;
			}
			for(int i=0; i<Lf.Length; i++)
			{
				if(!Lf[i].ZVariableQ) sum += -Lf[i].Z;
			}
			for(int i=0; i<Li.Length; i++)
			{
				if(Li[i].ZVariableQ) Li[i].Z = -sum;
			}
			for(int i=0; i<Lf.Length; i++)
			{
				if(Lf[i].ZVariableQ) Lf[i].Z = sum;
			}
		}
		public static void MomentumConservation(Momentum pi, Momentum pf)
		{
			if(pi.XVariableQ) pi.X = pf.X;
			if(pi.YVariableQ) pi.Y = pf.Y;
			if(pi.ZVariableQ) pi.Z = pf.Z;
			if(pf.XVariableQ) pf.X = pi.X;
			if(pf.YVariableQ) pf.Y = pi.Y;
			if(pf.ZVariableQ) pf.Z = pi.Z;			
		}
		public static void MomentumConservation(Momentum[] pi, Momentum pf)
		{
			double sum = 0.0;
			for(int i=0; i<pi.Length; i++)
			{
				if(!pi[i].XVariableQ) sum += pi[i].X;
			}
			if(!pf.XVariableQ) sum += -pf.X;
			for(int i=0; i<pi.Length; i++)
			{
				if(pi[i].XVariableQ) pi[i].X = -sum;
			}
			if(pf.XVariableQ) pf.X = sum;
			sum = 0.0;
			for(int i=0; i<pi.Length; i++)
			{
				if(!pi[i].YVariableQ) sum += pi[i].Y;
			}
			if(!pf.YVariableQ) sum += -pf.Y;
			for(int i=0; i<pi.Length; i++)
			{
				if(pi[i].YVariableQ) pi[i].Y = -sum;
			}
			if(pf.YVariableQ) pf.Y = sum;
			sum = 0.0;
			for(int i=0; i<pi.Length; i++)
			{
				if(!pi[i].ZVariableQ) sum += pi[i].Z;
			}
			if(!pf.ZVariableQ) sum += -pf.Z;
			for(int i=0; i<pi.Length; i++)
			{
				if(pi[i].ZVariableQ) pi[i].Z = -sum;
			}
			if(pf.ZVariableQ) pf.Z = sum;
		}
		public static void MomentumConservation(Momentum pi, Momentum[] pf)
		{
			double sum = 0.0;
			if(!pi.XVariableQ) sum += pi.X;
			for(int i=0; i<pf.Length; i++)
			{
				if(!pf[i].XVariableQ) sum += -pf[i].X;
			}
			if(pi.XVariableQ) pi.X = -sum;
			for(int i=0; i<pf.Length; i++)
			{
				if(pf[i].XVariableQ) pf[i].X = sum;
			}
			sum = 0.0;
			if(!pi.YVariableQ) sum += pi.Y;
			for(int i=0; i<pf.Length; i++)
			{
				if(!pf[i].YVariableQ) sum += -pf[i].Y;
			}
			if(pi.YVariableQ) pi.Y = -sum;
			for(int i=0; i<pf.Length; i++)
			{
				if(pf[i].YVariableQ) pf[i].Y = sum;
			}
			sum = 0.0;
			if(!pi.ZVariableQ) sum += pi.Z;
			for(int i=0; i<pf.Length; i++)
			{
				if(!pf[i].ZVariableQ) sum += -pf[i].Z;
			}
			if(pi.ZVariableQ) pi.Z = -sum;
			for(int i=0; i<pf.Length; i++)
			{
				if(pf[i].ZVariableQ) pf[i].Z = sum;
			}
		}
		public static void MomentumConservation(Momentum[] pi, Momentum[] pf)
		{
			double sum = 0.0;
			for(int i=0; i<pi.Length; i++)
			{
				if(!pi[i].XVariableQ) sum += pi[i].X;
			}
			for(int i=0; i<pf.Length; i++)
			{
				if(!pf[i].XVariableQ) sum += -pf[i].X;
			}
			for(int i=0; i<pi.Length; i++)
			{
				if(pi[i].XVariableQ) pi[i].X = -sum;
			}
			for(int i=0; i<pf.Length; i++)
			{
				if(pf[i].XVariableQ) pf[i].X = sum;
			}
			sum = 0.0;
			for(int i=0; i<pi.Length; i++)
			{
				if(!pi[i].YVariableQ) sum += pi[i].Y;
			}
			for(int i=0; i<pf.Length; i++)
			{
				if(!pf[i].YVariableQ) sum += -pf[i].Y;
			}
			for(int i=0; i<pi.Length; i++)
			{
				if(pi[i].YVariableQ) pi[i].Y = -sum;
			}
			for(int i=0; i<pf.Length; i++)
			{
				if(pf[i].YVariableQ) pf[i].Y = sum;
			}
			sum = 0.0;
			for(int i=0; i<pi.Length; i++)
			{
				if(!pi[i].ZVariableQ) sum += pi[i].Z;
			}
			for(int i=0; i<pf.Length; i++)
			{
				if(!pf[i].ZVariableQ) sum += -pf[i].Z;
			}
			for(int i=0; i<pi.Length; i++)
			{
				if(pi[i].ZVariableQ) pi[i].Z = -sum;
			}
			for(int i=0; i<pf.Length; i++)
			{
				if(pf[i].ZVariableQ) pf[i].Z = sum;
			}
		}
		public static void WorkEnergyTheorem(KineticEnergy i, Work w, KineticEnergy f)
		{
			double sum = 0.0;
			if(!w.VariableQ) sum += w.J;
			if(!i.VariableQ) sum += i.J;
			if(!f.VariableQ) sum += -f.J;
			if(w.VariableQ) w.J = -sum;
			if(i.VariableQ) i.J = -sum;
			if(f.VariableQ) f.J = sum;
		}
		public static void WorkEnergyTheorem(KineticEnergy i, Work[] w, KineticEnergy f)
		{
			double sum = 0.0;
			foreach(Work ww in w) if(!ww.VariableQ) sum += ww.J;
			if(!i.VariableQ) sum += i.J;
			if(!f.VariableQ) sum += -f.J;
			foreach(Work ww in w) if(ww.VariableQ) ww.J = -sum;
			if(i.VariableQ) i.J = -sum;
			if(f.VariableQ) f.J = sum;
		}
		public static void EnergyConservation(KineticEnergy Ki, PotentialEnergy[] Ui, 
			KineticEnergy Kf, PotentialEnergy[] Uf)
		{
			double sum = 0.0;

			if(!Ki.VariableQ) sum += Ki.J;
			foreach(PotentialEnergy pe in Ui) if(!pe.VariableQ) sum += pe.J;
			if(!Kf.VariableQ) sum += -Kf.J;
			foreach(PotentialEnergy pe in Uf) if(!pe.VariableQ) sum += -pe.J;

			if(Ki.VariableQ) Ki.J = -sum;
			foreach(PotentialEnergy pe in Ui) if(pe.VariableQ) pe.J = -sum;
			if(Kf.VariableQ) Kf.J = sum;
			foreach(PotentialEnergy pe in Uf) if(pe.VariableQ) pe.J = sum;
		}
		public static void EnergyConservation(KineticEnergy Ki, PotentialEnergy Ui, 
			KineticEnergy Kf, PotentialEnergy Uf)
		{
			double sum = 0.0;

			if(!Ki.VariableQ) sum += Ki.J;
			if(!Ui.VariableQ) sum += Ui.J;
			if(!Kf.VariableQ) sum += -Kf.J;
			if(!Uf.VariableQ) sum += -Uf.J;

			if(Ki.VariableQ) Ki.J = -sum;
			if(Ui.VariableQ) Ui.J = -sum;
			if(Kf.VariableQ) Kf.J = sum;
			if(Uf.VariableQ) Uf.J = sum;
		}
		public static void CoulombLaw(ElectricForce F2by1, 
			ElectricCharge q1, Position r1, 
			ElectricCharge q2, Position r2)
		{
			Vector del = r2 - r1;
			UnitVector rhat = new UnitVector(del);
		
			Vector v = (Constant.CoulombConstant*q1.C*q2.C/del.Norm/del.Norm)*rhat;
			F2by1.X = v.X;
			F2by1.Y = v.Y;
			F2by1.Z = v.Z;
		}
		public static void GaussLaw(ElectricFlux Phi, ElectricCharge q)
		{
			if(Phi.VariableQ) Phi.NmSQUAREPERC = q.C/Constant.PermittivityOfFreeSpace;
			else q.C = Constant.PermittivityOfFreeSpace*Phi.NmSQUAREPERC;
		}
		public static void GaussLawInMagnetism(MagneticFlux Phi)
		{
			if(Phi.VariableQ) 
			{
				Phi.Wb = 0.0;
		        Phi.VariableQ = false;
			}
			else Phi.Wb = 0.0;
		}
		public static void AmpereLaw(MagneticField B, Line C, 
			ElectricCurrent I, DisplacementCurrent Id, Time t)
		{
      		Scalar s = VectorCalculus.LineIntegralDot(B,C,t);
			if(I.VariableQ) I.A = s.Magnitude/Constant.PermeabilityOfFreeSpace - Id.A ;
			else Id.A = s.Magnitude/Constant.PermeabilityOfFreeSpace - I.A ;
		}
		public static void FaradayLaw(ElectricPotentialDifference V, MagneticFlux Phi, Time t)
		{
            Scalar s = VectorCalculus.TimeDerivative(Phi, t);
			V.V = - s.Magnitude;
		}
		public static void ThermodynamicsFirstLaw(Heat Q, Work W, Energy U)
		{   // U = Q + W  
			// Q : given by outside
			// W : done by outside
			if(Q.VariableQ) Q.J = -W.J + U.J;
			else if(W.VariableQ) W.J = -Q.J + U.J;
			else U.J = Q.J + W.J;
		}
		public static string ThermodynamicsSecondLaw(Entropy Si, Entropy Sf)
		{
			if(Si.JPERK > Sf.JPERK) return "Violation!";
			else return "Good!";
		}
		public static double BoltzmannDistribution(Energy E, Temperature T)
		{
			return Math.Exp(-E.J/Constant.BolzmannConstant/T.K);
		}
	}
}