//package PS3;
import javax.swing.*;
import java.util.*;     // For Vector

public class FluidTest {
    public static void main(String[] args) {
        
        // Input data- fluids
        Fluid[] substance= new Fluid[4];
        substance[0]= new Fluid("water", 1.0E3, 1.0E-3);
        substance[1]= new Fluid("air", 1.2, 1.8E-5);
        substance[2]= new Fluid("ethyl", 0.79E3, 1.2E-3);
        substance[3]= new Fluid("methyl", 0.79E3, 0.62E-3);
        
        // Input data- pipe network
        Vector network= new Vector();
        network.addElement(new Pipe(0.5, 50.0, -0.1, "AB", null));
        network.addElement(new Pipe(0.4, 15.0, -0.05, "BC", (Pipe) network.elementAt(0)));
        network.addElement(new Pipe(0.3, 5.0, -0.03, "CD", (Pipe) network.elementAt(1)));
        network.addElement(new Pipe(0.1*Math.sqrt(7), 8.0, -0.03, "CE", (Pipe) network.elementAt(1)));
        network.addElement(new Pipe(0.3, 25.0, 0.05, "BF", (Pipe) network.elementAt(0)));
               
        // Prompt user for fluid to be used
        Fluid chosen;
        String text= JOptionPane.showInputDialog("Enter fluid (water, air, ethyl, methyl):");
        if (text.equals("water"))
            chosen= substance[0];
        else if (text.equals("air"))
            chosen= substance[1];
        else if (text.equals("ethyl"))
            chosen= substance[2];
        else if (text.equals("methyl"))
            chosen= substance[3];
        else {
            chosen= null;
            System.out.println("You need to enter a valid fluid next time");
            System.exit(0);
        }
        double d= chosen.getDensity();      // For convenience later
        double q= chosen.getViscosity();
        
        text= JOptionPane.showInputDialog("Enter initial fluid pressure");
        double p1= Double.parseDouble(text);
        
        text= JOptionPane.showInputDialog("Enter initial fluid velocity");
        double velocity= Double.parseDouble(text);
        Pipe.setVelocity(velocity);
        
        text= JOptionPane.showInputDialog("Enter pipe roughness");
        double e= Double.parseDouble(text);
        Pipe.setRoughness(e);
        
        // Compute pipe pressure losses, etc.
        Pipe first= (Pipe) network.elementAt(0);
        first.calcOutletPressure(p1, d, q);
        for (int i=1; i < network.size(); i++) {
            Pipe p= (Pipe) network.elementAt(i);
            Pipe pup= p.getUpstreamPipe();
            double press= pup.getOutletPressure();
            p.calcOutletPressure(press, d, q);
        }
        
        // Output results
        System.out.println("Fluid type: " + chosen.getFluidName());
        for (int k=0; k < network.size(); k++) {
            Pipe pout= (Pipe) network.elementAt(k);
            pout.printData(chosen);
        }
        //System.exit(0);
    }
}

class Fluid {
    private double density;
    private double viscosity;
    private String name;
    
    Fluid(String n, double d, double v) {
        density= d;
        viscosity= v;
        name= n;
    }
    
    public double getDensity() {
        return density;
    }
    public double getViscosity() {
        return viscosity;
    }
    public String getFluidName() {
        return name;
    }
}

class Pipe {
    // Instance variables
    private double D;           // Diameter
    private double L;           // Length
    private double dz;          // Elevation change
    private String segment;     // Name, e.g., AB, BC
    private Pipe upstream;      // Upstream pipe
    private double pa;          // Initial pressure- input. This is a problem; it's never set anywhere (yet)
    private double pb= -1;      // Outlet pressure- computed. Init to -1 to flag if not computed yet
    
    // Static fields
    private static double v;                        // Fluid velocity
    private static double e;                        // Roughness
    private final static double critR= 2000;        // Critical Reynolds number
    private final static double g= 9.8;             // Gravity
    
    Pipe(double d1, double L1, double z1, String s, Pipe pipe1) {
        D= d1;
        L= L1;
        dz= z1;
        segment= s;
        upstream= pipe1;
    }
        
    public static double getReynoldsNumber(double dens, double vel, double diam, double visc) {
        return dens*vel*diam/visc;
    }
    
    public static double getFriction(double R, double e, double D) {
        if (R < critR)
            return 64.0/R;
        else {
            double t= 1.81*0.4343 *(Math.log(6.9/R + Math.pow((e/D/3.7), 1.11)));
            return 1.0/t/t;
        }
    }
    
    // Instance method, just takes init pressure, fluid density, viscosity as parameters
    public double calcOutletPressure(double p1, double dens, double visc) {
        pa= p1;                                             // Awkward
        double R= getReynoldsNumber(dens, v, D, visc);
        double f= getFriction(R, e, D);
        pb= pa - dens*g*(dz + f*L*v*v/(D*2*g));
        return pb;
    }
    
    public double getOutletPressure() {
        // Should check that it's been calculated. Not handled in this homework
        return pb;
    }
      
    public Pipe getUpstreamPipe() {
        return upstream;
    }
    
    public double getFlow() {
        return Math.PI*0.25*D*D*v;
    }
    
    public static void setRoughness(double rough) {
        e= rough;
    }
    
    public static void setVelocity(double vel) {
        v= vel;
    }
      
    public void printData(Fluid fl) {
        System.out.println("Pipe " + segment);
        double R= Pipe.getReynoldsNumber(fl.getDensity(), v, D, fl.getViscosity());
        System.out.println(" Reynolds number: " + R);
        System.out.println(" Friction: " + getFriction(R, e, D));
        System.out.println(" Pressure at inlet: " + pa);
        System.out.println(" Pressure at outlet: " + pb);
        System.out.println(" Pressure change: " + (pb - pa));
        System.out.println(" Volume flow rate: " + getFlow());
    }
}