/*
 *
 * Particle *
 */
import java.awt.*;
import java.applet.*;
import java.util.Random;

public class Particle 
{
        protected Applet m_Parent;
        protected Point m_CurrentLocation;
        protected Point m_MinLimit;
        protected Point m_MaxLimit;
        protected Point m_OldLoc;
        
        public int m_Barrier=10000;
        public int m_MembraneIndex=0;
        public Membrane m_Membrane=null;

        public int m_Charge;
        protected static Random m_r=new Random();
        public double m_StdDev=1.0;                                
        protected Color m_neg, m_pos, m_neut;
        public Color BG;
        public Image i_cation,i_anion,i_neutral,i_bpos,i_bneg;
        public String c_string="images/cation.gif",a_string="images/anion2.gif",n_string="images/Neutral0.gif",bp_string="images/bcation.gif",bn_string="images/banion.gif";
        public boolean Active=true, bouncing=true, bleached=false;
        public boolean Tether=false;

        //--------------------------------------------------------------------------
        public Particle(){

        }

        //--------------------------------------------------------------------------
        public Particle(Applet Parent){
                m_Parent=Parent;
        }
        
        //--------------------------------------------------------------------------
        public Particle(Applet Parent, int charge, Point P, Point Min, Point Max){
                m_Parent=Parent;
                Init(charge,P,Min,Max);
        }

        //--------------------------------------------------------------------------
        public void Init(int charge, Point P, Point Min, Point Max){
                m_Charge=charge;
                m_CurrentLocation= new Point(P.x,P.y);
                m_MinLimit= new Point(Min.x,Min.y);
                m_MaxLimit= new Point(Max.x,Max.y);
                m_neg=new Color(0,0,255);
                m_pos=new Color(255,0,0);
                m_neut=new Color(0,255,0);
                m_OldLoc=new Point(P.x,P.y);
                i_cation = m_Parent.getImage(m_Parent.getCodeBase(),c_string);
                i_anion = m_Parent.getImage(m_Parent.getCodeBase(),a_string);
                i_neutral = m_Parent.getImage(m_Parent.getCodeBase(),n_string);
                i_bpos = m_Parent.getImage(m_Parent.getCodeBase(),bp_string);
                i_bneg = m_Parent.getImage(m_Parent.getCodeBase(),bn_string);
                Active=true;

        }

        public void NewLimits(Point Min, Point Max) {
                m_MinLimit.x=Min.x; m_MinLimit.y=Min.y;
                m_MaxLimit.x=Max.x; m_MaxLimit.y=Max.y;
        }

        public void NewLocation(Point New){
                m_CurrentLocation=New;
                m_OldLoc=New;
                Active=true;
        }

        //--------------------------------------------------------------------------
        public Point Location(){
                return m_CurrentLocation;
        }


        public boolean IsInside(){
                if (m_Membrane==null) return false;
                if (m_CurrentLocation.x<= m_Barrier) return true;
                return false;
        }

        //--------------------------------------------------------------------------
        public void BarrierCross(){
                if (m_Membrane==null) return;
                if ( (m_OldLoc.x<=m_Barrier && m_CurrentLocation.x>m_Barrier) ){
                        if (!m_Membrane.Permeate(m_MembraneIndex,m_Charge,true)){         //from Inside
                                m_CurrentLocation.x=m_OldLoc.x;
                        }
                }else if ( (m_OldLoc.x>m_Barrier && m_CurrentLocation.x<=m_Barrier) ) {
                        if (!m_Membrane.Permeate(m_MembraneIndex,m_Charge,false)){
                                m_CurrentLocation.x=m_OldLoc.x;
                        }
                }
        }
        
        //--------------------------------------------------------------------------
        public void XBounce(){
                if (m_CurrentLocation.x < m_MinLimit.x){
                        if (bouncing)
                                m_CurrentLocation.x += 2*(m_MinLimit.x-m_CurrentLocation.x);
                        else Active=false;
                } else if (m_CurrentLocation.x > m_MaxLimit.x) {
                        if (bouncing)
                                m_CurrentLocation.x += 2*(m_MaxLimit.x-m_CurrentLocation.x);
                        else Active=false;
                }
        }

        //--------------------------------------------------------------------------
        public void YBounce(){
                if (m_CurrentLocation.y < m_MinLimit.y){
                        if (bouncing)
                                m_CurrentLocation.y += 2*(m_MinLimit.y-m_CurrentLocation.y);
                        else Active=false;
                } else if (m_CurrentLocation.y > m_MaxLimit.y) {
                        if (bouncing)
                                m_CurrentLocation.y += 2*(m_MaxLimit.y-m_CurrentLocation.y);
                        else Active=false;
                }
        }
        //--------------------------------------------------------------------------
        public void NewMove(){
                if (!Active) return;
                if (Tether){
                        m_CurrentLocation.x = m_OldLoc.x+(int)(m_r.nextGaussian()*m_StdDev);
                        m_CurrentLocation.y = m_OldLoc.y+(int)(m_r.nextGaussian()*m_StdDev);
                        return;
                }
                m_OldLoc.x=m_CurrentLocation.x;
                m_OldLoc.y=m_CurrentLocation.y;
                m_CurrentLocation.x += (int)(m_r.nextGaussian()*m_StdDev);
                m_CurrentLocation.y += (int)(m_r.nextGaussian()*m_StdDev);
                XBounce();
                YBounce();
                BarrierCross();
        }

        //--------------------------------------------------------------------------
        public void DrawParticle(Graphics g){
                if (!Active) return;
                Image i;
                if (m_Charge>0){ 
                        i=i_cation;
                        if (bleached) i=i_bpos;
                }
                else if (m_Charge==0) i=i_neutral;
                else{ 
                        i=i_anion;
                        if (bleached) i=i_bneg;
                }
                int x=i.getWidth(null)/2;
                int y=i.getHeight(null)/2;
                g.drawImage(i,m_CurrentLocation.x-x,m_CurrentLocation.y-y,null);
        }

        
        //--------------------------------------------------------------------------
        public void MoveParticle(Graphics g){
                if (!Active) return;
                Color c;
                if (m_Charge>0) c=m_pos;
                else if (m_Charge==0) c=m_neut;
                else c=m_neg;
                g.setColor(c);
                
                NewMove();
                g.drawLine(m_OldLoc.x,m_OldLoc.y,m_CurrentLocation.x,m_CurrentLocation.y);
        }





}