// File:    CurveManager.java

import java.awt.*;
import java.util.*;

/** Manages all the curves. **/

public class CurveManager {
  
  protected Vector curves = new Vector();
  protected PointManager pointManager;

  protected State state;

  public CurveManager(PointManager pointManager, State state) {
    this.pointManager = pointManager;
    this.state = state;
  }

  /** Returns the curves that contain cp as a control point. **/
  public Vector getCurves(ControlPoint cp) {
    Vector temp = new Vector();
    BezierCurve bc;
    Enumeration e = curves.elements();
    while (e.hasMoreElements()) {
      bc = (BezierCurve)e.nextElement();
      if (bc.contains(cp)) {
        temp.addElement(bc);
      }
    }
    return temp;
  }

  /** Create and add a new curve. Also perform any linking with other
      curves. **/
  public void addCurve(Point p0,
                       Point p1,
                       Point p2,
                       Point p3) {

    ControlPoint cp0, cp1, cp2, cp3;

    // The middle two are always new:
    cp1 = new ControlPoint(p1);
    cp2 = new ControlPoint(p2);
    
    // Potentially link ends with other curves:
    // *** This code has become pretty "hairy"... ***
    // *** Big bug-potential; should be rewritten ***

    // First end point:

    // Check if the point exists:
    if (pointManager.isControlPoint(p0)) {
      ControlPoint cp = pointManager.getControlPoint(p0);

      // Check if this is an endpoint an not a link between two
      // existing curves:
      // (Without this check we could get "forks")
      Vector curveList = getCurves(cp);
      if (curveList.size()==1) {
   BezierCurve theCurve = (BezierCurve)curveList.elementAt(0);
   int pointIndex = theCurve.getNumber(cp);
   switch (pointIndex) {
   case 0: {
     cp0 = cp;
     // Ensure continuity:
     ControlPoint temp = theCurve.getPoint(1);
     cp1.setController(temp);
     temp.setController(cp1);
     // Update the continuity:
     cp1.setPosition(cp1.getPosition());
     break;
   }
   case 1:
   case 2: {
     cp0 = new ControlPoint(p0);
     break;
   }
   case 3: {
     cp0 = cp;
     // Ensure continuity:
     ControlPoint temp = theCurve.getPoint(2);
     cp1.setController(temp);
     temp.setController(cp1);
     // Update the continuity:
     cp1.setPosition(cp1.getPosition());
     break;
   }
   default: {
     cp0 = new ControlPoint(p0);
   }
   } // End switch
      }
      else {
        cp0 = new ControlPoint(p0);
      }
    }
    else {
      cp0 = new ControlPoint(p0);
    }

    // Same thing with the second end point:

    // Check if the point exists:
    if (pointManager.isControlPoint(p3)) {
      ControlPoint cp = pointManager.getControlPoint(p3);

      // Check if this is an endpoint an not a link between two
      // existing curves:
      // (Without this check we could get "forks")
      Vector curveList = getCurves(cp);
      if (curveList.size()==1) {
   BezierCurve theCurve = (BezierCurve)curveList.elementAt(0);
   int pointIndex = theCurve.getNumber(cp);
   switch (pointIndex) {
   case 0: {
     cp3 = cp;
     // Ensure continuity:
     ControlPoint temp = theCurve.getPoint(1);
     cp2.setController(temp);
     temp.setController(cp2);
     // Update the continuity:
     cp2.setPosition(cp2.getPosition());
     break;
   }
   case 1:
   case 2: {
     cp3 = new ControlPoint(p3);
     break;
   }
   case 3: {
     cp3 = cp;
     // Ensure continuity:
     ControlPoint temp = theCurve.getPoint(2);
     cp2.setController(temp);
     temp.setController(cp2);
     // Update the continuity:
     cp2.setPosition(cp2.getPosition());
     break;
   }
   default: {
     cp3 = new ControlPoint(p3);
   }
   } // End switch
      }
      else {
        cp3 = new ControlPoint(p3);
      }
    }
    else {
      cp3 = new ControlPoint(p3);
    }
    

    // Set the anchors:

    cp1.setAnchor(cp0); // Link with corresponding end point

    cp2.setAnchor(cp3); // Link with corresponding end point

    pointManager.addPoint(cp0);
    pointManager.addPoint(cp1);
    pointManager.addPoint(cp2);
    pointManager.addPoint(cp3);

    BezierCurve bc = new BezierCurve(cp0,cp1,cp2,cp3,state);
    curves.addElement(bc);

  }

  public void paint(Graphics g, int samples) {
    Enumeration list = curves.elements();
    while (list.hasMoreElements()) {
      ((BezierCurve)list.nextElement()).paint(g,samples);
    }
  }

}