package com.dwave.gui;

import java.awt.event.FocusListener; 
import java.awt.event.FocusEvent;
import java.util.StringTokenizer;
import javax.swing.JTextField;
import javax.swing.BorderFactory;
import javax.swing.text.Document;
import com.dwave.util.ParseFunction;
import com.dwave.util.ParseException;

public class DMathTextField extends DTextField {
  public static final int INTEGER = 0,
                          DOUBLE = 1,
                          FLOAT = 2;
  private int objectType = 1;

    /**
     * Constructs a new TextField.  A default model is created, the initial
     * string is null, and the number of columns is set to 0.
     */
    public DMathTextField() {
        this(null, null, 0);
    }

    /**
     * Constructs a new TextField initialized with the specified text.
     * A default model is created and the number of columns is 0.
     *
     * @param text the text to be displayed, or null
     */
    public DMathTextField(String text) {
        this(null, text, 0);
    }

    /**
     * Constructs a new empty TextField with the specified number of columns.
     * A default model is created and the initial string is set to null.
     *
     * @param columns  the number of columns to use to calculate 
     *   the preferred width.  If columns is set to zero, the
     *   preferred width will be whatever naturally results from
     *   the component implementation.
     */ 
    public DMathTextField(int columns) {
        this(null, null, columns);
    }

    /**
     * Constructs a new TextField initialized with the specified text
     * and columns.  A default model is created.
     *
     * @param text the text to be displayed, or null
     * @param columns  the number of columns to use to calculate 
     *   the preferred width.  If columns is set to zero, the
     *   preferred width will be whatever naturally results from
     *   the component implementation.
     */
    public DMathTextField(String text, int columns) {
        this(null, text, columns);
    }

    /**
     * Constructs a new DMathTextField that uses the given text storage
     * model and the given number of columns.  This is the constructor
     * through which the other constructors feed.  If the document is null,
     * a default model is created.
     *
     * @param doc  the text storage to use.  If this is null, a default
     *   will be provided by calling the createDefaultModel method.
     * @param text  the initial string to display, or null
     * @param columns  the number of columns to use to calculate 
     *   the preferred width >= 0.  If columns is set to zero, the
     *   preferred width will be whatever naturally results from
     *   the component implementation.
     * @exception IllegalArgumentException if columns < 0
     */
    public DMathTextField(Document doc, String text, int columns) {
      super(doc, text, columns);
      this.addFocusListener(this);
      this.setBorder(BorderFactory.createLoweredBevelBorder());
    }
    
    public double getTextEvaluatedNumerically() throws ParseException {
      ParseFunction parser = new ParseFunction(this.getText());
      if(parser.parse())
        return parser.getResult();
      else
        throw new ParseException("Unable to parse expression: "+this.getText());
    }
    public void setTextToEvaluation() throws ParseException {
      ParseFunction parser = new ParseFunction(this.getText());
      if(parser.parse()) {
        switch(objectType) {
          case(DOUBLE):
            this.setText(new Double(parser.getResult()).toString());
           break;
          case(INTEGER):
            this.setText(new Integer((int)parser.getResult()).toString());
           break;
          case(FLOAT):
            this.setText(new Float((float)parser.getResult()).toString());
           break;
        }
        this.setCaretPosition(0);
      }
      else
        throw new ParseException("Unable to parse expression: "+this.getText());
    }          
    /**
     * Invoked when a component loses the keyboard focus.
     */
    public void focusLost(FocusEvent fe) {
      try {
        if(this.getText() != null)
          this.setTextToEvaluation();
        else
          this.setText("0.0");
      }
      catch(Exception e) {      
        this.setText("0.0");
      }
    }
    public boolean setNumericType(int type) {
      if(type >= 0 && type <= 3) {
        objectType = type;
        return true;
      }
      return false;
    }
    public int getNumericType() { return objectType; }
}