/*
    * Created on Apr 9, 2005 by davidson
    */
   package ca.spaz.cron.ui;
   
   import java.awt.BorderLayout;
   import java.awt.event.*;
   import java.util.*;
   
  import javax.swing.*;
  import javax.swing.event.*;
  
  import ca.spaz.cron.database.*;
  import ca.spaz.gui.DoubleField;
  
  /***
   * A measure widget displays the UI for choosing an amount of a food item, based
   * on various Measures stored for the particular food being weighed.
   * 
   * @author davidson
   */
  public class MeasureWidget extends JPanel implements ItemListener, ActionListener, KeyListener {
     // initial weight by default
     private Measure curMeasure = Measure.GRAM;
     
     // list of weights for selected food
     private JComboBox measures = new JComboBox();
     
     // multiplier (amount) of currently showing weight
     private DoubleField multiplier = new DoubleField(0,8);
     
     // change listeners
     private Vector listeners = new Vector();
     
     // determiens if multiplier value is linked to the weight
     private boolean linked = false;
     
     /***
      * Construct a new measure widget
      */
     public MeasureWidget() {
        multiplier.setRange(0,1000000);
        multiplier.setValue(1);
        
        measures.addItemListener(this);
        multiplier.addActionListener(this);
        multiplier.addKeyListener(this);
        
        setLayout(new BorderLayout(4,4));
        add(multiplier, BorderLayout.WEST);
        add(measures, BorderLayout.CENTER);
     }
  
     /***
      * Set the measure to display weights for a particular food.
      */
     public void setFood(Food f) {
        measures.setModel(new DefaultComboBoxModel(f.getMeasures().toArray()));
        curMeasure = Measure.GRAM;
        fireChangeEvent();
     }
  
     /***
      * Set the weight to display
      * @param w the type of measure
      * @param mult the multiplier for that measure
      */
     public void setMeasure(Measure w, double mult) {
        measures.setSelectedItem(w);
        multiplier.setValue(mult);
        fireChangeEvent();
     }
  
     /***
      * Update the widget after a weight change has occurred.
      * Called when weight menu is changed or edited
      */
     public void updateMeasure() {
        Measure w = getSelectedMeasure();
        if (w != curMeasure) {
           // if linked, the weight translates the multiplier from the last
           // selected weight, such that the actual amount of food stays constant.         
           if (linked) {
              double mult = w.getAmount();
              if (curMeasure != null) {
                 double grams = curMeasure.getGrams() * multiplier.getValue();
                 mult = grams/w.getGrams();
              }
              multiplier.setValue(mult);
           }
           focus();
           curMeasure = w;
        }
        fireChangeEvent();
     }      
  
     /***
      * Get the multiplier for the current weight and mult settings.
      * @return a multiple of the standard nutrient value (x per 100g)
     */
    public double getMultiplier() {
       return getGrams() / 100.0;
    }
 
    /***
     * Get the number of grams in this measure
     * @return the number of grams in this state
     */
    public double getGrams() {
       Measure w = getSelectedMeasure();
       if (w != null) {
          return multiplier.getValue() * w.getGrams();// * (1.0/w.getAmount()); 
       }
       return 0;
    }
    
    public Measure getSelectedMeasure() {
       return (Measure)measures.getSelectedItem();
    }
    
    /***
     * Focus the component, selecting the text field and giving it 
     * keyboard focus.
     */
    public void focus() {
       multiplier.requestFocus();
       multiplier.selectAll();      
    }
    
    public void addChangeListener(ChangeListener l) {
       listeners.add(l);
    }
 
    public void addRemoveListener(ChangeListener l) {
       listeners.remove(l);
    }
    
    public void fireChangeEvent() {
       ChangeEvent ce = new ChangeEvent(this);
       Iterator iter = listeners.iterator();
       while (iter.hasNext()) {
          ((ChangeListener)iter.next()).stateChanged(ce);
       }
    }
 
    /***
     * Called if the weight menu state is changed
     */
    public void itemStateChanged(ItemEvent e) {
       updateMeasure();
    }
 
    /***
     * Called when the text field is set
     */
    public void actionPerformed(ActionEvent arg0) {
       fireChangeEvent();
    }
 
    public void keyTyped(KeyEvent arg0) {
    }
 
    public void keyPressed(KeyEvent arg0) {
    }
 
    /***
     * Called when the text field is edited
     */
    public void keyReleased(KeyEvent arg0) {
       fireChangeEvent();
    }
 
    /***
     * If linked, changing a weight will update the multiplier
     * to keep the grams constant. Otherwise, the multiplier is left unchanged.
     * 
     * @return true if the multiplier is linked to the weight
     */
    public boolean isLinked() {
       return linked;
    }
 
 
    /***
     * If linked, changing a weight will update the multiplier
     * to keep the grams constant. Otherwise, the multiplier 
     * is left unchanged.
     */
    public void setLinked(boolean linked) {
       this.linked = linked;
    }
 }