package com.onaro.util.jfc;

import javax.swing.JComboBox;

import java.awt.Dimension;

/**
 * Fixes the toolbar's problem in which the combo-box consume all the
 * space available in the toolbar by limiting its size.
 */
/**
 * @param <T>
 */
public class OnaroComboBox<T> extends JComboBox<T> {
    private static final long serialVersionUID = 1L;

    private final int maxBoxWidth;
    private int minListWidth = -1;

    /**
     * Create a combo box containing the given items. The box will be as
     * wide as the widest item string up to the specified maximum width.
     * Its size will not vary. The drop-down list will be as wide as necessary
     * to show all the item strings.
     * <p>
     * If {@link #setPreferredSize} or  {@link #setPreferredSize} is invoked
     * before the box is rendered, then the arguments passed to those methods
     * will determine the box and list size.
     * 
     * @param maxBoxWidth Maximum allowed width of the box
     * @param items Objects selected in drop-down list
     */
    @SafeVarargs
    public OnaroComboBox(int maxBoxWidth, T... items) {
        super(items);
        this.maxBoxWidth = maxBoxWidth;
    }

    /**
     * Create a combo box containing the given items. The box will be as wide
     * as the widest item string. Its size will not vary.
     * 
     * @param items Objects selected in drop-down list
     */
    @SafeVarargs
    public OnaroComboBox(T... items) {
        this (Integer.MAX_VALUE, items);
    }

    /**
     * Fixes the toolbar's problem in which the combo-box consume all the
     * space available in the toolbar by limiting its size.
     * <p>
     * BSK: This method doesn't do exactly what it says above, but retaining
     * it for backward compatibility. What it does is prevent the box
     * from getting bigger than its preferred size. If its preferred
     * size is very wide, it will still consume all the width available
     * in the toolbar. To limit the preferred size, pass an int to the
     * {@link #OnaroComboBox constructor}.
     *
     * @return the maximum allowed size for this combo-box
     */
    @Override
    public Dimension getMaximumSize() {
        return getPreferredSize();
    }

    @SuppressWarnings("unchecked")
    public T getSelectedObject() {
        return (T) getSelectedItem();
    }

    /*
     * This gets the size of the box in the toolbar. Generally,
     * the minimum and preferred sizes of this box are the same.
     * The only possible exception is if the caller has invoked
     * setPreferredSize and/or setMinimumSize().
     * 
     * The width of the box is limited if maxWidth is passed to
     * the constructor.
     * 
     * @see javax.swing.JComponent#getPreferredSize()
     */
    @Override
    public Dimension getPreferredSize() {
        Dimension size = super.getPreferredSize();
        // Adjust box size if requested and not done yet.
        if (! isPreferredSizeSet() && size.width > maxBoxWidth) {
            size.width = maxBoxWidth;
            setPreferredSize (size);
        }
        return size;
    }
    
    /*
     * This gets the size of the box in the toolbar. Generally,
     * the minimum and preferred sizes of this box are the same.
     * The only possible exception is if the caller has invoked
     * setPreferredSize and/or setMinimumSize().
     * 
     * The original width of the toolbar box is saved so that it
     * can be used when setting the size of the drop-down list.
     * 
     * @see javax.swing.JComponent#getMinimumSize()
     */
    @Override
    public Dimension getMinimumSize() {
        Dimension size = super.getMinimumSize();
        // Adjust box size if necessary, but not list size.
        if (! isMinimumSizeSet() && maxBoxWidth < Integer.MAX_VALUE) {
            // Minimum list width is original box width.
            minListWidth = size.width;
            setMinimumSize (getPreferredSize());
        }
        return size;
    }
    
    /*
     * This gets the size of the drop-down list box.
     * 
     * Normally, the width of the list is the same as the width
     * of the toolbar box. But when the width of the toolbar box
     * has been reduced, we want to restore the list width to its
     * original width. In that case, the list width will be wider
     * than the toolbar box. That way the complete text for each
     * item will be visible when changing the selection.
     * 
     * @see java.awt.Component#getSize()
     */
    @Override
    public Dimension getSize() {
        Dimension size = super.getSize();
        // Ensure drop-down list width is wide enough for widest item.
        if (minListWidth > 0) {
            size.width = minListWidth;
        }
        return size;
    }
    
    @Override
    public void setSize (Dimension size) {
        if (minListWidth > 0 && minListWidth < size.width) {
            minListWidth = size.width;
        }
        super.setSize (size);
    }
}