/**
 * The contents of this file are subject to the license and copyright
 * detailed in the LICENSE and NOTICE files at the root of the source
 * tree and available online at
 *
 * http://www.dspace.org/license/
 */
package org.purl.sword.client;

import java.awt.Component;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.Insets;

import javax.swing.JPanel;

/**
 * Utility class. Creates a two column form. The left column is used to show 
 * the label for the row. The right column is used to show the control, e.g. 
 * text box, combo box or checkbox, for the row. 
 * 
 * @author Neil Taylor
 */
public class SWORDFormPanel extends JPanel
{
    /**
     * Constraints used to control the layout on the panel. 
     */
    private GridBagConstraints labelConstraints; 
    
    /**
     * Constraints used to control the layout of the input controls on the panel. 
     */
    private GridBagConstraints controlConstraints; 
    
    /** 
     * Index to the next row.
     */
    private int rowIndex = 0; 
    
    /**
     * Insets for the top row of the label column. 
     */
    private Insets labelTop = new Insets(10, 10, 0, 0);
    
    /**
     * Insets for the top row of the control column. 
     */
    private Insets controlTop = new Insets(10, 4, 0, 10);
    
    /**
     * Insets for a general row in the label column. 
     */
    private Insets labelGeneral = new Insets(3, 10, 0, 0);
    
    /**
     * Insets for a general row in the control column. 
     */
    private Insets controlGeneral = new Insets(3, 4, 0, 10); 
    
    /**
     * Create a new instance of the class. 
     */
    public SWORDFormPanel() 
    {
        super(); 
        setLayout(new GridBagLayout());
        
        labelConstraints = new GridBagConstraints();
        labelConstraints.fill = GridBagConstraints.NONE;
        labelConstraints.anchor = GridBagConstraints.LINE_END;
        labelConstraints.weightx = 0.1;
       
        controlConstraints = new GridBagConstraints();
        controlConstraints.fill = GridBagConstraints.HORIZONTAL;
        controlConstraints.weightx = 0.9;
    }
    
    /**
     * Add the specified component as the first row. It will occupy two 
     * columns. 
     * 
     * @param one The control to add.
     */
    public void addFirstRow(Component one)
    {
        addRow(one, null, labelTop, controlTop);
    }
    
    /**
     * Add the specified components as the first row in the form. 
     * @param one The label component. 
     * @param two The control component. 
     */
    public void addFirstRow(Component one, Component two)
    {
        addRow(one, two, labelTop, controlTop);
    }
    
    /**
     * Add a component to the general row. This will be added in the label column.  
     * @param one The component. 
     */
    public void addRow(Component one)
    {
        addRow(one, null);
    }
    
    /**
     * Add a component to the general row. 
     * @param one The component to add to the label column. 
     * @param two The component to add to the control column. 
     */
    public void addRow(Component one, Component two)
    {
        addRow(one, two, labelGeneral, controlGeneral);
    }
    
    /**
     * Add a row to the table. 
     * 
     * @param one The component to display in the label column. 
     * @param two The component to display in the control column. 
     * @param labels The insets for the label column. 
     * @param controls The insets for the controls column. 
     */
    protected void addRow(Component one, Component two, Insets labels, Insets controls )
    {
        labelConstraints.insets = labels; 
        labelConstraints.gridx = 0;
        labelConstraints.gridy = rowIndex;
        if ( two == null )
        {
            labelConstraints.gridwidth = 2;
        }
        else
        {
            labelConstraints.gridwidth = 1;
        }
        
        add(one, labelConstraints);
        
        if ( two != null )
        {
            controlConstraints.insets = controls; 
            controlConstraints.gridx = 1;
            controlConstraints.gridy = rowIndex;
            add(two, controlConstraints);
        }
        
        rowIndex++; 
    }
}