package com.onaro.util.jfc;

import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.Font;
import java.awt.Insets;
import java.beans.PropertyChangeEvent;
import java.beans.PropertyChangeListener;

import javax.swing.JButton;
import javax.swing.JComponent;
import javax.swing.JLabel;
import javax.swing.JPanel;

import org.apache.commons.lang3.StringUtils;

import com.onaro.commons.beans.IPropertyChangeSupport;

/**
 * UI component for showing/hiding a component using a collapsible section. The section consists
 * of an arrow icon indicating whether the section is expanded or collapsed and header text that the user
 * can click on to expand/collapse the section. When the section is expanded the child component is displayed,
 * indented from the section's justification. This class has the following bound properties: {@link #PROP_EXPANDED},
 * {@link #PROP_HEADER_TEXT}, {@link #PROP_CHILD_COMPONENT}.
 */
public class CollapsibleSection extends JPanel implements IPropertyChangeSupport {
    
    private static final long serialVersionUID = 1L;
    
    /**
     * Property used for notification of changes to the CollapsibleSection's expansion state
     */
    public static final String PROP_EXPANDED = Accordion.PROP_EXPANDED;
    
    /**
     * Property used for notification of changes to the CollapsibleSection's header text
     */
    public static final String PROP_HEADER_TEXT = "headerText"; //$NON-NLS-1$
    
    /**
     * Property used for notification of changes to the CollapsibleSection's child component
     */
    public static final String PROP_CHILD_COMPONENT = "childComponent"; //$NON-NLS-1$
        
    protected final Accordion accordion;
    protected final JLabel spacerLabel;
    
    protected JComponent childComponent;
    
    /**
     * Create a collapsible section with the given child component to display when
     * in the expanded state. The section is collapsed by default (can be changed 
     * using {@link #setExpanded(boolean)}).
     * 
     * @param headerText the text to display in the section header (the clickable text used to 
     *      expand/collapse the section). 
     * @param childComponent the component that's shown when the section is expanded.
     */
    public CollapsibleSection(String headerText, JComponent childComponent) {
        this(headerText);
        setChildComponent(childComponent);
    }
    
    /**
     * Create a collapsible section without specifying the child component. The child
     * component must be specified later using {@link #setChildComponent(JComponent)} for
     * the collapsible section to be useful. The section is collapsed by default (can be changed 
     * using {@link #setExpanded(boolean)}).
     * @param headerText the text to display in the section header (the clickable text used to 
     *      expand/collapse the section).
     */
    public CollapsibleSection(String headerText) {
        JButton sectionHeader = new ButtonField(headerText);
        sectionHeader.setMargin(new Insets(1, 1, 1, 1));
        sectionHeader.setFont(sectionHeader.getFont().deriveFont(Font.BOLD));

        accordion = new Accordion(sectionHeader);
        accordion.addPropertyChangeListener (PROP_EXPANDED, new PropertyChangeListener() {
            @Override
            public void propertyChange (PropertyChangeEvent event) {
                spacerLabel.setVisible(accordion.isExpanded());
                if (childComponent != null) {
                    childComponent.setVisible (accordion.isExpanded());
                }
                validate();
                setPreferredSize(getMinimumSize());
                firePropertyChange(PROP_EXPANDED, event.getOldValue(), event.getNewValue());
            }
        });
        
        spacerLabel = new JLabel();
        Dimension size = new Dimension(20, 1);
        spacerLabel.setSize(size);
        spacerLabel.setMinimumSize(size);
        spacerLabel.setPreferredSize(size);
        spacerLabel.setMaximumSize(size);
        spacerLabel.setVisible(accordion.isExpanded());
        
        setLayout(new BorderLayout());
        add(sectionHeader, BorderLayout.NORTH);
        add(spacerLabel, BorderLayout.WEST);
        setPreferredSize(getMinimumSize());
    }
    
    /**
     * Set the expansion state of the collapsible section
     * @param expanded true to expand the section, false to collapse
     */
    public void setExpanded(boolean expanded) {
        accordion.setExpanded(expanded);
    }
    
    /**
     * Get the expansion state of the collapsible section.
     * @return true if the section is expanded, false if collapsed
     */
    public boolean isExpanded() {
        return accordion.isExpanded();
    }
    
    /**
     * Set the component to display within the collapsible section when expanded.
     * @param childComponent the component to display
     */
    public void setChildComponent(JComponent childComponent) {
        if (this.childComponent == childComponent) {
            return;
        }
        
        JComponent oldComponent = this.childComponent;
        if (oldComponent != null) {
            remove(oldComponent);
        }
        this.childComponent = childComponent;
        add(this.childComponent, BorderLayout.CENTER);
        
        this.childComponent.setVisible(accordion.isExpanded());
        
        validate();
        setPreferredSize(getMinimumSize());
        firePropertyChange(PROP_CHILD_COMPONENT, oldComponent, childComponent);
    }
    
    /**
     * Get the component that's displayed in the collapsible section when expanded.
     * @return the display component
     */
    public JComponent getChildComponent() {
        return childComponent;
    }
    
    /**
     * Set the text shown in the section header (the clickable text used to expand/collapse the section).
     * @param headerText the text for the header
     */
    public void setHeaderText(String headerText) {
        String oldText = getHeaderText();
        if (StringUtils.equals(oldText, headerText)) {
            return;
        }
        
        accordion.getController().setText(headerText);
        firePropertyChange(PROP_HEADER_TEXT, oldText, headerText);
    }
    
    /**
     * Get the text shown in the section header (the clickable text used to expand/collapse the section).
     * @return the text for the header
     */
    public String getHeaderText() {
        return accordion.getController().getText();
    }
}