/**
*
* @title DictSearch
* @author James McElvenny
*
* This class reads the parameters passed to the applet, sets up the user interface and calls the IndexSearcher
* when the user clicks the search button.
*
*/

import javax.swing.JButton;
import javax.swing.JTextField;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JApplet;
import javax.swing.JList;
import javax.swing.JScrollPane;
import javax.swing.ListSelectionModel;
import javax.swing.DefaultListModel;

import java.awt.Container;
import java.awt.BorderLayout;
import java.awt.FlowLayout;
import java.awt.Dimension;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;

import java.net.URL;
import java.net.MalformedURLException;

import java.io.IOException;

import javax.xml.xpath.XPathExpressionException;
import org.xml.sax.SAXException;
import javax.xml.parsers.ParserConfigurationException;

public class DictSearch extends JApplet
{
	public static final String ERROR_MESSAGE = "No matches found.";

	private int appletWidth;
	private int appletHeight;

	private String[] indexes;
	private String entryPath;
	private String indexFile;
	private String server;
	
	private IndexSearcher searcher;

	public void init()
	{
		getSettings();
		
		try 
		{
			searcher = new IndexSearcher(server, indexFile, entryPath);
		}
		catch(ParserConfigurationException pce)
		{
			System.out.println("Exception occurred: " + pce);
		}
	
		setupGUI();
	}
	
	/**
	*
	* This method reads the applet parameters from the HTML code and sets up the other applet settings.
	*
	*/
	private void getSettings()
	{
		String appletWidthIn = getParameter("width");
		if(appletWidthIn == null)
		{
			appletWidth = 640;
		}
		else
		{
			appletWidth = Integer.parseInt(appletWidthIn);
		}

		String appletHeightIn = getParameter("height");
		if(appletHeightIn == null)
		{
			appletHeight = 480;
		}
		else
		{
			appletHeight = Integer.parseInt(appletHeightIn);
		}		
		
		String indexesInput = getParameter("indexes");
		if(indexesInput == null)
		{
			System.out.println("OICH!");
			//need some error code here!!
		}
		else
		{	
			indexes = indexesInput.split("[\\s|,]");
		}
		
		entryPath = getParameter("entryPath");
		if(entryPath == null)
		{
			entryPath = "/index/entry";
		}
		
		indexFile = getParameter("indexFile");
		if(indexFile == null)
		{
			indexFile = "index.xml";
		}
		
		//Get the address of the server
		String docBase = this.getDocumentBase().toString();
		int endIndex = docBase.lastIndexOf("/");
		server = new String(docBase.substring(0,endIndex) + "/");
	}
	
	/**
	*
	* This method sets up the applet GUI.
	*
	*/
	private void setupGUI()
	{		
		int searchAreaHeight = 30;
		int buttonWidth = 100;
		int textFieldWidth = appletWidth - (buttonWidth * 2);
		int searchPanelHeight = searchAreaHeight * 2;
		int resultsHeight = appletHeight - (searchAreaHeight + searchPanelHeight);
		
		Dimension buttonSize = new Dimension(buttonWidth, searchAreaHeight);
		Dimension textSize = new Dimension(textFieldWidth, searchAreaHeight);
		Dimension indexSize = new Dimension(appletWidth, searchAreaHeight);
		Dimension resultsSize = new Dimension(appletWidth, resultsHeight);
		Dimension searchPanelSize = new Dimension(appletWidth, searchPanelHeight);
		
		//Set up the search text field
		final JTextField searchText = new JTextField();
		searchText.setMinimumSize(textSize);
		searchText.setPreferredSize(textSize);
		
		//Set up the search button
		JButton searchButton = new JButton("Search");
		searchButton.setMinimumSize(buttonSize);
		searchButton.setPreferredSize(buttonSize);
		
		//Set up panel for the search area
		JPanel searchPanel = new JPanel(new FlowLayout());
		searchPanel.setMinimumSize(searchPanelSize);
		searchPanel.setPreferredSize(searchPanelSize);
		searchPanel.add(searchText);
		searchPanel.add(searchButton);
		
		//Set up the index selection box
		DefaultListModel indexListModel = new DefaultListModel();
		
		final JList indexList = new JList(indexListModel);
		indexList.setSelectionMode(ListSelectionModel.SINGLE_INTERVAL_SELECTION);
		indexList.setLayoutOrientation(JList.HORIZONTAL_WRAP);
		indexList.setVisibleRowCount(-1);
		
		for (String e : indexes)
			indexListModel.addElement(e);
			
		indexList.setSelectedIndex(0);
		
		//Set up the results list
		final DefaultListModel resultsListModel = new DefaultListModel();
		
		final JList resultsList = new JList(resultsListModel);
		resultsList.setSelectionMode(ListSelectionModel.SINGLE_INTERVAL_SELECTION);
		resultsList.setLayoutOrientation(JList.VERTICAL);
		resultsList.setVisibleRowCount(-1);
		
		//Set up the scroll pane for the list
		JScrollPane listScroller = new JScrollPane(resultsList);
		listScroller.setPreferredSize(resultsSize);
		listScroller.setMaximumSize(resultsSize);
		
		//Add components to the GUI and display
		JPanel topPanel = new JPanel(new BorderLayout());
		topPanel.add(listScroller, BorderLayout.SOUTH);
		topPanel.add(indexList, BorderLayout.CENTER);
		topPanel.add(searchPanel, BorderLayout.NORTH);
	
		Container content = getContentPane();
		content.add(topPanel);
				
		/**
		*
		* This is an embedded class that provides the action for the button
		*
		*/
		class SearchClickListener implements ActionListener
		{
			public void actionPerformed(ActionEvent event)
			{
				resultsListModel.clear();
			
				String index = (String) indexList.getSelectedValue();	
				String searchString = searchText.getText();
				DefaultListModel outputTarget = resultsListModel;
			
				try
				{
					searcher.searchIndex(index, searchString, outputTarget);
				}
				catch(SAXException se)
				{
					System.out.println(se + " occurred.");
				}
				catch(IOException ioe)
				{
					System.out.println(ioe + "occurred.");
				}
				catch(XPathExpressionException xpe)
				{
					System.out.println(xpe + "occurred.");
				}				
			}
		}
		
		/**
		*
		* This is an embedded class that detects double-clicks on the resultsList
		*
		*/
		class ResultsDoubleClick extends MouseAdapter
		{
			public void mouseClicked(MouseEvent event)
			{
				if(event.getClickCount() == 2)
				{
					String entryToOpen = (String) resultsList.getSelectedValue();
					
					if(entryToOpen != null && entryToOpen != ERROR_MESSAGE)
					{
						try
						{
							URL destination = new URL(server + entryToOpen);
							getAppletContext().showDocument(destination);
						}
							catch(MalformedURLException mue)
						{
							System.out.println(mue + " occurred.");
						}
					}
				}
			}			
		}
		
		//Link embedded action listener class to the button
		ActionListener searchButtonListener = new SearchClickListener();
		searchButton.addActionListener(searchButtonListener);	
		
		//Link embedded mouse listener to resultsList
		MouseAdapter resultsListListener = new ResultsDoubleClick();
		resultsList.addMouseListener(resultsListListener);
	}
}