/*******************************************************************************
 * Copyright (C) 2007 The University of Manchester   
 * 
 *  Modifications to the initial code base are copyright of their
 *  respective authors, or their employers as appropriate.
 * 
 *  This program is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU Lesser General Public License
 *  as published by the Free Software Foundation; either version 2.1 of
 *  the License, or (at your option) any later version.
 *    
 *  This program is distributed in the hope that it will be useful, but
 *  WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 *  Lesser General Public License for more details.
 *    
 *  You should have received a copy of the GNU Lesser General Public
 *  License along with this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
 ******************************************************************************/
package net.sf.taverna.t2.workbench.ui.credentialmanager;

import static java.awt.BorderLayout.CENTER;
import static java.awt.BorderLayout.SOUTH;
import static java.awt.BorderLayout.WEST;
import static java.awt.Font.PLAIN;
import static javax.security.auth.x500.X500Principal.RFC2253;
import static javax.swing.BoxLayout.Y_AXIS;
import static javax.swing.JOptionPane.WARNING_MESSAGE;
import static javax.swing.JOptionPane.showMessageDialog;
import static javax.swing.ListSelectionModel.MULTIPLE_INTERVAL_SELECTION;
import static javax.swing.ScrollPaneConstants.HORIZONTAL_SCROLLBAR_AS_NEEDED;
import static javax.swing.ScrollPaneConstants.VERTICAL_SCROLLBAR_AS_NEEDED;
import static net.sf.taverna.t2.workbench.ui.credentialmanager.CMStrings.ALERT_TITLE;

import java.awt.BorderLayout;
import java.awt.FlowLayout;
import java.awt.Font;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import java.security.cert.X509Certificate;
import java.util.ArrayList;

import javax.swing.BoxLayout;
import javax.swing.JButton;
import javax.swing.JDialog;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JList;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.border.CompoundBorder;
import javax.swing.border.EmptyBorder;
import javax.swing.border.EtchedBorder;
import javax.swing.event.ListSelectionEvent;
import javax.swing.event.ListSelectionListener;

import org.apache.taverna.security.credentialmanager.DistinguishedNameParser;
import org.apache.taverna.security.credentialmanager.ParsedDistinguishedName;
import net.sf.taverna.t2.workbench.helper.NonBlockedHelpEnabledDialog;

/**
 * Allows the user to import one or more trusted certificates from a file.
 */
@SuppressWarnings("serial")
public class NewTrustCertsDialog extends NonBlockedHelpEnabledDialog {
	private JList<String> trustedCertsJList;
	/** List of trusted certs read from the file and available for import */
	private ArrayList<X509Certificate> availableTrustedCerts = new ArrayList<>();
	/** List of trusted certs selected for import */
	private ArrayList<X509Certificate> selectedTrustedCerts;
	private final DistinguishedNameParser dnParser;

	public NewTrustCertsDialog(JFrame parent, String title, boolean modal,
			ArrayList<X509Certificate> lCerts, DistinguishedNameParser dnParser) {
		super(parent, title, modal);
		availableTrustedCerts = lCerts;
		this.dnParser = dnParser;
		initComponents();
	}

	public NewTrustCertsDialog(JDialog parent, String title, boolean modal,
			ArrayList<X509Certificate> lCerts, DistinguishedNameParser dnParser) {
		super(parent, title, modal);
		availableTrustedCerts = lCerts;
		this.dnParser = dnParser;
		initComponents();
	}

	private void initComponents() {
		// Instructions
		JLabel instructionsLabel = new JLabel(
				"Select one or more certificates for import:");
		instructionsLabel.setFont(new Font(null, PLAIN, 11));
		instructionsLabel.setBorder(new EmptyBorder(5, 5, 5, 5));
		JPanel instructionsPanel = new JPanel(new BorderLayout());
		instructionsPanel.add(instructionsLabel, WEST);

		// Import button
		final JButton importButton = new JButton("Import");
		importButton.setEnabled(false);
		importButton.addActionListener(new ActionListener() {
			@Override
			public void actionPerformed(ActionEvent evt) {
				importPressed();
			}
		});

		// Certificate details button
		final JButton certificateDetailsButton = new JButton(
				"Certificate Details");
		certificateDetailsButton.setEnabled(false);
		certificateDetailsButton.addActionListener(new ActionListener() {
			@Override
			public void actionPerformed(ActionEvent evt) {
				certificateDetailsPressed();
			}
		});

		// List with trusted certs' aliases
		trustedCertsJList = new JList<>();
		trustedCertsJList.setSelectionMode(MULTIPLE_INTERVAL_SELECTION);
		trustedCertsJList.addListSelectionListener(new ListSelectionListener() {
			@Override
			public void valueChanged(ListSelectionEvent evt) {
				boolean enabled = trustedCertsJList.getSelectedIndex() >= 0;
				importButton.setEnabled(enabled);
				certificateDetailsButton.setEnabled(enabled);
			}
		});
		// Populate the list - get the certificate subjects' CNs
		ArrayList<String> cns = new ArrayList<>();
		for (int i = 0; i < availableTrustedCerts.size(); i++) {
			String subjectDN = ((X509Certificate) availableTrustedCerts.get(i))
					.getSubjectX500Principal().getName(RFC2253);
			ParsedDistinguishedName parsedDN = dnParser.parseDN(subjectDN);
			String subjectCN = parsedDN.getCN();
			cns.add(i, subjectCN);
		}
		trustedCertsJList.setListData(cns.toArray(new String[0]));
		trustedCertsJList.setSelectedIndex(0);

		// Put the list into a scroll pane
		JScrollPane trustedCertsScrollPanel = new JScrollPane(
				trustedCertsJList, VERTICAL_SCROLLBAR_AS_NEEDED,
				HORIZONTAL_SCROLLBAR_AS_NEEDED);
		trustedCertsScrollPanel.getViewport().setBackground(
				trustedCertsJList.getBackground());

		JPanel trustedCertsPanel = new JPanel();
		trustedCertsPanel.setLayout(new BoxLayout(trustedCertsPanel, Y_AXIS));
		trustedCertsPanel.setBorder(new CompoundBorder(new CompoundBorder(
				new EmptyBorder(5, 5, 5, 5), new EtchedBorder()),
				new EmptyBorder(5, 5, 5, 5)));

		instructionsPanel.setAlignmentY(LEFT_ALIGNMENT);
		trustedCertsPanel.add(instructionsPanel);
		trustedCertsScrollPanel.setAlignmentY(LEFT_ALIGNMENT);
		trustedCertsPanel.add(trustedCertsScrollPanel);
		certificateDetailsButton.setAlignmentY(RIGHT_ALIGNMENT);
		trustedCertsPanel.add(certificateDetailsButton);

		// Cancel button
		final JButton cancelButton = new JButton("Cancel");
		cancelButton.addActionListener(new ActionListener() {
			@Override
			public void actionPerformed(ActionEvent evt) {
				cancelPressed();
			}
		});

		JPanel jpButtons = new JPanel(new FlowLayout(FlowLayout.CENTER));
		jpButtons.add(importButton);
		jpButtons.add(cancelButton);

		getContentPane().setLayout(new BorderLayout());
		getContentPane().add(trustedCertsPanel, CENTER);
		getContentPane().add(jpButtons, SOUTH);

		addWindowListener(new WindowAdapter() {
			@Override
			public void windowClosing(WindowEvent evt) {
				closeDialog();
			}
		});

		setResizable(false);
		getRootPane().setDefaultButton(importButton);
		pack();
	}

	/**
	 * Shows the selected key pair's certificate.
	 */
	private void certificateDetailsPressed() {
		try {
			int i = trustedCertsJList.getSelectedIndex();

			X509Certificate cert = (X509Certificate) availableTrustedCerts
					.get(i);

			ViewCertDetailsDialog viewCertificateDialog = new ViewCertDetailsDialog(
					this, "Certificate details", true, cert, null, dnParser);
			viewCertificateDialog.setLocationRelativeTo(this);
			viewCertificateDialog.setVisible(true);
		} catch (Exception ex) {
			showMessageDialog(this,
					"Failed to obtain certificate details to show",
					ALERT_TITLE, WARNING_MESSAGE);
			closeDialog();
		}
	}

	/**
	 * Get the trusted certificates selected for import.
	 */
	public ArrayList<X509Certificate> getTrustedCertificates() {
		return selectedTrustedCerts;
	}

	/**
	 * Store the selected trusted certs.
	 */
	public void importPressed() {
		int[] selectedValues = trustedCertsJList.getSelectedIndices();
		selectedTrustedCerts = new ArrayList<>();
		for (int i = 0; i < selectedValues.length; i++)
			selectedTrustedCerts.add(availableTrustedCerts
					.get(selectedValues[i]));
		closeDialog();
	}

	public void cancelPressed() {
		/*
		 * Set selectedTrustCerts to null to indicate that user has cancelled
		 * the import
		 */
		selectedTrustedCerts = null;
		closeDialog();
	}

	private void closeDialog() {
		setVisible(false);
		dispose();
	}
}