package com.onaro.sanscreen.client.login;


import javax.swing.DefaultListCellRenderer;
import javax.swing.JComboBox;
import javax.swing.JList;
import javax.swing.JOptionPane;
import java.awt.Component;
import java.security.KeyStore;
import java.security.KeyStoreException;
import java.security.cert.X509Certificate;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Enumeration;
import java.util.List;

/**
 * A very basic UI component that presents the certificates available in a provided KeyStore, and enables the
 * user to select the preferred certificate.<p/>
 *
 * @author Joshua M. Eisenthal  Copyright 2014 NetApp, Inc.
 */
public class CertificateChooser{
    static public CertificateWrapper chooseCertificate(final KeyStore keyStore) {
        try {
            List<String> aliases = new ArrayList<String>();
            Enumeration<String> aliasEnum = keyStore.aliases();
            while (aliasEnum.hasMoreElements()) {
                aliases.add(aliasEnum.nextElement());
            }
            Collections.sort(aliases);
            JComboBox<Object> certCombo = new JComboBox<Object>(aliases.toArray());
            certCombo.setRenderer(new DefaultListCellRenderer() {
                private static final long serialVersionUID = 1L;

                @Override
                public Component getListCellRendererComponent(JList<?> list, Object value, int index, boolean isSelected, boolean cellHasFocus) {
                    String alias = (String) value;
                    X509Certificate certificate = null;
                    try {
                        certificate = (X509Certificate) keyStore.getCertificate(alias);
                    } catch (KeyStoreException e) {
                        e.printStackTrace();
                    }
                    String certString = certificate != null ? certificate.getSubjectDN().toString() : null;
                    value = "<html><b>" + alias + "</b>" + ": " + certString + "</html>"; //$NON-NLS-1$ //$NON-NLS-2$ //$NON-NLS-3$ //$NON-NLS-4$ $NON-NLS-2$ /$NON-NLS-3$
                    return super.getListCellRendererComponent(list, value, index, isSelected, cellHasFocus);
                }
            });
            int result = JOptionPane.showConfirmDialog(null, certCombo, "Choose a Client Certificate", JOptionPane.OK_CANCEL_OPTION, JOptionPane.INFORMATION_MESSAGE); //$NON-NLS-1$
            String selected = (String) certCombo.getSelectedItem();
            if (result == JOptionPane.OK_OPTION && selected != null) {
                return new CertificateWrapper((X509Certificate) keyStore.getCertificate(selected), selected);
            }
        } catch (KeyStoreException e) {
            e.printStackTrace();
        }
        return null;
    }

    static class CertificateWrapper {
        private X509Certificate certificate;
        private String alias;

        public CertificateWrapper(X509Certificate certificate, String alias) {
            this.certificate = certificate;
            this.alias = alias;
        }

        public X509Certificate getCertificate() {
            return certificate;
        }

        public String getAlias() {
            return alias;
        }

    }
}