// License: GPL. Copyright 2007 by Immanuel Scholz and others
package org.openstreetmap.josm.io;

import static org.openstreetmap.josm.tools.I18n.tr;

import java.awt.Font;
import java.awt.GridBagLayout;
import java.net.Authenticator;
import java.net.HttpURLConnection;
import java.net.PasswordAuthentication;
import java.nio.ByteBuffer;
import java.nio.CharBuffer;
import java.nio.charset.Charset;
import java.nio.charset.CharsetEncoder;
import java.nio.charset.CharacterCodingException;

import javax.swing.JCheckBox;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JPasswordField;
import javax.swing.JTextField;

import org.openstreetmap.josm.Main;
import org.openstreetmap.josm.gui.ExtendedDialog;
import org.openstreetmap.josm.tools.Base64;
import org.openstreetmap.josm.tools.GBC;

/**
 * Base class that handles common things like authentication for the reader and writer
 * to the osm server.
 *
 * @author imi
 */
public class OsmConnection {

    protected boolean cancel = false;
    protected HttpURLConnection activeConnection;

    private static OsmAuth authentication = new OsmAuth();
    /**
     * Initialize the http defaults and the authenticator.
     */
    static {
        // TODO: current authentication handling is sub-optimal in that it seems to use the same authenticator for
        // any kind of request. HTTP requests executed by plugins, e.g. to password-protected WMS servers,
        // will use the same username/password which is undesirable.
        try {
            HttpURLConnection.setFollowRedirects(true);
            Authenticator.setDefault(authentication);
        } catch (SecurityException e) {
        }
    }

    /**
     * The authentication class handling the login requests.
     */
    private static class OsmAuth extends Authenticator {
        /**
         * Set to true, when the autenticator tried the password once.
         */
        boolean passwordtried = false;
        /**
         * Whether the user cancelled the password dialog
         */
        boolean authCancelled = false;

        @Override protected PasswordAuthentication getPasswordAuthentication() {
            String username = Main.pref.get("osm-server.username");
            String password = Main.pref.get("osm-server.password");
            if (passwordtried || username.equals("") || password.equals("")) {
                JPanel p = new JPanel(new GridBagLayout());
                if (!username.equals("") && !password.equals("")) {
                    p.add(new JLabel(tr("Incorrect password or username.")), GBC.eop());
                }
                p.add(new JLabel(tr("Username")), GBC.std().insets(0,0,10,0));
                JTextField usernameField = new JTextField(username, 20);
                p.add(usernameField, GBC.eol());
                p.add(new JLabel(tr("Password")), GBC.std().insets(0,0,10,0));
                JPasswordField passwordField = new JPasswordField(password, 20);
                p.add(passwordField, GBC.eol());
                JLabel warning = new JLabel(tr("Warning: The password is transferred unencrypted."));
                warning.setFont(warning.getFont().deriveFont(Font.ITALIC));
                p.add(warning, GBC.eop());

                JCheckBox savePassword = new JCheckBox(tr("Save user and password (unencrypted)"), !username.equals("") && !password.equals(""));
                p.add(savePassword, GBC.eop());

                int choice = new ExtendedDialog(Main.parent,
                        tr("Enter Password"),
                        p,
                        new String[] {tr("Login"), tr("Cancel")},
                        new String[] {"ok.png", "cancel.png"}).getValue();

                if (choice != 1) {
                    authCancelled = true;
                    return null;
                }
                username = usernameField.getText();
                password = String.valueOf(passwordField.getPassword());
                if (savePassword.isSelected()) {
                    Main.pref.put("osm-server.username", username);
                    Main.pref.put("osm-server.password", password);
                }
                if (username.equals(""))
                    return null;
            }
            passwordtried = true;
            return new PasswordAuthentication(username, password.toCharArray());
        }
    }

    /**
     * Must be called before each connection attemp to initialize the authentication.
     */
    protected final void initAuthentication() {
        authentication.authCancelled = false;
        authentication.passwordtried = false;
    }

    /**
     * @return Whether the connection was cancelled.
     */
    protected final boolean isAuthCancelled() {
        return authentication.authCancelled;
    }

    public void cancel() {
        Main.pleaseWaitDlg.currentAction.setText(tr("Aborting..."));
        cancel = true;
        if (activeConnection != null) {
            activeConnection.setConnectTimeout(100);
            activeConnection.setReadTimeout(100);
            try {
                Thread.sleep(100);
            } catch (InterruptedException ex) {}
            activeConnection.disconnect();
        }
    }

    protected void addAuth(HttpURLConnection con) throws CharacterCodingException {
        CharsetEncoder encoder = Charset.forName("UTF-8").newEncoder();
        String auth = Main.pref.get("osm-server.username") + ":" + Main.pref.get("osm-server.password");
        ByteBuffer bytes = encoder.encode(CharBuffer.wrap(auth));
        con.addRequestProperty("Authorization", "Basic "+Base64.encode(bytes));
    }
}