/*
 * ConnectBot: simple, powerful, open-source SSH client for Android
 * Copyright 2007 Kenny Root, Jeffrey Sharkey
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.five_ten_sg.connectbot.util;

import java.nio.charset.Charset;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;

import com.five_ten_sg.connectbot.bean.HostBean;
import com.five_ten_sg.connectbot.bean.PortForwardBean;
import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteException;
import android.util.Log;

import com.trilead.ssh2.KnownHosts;

/**
 * Contains information about various SSH hosts, include public hostkey if known
 * from previous sessions.
 *
 * @author jsharkey
 */
public class HostDatabase extends RobustSQLiteOpenHelper {

    public final static String TAG = "ConnectBot.HostDatabase";

    public final static String DB_NAME = "hosts";
    public final static int DB_VERSION = 25;

    public final static String TABLE_HOSTS = "hosts";
    public final static String FIELD_HOST_NICKNAME = "nickname";
    public final static String FIELD_HOST_PROTOCOL = "protocol";
    public final static String FIELD_HOST_USERNAME = "username";
    public final static String FIELD_HOST_HOSTNAME = "hostname";
    public final static String FIELD_HOST_PORT = "port";
    public final static String FIELD_HOST_HOSTKEYALGO = "hostkeyalgo";
    public final static String FIELD_HOST_HOSTKEY = "hostkey";
    public final static String FIELD_HOST_LASTCONNECT = "lastconnect";
    public final static String FIELD_HOST_COLOR = "color";
    public final static String FIELD_HOST_USEKEYS = "usekeys";
    public final static String FIELD_HOST_USEAUTHAGENT = "useauthagent";
    public final static String FIELD_HOST_POSTLOGIN = "postlogin";
    public final static String FIELD_HOST_PUBKEYID = "pubkeyid";
    public final static String FIELD_HOST_WANTSESSION = "wantsession";
    public final static String FIELD_HOST_DELKEY = "delkey";
    public final static String FIELD_HOST_FONTSIZE = "fontsize";
    public final static String FIELD_HOST_COMPRESSION = "compression";
    public final static String FIELD_HOST_HTTPPROXY = "httpproxy";
    public final static String FIELD_HOST_ENCODING = "encoding";
    public final static String FIELD_HOST_STAYCONNECTED = "stayconnected";
    public final static String FIELD_HOST_WANTX11FORWARD = "wantx11forward";
    public final static String FIELD_HOST_X11HOST = "x11host";
    public final static String FIELD_HOST_X11PORT = "x11port";
    public final static String FIELD_HOST_MONITOR = "monitor";

    public final static String TABLE_PORTFORWARDS = "portforwards";
    public final static String FIELD_PORTFORWARD_HOSTID = "hostid";
    public final static String FIELD_PORTFORWARD_NICKNAME = "nickname";
    public final static String FIELD_PORTFORWARD_TYPE = "type";
    public final static String FIELD_PORTFORWARD_SOURCEPORT = "sourceport";
    public final static String FIELD_PORTFORWARD_DESTADDR = "destaddr";
    public final static String FIELD_PORTFORWARD_DESTPORT = "destport";

    public final static String TABLE_COLORS = "colors";
    public final static String FIELD_COLOR_SCHEME = "scheme";
    public final static String FIELD_COLOR_NUMBER = "number";
    public final static String FIELD_COLOR_VALUE = "value";

    public final static String TABLE_COLOR_DEFAULTS = "colorDefaults";
    public final static String FIELD_COLOR_FG = "fg";
    public final static String FIELD_COLOR_BG = "bg";

    public final static int DEFAULT_FG_COLOR = 7;
    public final static int DEFAULT_BG_COLOR = 0;

    public final static String COLOR_RED = "red";
    public final static String COLOR_GREEN = "green";
    public final static String COLOR_BLUE = "blue";
    public final static String COLOR_GRAY = "gray";

    public final static String PORTFORWARD_LOCAL = "local";
    public final static String PORTFORWARD_REMOTE = "remote";
    public final static String PORTFORWARD_DYNAMIC4 = "dynamic4";
    public final static String PORTFORWARD_DYNAMIC5 = "dynamic5";

    public final static String DELKEY_DEL = "del";
    public final static String DELKEY_BACKSPACE = "backspace";

    public final static String AUTHAGENT_NO = "no";
    public final static String AUTHAGENT_CONFIRM = "confirm";
    public final static String AUTHAGENT_YES = "yes";

    public final static String ENCODING_DEFAULT = Charset.defaultCharset().name();

    public final static String X11HOST_DEFAULT = "localhost";
    public final static int X11PORT_DEFAULT = 6000;

    public final static long PUBKEYID_NEVER = -2;
    public final static long PUBKEYID_ANY = -1;

    public static final int DEFAULT_COLOR_SCHEME = 0;

    // Table creation strings
    public static final String CREATE_TABLE_COLOR_DEFAULTS =
        "CREATE TABLE " + TABLE_COLOR_DEFAULTS
        + " (" + FIELD_COLOR_SCHEME + " INTEGER NOT NULL, "
        + FIELD_COLOR_FG + " INTEGER NOT NULL DEFAULT " + DEFAULT_FG_COLOR + ", "
        + FIELD_COLOR_BG + " INTEGER NOT NULL DEFAULT " + DEFAULT_BG_COLOR + ")";
    public static final String CREATE_TABLE_COLOR_DEFAULTS_INDEX =
        "CREATE INDEX " + TABLE_COLOR_DEFAULTS + FIELD_COLOR_SCHEME + "index ON "
        + TABLE_COLOR_DEFAULTS + " (" + FIELD_COLOR_SCHEME + ");";

    private static final String WHERE_SCHEME_AND_COLOR = FIELD_COLOR_SCHEME + " = ? AND "
            + FIELD_COLOR_NUMBER + " = ?";

    static {
        addTableName(TABLE_HOSTS);
        addTableName(TABLE_PORTFORWARDS);
        addIndexName(TABLE_PORTFORWARDS + FIELD_PORTFORWARD_HOSTID + "index");
        addTableName(TABLE_COLORS);
        addIndexName(TABLE_COLORS + FIELD_COLOR_SCHEME + "index");
        addTableName(TABLE_COLOR_DEFAULTS);
        addIndexName(TABLE_COLOR_DEFAULTS + FIELD_COLOR_SCHEME + "index");
    }

    public static final Object[] dbLock = new Object[0];

    public HostDatabase(Context context) {
        super(context, DB_NAME, null, DB_VERSION);
        getWritableDatabase().close();
    }

    @Override
    public void onCreate(SQLiteDatabase db) {
        super.onCreate(db);
        db.execSQL("CREATE TABLE " + TABLE_HOSTS
                   + " (_id INTEGER PRIMARY KEY, "
                   + FIELD_HOST_NICKNAME + " TEXT, "
                   + FIELD_HOST_PROTOCOL + " TEXT DEFAULT 'ssh', "
                   + FIELD_HOST_USERNAME + " TEXT, "
                   + FIELD_HOST_HOSTNAME + " TEXT, "
                   + FIELD_HOST_PORT + " INTEGER, "
                   + FIELD_HOST_HOSTKEYALGO + " TEXT, "
                   + FIELD_HOST_HOSTKEY + " BLOB, "
                   + FIELD_HOST_LASTCONNECT + " INTEGER, "
                   + FIELD_HOST_COLOR + " TEXT, "
                   + FIELD_HOST_USEKEYS + " TEXT, "
                   + FIELD_HOST_USEAUTHAGENT + " TEXT, "
                   + FIELD_HOST_POSTLOGIN + " TEXT, "
                   + FIELD_HOST_PUBKEYID + " INTEGER DEFAULT " + PUBKEYID_ANY + ", "
                   + FIELD_HOST_DELKEY + " TEXT DEFAULT '" + DELKEY_DEL + "', "
                   + FIELD_HOST_FONTSIZE + " INTEGER, "
                   + FIELD_HOST_WANTSESSION + " TEXT DEFAULT '" + Boolean.toString(true) + "', "
                   + FIELD_HOST_COMPRESSION + " TEXT DEFAULT '" + Boolean.toString(false) + "', "
                   + FIELD_HOST_HTTPPROXY + " TEXT, "
                   + FIELD_HOST_ENCODING + " TEXT DEFAULT '" + ENCODING_DEFAULT + "', "
                   + FIELD_HOST_STAYCONNECTED + " TEXT, "
                   + FIELD_HOST_WANTX11FORWARD + " TEXT DEFAULT '" + Boolean.toString(false) + "', "
                   + FIELD_HOST_X11HOST + " TEXT DEFAULT '" + X11HOST_DEFAULT + "', "
                   + FIELD_HOST_X11PORT + " INTEGER DEFAULT " + X11PORT_DEFAULT + ", "
                   + FIELD_HOST_MONITOR + " TEXT)");
        db.execSQL("CREATE TABLE " + TABLE_PORTFORWARDS
                   + " (_id INTEGER PRIMARY KEY, "
                   + FIELD_PORTFORWARD_HOSTID + " INTEGER, "
                   + FIELD_PORTFORWARD_NICKNAME + " TEXT, "
                   + FIELD_PORTFORWARD_TYPE + " TEXT NOT NULL DEFAULT " + PORTFORWARD_LOCAL + ", "
                   + FIELD_PORTFORWARD_SOURCEPORT + " INTEGER NOT NULL DEFAULT 8080, "
                   + FIELD_PORTFORWARD_DESTADDR + " TEXT, "
                   + FIELD_PORTFORWARD_DESTPORT + " TEXT)");
        db.execSQL("CREATE INDEX " + TABLE_PORTFORWARDS + FIELD_PORTFORWARD_HOSTID + "index ON "
                   + TABLE_PORTFORWARDS + " (" + FIELD_PORTFORWARD_HOSTID + ");");
        db.execSQL("CREATE TABLE " + TABLE_COLORS
                   + " (_id INTEGER PRIMARY KEY, "
                   + FIELD_COLOR_NUMBER + " INTEGER, "
                   + FIELD_COLOR_VALUE + " INTEGER, "
                   + FIELD_COLOR_SCHEME + " INTEGER)");
        db.execSQL("CREATE INDEX " + TABLE_COLORS + FIELD_COLOR_SCHEME + "index ON "
                   + TABLE_COLORS + " (" + FIELD_COLOR_SCHEME + ");");
        db.execSQL(CREATE_TABLE_COLOR_DEFAULTS);
        db.execSQL(CREATE_TABLE_COLOR_DEFAULTS_INDEX);
    }

    @Override
    public void onRobustUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) throws SQLiteException {
        // Versions of the database before the Android Market release will be
        // shot without warning.
        if (oldVersion <= 9) {
            db.execSQL("DROP TABLE IF EXISTS " + TABLE_HOSTS);
            onCreate(db);
            return;
        }

        switch (oldVersion) {
            case 10:
                db.execSQL("ALTER TABLE " + TABLE_HOSTS
                           + " ADD COLUMN " + FIELD_HOST_PUBKEYID + " INTEGER DEFAULT " + PUBKEYID_ANY);

            case 11:
                db.execSQL("CREATE TABLE " + TABLE_PORTFORWARDS
                           + " (_id INTEGER PRIMARY KEY, "
                           + FIELD_PORTFORWARD_HOSTID + " INTEGER, "
                           + FIELD_PORTFORWARD_NICKNAME + " TEXT, "
                           + FIELD_PORTFORWARD_TYPE + " TEXT NOT NULL DEFAULT " + PORTFORWARD_LOCAL + ", "
                           + FIELD_PORTFORWARD_SOURCEPORT + " INTEGER NOT NULL DEFAULT 8080, "
                           + FIELD_PORTFORWARD_DESTADDR + " TEXT, "
                           + FIELD_PORTFORWARD_DESTPORT + " INTEGER)");

            case 12:
                db.execSQL("ALTER TABLE " + TABLE_HOSTS
                           + " ADD COLUMN " + FIELD_HOST_WANTSESSION + " TEXT DEFAULT '" + Boolean.toString(true) + "'");

            case 13:
                db.execSQL("ALTER TABLE " + TABLE_HOSTS
                           + " ADD COLUMN " + FIELD_HOST_COMPRESSION + " TEXT DEFAULT '" + Boolean.toString(false) + "'");

            case 14:
                db.execSQL("ALTER TABLE " + TABLE_HOSTS
                           + " ADD COLUMN " + FIELD_HOST_ENCODING + " TEXT DEFAULT '" + ENCODING_DEFAULT + "'");

            case 15:
                db.execSQL("ALTER TABLE " + TABLE_HOSTS
                           + " ADD COLUMN " + FIELD_HOST_PROTOCOL + " TEXT DEFAULT 'ssh'");

            case 16:
                db.execSQL("ALTER TABLE " + TABLE_HOSTS
                           + " ADD COLUMN " + FIELD_HOST_DELKEY + " TEXT DEFAULT '" + DELKEY_DEL + "'");

            case 17:
                db.execSQL("CREATE INDEX " + TABLE_PORTFORWARDS + FIELD_PORTFORWARD_HOSTID + "index ON "
                           + TABLE_PORTFORWARDS + " (" + FIELD_PORTFORWARD_HOSTID + ");");
                // Add colors
                db.execSQL("CREATE TABLE " + TABLE_COLORS
                           + " (_id INTEGER PRIMARY KEY, "
                           + FIELD_COLOR_NUMBER + " INTEGER, "
                           + FIELD_COLOR_VALUE + " INTEGER, "
                           + FIELD_COLOR_SCHEME + " INTEGER)");
                db.execSQL("CREATE INDEX " + TABLE_COLORS + FIELD_COLOR_SCHEME + "index ON "
                           + TABLE_COLORS + " (" + FIELD_COLOR_SCHEME + ");");

            case 18:
                db.execSQL("ALTER TABLE " + TABLE_HOSTS
                           + " ADD COLUMN " + FIELD_HOST_USEAUTHAGENT + " TEXT DEFAULT '" + AUTHAGENT_NO + "'");

            case 19:
                db.execSQL("ALTER TABLE " + TABLE_HOSTS
                           + " ADD COLUMN " + FIELD_HOST_STAYCONNECTED + " TEXT");

            case 20:
                db.execSQL("ALTER TABLE " + TABLE_HOSTS
                           + " ADD COLUMN " + FIELD_HOST_FONTSIZE + " INTEGER");

            case 21:
                db.execSQL("DROP TABLE " + TABLE_COLOR_DEFAULTS);
                db.execSQL(CREATE_TABLE_COLOR_DEFAULTS);
                db.execSQL(CREATE_TABLE_COLOR_DEFAULTS_INDEX);

            case 22:
                db.execSQL("ALTER TABLE " + TABLE_HOSTS
                           + " ADD COLUMN " + FIELD_HOST_WANTX11FORWARD + " TEXT DEFAULT '" + Boolean.toString(false) + "'");
                db.execSQL("ALTER TABLE " + TABLE_HOSTS
                           + " ADD COLUMN " + FIELD_HOST_X11HOST + " TEXT DEFAULT '" + X11HOST_DEFAULT + "'");
                db.execSQL("ALTER TABLE " + TABLE_HOSTS
                           + " ADD COLUMN " + FIELD_HOST_X11PORT + " INTEGER DEFAULT " + X11PORT_DEFAULT);

            case 23:
                db.execSQL("ALTER TABLE " + TABLE_HOSTS
                           + " ADD COLUMN " + FIELD_HOST_HTTPPROXY + " TEXT");

            case 24:
                db.execSQL("ALTER TABLE " + TABLE_HOSTS
                           + " ADD COLUMN " + FIELD_HOST_MONITOR + " TEXT");
        }
    }

    /**
     * Touch a specific host to update its "last connected" field.
     * @param nickname Nickname field of host to update
     */
    public void touchHost(HostBean host) {
        long now = System.currentTimeMillis() / 1000;
        ContentValues values = new ContentValues();
        values.put(FIELD_HOST_LASTCONNECT, now);

        synchronized (dbLock) {
            SQLiteDatabase db = this.getWritableDatabase();
            db.update(TABLE_HOSTS, values, "_id = ?", new String[] { String.valueOf(host.getId()) });
        }
    }

    /**
     * Create a new host using the given parameters.
     */
    public HostBean saveHost(HostBean host) {
        long id;

        synchronized (dbLock) {
            SQLiteDatabase db = this.getWritableDatabase();
            id = db.insert(TABLE_HOSTS, null, host.getValues());
        }

        host.setId(id);
        return host;
    }

    /**
     * Update a field in a host record.
     */
    public boolean updateFontSize(HostBean host) {
        long id = host.getId();

        if (id < 0)
            return false;

        ContentValues updates = new ContentValues();
        updates.put(FIELD_HOST_FONTSIZE, host.getFontSize());

        synchronized (dbLock) {
            SQLiteDatabase db = getWritableDatabase();
            db.update(TABLE_HOSTS, updates, "_id = ?",
                      new String[] { String.valueOf(id) });
        }

        return true;
    }

    /**
     * Delete a specific host by its <code>_id</code> value.
     */
    public void deleteHost(HostBean host) {
        if (host.getId() < 0)
            return;

        synchronized (dbLock) {
            SQLiteDatabase db = this.getWritableDatabase();
            db.delete(TABLE_HOSTS, "_id = ?", new String[] { String.valueOf(host.getId()) });
        }
    }

    /**
     * Return a cursor that contains information about all known hosts.
     * @param sortColors If true, sort by color, otherwise sort by nickname.
     */
    public List<HostBean> getHosts(boolean sortColors) {
        String sortField = sortColors ? FIELD_HOST_COLOR : FIELD_HOST_NICKNAME;
        List<HostBean> hosts;

        synchronized (dbLock) {
            SQLiteDatabase db = this.getReadableDatabase();
            Cursor c = db.query(TABLE_HOSTS, null, null, null, null, null, sortField + " ASC");
            hosts = createHostBeans(c);
            c.close();
        }

        return hosts;
    }

    /**
     * @param hosts
     * @param c
     */
    private List<HostBean> createHostBeans(Cursor c) {
        List<HostBean> hosts = new LinkedList<HostBean>();
        final int COL_ID = c.getColumnIndexOrThrow("_id"),
                  COL_NICKNAME = c.getColumnIndexOrThrow(FIELD_HOST_NICKNAME),
                  COL_PROTOCOL = c.getColumnIndexOrThrow(FIELD_HOST_PROTOCOL),
                  COL_USERNAME = c.getColumnIndexOrThrow(FIELD_HOST_USERNAME),
                  COL_HOSTNAME = c.getColumnIndexOrThrow(FIELD_HOST_HOSTNAME),
                  COL_PORT = c.getColumnIndexOrThrow(FIELD_HOST_PORT),
                  COL_LASTCONNECT = c.getColumnIndexOrThrow(FIELD_HOST_LASTCONNECT),
                  COL_COLOR = c.getColumnIndexOrThrow(FIELD_HOST_COLOR),
                  COL_USEKEYS = c.getColumnIndexOrThrow(FIELD_HOST_USEKEYS),
                  COL_USEAUTHAGENT = c.getColumnIndexOrThrow(FIELD_HOST_USEAUTHAGENT),
                  COL_POSTLOGIN = c.getColumnIndexOrThrow(FIELD_HOST_POSTLOGIN),
                  COL_PUBKEYID = c.getColumnIndexOrThrow(FIELD_HOST_PUBKEYID),
                  COL_WANTSESSION = c.getColumnIndexOrThrow(FIELD_HOST_WANTSESSION),
                  COL_DELKEY = c.getColumnIndexOrThrow(FIELD_HOST_DELKEY),
                  COL_FONTSIZE = c.getColumnIndexOrThrow(FIELD_HOST_FONTSIZE),
                  COL_COMPRESSION = c.getColumnIndexOrThrow(FIELD_HOST_COMPRESSION),
                  COL_HTTPPROXY = c.getColumnIndexOrThrow(FIELD_HOST_HTTPPROXY),
                  COL_ENCODING = c.getColumnIndexOrThrow(FIELD_HOST_ENCODING),
                  COL_STAYCONNECTED = c.getColumnIndexOrThrow(FIELD_HOST_STAYCONNECTED),
                  COL_WANTX11FORWARD = c.getColumnIndexOrThrow(FIELD_HOST_WANTX11FORWARD),
                  COL_X11HOST = c.getColumnIndexOrThrow(FIELD_HOST_X11HOST),
                  COL_X11PORT = c.getColumnIndexOrThrow(FIELD_HOST_X11PORT),
                  COL_MONITOR = c.getColumnIndexOrThrow(FIELD_HOST_MONITOR);

        while (c.moveToNext()) {
            HostBean host = new HostBean();
            host.setId(c.getLong(COL_ID));
            host.setNickname(c.getString(COL_NICKNAME));
            host.setProtocol(c.getString(COL_PROTOCOL));
            host.setUsername(c.getString(COL_USERNAME));
            host.setHostname(c.getString(COL_HOSTNAME));
            host.setPort(c.getInt(COL_PORT));
            host.setLastConnect(c.getLong(COL_LASTCONNECT));
            host.setColor(c.getString(COL_COLOR));
            host.setUseKeys(Boolean.valueOf(c.getString(COL_USEKEYS)));
            host.setUseAuthAgent(c.getString(COL_USEAUTHAGENT));
            host.setPostLogin(c.getString(COL_POSTLOGIN));
            host.setPubkeyId(c.getLong(COL_PUBKEYID));
            host.setWantSession(Boolean.valueOf(c.getString(COL_WANTSESSION)));
            host.setDelKey(c.getString(COL_DELKEY));
            host.setFontSize(c.getInt(COL_FONTSIZE));
            host.setCompression(Boolean.valueOf(c.getString(COL_COMPRESSION)));
            host.setHttpproxy(c.getString(COL_HTTPPROXY));
            host.setEncoding(c.getString(COL_ENCODING));
            host.setStayConnected(Boolean.valueOf(c.getString(COL_STAYCONNECTED)));
            host.setWantX11Forward(Boolean.valueOf(c.getString(COL_WANTX11FORWARD)));
            host.setX11Host(c.getString(COL_X11HOST));
            host.setX11Port(c.getInt(COL_X11PORT));
            host.setMonitor(c.getString(COL_MONITOR));
            hosts.add(host);
        }

        return hosts;
    }

    /**
     * @param c
     * @return
     */
    private HostBean getFirstHostBean(Cursor c) {
        HostBean host = null;
        List<HostBean> hosts = createHostBeans(c);

        if (hosts.size() > 0)
            host = hosts.get(0);

        c.close();
        return host;
    }

    /**
     * @param nickname
     * @param protocol
     * @param username
     * @param hostname
     * @param hostname2
     * @param port
     * @return
     */
    public HostBean findHost(Map<String, String> selection) {
        StringBuilder selectionBuilder = new StringBuilder();
        Iterator<Entry<String, String>> i = selection.entrySet().iterator();
        List<String> selectionValuesList = new LinkedList<String>();
        int n = 0;

        while (i.hasNext()) {
            Entry<String, String> entry = i.next();

            if (entry.getValue() == null)
                continue;

            if (n++ > 0)
                selectionBuilder.append(" AND ");

            selectionBuilder.append(entry.getKey())
            .append(" = ?");
            selectionValuesList.add(entry.getValue());
        }

        String selectionValues[] = new String[selectionValuesList.size()];
        selectionValuesList.toArray(selectionValues);
        selectionValuesList = null;
        HostBean host;

        synchronized (dbLock) {
            SQLiteDatabase db = getReadableDatabase();
            Cursor c = db.query(TABLE_HOSTS, null,
                                selectionBuilder.toString(),
                                selectionValues,
                                null, null, null);
            host = getFirstHostBean(c);
        }

        return host;
    }

    /**
     * @param hostId
     * @return
     */
    public HostBean findHostById(long hostId) {
        HostBean host;

        synchronized (dbLock) {
            SQLiteDatabase db = getReadableDatabase();
            Cursor c = db.query(TABLE_HOSTS, null,
                                "_id = ?", new String[] { String.valueOf(hostId) },
                                null, null, null);
            host = getFirstHostBean(c);
        }

        return host;
    }

    /**
     * Record the given hostkey into database under this nickname.
     * @param hostname
     * @param port
     * @param hostkeyalgo
     * @param hostkey
     */
    public void saveKnownHost(String hostname, int port, String hostkeyalgo, byte[] hostkey) {
        ContentValues values = new ContentValues();
        values.put(FIELD_HOST_HOSTKEYALGO, hostkeyalgo);
        values.put(FIELD_HOST_HOSTKEY, hostkey);

        synchronized (dbLock) {
            SQLiteDatabase db = getReadableDatabase();
            db.update(TABLE_HOSTS, values,
                      FIELD_HOST_HOSTNAME + " = ? AND " + FIELD_HOST_PORT + " = ?",
                      new String[] { hostname, String.valueOf(port) });
            Log.d(TAG, String.format("Finished saving hostkey information for '%s'", hostname));
        }
    }

    /**
     * Build list of known hosts for Trilead library.
     * @return
     */
    public KnownHosts getKnownHosts() {
        KnownHosts known = new KnownHosts();

        synchronized (dbLock) {
            SQLiteDatabase db = this.getReadableDatabase();
            Cursor c = db.query(TABLE_HOSTS, new String[] { FIELD_HOST_HOSTNAME,
                                FIELD_HOST_PORT, FIELD_HOST_HOSTKEYALGO, FIELD_HOST_HOSTKEY
                                                          },
                                null, null, null, null, null);

            if (c != null) {
                int COL_HOSTNAME = c.getColumnIndexOrThrow(FIELD_HOST_HOSTNAME),
                    COL_PORT = c.getColumnIndexOrThrow(FIELD_HOST_PORT),
                    COL_HOSTKEYALGO = c.getColumnIndexOrThrow(FIELD_HOST_HOSTKEYALGO),
                    COL_HOSTKEY = c.getColumnIndexOrThrow(FIELD_HOST_HOSTKEY);

                while (c.moveToNext()) {
                    String hostname = c.getString(COL_HOSTNAME),
                           hostkeyalgo = c.getString(COL_HOSTKEYALGO);
                    int port = c.getInt(COL_PORT);
                    byte[] hostkey = c.getBlob(COL_HOSTKEY);

                    if (hostkeyalgo == null || hostkeyalgo.length() == 0) continue;

                    if (hostkey == null || hostkey.length == 0) continue;

                    try {
                        known.addHostkey(new String[] { String.format("%s:%d", hostname, port) }, hostkeyalgo, hostkey);
                    }
                    catch (Exception e) {
                        Log.e(TAG, "Problem while adding a known host from database", e);
                    }
                }

                c.close();
            }
        }

        return known;
    }

    /**
     * Unset any hosts using a pubkey ID that has been deleted.
     * @param pubkeyId
     */
    public void stopUsingPubkey(long pubkeyId) {
        if (pubkeyId < 0) return;

        ContentValues values = new ContentValues();
        values.put(FIELD_HOST_PUBKEYID, PUBKEYID_ANY);

        synchronized (dbLock) {
            SQLiteDatabase db = this.getWritableDatabase();
            db.update(TABLE_HOSTS, values, FIELD_HOST_PUBKEYID + " = ?", new String[] { String.valueOf(pubkeyId) });
        }

        Log.d(TAG, String.format("Set all hosts using pubkey id %d to -1", pubkeyId));
    }

    /*
     * Methods for dealing with port forwards attached to hosts
     */

    /**
     * Returns a list of all the port forwards associated with a particular host ID.
     * @param host the host for which we want the port forward list
     * @return port forwards associated with host ID
     */
    public List<PortForwardBean> getPortForwardsForHost(HostBean host) {
        List<PortForwardBean> portForwards = new LinkedList<PortForwardBean>();

        synchronized (dbLock) {
            SQLiteDatabase db = this.getReadableDatabase();
            Cursor c = db.query(TABLE_PORTFORWARDS, new String[] {
                                    "_id", FIELD_PORTFORWARD_NICKNAME, FIELD_PORTFORWARD_TYPE, FIELD_PORTFORWARD_SOURCEPORT,
                                    FIELD_PORTFORWARD_DESTADDR, FIELD_PORTFORWARD_DESTPORT
                                },
                                FIELD_PORTFORWARD_HOSTID + " = ?", new String[] { String.valueOf(host.getId()) },
                                null, null, null);

            while (c.moveToNext()) {
                PortForwardBean pfb = new PortForwardBean(
                    c.getInt(0),
                    host.getId(),
                    c.getString(1),
                    c.getString(2),
                    c.getInt(3),
                    c.getString(4),
                    c.getInt(5));
                portForwards.add(pfb);
            }

            c.close();
        }

        return portForwards;
    }

    /**
     * Update the parameters of a port forward in the database.
     * @param pfb {@link PortForwardBean} to save
     * @return true on success
     */
    public boolean savePortForward(PortForwardBean pfb) {
        boolean success = false;

        synchronized (dbLock) {
            SQLiteDatabase db = getWritableDatabase();

            if (pfb.getId() < 0) {
                long id = db.insert(TABLE_PORTFORWARDS, null, pfb.getValues());
                pfb.setId(id);
                success = true;
            }
            else {
                if (db.update(TABLE_PORTFORWARDS, pfb.getValues(), "_id = ?", new String[] { String.valueOf(pfb.getId()) }) > 0)
                    success = true;
            }
        }

        return success;
    }

    /**
     * Deletes a port forward from the database.
     * @param pfb {@link PortForwardBean} to delete
     */
    public void deletePortForward(PortForwardBean pfb) {
        if (pfb.getId() < 0)
            return;

        synchronized (dbLock) {
            SQLiteDatabase db = this.getWritableDatabase();
            db.delete(TABLE_PORTFORWARDS, "_id = ?", new String[] { String.valueOf(pfb.getId()) });
        }
    }

    public Integer[] getColorsForScheme(int scheme) {
        Integer[] colors = Colors.defaults.clone();

        synchronized (dbLock) {
            SQLiteDatabase db = getReadableDatabase();
            Cursor c = db.query(TABLE_COLORS, new String[] {
                                    FIELD_COLOR_NUMBER, FIELD_COLOR_VALUE
                                },
                                FIELD_COLOR_SCHEME + " = ?",
                                new String[] { String.valueOf(scheme) },
                                null, null, null);

            while (c.moveToNext()) {
                colors[c.getInt(0)] = Integer.valueOf(c.getInt(1));
            }

            c.close();
        }

        return colors;
    }

    public void setColorForScheme(int scheme, int number, int value) {
        final SQLiteDatabase db;
        final String[] whereArgs = new String[] { String.valueOf(scheme), String.valueOf(number) };

        if (value == Colors.defaults[number]) {
            synchronized (dbLock) {
                db = getWritableDatabase();
                db.delete(TABLE_COLORS,
                          WHERE_SCHEME_AND_COLOR, whereArgs);
            }
        }
        else {
            final ContentValues values = new ContentValues();
            values.put(FIELD_COLOR_VALUE, value);

            synchronized (dbLock) {
                db = getWritableDatabase();
                final int rowsAffected = db.update(TABLE_COLORS, values,
                                                   WHERE_SCHEME_AND_COLOR, whereArgs);

                if (rowsAffected == 0) {
                    values.put(FIELD_COLOR_SCHEME, scheme);
                    values.put(FIELD_COLOR_NUMBER, number);
                    db.insert(TABLE_COLORS, null, values);
                }
            }
        }
    }

    public void setGlobalColor(int number, int value) {
        setColorForScheme(DEFAULT_COLOR_SCHEME, number, value);
    }

    public int[] getDefaultColorsForScheme(int scheme) {
        int[] colors = new int[] { DEFAULT_FG_COLOR, DEFAULT_BG_COLOR };

        synchronized (dbLock) {
            SQLiteDatabase db = getReadableDatabase();
            Cursor c = db.query(TABLE_COLOR_DEFAULTS,
                                new String[] { FIELD_COLOR_FG, FIELD_COLOR_BG },
                                FIELD_COLOR_SCHEME + " = ?",
                                new String[] { String.valueOf(scheme) },
                                null, null, null);

            if (c.moveToFirst()) {
                colors[0] = c.getInt(0);
                colors[1] = c.getInt(1);
            }

            c.close();
        }

        return colors;
    }

    public int[] getGlobalDefaultColors() {
        return getDefaultColorsForScheme(DEFAULT_COLOR_SCHEME);
    }

    public void setDefaultColorsForScheme(int scheme, int fg, int bg) {
        SQLiteDatabase db;
        String schemeWhere = null;
        String[] whereArgs;
        schemeWhere = FIELD_COLOR_SCHEME + " = ?";
        whereArgs = new String[] { String.valueOf(scheme) };
        ContentValues values = new ContentValues();
        values.put(FIELD_COLOR_FG, fg);
        values.put(FIELD_COLOR_BG, bg);

        synchronized (dbLock) {
            db = getWritableDatabase();
            int rowsAffected = db.update(TABLE_COLOR_DEFAULTS, values,
                                         schemeWhere, whereArgs);

            if (rowsAffected == 0) {
                values.put(FIELD_COLOR_SCHEME, scheme);
                db.insert(TABLE_COLOR_DEFAULTS, null, values);
            }
        }
    }
}