/*
 * 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.util.LinkedList;
import java.util.List;

import com.five_ten_sg.connectbot.bean.PubkeyBean;
import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteException;

/**
 * Public Key Encryption database. Contains private and public key pairs
 * for public key authentication.
 *
 * @author Kenny Root
 */
public class PubkeyDatabase extends RobustSQLiteOpenHelper {
    public final static String TAG = "ConnectBot.PubkeyDatabase";

    public final static String DB_NAME = "pubkeys";
    public final static int DB_VERSION = 2;

    public final static String TABLE_PUBKEYS = "pubkeys";
    public final static String FIELD_PUBKEY_NICKNAME = "nickname";
    public final static String FIELD_PUBKEY_TYPE = "type";
    public final static String FIELD_PUBKEY_PRIVATE = "private";
    public final static String FIELD_PUBKEY_PUBLIC = "public";
    public final static String FIELD_PUBKEY_ENCRYPTED = "encrypted";
    public final static String FIELD_PUBKEY_STARTUP = "startup";
    public final static String FIELD_PUBKEY_CONFIRMUSE = "confirmuse";
    public final static String FIELD_PUBKEY_LIFETIME = "lifetime";

    public final static String KEY_TYPE_RSA = "RSA",
                               KEY_TYPE_DSA = "DSA",
                               KEY_TYPE_IMPORTED = "IMPORTED",
                               KEY_TYPE_EC = "EC";

    private Context context;

    static {
        addTableName(TABLE_PUBKEYS);
    }

    public PubkeyDatabase(Context context) {
        super(context, DB_NAME, null, DB_VERSION);
        this.context = context;
    }

    @Override
    public void onCreate(SQLiteDatabase db) {
        super.onCreate(db);
        db.execSQL("CREATE TABLE " + TABLE_PUBKEYS
                   + " (_id INTEGER PRIMARY KEY, "
                   + FIELD_PUBKEY_NICKNAME + " TEXT, "
                   + FIELD_PUBKEY_TYPE + " TEXT, "
                   + FIELD_PUBKEY_PRIVATE + " BLOB, "
                   + FIELD_PUBKEY_PUBLIC + " BLOB, "
                   + FIELD_PUBKEY_ENCRYPTED + " INTEGER, "
                   + FIELD_PUBKEY_STARTUP + " INTEGER, "
                   + FIELD_PUBKEY_CONFIRMUSE + " INTEGER DEFAULT 0, "
                   + FIELD_PUBKEY_LIFETIME + " INTEGER DEFAULT 0)");
    }

    @Override
    public void onRobustUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) throws SQLiteException {
        switch (oldVersion) {
            case 1:
                db.execSQL("ALTER TABLE " + TABLE_PUBKEYS
                           + " ADD COLUMN " + FIELD_PUBKEY_CONFIRMUSE + " INTEGER DEFAULT 0");
                db.execSQL("ALTER TABLE " + TABLE_PUBKEYS
                           + " ADD COLUMN " + FIELD_PUBKEY_LIFETIME + " INTEGER DEFAULT 0");
        }
    }

    /**
     * Delete a specific host by its <code>_id</code> value.
     */
    public void deletePubkey(PubkeyBean pubkey) {
        HostDatabase hostdb = new HostDatabase(context);
        hostdb.stopUsingPubkey(pubkey.getId());
        hostdb.close();
        SQLiteDatabase db = getWritableDatabase();
        db.delete(TABLE_PUBKEYS, "_id = ?", new String[] { Long.toString(pubkey.getId()) });
        db.close();
    }

    /**
     * Return a cursor that contains information about all known hosts.
     */
    /*
    public Cursor allPubkeys() {
        SQLiteDatabase db = this.getReadableDatabase();
        return db.query(TABLE_PUBKEYS, new String[] { "_id",
                FIELD_PUBKEY_NICKNAME, FIELD_PUBKEY_TYPE, FIELD_PUBKEY_PRIVATE,
                FIELD_PUBKEY_PUBLIC, FIELD_PUBKEY_ENCRYPTED, FIELD_PUBKEY_STARTUP },
                null, null, null, null, null);
    }*/

    public List<PubkeyBean> allPubkeys() {
        return getPubkeys(null, null);
    }

    public List<PubkeyBean> getAllStartPubkeys() {
        return getPubkeys(FIELD_PUBKEY_STARTUP + " = 1 AND " + FIELD_PUBKEY_ENCRYPTED + " = 0", null);
    }

    private List<PubkeyBean> getPubkeys(String selection, String[] selectionArgs) {
        SQLiteDatabase db = getReadableDatabase();
        List<PubkeyBean> pubkeys = new LinkedList<PubkeyBean>();
        Cursor c = db.query(TABLE_PUBKEYS, null, selection, selectionArgs, null, null, null);

        if (c != null) {
            final int COL_ID = c.getColumnIndexOrThrow("_id"),
                      COL_NICKNAME = c.getColumnIndexOrThrow(FIELD_PUBKEY_NICKNAME),
                      COL_TYPE = c.getColumnIndexOrThrow(FIELD_PUBKEY_TYPE),
                      COL_PRIVATE = c.getColumnIndexOrThrow(FIELD_PUBKEY_PRIVATE),
                      COL_PUBLIC = c.getColumnIndexOrThrow(FIELD_PUBKEY_PUBLIC),
                      COL_ENCRYPTED = c.getColumnIndexOrThrow(FIELD_PUBKEY_ENCRYPTED),
                      COL_STARTUP = c.getColumnIndexOrThrow(FIELD_PUBKEY_STARTUP),
                      COL_CONFIRMUSE = c.getColumnIndexOrThrow(FIELD_PUBKEY_CONFIRMUSE),
                      COL_LIFETIME = c.getColumnIndexOrThrow(FIELD_PUBKEY_LIFETIME);

            while (c.moveToNext()) {
                PubkeyBean pubkey = new PubkeyBean();
                pubkey.setId(c.getLong(COL_ID));
                pubkey.setNickname(c.getString(COL_NICKNAME));
                pubkey.setType(c.getString(COL_TYPE));
                pubkey.setPrivateKey(c.getBlob(COL_PRIVATE));
                pubkey.setPublicKey(c.getBlob(COL_PUBLIC));
                pubkey.setEncrypted(c.getInt(COL_ENCRYPTED) > 0);
                pubkey.setStartup(c.getInt(COL_STARTUP) > 0);
                pubkey.setConfirmUse(c.getInt(COL_CONFIRMUSE) > 0);
                pubkey.setLifetime(c.getInt(COL_LIFETIME));
                pubkeys.add(pubkey);
            }

            c.close();
        }

        db.close();
        return pubkeys;
    }

    /**
     * @param hostId
     * @return
     */
    public PubkeyBean findPubkeyById(long pubkeyId) {
        SQLiteDatabase db = getReadableDatabase();
        Cursor c = db.query(TABLE_PUBKEYS, null,
                            "_id = ?", new String[] { String.valueOf(pubkeyId) },
                            null, null, null);
        PubkeyBean pubkey = null;

        if (c != null) {
            if (c.moveToFirst())
                pubkey = createPubkeyBean(c);

            c.close();
        }

        db.close();
        return pubkey;
    }

    private PubkeyBean createPubkeyBean(Cursor c) {
        PubkeyBean pubkey = new PubkeyBean();
        pubkey.setId(c.getLong(c.getColumnIndexOrThrow("_id")));
        pubkey.setNickname(c.getString(c.getColumnIndexOrThrow(FIELD_PUBKEY_NICKNAME)));
        pubkey.setType(c.getString(c.getColumnIndexOrThrow(FIELD_PUBKEY_TYPE)));
        pubkey.setPrivateKey(c.getBlob(c.getColumnIndexOrThrow(FIELD_PUBKEY_PRIVATE)));
        pubkey.setPublicKey(c.getBlob(c.getColumnIndexOrThrow(FIELD_PUBKEY_PUBLIC)));
        pubkey.setEncrypted(c.getInt(c.getColumnIndexOrThrow(FIELD_PUBKEY_ENCRYPTED)) > 0);
        pubkey.setStartup(c.getInt(c.getColumnIndexOrThrow(FIELD_PUBKEY_STARTUP)) > 0);
        pubkey.setConfirmUse(c.getInt(c.getColumnIndexOrThrow(FIELD_PUBKEY_CONFIRMUSE)) > 0);
        pubkey.setLifetime(c.getInt(c.getColumnIndexOrThrow(FIELD_PUBKEY_LIFETIME)));
        return pubkey;
    }

    /**
     * Pull all values for a given column as a list of Strings, probably for use
     * in a ListPreference. Sorted by <code>_id</code> ascending.
     */
    public List<CharSequence> allValues(String column) {
        List<CharSequence> list = new LinkedList<CharSequence>();
        SQLiteDatabase db = this.getReadableDatabase();
        Cursor c = db.query(TABLE_PUBKEYS, new String[] { "_id", column },
                            null, null, null, null, "_id ASC");

        if (c != null) {
            int COL = c.getColumnIndexOrThrow(column);

            while (c.moveToNext())
                list.add(c.getString(COL));

            c.close();
        }

        db.close();
        return list;
    }

    public String getNickname(long id) {
        String nickname = null;
        SQLiteDatabase db = this.getReadableDatabase();
        Cursor c = db.query(TABLE_PUBKEYS, new String[] { "_id",
                            FIELD_PUBKEY_NICKNAME
                                                        }, "_id = ?",
                            new String[] { Long.toString(id) }, null, null, null);

        if (c != null) {
            if (c.moveToFirst())
                nickname = c.getString(c.getColumnIndexOrThrow(FIELD_PUBKEY_NICKNAME));

            c.close();
        }

        db.close();
        return nickname;
    }

    /*
        public void setOnStart(long id, boolean onStart) {

            SQLiteDatabase db = this.getWritableDatabase();

            ContentValues values = new ContentValues();
            values.put(FIELD_PUBKEY_STARTUP, onStart ? 1 : 0);

            db.update(TABLE_PUBKEYS, values, "_id = ?", new String[] { Long.toString(id) });

        }

        public boolean changePassword(long id, String oldPassword, String newPassword) throws NoSuchAlgorithmException, NoSuchPaddingException, IllegalBlockSizeException, InvalidKeyException, BadPaddingException {
            SQLiteDatabase db = this.getWritableDatabase();

            Cursor c = db.query(TABLE_PUBKEYS, new String[] { FIELD_PUBKEY_TYPE,
                    FIELD_PUBKEY_PRIVATE, FIELD_PUBKEY_ENCRYPTED },
                    "_id = ?", new String[] { String.valueOf(id) },
                    null, null, null);

            if (!c.moveToFirst())
                return false;

            String keyType = c.getString(0);
            byte[] encPriv = c.getBlob(1);
            c.close();

            PrivateKey priv;
            try {
                priv = PubkeyUtils.decodePrivate(encPriv, keyType, oldPassword);
            } catch (InvalidKeyException e) {
                return false;
            } catch (BadPaddingException e) {
                return false;
            } catch (InvalidKeySpecException e) {
                return false;
            }

            ContentValues values = new ContentValues();
            values.put(FIELD_PUBKEY_PRIVATE, PubkeyUtils.getEncodedPrivate(priv, newPassword));
            values.put(FIELD_PUBKEY_ENCRYPTED, newPassword.length() > 0 ? 1 : 0);
            db.update(TABLE_PUBKEYS, values, "_id = ?", new String[] { String.valueOf(id) });

            return true;
        }
        */

    /**
     * @param pubkey
     */
    public PubkeyBean savePubkey(PubkeyBean pubkey) {
        SQLiteDatabase db = this.getWritableDatabase();
        boolean success = false;
        ContentValues values = pubkey.getValues();

        if (pubkey.getId() > 0) {
            values.remove("_id");

            if (db.update(TABLE_PUBKEYS, values, "_id = ?", new String[] { String.valueOf(pubkey.getId()) }) > 0)
                success = true;
        }

        if (!success) {
            long id = db.insert(TABLE_PUBKEYS, null, pubkey.getValues());
            pubkey.setId(id);
        }

        db.close();
        return pubkey;
    }
}