/*

    BEEM is a videoconference application on the Android Platform.

    Copyright (C) 2009-2011 by Frederic-Charles Barthelery,

                               Nikita Kozlov,

                               Vincent Veronis.

    This file is part of BEEM.

    BEEM is free software: you can redistribute it and/or modify

    it under the terms of the GNU General Public License as published by

    the Free Software Foundation, either version 3 of the License, or

    (at your option) any later version.

    BEEM 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 General Public License for more details.

    You should have received a copy of the GNU General Public License

    along with BEEM.  If not, see <http://www.gnu.org/licenses/>.

    Please send bug reports with examples or suggestions to

    contact@beem-project.com or http://www.beem-project.com/

*/

package com.beem.project.beem.otr;

import java.io.IOException;

import java.security.KeyPair;

import java.util.HashMap;

import java.util.Map;

import net.java.otr4j.OtrEngine;

import net.java.otr4j.OtrEngineHost;

import net.java.otr4j.OtrEngineImpl;

import net.java.otr4j.OtrEngineListener;

import net.java.otr4j.OtrException;

import net.java.otr4j.OtrKeyManagerImpl;

import net.java.otr4j.OtrPolicy;

import net.java.otr4j.OtrPolicyImpl;

import net.java.otr4j.session.SessionID;

import net.java.otr4j.session.SessionStatus;

import android.util.Log;

import com.beem.project.beem.service.ChatAdapter;

/**

 * BeemOtrManager.

 */

public class BeemOtrManager implements OtrEngineHost {

    private static final String TAG = "BeemOtrEngineHostImpl";

    private static BeemOtrManager INSTANCE;

    //We will have a global policy for Beem as long as we won't need to modify the policy per chat.

    private static final OtrPolicy mGlobalPolicy = new OtrPolicyImpl(OtrPolicy.ALLOW_V2 | OtrPolicy.ERROR_START_AKE);

    private OtrEngine mOtrEngine;

    private OtrKeyManagerImpl mOtrKeyManager;

    //Map of chat, needed because of the message injection

    private final Map<SessionID, ChatAdapter> mChats = new HashMap<SessionID, ChatAdapter>();

    /**

     * Private constructor prevents instantiation from other classes.

     */

    private BeemOtrManager() {

	mOtrEngine = new OtrEngineImpl(this);

	mOtrEngine.addOtrEngineListener(new BeemOtrListener());

	try {

	    mOtrKeyManager = new OtrKeyManagerImpl("/sdcard/beem.keystore");

	} catch (IOException e) {

	    e.printStackTrace();

	}

    }

    /**

     * getOtrManager.

     * @return OtrEngine

     */

    public OtrEngine getOtrManager() {

	return mOtrEngine;

    }

    /**

     * BeemOtrManager.getInstance.

     * @return BeemOtrManager

     */

    public static BeemOtrManager getInstance() {

	if (INSTANCE == null)

	    INSTANCE = new BeemOtrManager();

	return INSTANCE;

    }

    /**

     * We must call addChat before stating a new otr session because we will need the chat instance for message

     * injection.

     * @param sessionID the otr sessionID.

     * @param chat instance.

     */

    public void addChat(final SessionID sessionID, final ChatAdapter chat) {

	mChats.put(sessionID, chat);

	Log.d(TAG, "adding new OTR session " + sessionID);

    }

    /**

     * We must remove the chat from the map after we ended the corresponding otr session.

     * @param sessionID the otr sessionID to remove.

     */

    public void removeChat(final SessionID sessionID) {

	mChats.remove(sessionID);

    }

    /**

     * get the fingerprint of the remote part.

     * @param sessionID the otr session

     * @return a string containing the fingerprint

     */

    public String getRemoteFingerprint(final SessionID sessionID) {

	return mOtrKeyManager.getRemoteFingerprint(sessionID);

    }

    /**

     * set the remote fingerprint as verified.

     * @param sessionId the current otr session

     */

    public void verifyRemoteFingerprint(final SessionID sessionId) {

	mOtrKeyManager.verify(sessionId);

    }

    /**

     * unsetthe remote fingerprint as verified.

     * @param sessionId the current otr session

     */

    public void unverifyRemoteFingerprint(final SessionID sessionId) {

	mOtrKeyManager.unverify(sessionId);

    }

    /**

     * get the local fingerprint.

     * @param sessionID the otr session

     * @return a string containing the fingerprint

     */

    public String getLocalFingerprint(final SessionID sessionID) {

	return mOtrKeyManager.getLocalFingerprint(sessionID);

    }

    @Override

    public void injectMessage(SessionID sessionID, String msg) {

	ChatAdapter chat = mChats.get(sessionID);

	chat.injectMessage(msg);

    }

    @Override

    public void showWarning(SessionID sessionID, String warning) {

	Log.d(TAG, "Warning for " + sessionID + " : " + warning);

    }

    @Override

    public void showError(SessionID sessionID, String error) {

	Log.d(TAG, "Error for " + sessionID + " : " + error);

    }

    @Override

    public OtrPolicy getSessionPolicy(SessionID sessionID) {

	return mGlobalPolicy;

    }

    @Override

    public KeyPair getKeyPair(SessionID sessionID) {

	KeyPair kp = mOtrKeyManager.loadLocalKeyPair(sessionID);

	if (kp != null)

	    return kp;

	mOtrKeyManager.generateLocalKeyPair(sessionID);

	return mOtrKeyManager.loadLocalKeyPair(sessionID);

    }

    /**

     * BeemOtrListener.

     */

    private class BeemOtrListener implements OtrEngineListener {

	@Override

	public void sessionStatusChanged(final SessionID sessionID) {

	    Log.d(TAG, "OTR Status changed for " + sessionID + " : " + mOtrEngine.getSessionStatus(sessionID));

	    if (mOtrKeyManager.loadRemotePublicKey(sessionID) == null) {

		mOtrKeyManager.savePublicKey(sessionID, mOtrEngine.getRemotePublicKey(sessionID));

	    }

	    SessionStatus status = mOtrEngine.getSessionStatus(sessionID);

	    if (status.equals(SessionStatus.ENCRYPTED) && mOtrKeyManager.isVerified(sessionID)) {

		mChats.get(sessionID).otrStateChanged("AUTHENTICATED");

	    } else {

		if (status.equals(SessionStatus.FINISHED)) {

		    try {

			mChats.get(sessionID).localEndOtrSession();

		    } catch (OtrException e) {

			Log.w(TAG, "error when closing local otr session", e);

		    }

		}

		else {

		    mChats.get(sessionID).otrStateChanged(status.toString());

		}

	    }

	}

    }

}