/*
 * Copyright (C) 2009, The Android Open Source Project
 *
 * 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 android.net.vpn;

import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.os.Environment;
import android.os.IBinder;
import android.os.RemoteException;
import android.os.ServiceManager;
import android.os.SystemProperties;
import android.util.Log;

import com.android.server.vpn.VpnServiceBinder;

/**
 * The class provides interface to manage all VPN-related tasks, including:
 * <ul>
 * <li>The list of supported VPN types.
 * <li>API's to start/stop the service of a particular type.
 * <li>API's to start the settings activity.
 * <li>API's to create a profile.
 * <li>API's to register/unregister a connectivity receiver and the keys to
 *      access the fields in a connectivity broadcast event.
 * </ul>
 * {@hide}
 */
public class VpnManager {
    /** Key to the profile name of a connectivity broadcast event. */
    public static final String BROADCAST_PROFILE_NAME = "profile_name";
    /** Key to the connectivity state of a connectivity broadcast event. */
    public static final String BROADCAST_CONNECTION_STATE = "connection_state";
    /** Key to the error code of a connectivity broadcast event. */
    public static final String BROADCAST_ERROR_CODE = "err";
    /** Error code to indicate an error from authentication. */
    public static final int VPN_ERROR_AUTH = 51;
    /** Error code to indicate the connection attempt failed. */
    public static final int VPN_ERROR_CONNECTION_FAILED = 101;
    /** Error code to indicate the server is not known. */
    public static final int VPN_ERROR_UNKNOWN_SERVER = 102;
    /** Error code to indicate an error from challenge response. */
    public static final int VPN_ERROR_CHALLENGE = 5;
    /** Error code to indicate an error of remote server hanging up. */
    public static final int VPN_ERROR_REMOTE_HUNG_UP = 7;
    /** Error code to indicate an error of remote PPP server hanging up. */
    public static final int VPN_ERROR_REMOTE_PPP_HUNG_UP = 48;
    /** Error code to indicate a PPP negotiation error. */
    public static final int VPN_ERROR_PPP_NEGOTIATION_FAILED = 42;
    /** Error code to indicate an error of losing connectivity. */
    public static final int VPN_ERROR_CONNECTION_LOST = 103;
    /** Largest error code used by VPN. */
    public static final int VPN_ERROR_LARGEST = 200;
    /** Error code to indicate a successful connection. */
    public static final int VPN_ERROR_NO_ERROR = 0;

    public static final String PROFILES_PATH = "/misc/vpn/profiles";

    private static final String PACKAGE_PREFIX =
            VpnManager.class.getPackage().getName() + ".";

    // Action for broadcasting a connectivity state.
    private static final String ACTION_VPN_CONNECTIVITY = "vpn.connectivity";

    private static final String VPN_SERVICE_NAME = "vpn";

    // Action to start VPN settings
    private static final String ACTION_VPN_SETTINGS =
            PACKAGE_PREFIX + "SETTINGS";

    public static final String TAG = VpnManager.class.getSimpleName();

    // TODO(oam): Test VPN when EFS is enabled (will do later)...
    public static String getProfilePath() {
        // This call will return the correct path if Encrypted FS is enabled or not.
        return Environment.getSecureDataDirectory().getPath() + PROFILES_PATH;
    }

    /**
     * Returns all supported VPN types.
     */
    public static VpnType[] getSupportedVpnTypes() {
        return VpnType.values();
    }

    public static void startVpnService(Context c) {
        ServiceManager.addService(VPN_SERVICE_NAME, new VpnServiceBinder(c));
    }

    private Context mContext;
    private IVpnService mVpnService;

    /**
     * Creates a manager object with the specified context.
     */
    public VpnManager(Context c) {
        mContext = c;
        createVpnServiceClient();
    }

    private void createVpnServiceClient() {
        IBinder b = ServiceManager.getService(VPN_SERVICE_NAME);
        mVpnService = IVpnService.Stub.asInterface(b);
    }

    /**
     * Sets up a VPN connection.
     * @param profile the profile object
     * @param username the username for authentication
     * @param password the corresponding password for authentication
     * @return true if VPN is successfully connected
     */
    public boolean connect(VpnProfile p, String username, String password) {
        try {
            return mVpnService.connect(p, username, password);
        } catch (RemoteException e) {
            Log.e(TAG, "connect()", e);
            return false;
        }
    }

    /**
     * Tears down the VPN connection.
     */
    public void disconnect() {
        try {
            mVpnService.disconnect();
        } catch (RemoteException e) {
            Log.e(TAG, "disconnect()", e);
        }
    }

    /**
     * Gets the the current connection state.
     */
    public VpnState getState(VpnProfile p) {
        try {
            return Enum.valueOf(VpnState.class, mVpnService.getState(p));
        } catch (RemoteException e) {
            Log.e(TAG, "getState()", e);
            return VpnState.IDLE;
        }
    }

    /**
     * Returns the idle state.
     * @return true if the system is not connecting/connected to a VPN
     */
    public boolean isIdle() {
        try {
            return mVpnService.isIdle();
        } catch (RemoteException e) {
            Log.e(TAG, "isIdle()", e);
            return true;
        }
    }

    /**
     * Creates a VPN profile of the specified type.
     *
     * @param type the VPN type
     * @return the profile object
     */
    public VpnProfile createVpnProfile(VpnType type) {
        return createVpnProfile(type, false);
    }

    /**
     * Creates a VPN profile of the specified type.
     *
     * @param type the VPN type
     * @param customized true if the profile is custom made
     * @return the profile object
     */
    public VpnProfile createVpnProfile(VpnType type, boolean customized) {
        try {
            VpnProfile p = (VpnProfile) type.getProfileClass().newInstance();
            p.setCustomized(customized);
            return p;
        } catch (InstantiationException e) {
            return null;
        } catch (IllegalAccessException e) {
            return null;
        }
    }

    /** Broadcasts the connectivity state of the specified profile. */
    public void broadcastConnectivity(String profileName, VpnState s) {
        broadcastConnectivity(profileName, s, VPN_ERROR_NO_ERROR);
    }

    /** Broadcasts the connectivity state with an error code. */
    public void broadcastConnectivity(String profileName, VpnState s,
            int error) {
        Intent intent = new Intent(ACTION_VPN_CONNECTIVITY);
        intent.putExtra(BROADCAST_PROFILE_NAME, profileName);
        intent.putExtra(BROADCAST_CONNECTION_STATE, s);
        if (error != VPN_ERROR_NO_ERROR) {
            intent.putExtra(BROADCAST_ERROR_CODE, error);
        }
        mContext.sendBroadcast(intent);
    }

    public void registerConnectivityReceiver(BroadcastReceiver r) {
        IntentFilter filter = new IntentFilter();
        filter.addAction(VpnManager.ACTION_VPN_CONNECTIVITY);
        mContext.registerReceiver(r, filter);
    }

    public void unregisterConnectivityReceiver(BroadcastReceiver r) {
        mContext.unregisterReceiver(r);
    }

    /** Starts the VPN settings activity. */
    public void startSettingsActivity() {
        Intent intent = new Intent(ACTION_VPN_SETTINGS);
        intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
        mContext.startActivity(intent);
    }

    /** Creates an intent to start the VPN settings activity. */
    public Intent createSettingsActivityIntent() {
        Intent intent = new Intent(ACTION_VPN_SETTINGS);
        intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
        return intent;
    }
}