/*----------------------------------------------------------------------------
 * Copyright IBM Corp. 2015, 2015 All Rights Reserved
 * 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.
 * ---------------------------------------------------------------------------
 */

/*============================================================================
 DD-MMM-2014    eranr       Initial implementation as sChannel.
 Introducing wrapping structures.
 30-Jun-2014    evgenyl     Switching to SBus. Code refactoring.
 Simplifying API. Extracting business logic.
 ===========================================================================*/

package org.openstack.storlet.sbus;

import java.io.IOException;

/*----------------------------------------------------------------------------
 * SBusBackend
 * 
 * This class wraps and transfers calls to the JNI implementation
 * */
public class SBusBackend {
    /*------------------------------------------------------------------------
     * JNI layer delegate, common to every instance of SBusBackend
     * */
    private static SBusJNI SBusJNIObj_ = new SBusJNI();

    /*------------------------------------------------------------------------
     * Enumerating logging levels
     * The values are suitable to syslog constants
     * */
    public static enum eLogLevel {
        SBUS_LOG_DEBUG, SBUS_LOG_INFO, SBUS_LOG_WARNING, SBUS_LOG_CRITICAL, SBUS_LOG_OFF
    };

    /*------------------------------------------------------------------------
     * Initiate logging with the required detail level
     * */
    public void startLogger(eLogLevel eLogLevel, String contId) {
        String strLogLevel = null;
        switch (eLogLevel) {
        case SBUS_LOG_DEBUG:
            strLogLevel = "DEBUG";
            break;
        case SBUS_LOG_INFO:
            strLogLevel = "INFO";
            break;
        case SBUS_LOG_WARNING:
            strLogLevel = "WARNING";
            break;
        case SBUS_LOG_CRITICAL:
            strLogLevel = "CRITICAL";
            break;
        case SBUS_LOG_OFF:
            strLogLevel = "OFF";
            break;
        default:
            strLogLevel = "WARNINIG";
            break;
        }
        SBusJNIObj_.startLogger(strLogLevel, contId);
    }

    /*------------------------------------------------------------------------
     * Stop logging
     * */
    public void stopLogger() {
        SBusJNIObj_.stopLogger();
    }

    /*------------------------------------------------------------------------
     * Create the bus.
     * */
    public SBusHandler createSBus(final String strSBusName) throws IOException {
        int nSBus = SBusJNIObj_.createSBus(strSBusName);
        if (0 > nSBus)
            throw new IOException("Unable to create SBus - " + strSBusName);
        return new SBusHandler(nSBus);
    }

    /*------------------------------------------------------------------------
     * Wait and listen to the bus.
     * The executing thread is suspended until some data arrives.
     * */
    public boolean listenSBus(final SBusHandler hSBus) throws IOException {
        int nStatus = SBusJNIObj_.listenSBus(hSBus.getFD());
        if (0 > nStatus)
            throw new IOException("Unable to listen to SBus");
        return true;
    }

    /*------------------------------------------------------------------------
     * Take the message and send it.
     * */
    public int sendRawMessage(final String strBusName, final SBusRawMessage Msg)
            throws IOException {
        int nStatus = SBusJNIObj_.sendRawMessage(strBusName, Msg);
        if (0 > nStatus)
            throw new IOException("Unable to send message");
        return nStatus;
    }

    /*------------------------------------------------------------------------
     * Read some actual raw data from the bus
     * */
    public SBusRawMessage receiveRawMessage(final SBusHandler hSBus)
            throws IOException {
        SBusRawMessage Msg = SBusJNIObj_.receiveRawMessage(hSBus.getFD());
        if (null == Msg)
            throw new IOException("Unable to retrieve a message");
        return Msg;
    }

}