/*-
 * ============LICENSE_START=======================================================
 * feature-state-management
 * ================================================================================
 * Copyright (C) 2017-2021 AT&T Intellectual Property. 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.
 * ============LICENSE_END=========================================================
 */

package org.onap.policy.drools.statemanagement;

import java.io.IOException;
import org.onap.policy.common.im.AllSeemsWellException;
import org.onap.policy.common.im.IntegrityMonitorException;
import org.onap.policy.common.im.StateChangeNotifier;
import org.onap.policy.common.im.StateManagement;
import org.onap.policy.common.im.StateManagementException;
import org.onap.policy.drools.core.PolicySessionFeatureApi;
import org.onap.policy.drools.features.PolicyEngineFeatureApi;
import org.onap.policy.drools.utils.PropertyUtil;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * If this feature is supported, there is a single instance of it.
 * It adds persistence to Drools sessions, but it is also intertwined with
 * active/standby state management and IntegrityMonitor. For now, they are
 * all treated as a single feature, but it would be nice to separate them.
 *
 * <p>The bulk of the code here was once in other classes, such as
 * 'PolicyContainer' and 'Main'. It was moved here as part of making this
 * a separate optional feature.
 */

public class StateManagementFeature implements StateManagementFeatureApi,
    PolicySessionFeatureApi, PolicyEngineFeatureApi {
    // get an instance of logger
    private static final Logger logger =
            LoggerFactory.getLogger(StateManagementFeature.class);

    private DroolsPdpIntegrityMonitor droolsPdpIntegrityMonitor = null;
    private StateManagement stateManagement = null;

    public StateManagementFeature() {
        logger.debug("StateManagementFeature() constructor");
    }

    @Override
    public void globalInit(String[] args, String configDir) {
        // Initialization code associated with 'PolicyContainer'
        logger.debug("StateManagementFeature.globalInit({}) entry", configDir);

        try {
            droolsPdpIntegrityMonitor = DroolsPdpIntegrityMonitor.init(configDir);
        } catch (Exception e) {
            logger.debug("DroolsPDPIntegrityMonitor initialization exception: ", e);
            logger.error("DroolsPDPIntegrityMonitor.init()", e);
        }

        initializeProperties(configDir);

        //At this point the DroolsPDPIntegrityMonitor instance must exist. Let's check it.
        try {
            droolsPdpIntegrityMonitor = DroolsPdpIntegrityMonitor.getInstance();
            stateManagement = droolsPdpIntegrityMonitor.getStateManager();

            if (stateManagement == null) {
                logger.debug("StateManagementFeature.globalInit(): stateManagement is NULL!");
            } else {
                logger.debug("StateManagementFeature.globalInit(): "
                        + "stateManagement.getAdminState(): {}", stateManagement.getAdminState());
            }
        } catch (Exception e1) {
            logger.debug("StateManagementFeature.globalInit(): DroolsPDPIntegrityMonitor"
                    + " initialization failed with exception:", e1);
            logger.error("DroolsPDPIntegrityMonitor.init(): StateManagementFeature startup failed "
                    + "to get DroolsPDPIntegrityMonitor instance:", e1);
        }
    }

    /**
     * {@inheritDoc}.
     */
    @Override
    public void addObserver(StateChangeNotifier stateChangeObserver) {
        logger.debug("StateManagementFeature.addObserver() entry\n"
                + "StateManagementFeature.addObserver(): "
                + "stateManagement.getAdminState(): {}", stateManagement.getAdminState());

        stateManagement.addObserver(stateChangeObserver);

        logger.debug("StateManagementFeature.addObserver() exit");
    }

    /**
     * {@inheritDoc}.
     */
    @Override
    public String getAdminState() {
        return stateManagement.getAdminState();
    }

    /**
     * {@inheritDoc}.
     */
    @Override
    public String getOpState() {
        return stateManagement.getOpState();
    }

    /**
     * {@inheritDoc}.
     */
    @Override
    public String getAvailStatus() {
        return stateManagement.getAvailStatus();
    }

    /**
     * {@inheritDoc}.
     */
    @Override
    public String getStandbyStatus() {
        return stateManagement.getStandbyStatus();
    }

    /**
     * {@inheritDoc}.
     */
    @Override
    public String getStandbyStatus(String resourceName) {
        return stateManagement.getStandbyStatus(resourceName);
    }

    /**
     * {@inheritDoc}.
     */
    @Override
    public void disableFailed(String resourceName) throws StateManagementException {
        stateManagement.disableFailed(resourceName);

    }

    /**
     * {@inheritDoc}.
     */
    @Override
    public void disableFailed() throws StateManagementException {
        stateManagement.disableFailed();
    }

    /**
     * {@inheritDoc}.
     */
    @Override
    public void promote() throws IntegrityMonitorException {
        stateManagement.promote();
    }

    /**
     * {@inheritDoc}.
     */
    @Override
    public void demote() throws StateManagementException {
        stateManagement.demote();
    }

    /**
     * {@inheritDoc}.
     */
    @Override
    public String getResourceName() {
        return StateManagementProperties.getProperty(StateManagementProperties.NODE_NAME);
    }

    /**
     * {@inheritDoc}.
     *
     * @return true if locked or false if failed
     */
    @Override
    public boolean lock() {
        try {
            stateManagement.lock();
        } catch (Exception e) {
            logger.error("StateManagementFeature.lock() failed with exception", e);
            return false;
        }
        return true;
    }

    /**
     * {@inheritDoc}.
     *
     * @throws Exception exception
     */
    @Override
    public boolean unlock() {
        try {
            stateManagement.unlock();
        } catch (Exception e) {
            logger.error("StateManagementFeature.unlock() failed with exception", e);
            return false;
        }
        return true;
    }

    /**
     * {@inheritDoc}.
     *
     * @throws Exception exception
     */
    @Override
    public boolean isLocked() {
        return StateManagement.LOCKED.equals(stateManagement.getAdminState());
    }

    @Override
    public int getSequenceNumber() {
        return StateManagementFeatureApiConstants.SEQ_NUM;
    }

    /**
     * Read in the properties and initialize the StateManagementProperties.
     */
    private static void initializeProperties(String configDir) {
        //Get the state management properties
        try {
            var props = PropertyUtil.getProperties(configDir + "/feature-state-management.properties");
            StateManagementProperties.initProperties(props);
            logger.info("initializeProperties: resourceName= {}",
                    StateManagementProperties.getProperty(StateManagementProperties.NODE_NAME));
        } catch (IOException e1) {
            logger.error("initializeProperties", e1);
        }
    }

    @Override
    public void allSeemsWell(String key, Boolean asw, String msg)
            throws AllSeemsWellException {

        droolsPdpIntegrityMonitor.allSeemsWell(key, asw, msg);

    }
}