/*
 * Copyright (c) 2018 Orange and/or its affiliates.
 *
 * 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 io.fd.honeycomb.infra.distro.initializer;

import com.google.common.base.Preconditions;

import java.util.Collection;
import java.util.Iterator;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.Future;

import org.opendaylight.controller.md.sal.binding.api.DataBroker;
import org.opendaylight.controller.md.sal.binding.api.DataObjectModification;
import org.opendaylight.controller.md.sal.binding.api.DataTreeChangeListener;
import org.opendaylight.controller.md.sal.binding.api.DataTreeIdentifier;
import org.opendaylight.controller.md.sal.binding.api.DataTreeModification;
import org.opendaylight.controller.md.sal.binding.api.WriteTransaction;
import org.opendaylight.controller.md.sal.common.api.data.LogicalDatastoreType;
import org.opendaylight.yang.gen.v1.http.org.openroadm.device.rev170206.interfaces.grp.Interface;
import org.opendaylight.yang.gen.v1.http.org.openroadm.device.rev170206.interfaces.grp.InterfaceKey;
import org.opendaylight.yang.gen.v1.http.org.openroadm.device.rev170206.org.openroadm.device.container.OrgOpenroadmDevice;
import org.opendaylight.yang.gen.v1.http.org.openroadm.device.rev170206.org.openroadm.device.container.org.openroadm.device.RoadmConnections;
import org.opendaylight.yang.gen.v1.http.org.openroadm.device.rev170206.org.openroadm.device.container.org.openroadm.device.RoadmConnectionsKey;
import org.opendaylight.yangtools.yang.binding.DataObject;
import org.opendaylight.yangtools.yang.binding.InstanceIdentifier;
import org.opendaylight.yangtools.yang.binding.InstanceIdentifier.PathArgument;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * @author Martial COULIBALY ( mcoulibaly.ext@orange.com ) on behalf of Orange
 */
final class DeviceChangeListener implements DataTreeChangeListener<OrgOpenroadmDevice> {

    private static final Logger LOG = LoggerFactory.getLogger(DeviceChangeListener.class);
    private final DataBroker honeyCombDB;
    private final DataBroker dataBroker;

    public DeviceChangeListener(DataBroker deviceDataBroker, DataBroker honeycombDB) {
        this.dataBroker = deviceDataBroker;
        this.honeyCombDB = honeycombDB;
        Preconditions.checkArgument(this.dataBroker != null, "Device datastore is null");
        Preconditions.checkArgument(this.honeyCombDB != null, "HC datastore is null");
    }

    @Override
    public void onDataTreeChanged(Collection<DataTreeModification<OrgOpenroadmDevice>> changes) {
        LOG.info("onDataTreeChanged");
        for (DataTreeModification<OrgOpenroadmDevice> change : changes) {
            final DataObjectModification<OrgOpenroadmDevice> rootNode = change.getRootNode();
            final DataTreeIdentifier<OrgOpenroadmDevice> rootPath = change.getRootPath();
            if (rootNode != null ) {
                final OrgOpenroadmDevice dataBefore = rootNode.getDataBefore();
                final OrgOpenroadmDevice dataAfter = rootNode.getDataAfter();
                LOG.info("Received Device change({}):\n before={} \n after={}", rootNode.getModificationType(), dataBefore,
                        dataAfter);
                Collection<DataObjectModification<? extends DataObject>> modifiedChildren = rootNode.getModifiedChildren();
                switch (rootNode.getModificationType()) {
                    case SUBTREE_MODIFIED:
                        if (!modifiedChildren.isEmpty()) {
                            Iterator<DataObjectModification<? extends DataObject>> iterator = modifiedChildren.iterator();
                            while (iterator.hasNext()) {
                                DataObjectModification<? extends DataObject> modified = iterator.next();
                                LOG.info("modified = \ndataType : {}\nid : {}\nmodifiedType : {}\noldData : {}\nnewData : {} \n",
                                        modified.getDataType(), modified.getIdentifier(),modified.getModificationType(),
                                        modified.getDataBefore(), modified.getDataAfter());
                                switch (modified.getModificationType()) {
                                  case SUBTREE_MODIFIED:
                                  case WRITE :
                                      processChange(rootPath.getRootIdentifier(), dataAfter);
                                      break;
                                  case DELETE:
                                      deleteContainer(rootPath, modified, dataAfter);
                                      break;
                                  default:
                                      break;
                               }
                            }
                        }
                        processChange(rootPath.getRootIdentifier(), dataAfter);
                        break;
                    case WRITE :
                        processChange(rootPath.getRootIdentifier(), dataAfter);
                        break;
                    case DELETE:
                        deleteChange(rootPath.getRootIdentifier(),dataBefore);
                        break;
                    default:
                        break;
                }
            } else {
                LOG.error("rootNode is null !");
            }
        }
    }

    /**
     * Delete change from device
     * oper datastore.
     *
     * @param id container identifier
     */
    private void deleteContainer(DataTreeIdentifier<OrgOpenroadmDevice> rootPath,
            DataObjectModification<? extends DataObject> modified, final OrgOpenroadmDevice dataAfter) {
        final String ROADM_CONNECTIONS = "interface org.opendaylight.yang.gen.v1.http.org.openroadm.device.rev170206"
                + ".org.openroadm.device.container.org.openroadm.device.RoadmConnections";
        final String INTERFACE_GRP = "interface org.opendaylight.yang.gen.v1.http.org.openroadm.device.rev170206"
                + ".interfaces.grp.Interface";
        Class<? extends DataObject> type = modified.getDataType();
        PathArgument path = modified.getIdentifier();
        LOG.info("deleting container type '{}' with id '{}' ...", type.toString(), path);
        String key = extractKey(path.toString());
        if ( key != null) {
            InstanceIdentifier<?> iid = null;
            switch (type.toString()) {
                case ROADM_CONNECTIONS:
                    LOG.info("roadm-connections ...");
                    iid = rootPath.getRootIdentifier().child(RoadmConnections.class,
                        new RoadmConnectionsKey(key));
                    break;
                case INTERFACE_GRP:
                    LOG.info("interface ....");
                    iid = rootPath.getRootIdentifier().child(Interface.class,
                            new InterfaceKey(key));
                default:
                    break;
            }
            LOG.info("iid : {}", iid);
            WriteTransaction writeTx = this.dataBroker.newWriteOnlyTransaction();
            WriteTransaction writeHCTx = this.honeyCombDB.newWriteOnlyTransaction();
            if (writeTx != null && writeHCTx != null) {
                LOG.info("WriteTransaction is ok, delete container device from device oper datastore");
                try {
                    LOG.info("deleting container element from device oper DS ...");
                    writeTx.delete(LogicalDatastoreType.OPERATIONAL, iid);
                    Future<Void> future = writeTx.submit();
                    future.get();
                    LOG.info("container element '{}' deleted from device oper datastore", iid);
                    LOG.info("deleting from HC config DS ...");
                    writeHCTx.put(LogicalDatastoreType.CONFIGURATION, rootPath.getRootIdentifier(),dataAfter);
                    future = writeHCTx.submit();
                    future.get();
                    LOG.info("device config DS '{}' updated to HC config DS", rootPath.getRootIdentifier());
                } catch (InterruptedException | ExecutionException e) {
                    LOG.error("Failed to process WriteTransactions",e);
                }
            } else {
                LOG.error("WriteTransaction object is null");
            }
        } else {
            LOG.error("extract key is null");
        }
    }

    private String extractKey(String path) {
        LOG.info("getting key from pathArgument ...");
        String result = null;
        if (path != null && path.length() > 2) {
            result = path.substring(path.lastIndexOf("=") + 1, path.length()-2);
            LOG.info("result : {}", result);
        } else {
            LOG.error("String pathArgument is not compliant !!");
        }
        return result;
    }

    /**
     * Delete change from Honeycomb
     * config datastore.
     *
     * @param id OrgOpenroadmDevice identifier
     * @param dataBefore OrgOpenroadmDevice before delete action
     */
    private void deleteChange(final InstanceIdentifier<OrgOpenroadmDevice> id, final OrgOpenroadmDevice dataBefore) {
        LOG.info("deleting change ...");
        WriteTransaction writeHCTx = this.honeyCombDB.newWriteOnlyTransaction();
        if (writeHCTx != null) {
            LOG.info("WriteTransaction is ok, delete device info from HC config datastore");
            if(dataBefore != null) {
                String deviceId = dataBefore.getInfo().getNodeId();
                try {
                    writeHCTx.delete(LogicalDatastoreType.CONFIGURATION, id);
                    Future<Void> future = writeHCTx.submit();
                    future.get();
                    LOG.info("device '{}' deleted from HC config  datastore", deviceId);
                } catch (InterruptedException | ExecutionException e) {
                    LOG.error("Failed to delete Element '{}' from datastore", deviceId);
                }
            } else {
                LOG.error("OrgOpenroadmDevice is null");
            }
        } else {
            LOG.error("WriteTransaction object is null");
        }

    }

    /**
     * Merge change to Honeycomb
     * config datastore and device
     * config datastore.
     *
     * @param id OrgOpenroadmDevice identifier
     * @param dataAfter OrgOpenroadmDevice to be merged
     */
    private void processChange(final InstanceIdentifier<OrgOpenroadmDevice> id, final OrgOpenroadmDevice dataAfter) {
        LOG.info("processing change ...");
        WriteTransaction writeTx = this.dataBroker.newWriteOnlyTransaction();
        WriteTransaction writeHCTx = this.honeyCombDB.newWriteOnlyTransaction();
        if (writeTx != null && writeHCTx != null) {
            LOG.info("WriteTransactions are ok, merge device info to datastores");
            if(dataAfter != null) {
                String deviceId = dataAfter.getInfo().getNodeId();
                writeTx.merge(LogicalDatastoreType.OPERATIONAL, id, dataAfter);
                Future<Void> future = writeTx.submit();
                try {
                    future.get();
                    LOG.info("device '{}' merged to device oper datastore", deviceId);
                    writeHCTx.merge(LogicalDatastoreType.CONFIGURATION, id, dataAfter);
                    future = writeHCTx.submit();
                    future.get();
                    LOG.info("device '{}' merged to HC config datastore", deviceId);
                } catch (InterruptedException | ExecutionException e) {
                    LOG.error("Failed to merge Element '{}' to datastores", deviceId);
                }
            } else {
                LOG.error("device is null");
            }
        } else {
            LOG.error("WriteTransaction object is null");
        }
    }

}