/**
 * Copyright (c) 2014 Cisco Systems, Inc. and others.  All rights reserved.
 *
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Public License v1.0 which accompanies this distribution,
 * and is available at http://www.eclipse.org/legal/epl-v10.html
 */

package org.opendaylight.openflowplugin.applications.frm.impl;

import com.google.common.base.Optional;
import com.google.common.base.Preconditions;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.Lists;
import com.google.common.util.concurrent.CheckedFuture;
import com.google.common.util.concurrent.FutureCallback;
import com.google.common.util.concurrent.Futures;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.ListIterator;
import java.util.Map;
import java.util.Set;
import java.util.concurrent.Callable;
import org.opendaylight.controller.md.sal.binding.api.DataBroker;
import org.opendaylight.controller.md.sal.binding.api.DataChangeListener;
import org.opendaylight.controller.md.sal.binding.api.ReadOnlyTransaction;
import org.opendaylight.controller.md.sal.binding.api.WriteTransaction;
import org.opendaylight.controller.md.sal.common.api.data.AsyncDataBroker.DataChangeScope;
import org.opendaylight.controller.md.sal.common.api.data.AsyncDataChangeEvent;
import org.opendaylight.controller.md.sal.common.api.data.LogicalDatastoreType;
import org.opendaylight.controller.md.sal.common.api.data.TransactionCommitFailedException;
import org.opendaylight.openflowplugin.applications.frm.FlowNodeReconciliation;
import org.opendaylight.openflowplugin.applications.frm.ForwardingRulesManager;
import org.opendaylight.openflowplugin.common.wait.SimpleTaskRetryLooper;
import org.opendaylight.yang.gen.v1.urn.opendaylight.action.types.rev131112.action.action.GroupActionCase;
import org.opendaylight.yang.gen.v1.urn.opendaylight.action.types.rev131112.action.list.Action;
import org.opendaylight.yang.gen.v1.urn.opendaylight.flow.inventory.rev130819.FlowCapableNode;
import org.opendaylight.yang.gen.v1.urn.opendaylight.flow.inventory.rev130819.FlowId;
import org.opendaylight.yang.gen.v1.urn.opendaylight.flow.inventory.rev130819.meters.Meter;
import org.opendaylight.yang.gen.v1.urn.opendaylight.flow.inventory.rev130819.meters.MeterBuilder;
import org.opendaylight.yang.gen.v1.urn.opendaylight.flow.inventory.rev130819.meters.MeterKey;
import org.opendaylight.yang.gen.v1.urn.opendaylight.flow.inventory.rev130819.meters.StaleMeter;
import org.opendaylight.yang.gen.v1.urn.opendaylight.flow.inventory.rev130819.meters.StaleMeterKey;
import org.opendaylight.yang.gen.v1.urn.opendaylight.flow.inventory.rev130819.tables.Table;
import org.opendaylight.yang.gen.v1.urn.opendaylight.flow.inventory.rev130819.tables.TableKey;
import org.opendaylight.yang.gen.v1.urn.opendaylight.flow.inventory.rev130819.tables.table.Flow;
import org.opendaylight.yang.gen.v1.urn.opendaylight.flow.inventory.rev130819.tables.table.FlowBuilder;
import org.opendaylight.yang.gen.v1.urn.opendaylight.flow.inventory.rev130819.tables.table.FlowKey;
import org.opendaylight.yang.gen.v1.urn.opendaylight.flow.inventory.rev130819.tables.table.StaleFlow;
import org.opendaylight.yang.gen.v1.urn.opendaylight.flow.inventory.rev130819.tables.table.StaleFlowKey;
import org.opendaylight.yang.gen.v1.urn.opendaylight.group.types.rev131018.GroupId;
import org.opendaylight.yang.gen.v1.urn.opendaylight.group.types.rev131018.group.buckets.Bucket;
import org.opendaylight.yang.gen.v1.urn.opendaylight.group.types.rev131018.groups.Group;
import org.opendaylight.yang.gen.v1.urn.opendaylight.group.types.rev131018.groups.GroupBuilder;
import org.opendaylight.yang.gen.v1.urn.opendaylight.group.types.rev131018.groups.GroupKey;
import org.opendaylight.yang.gen.v1.urn.opendaylight.group.types.rev131018.groups.StaleGroup;
import org.opendaylight.yang.gen.v1.urn.opendaylight.group.types.rev131018.groups.StaleGroupKey;
import org.opendaylight.yang.gen.v1.urn.opendaylight.inventory.rev130819.Nodes;
import org.opendaylight.yang.gen.v1.urn.opendaylight.inventory.rev130819.nodes.Node;
import org.opendaylight.yang.gen.v1.urn.opendaylight.meter.types.rev130918.MeterId;
import org.opendaylight.yang.gen.v1.urn.opendaylight.table.types.rev131026.table.features.TableFeatures;
import org.opendaylight.yang.gen.v1.urn.opendaylight.table.types.rev131026.table.features.TableFeaturesKey;
import org.opendaylight.yangtools.concepts.ListenerRegistration;
import org.opendaylight.yangtools.yang.binding.DataObject;
import org.opendaylight.yangtools.yang.binding.InstanceIdentifier;
import org.opendaylight.yangtools.yang.binding.KeyedInstanceIdentifier;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;


/**
 * forwardingrules-manager
 * org.opendaylight.openflowplugin.applications.frm
 *
 * FlowNode Reconciliation Listener
 * Reconciliation for a new FlowNode
 *
 * @author <a href="mailto:vdemcak@cisco.com">Vaclav Demcak</a>
 *
 * Created: Jun 13, 2014
 */
public class FlowNodeReconciliationImpl implements FlowNodeReconciliation {

    private static final Logger LOG = LoggerFactory.getLogger(FlowNodeReconciliationImpl.class);

    private final DataBroker dataBroker;

    private final ForwardingRulesManager provider;

    private ListenerRegistration<DataChangeListener> listenerRegistration;

    public FlowNodeReconciliationImpl (final ForwardingRulesManager manager, final DataBroker db) {
        this.provider = Preconditions.checkNotNull(manager, "ForwardingRulesManager can not be null!");
        dataBroker = Preconditions.checkNotNull(db, "DataBroker can not be null!");
        /* Build Path */
        final InstanceIdentifier<FlowCapableNode> flowNodeWildCardIdentifier = InstanceIdentifier.create(Nodes.class)
                .child(Node.class).augmentation(FlowCapableNode.class);

        SimpleTaskRetryLooper looper = new SimpleTaskRetryLooper(ForwardingRulesManagerImpl.STARTUP_LOOP_TICK,
                ForwardingRulesManagerImpl.STARTUP_LOOP_MAX_RETRIES);
        try {
            listenerRegistration = looper.loopUntilNoException(new Callable<ListenerRegistration<DataChangeListener>>() {
                @Override
                public ListenerRegistration<DataChangeListener> call() throws Exception {
                    return db.registerDataChangeListener(LogicalDatastoreType.OPERATIONAL,
                            flowNodeWildCardIdentifier, FlowNodeReconciliationImpl.this, DataChangeScope.BASE);
                }
            });
        } catch (Exception e) {
            LOG.warn("data listener registration failed: {}", e.getMessage());
            LOG.debug("data listener registration failed.. ", e);
            throw new IllegalStateException("FlowNodeReconciliation startup fail! System needs restart.", e);
        }
    }

    @Override
    public void close() {
        if (listenerRegistration != null) {
            try {
                listenerRegistration.close();
            } catch (Exception e) {
                LOG.warn("Error by stop FRM FlowNodeReconilListener: {}", e.getMessage());
                LOG.debug("Error by stop FRM FlowNodeReconilListener..", e);
            }
            listenerRegistration = null;
        }
    }

    @Override
    public void onDataChanged(final AsyncDataChangeEvent<InstanceIdentifier<?>, DataObject> changeEvent) {
        Preconditions.checkNotNull(changeEvent,"Async ChangeEvent can not be null!");
        /* All DataObjects for create */
        final Set<InstanceIdentifier<?>>  createdData = changeEvent.getCreatedData() != null
                ? changeEvent.getCreatedData().keySet() : Collections.<InstanceIdentifier<?>> emptySet();
        /* All DataObjects for remove */
        final Set<InstanceIdentifier<?>> removeData = changeEvent.getRemovedPaths() != null
                ? changeEvent.getRemovedPaths() : Collections.<InstanceIdentifier<?>> emptySet();
        /* All updated DataObjects */
        final Map<InstanceIdentifier<?>, DataObject> updateData = changeEvent.getUpdatedData() != null
                ? changeEvent.getUpdatedData() : Collections.<InstanceIdentifier<?>, DataObject>emptyMap();

        for (InstanceIdentifier<?> entryKey : removeData) {
            final InstanceIdentifier<FlowCapableNode> nodeIdent = entryKey
                    .firstIdentifierOf(FlowCapableNode.class);
            if ( ! nodeIdent.isWildcarded()) {
                flowNodeDisconnected(nodeIdent);
            }
        }
        for (InstanceIdentifier<?> entryKey : createdData) {
            final InstanceIdentifier<FlowCapableNode> nodeIdent = entryKey
                    .firstIdentifierOf(FlowCapableNode.class);
            if ( ! nodeIdent.isWildcarded()) {
                flowNodeConnected(nodeIdent);
            }
        }

        // FIXME: just a hack to cover DS/operational dirty start
        // if all conventional ways failed and there is update
        if (removeData.isEmpty() && createdData.isEmpty() && updateData.size() == 1) {
            for (Map.Entry<InstanceIdentifier<?>, DataObject> entry : updateData.entrySet()) {
                // and only if this update covers top element (flow-capable-node)
                if (FlowCapableNode.class.equals(entry.getKey().getTargetType())) {
                    final InstanceIdentifier<FlowCapableNode> nodeIdent = entry.getKey()
                            .firstIdentifierOf(FlowCapableNode.class);
                    if (!nodeIdent.isWildcarded()) {
                        // then force registration to local node cache and reconcile
                        flowNodeConnected(nodeIdent, true);
                    }
                }
            }
        }
    }

    @Override
    public void flowNodeDisconnected(InstanceIdentifier<FlowCapableNode> disconnectedNode) {
        provider.unregistrateNode(disconnectedNode);
    }

    @Override
    public void flowNodeConnected(InstanceIdentifier<FlowCapableNode> connectedNode) {
        flowNodeConnected(connectedNode, false);
    }

    private void flowNodeConnected(InstanceIdentifier<FlowCapableNode> connectedNode, boolean force) {
        if (force || !provider.isNodeActive(connectedNode)) {
            provider.registrateNewNode(connectedNode);

            if(!provider.isNodeOwner(connectedNode)) { return; }

            if (provider.getConfiguration().isStaleMarkingEnabled()) {
                LOG.info("Stale-Marking is ENABLED and proceeding with deletion of stale-marked entities on switch {}",
                        connectedNode.toString());
                reconciliationPreProcess(connectedNode);
            }
            reconciliation(connectedNode);
        }
    }

    private void reconciliation(final InstanceIdentifier<FlowCapableNode> nodeIdent) {

        ReadOnlyTransaction trans = provider.getReadTranaction();
        Optional<FlowCapableNode> flowNode = Optional.absent();

        try {
            flowNode = trans.read(LogicalDatastoreType.CONFIGURATION, nodeIdent).get();
        }
        catch (Exception e) {
            LOG.error("Fail with read Config/DS for Node {} !", nodeIdent, e);
        }

        if (flowNode.isPresent()) {
            /* Tables - have to be pushed before groups */
            // CHECK if while pusing the update, updateTableInput can be null to emulate a table add
            List<Table> tableList = flowNode.get().getTable() != null
                    ? flowNode.get().getTable() : Collections.<Table> emptyList() ;
            for (Table table : tableList) {
                TableKey tableKey = table.getKey();
                KeyedInstanceIdentifier<TableFeatures, TableFeaturesKey> tableFeaturesII
                    = nodeIdent.child(Table.class, tableKey).child(TableFeatures.class, new TableFeaturesKey(tableKey.getId()));
                List<TableFeatures> tableFeatures = table.getTableFeatures();
                if (tableFeatures != null) {
                    for (TableFeatures tableFeaturesItem : tableFeatures) {
                        provider.getTableFeaturesCommiter().update(tableFeaturesII, tableFeaturesItem, null, nodeIdent);
                    }
                }
            }

            /* Groups - have to be first */
                List<Group> groups = flowNode.get().getGroup() != null
                        ? flowNode.get().getGroup() : Collections.<Group>emptyList();
                List<Group> toBeInstalledGroups = new ArrayList<>();
                toBeInstalledGroups.addAll(groups);
                List<Long> alreadyInstalledGroupids = new ArrayList<>();

                while (!toBeInstalledGroups.isEmpty()) {
                    ListIterator<Group> iterator = toBeInstalledGroups.listIterator();
                    while (iterator.hasNext()) {
                        Group group = iterator.next();
                        boolean okToInstall = true;
                        for (Bucket bucket : group.getBuckets().getBucket()) {
                            for (Action action : bucket.getAction()) {
                                if (action.getAction().getImplementedInterface().getName()
                                        .equals("org.opendaylight.yang.gen.v1.urn.opendaylight.action.types.rev131112.action.action.GroupActionCase")) {
                                    Long groupId = ((GroupActionCase) (action.getAction())).getGroupAction().getGroupId();
                                    if (!alreadyInstalledGroupids.contains(groupId)) {
                                        okToInstall = false;
                                        break;
                                    }
                                }
                            }
                            if (!okToInstall){
                                break;
                            }
                        }


                        if (okToInstall) {
                            final KeyedInstanceIdentifier<Group, GroupKey> groupIdent =
                                    nodeIdent.child(Group.class, group.getKey());
                            this.provider.getGroupCommiter().add(groupIdent, group, nodeIdent);
                            alreadyInstalledGroupids.add(group.getGroupId().getValue());
                            iterator.remove();
                        }
                    }
                }
            /* Meters */
            List<Meter> meters = flowNode.get().getMeter() != null
                    ? flowNode.get().getMeter() : Collections.<Meter> emptyList();
            for (Meter meter : meters) {
                final KeyedInstanceIdentifier<Meter, MeterKey> meterIdent =
                        nodeIdent.child(Meter.class, meter.getKey());
                this.provider.getMeterCommiter().add(meterIdent, meter, nodeIdent);
            }
            /* Flows */
            List<Table> tables = flowNode.get().getTable() != null
                    ? flowNode.get().getTable() : Collections.<Table> emptyList();
            for (Table table : tables) {
                final KeyedInstanceIdentifier<Table, TableKey> tableIdent =
                        nodeIdent.child(Table.class, table.getKey());
                List<Flow> flows = table.getFlow() != null ? table.getFlow() : Collections.<Flow> emptyList();
                for (Flow flow : flows) {
                    final KeyedInstanceIdentifier<Flow, FlowKey> flowIdent =
                            tableIdent.child(Flow.class, flow.getKey());
                    this.provider.getFlowCommiter().add(flowIdent, flow, nodeIdent);
                }
            }
        }
        /* clean transaction */
        trans.close();
    }



    private void reconciliationPreProcess(final InstanceIdentifier<FlowCapableNode> nodeIdent) {


        List<InstanceIdentifier<StaleFlow>> staleFlowsToBeBulkDeleted = Lists.newArrayList();
        List<InstanceIdentifier<StaleGroup>> staleGroupsToBeBulkDeleted = Lists.newArrayList();
        List<InstanceIdentifier<StaleMeter>> staleMetersToBeBulkDeleted = Lists.newArrayList();


        ReadOnlyTransaction trans = provider.getReadTranaction();
        Optional<FlowCapableNode> flowNode = Optional.absent();

        try {
            flowNode = trans.read(LogicalDatastoreType.CONFIGURATION, nodeIdent).get();
        }
        catch (Exception e) {
            LOG.error("Reconciliation Pre-Processing Fail with read Config/DS for Node {} !", nodeIdent, e);
        }

        if (flowNode.isPresent()) {

            LOG.debug("Proceeding with deletion of stale-marked Flows on switch {} using Openflow interface",
                    nodeIdent.toString());
            /* Stale-Flows - Stale-marked Flows have to be removed first for safety */
            List<Table> tables = flowNode.get().getTable() != null
                    ? flowNode.get().getTable() : Collections.<Table> emptyList();
            for (Table table : tables) {
                final KeyedInstanceIdentifier<Table, TableKey> tableIdent =
                        nodeIdent.child(Table.class, table.getKey());
                List<StaleFlow> staleFlows = table.getStaleFlow() != null ? table.getStaleFlow() : Collections.<StaleFlow> emptyList();
                for (StaleFlow staleFlow : staleFlows) {

                    FlowBuilder flowBuilder = new FlowBuilder(staleFlow);
                    Flow toBeDeletedFlow = flowBuilder.setId(staleFlow.getId()).build();

                    final KeyedInstanceIdentifier<Flow, FlowKey> flowIdent =
                            tableIdent.child(Flow.class, toBeDeletedFlow.getKey());


                    this.provider.getFlowCommiter().remove(flowIdent, toBeDeletedFlow, nodeIdent);

                    staleFlowsToBeBulkDeleted.add(getStaleFlowInstanceIdentifier(staleFlow, nodeIdent));
                }
            }


            LOG.debug("Proceeding with deletion of stale-marked Groups for switch {} using Openflow interface",
                    nodeIdent.toString());

            // TODO: Should we collate the futures of RPC-calls to be sure that groups are Flows are fully deleted
            // before attempting to delete groups - just in case there are references

            /* Stale-marked Groups - Can be deleted after flows */
            List<StaleGroup> staleGroups = flowNode.get().getStaleGroup() != null
                    ? flowNode.get().getStaleGroup() : Collections.<StaleGroup> emptyList();
            for (StaleGroup staleGroup : staleGroups) {

                GroupBuilder groupBuilder = new GroupBuilder(staleGroup);
                Group toBeDeletedGroup = groupBuilder.setGroupId(staleGroup.getGroupId()).build();

                final KeyedInstanceIdentifier<Group, GroupKey> groupIdent =
                        nodeIdent.child(Group.class, toBeDeletedGroup.getKey());

                this.provider.getGroupCommiter().add(groupIdent, toBeDeletedGroup, nodeIdent);

                staleGroupsToBeBulkDeleted.add(getStaleGroupInstanceIdentifier(staleGroup, nodeIdent));
            }

            LOG.debug("Proceeding with deletion of stale-marked Meters for switch {} using Openflow interface",
                    nodeIdent.toString());
            /* Stale-marked Meters - can be deleted anytime - so least priority */
            List<StaleMeter> staleMeters = flowNode.get().getStaleMeter() != null
                    ? flowNode.get().getStaleMeter() : Collections.<StaleMeter> emptyList();

            for (StaleMeter staleMeter : staleMeters) {

                MeterBuilder meterBuilder = new MeterBuilder(staleMeter);
                Meter toBeDeletedMeter = meterBuilder.setMeterId(staleMeter.getMeterId()).build();

                final KeyedInstanceIdentifier<Meter, MeterKey> meterIdent =
                        nodeIdent.child(Meter.class, toBeDeletedMeter.getKey());


                this.provider.getMeterCommiter().add(meterIdent, toBeDeletedMeter, nodeIdent);

                staleMetersToBeBulkDeleted.add(getStaleMeterInstanceIdentifier(staleMeter, nodeIdent));
            }

        }
        /* clean transaction */
        trans.close();

        LOG.debug("Deleting all stale-marked flows/groups/meters of for switch {} in Configuration DS",
                nodeIdent.toString());
                // Now, do the bulk deletions
                deleteDSStaleFlows(staleFlowsToBeBulkDeleted);
        deleteDSStaleGroups(staleGroupsToBeBulkDeleted);
        deleteDSStaleMeters(staleMetersToBeBulkDeleted);

    }


    private void deleteDSStaleFlows(List<InstanceIdentifier<StaleFlow>> flowsForBulkDelete){
        ImmutableList.Builder<InstanceIdentifier<StaleFlow>> builder = ImmutableList.builder();
        ImmutableList<InstanceIdentifier<StaleFlow>> bulkDelFlows = builder.addAll(flowsForBulkDelete.iterator()).build();

        WriteTransaction writeTransaction = dataBroker.newWriteOnlyTransaction();

        for (InstanceIdentifier<StaleFlow> staleFlowIId : flowsForBulkDelete){
            writeTransaction.delete(LogicalDatastoreType.CONFIGURATION, staleFlowIId);
        }

        CheckedFuture<Void, TransactionCommitFailedException> submitFuture = writeTransaction.submit();
        handleStaleEntityDeletionResultFuture(submitFuture);
    }

    private void deleteDSStaleGroups(List<InstanceIdentifier<StaleGroup>> groupsForBulkDelete){
        ImmutableList.Builder<InstanceIdentifier<StaleGroup>> builder = ImmutableList.builder();
        ImmutableList<InstanceIdentifier<StaleGroup>> bulkDelGroups = builder.addAll(groupsForBulkDelete.iterator()).build();

        WriteTransaction writeTransaction = dataBroker.newWriteOnlyTransaction();

        for (InstanceIdentifier<StaleGroup> staleGroupIId : groupsForBulkDelete){
            writeTransaction.delete(LogicalDatastoreType.CONFIGURATION, staleGroupIId);
        }

        CheckedFuture<Void, TransactionCommitFailedException> submitFuture = writeTransaction.submit();
        handleStaleEntityDeletionResultFuture(submitFuture);

    }

    private void deleteDSStaleMeters(List<InstanceIdentifier<StaleMeter>> metersForBulkDelete){
        ImmutableList.Builder<InstanceIdentifier<StaleMeter>> builder = ImmutableList.builder();
        ImmutableList<InstanceIdentifier<StaleMeter>> bulkDelGroups = builder.addAll(metersForBulkDelete.iterator()).build();

        WriteTransaction writeTransaction = dataBroker.newWriteOnlyTransaction();

        for (InstanceIdentifier<StaleMeter> staleMeterIId : metersForBulkDelete){
            writeTransaction.delete(LogicalDatastoreType.CONFIGURATION, staleMeterIId);
        }

        CheckedFuture<Void, TransactionCommitFailedException> submitFuture = writeTransaction.submit();
        handleStaleEntityDeletionResultFuture(submitFuture);


    }


    private InstanceIdentifier<org.opendaylight.yang.gen.v1.urn.opendaylight.flow.inventory.rev130819.tables.table.StaleFlow> getStaleFlowInstanceIdentifier(StaleFlow staleFlow, InstanceIdentifier<FlowCapableNode> nodeIdent) {
        return nodeIdent
                .child(Table.class, new TableKey(staleFlow.getTableId()))
                .child(org.opendaylight.yang.gen.v1.urn.opendaylight.flow.inventory.rev130819.tables.table.StaleFlow.class,
                        new StaleFlowKey(new FlowId(staleFlow.getId())));
    }

    private InstanceIdentifier<org.opendaylight.yang.gen.v1.urn.opendaylight.group.types.rev131018.groups.StaleGroup> getStaleGroupInstanceIdentifier(StaleGroup staleGroup, InstanceIdentifier<FlowCapableNode> nodeIdent) {
        return nodeIdent
                .child(StaleGroup.class, new StaleGroupKey(new GroupId(staleGroup.getGroupId())));
    }


    private InstanceIdentifier<org.opendaylight.yang.gen.v1.urn.opendaylight.flow.inventory.rev130819.meters.StaleMeter> getStaleMeterInstanceIdentifier(StaleMeter staleMeter, InstanceIdentifier<FlowCapableNode> nodeIdent) {
        return nodeIdent
                .child(StaleMeter.class, new StaleMeterKey(new MeterId(staleMeter.getMeterId())));
    }


    private void handleStaleEntityDeletionResultFuture(CheckedFuture<Void, TransactionCommitFailedException> submitFuture) {
        Futures.addCallback(submitFuture, new FutureCallback<Void>() {
            @Override
            public void onSuccess(Void result) { LOG.debug("Stale entity removal success");
            }

            @Override
            public void onFailure(Throwable t) {
                LOG.error("Stale entity removal failed {}", t);
            }
        });

    }





}