/*
 * Licensed to Elasticsearch under one or more contributor
 * license agreements. See the NOTICE file distributed with
 * this work for additional information regarding copyright
 * ownership. Elasticsearch licenses this file to you 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 org.elasticsearch.indices.store;

import com.google.common.collect.Lists;
import org.elasticsearch.ElasticsearchException;
import org.elasticsearch.action.ActionListener;
import org.elasticsearch.action.FailedNodeException;
import org.elasticsearch.action.support.ActionFilters;
import org.elasticsearch.action.support.nodes.*;
import org.elasticsearch.cluster.ClusterName;
import org.elasticsearch.cluster.ClusterService;
import org.elasticsearch.cluster.ClusterState;
import org.elasticsearch.cluster.metadata.IndexMetaData;
import org.elasticsearch.cluster.node.DiscoveryNode;
import org.elasticsearch.common.inject.Inject;
import org.elasticsearch.common.io.stream.StreamInput;
import org.elasticsearch.common.io.stream.StreamOutput;
import org.elasticsearch.common.io.stream.Streamable;
import org.elasticsearch.common.settings.Settings;
import org.elasticsearch.common.unit.TimeValue;
import org.elasticsearch.env.NodeEnvironment;
import org.elasticsearch.gateway.AsyncShardFetch;
import org.elasticsearch.index.IndexService;
import org.elasticsearch.index.shard.IndexShard;
import org.elasticsearch.index.shard.ShardId;
import org.elasticsearch.index.store.Store;
import org.elasticsearch.index.store.StoreFileMetaData;
import org.elasticsearch.indices.IndicesService;
import org.elasticsearch.threadpool.ThreadPool;
import org.elasticsearch.transport.TransportService;

import java.io.File;
import java.io.IOException;
import java.util.Iterator;
import java.util.List;
import java.util.Set;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicReferenceArray;

/**
 *
 */
public class TransportNodesListShardStoreMetaData extends TransportNodesOperationAction<TransportNodesListShardStoreMetaData.Request, TransportNodesListShardStoreMetaData.NodesStoreFilesMetaData, TransportNodesListShardStoreMetaData.NodeRequest, TransportNodesListShardStoreMetaData.NodeStoreFilesMetaData>
        implements AsyncShardFetch.List<TransportNodesListShardStoreMetaData.NodesStoreFilesMetaData, TransportNodesListShardStoreMetaData.NodeStoreFilesMetaData> {

    public static final String ACTION_NAME = "internal:cluster/nodes/indices/shard/store";

    private final IndicesService indicesService;

    private final NodeEnvironment nodeEnv;

    @Inject
    public TransportNodesListShardStoreMetaData(Settings settings, ClusterName clusterName, ThreadPool threadPool, ClusterService clusterService, TransportService transportService,
                                                IndicesService indicesService, NodeEnvironment nodeEnv, ActionFilters actionFilters) {
        super(settings, ACTION_NAME, clusterName, threadPool, clusterService, transportService, actionFilters);
        this.indicesService = indicesService;
        this.nodeEnv = nodeEnv;
    }

    @Override
    public void list(ShardId shardId, IndexMetaData indexMetaData, String[] nodesIds, ActionListener<NodesStoreFilesMetaData> listener) {
        execute(new Request(shardId, false, nodesIds), listener);
    }

    @Override
    protected String executor() {
        return ThreadPool.Names.FETCH_SHARD_STORE;
    }

    @Override
    protected Request newRequest() {
        return new Request();
    }

    @Override
    protected NodeRequest newNodeRequest() {
        return new NodeRequest();
    }

    @Override
    protected String[] resolveNodes(Request request, ClusterState clusterState) {
        // default implementation may filter out non existent nodes. it's important to keep exactly the ids
        // we were given for accounting on the caller
        return request.nodesIds();
    }

    @Override
    protected NodeRequest newNodeRequest(String nodeId, Request request) {
        return new NodeRequest(nodeId, request);
    }

    @Override
    protected NodeStoreFilesMetaData newNodeResponse() {
        return new NodeStoreFilesMetaData();
    }

    @Override
    protected NodesStoreFilesMetaData newResponse(Request request, AtomicReferenceArray responses) {
        final List<NodeStoreFilesMetaData> nodeStoreFilesMetaDatas = Lists.newArrayList();
        final List<FailedNodeException> failures = Lists.newArrayList();
        for (int i = 0; i < responses.length(); i++) {
            Object resp = responses.get(i);
            if (resp instanceof NodeStoreFilesMetaData) { // will also filter out null response for unallocated ones
                nodeStoreFilesMetaDatas.add((NodeStoreFilesMetaData) resp);
            } else if (resp instanceof FailedNodeException) {
                failures.add((FailedNodeException) resp);
            } else {
                logger.warn("unknown response type [{}], expected NodeStoreFilesMetaData or FailedNodeException", resp);
            }
        }
        return new NodesStoreFilesMetaData(clusterName, nodeStoreFilesMetaDatas.toArray(new NodeStoreFilesMetaData[nodeStoreFilesMetaDatas.size()]),
                failures.toArray(new FailedNodeException[failures.size()]));
    }

    @Override
    protected NodeStoreFilesMetaData nodeOperation(NodeRequest request) throws ElasticsearchException {
        if (request.unallocated) {
            IndexService indexService = indicesService.indexService(request.shardId.index().name());
            if (indexService == null) {
                return new NodeStoreFilesMetaData(clusterService.localNode(), null);
            }
            if (!indexService.hasShard(request.shardId.id())) {
                return new NodeStoreFilesMetaData(clusterService.localNode(), null);
            }
        }
        IndexMetaData metaData = clusterService.state().metaData().index(request.shardId.index().name());
        if (metaData == null) {
            return new NodeStoreFilesMetaData(clusterService.localNode(), null);
        }
        try {
            return new NodeStoreFilesMetaData(clusterService.localNode(), listStoreMetaData(request.shardId));
        } catch (IOException e) {
            throw new ElasticsearchException("Failed to list store metadata for shard [" + request.shardId + "]", e);
        }
    }

    private StoreFilesMetaData listStoreMetaData(ShardId shardId) throws IOException {
        logger.trace("listing store meta data for {}", shardId);
        long startTimeNS = System.nanoTime();
        boolean exists = false;
        try {
            IndexService indexService = indicesService.indexService(shardId.index().name());
            if (indexService != null) {
                IndexShard indexShard = indexService.shard(shardId.id());
                if (indexShard != null) {
                    final Store store = indexShard.store();
                    store.incRef();
                    try {
                        exists = true;
                        return new StoreFilesMetaData(true, shardId, store.getMetadataOrEmpty());
                    } finally {
                        store.decRef();
                    }
                }
            }
            // try and see if we an list unallocated
            IndexMetaData metaData = clusterService.state().metaData().index(shardId.index().name());
            if (metaData == null) {
                return new StoreFilesMetaData(false, shardId, Store.MetadataSnapshot.EMPTY);
            }
            String storeType = metaData.settings().get("index.store.type", "fs");
            if (!storeType.contains("fs")) {
                return new StoreFilesMetaData(false, shardId, Store.MetadataSnapshot.EMPTY);
            }
            File[] shardLocations = nodeEnv.shardDataLocations(shardId, metaData.settings());
            File[] shardIndexLocations = new File[shardLocations.length];
            for (int i = 0; i < shardLocations.length; i++) {
                shardIndexLocations[i] = new File(shardLocations[i], "index");
            }
            for (File shardIndexLocation : shardIndexLocations) {
                if (shardIndexLocation.exists()) {
                    exists = true;
                    break;
                }
            }
            if (!exists) {
                return new StoreFilesMetaData(false, shardId, Store.MetadataSnapshot.EMPTY);
            }
            return new StoreFilesMetaData(false, shardId, Store.readMetadataSnapshot(shardIndexLocations, logger));
        } finally {
            TimeValue took = new TimeValue(System.nanoTime() - startTimeNS, TimeUnit.NANOSECONDS);
            if (exists) {
                logger.debug("{} loaded store meta data (took [{}])", shardId, took);
            } else {
                logger.trace("{} didn't find any store meta data to load (took [{}])", shardId, took);
            }
        }
    }

    @Override
    protected boolean accumulateExceptions() {
        return true;
    }

    public static class StoreFilesMetaData implements Iterable<StoreFileMetaData>, Streamable {
        // here also trasmit sync id, else recovery will not use sync id because of stupid gateway allocator every now and then...
        private boolean allocated;
        private ShardId shardId;
        Store.MetadataSnapshot metadataSnapshot;

        StoreFilesMetaData() {
        }

        public StoreFilesMetaData(boolean allocated, ShardId shardId, Store.MetadataSnapshot metadataSnapshot) {
            this.allocated = allocated;
            this.shardId = shardId;
            this.metadataSnapshot = metadataSnapshot;
        }

        public boolean allocated() {
            return allocated;
        }

        public ShardId shardId() {
            return this.shardId;
        }

        public long totalSizeInBytes() {
            long totalSizeInBytes = 0;
            for (StoreFileMetaData file : this) {
                totalSizeInBytes += file.length();
            }
            return totalSizeInBytes;
        }

        @Override
        public Iterator<StoreFileMetaData> iterator() {
            return metadataSnapshot.iterator();
        }

        public boolean fileExists(String name) {
            return metadataSnapshot.asMap().containsKey(name);
        }

        public StoreFileMetaData file(String name) {
            return metadataSnapshot.asMap().get(name);
        }

        public static StoreFilesMetaData readStoreFilesMetaData(StreamInput in) throws IOException {
            StoreFilesMetaData md = new StoreFilesMetaData();
            md.readFrom(in);
            return md;
        }

        @Override
        public void readFrom(StreamInput in) throws IOException {
            allocated = in.readBoolean();
            shardId = ShardId.readShardId(in);
            this.metadataSnapshot = new Store.MetadataSnapshot(in);
        }

        @Override
        public void writeTo(StreamOutput out) throws IOException {
            out.writeBoolean(allocated);
            shardId.writeTo(out);
            metadataSnapshot.writeTo(out);
        }

        /**
         * @return commit sync id if exists, else null
         */
        public String syncId() {
            return metadataSnapshot.getSyncId();
        }
    }


    static class Request extends NodesOperationRequest<Request> {

        private ShardId shardId;

        private boolean unallocated;

        public Request() {
        }

        public Request(ShardId shardId, boolean unallocated, Set<String> nodesIds) {
            super(nodesIds.toArray(new String[nodesIds.size()]));
            this.shardId = shardId;
            this.unallocated = unallocated;
        }

        public Request(ShardId shardId, boolean unallocated, String... nodesIds) {
            super(nodesIds);
            this.shardId = shardId;
            this.unallocated = unallocated;
        }

        @Override
        public void readFrom(StreamInput in) throws IOException {
            super.readFrom(in);
            shardId = ShardId.readShardId(in);
            unallocated = in.readBoolean();
        }

        @Override
        public void writeTo(StreamOutput out) throws IOException {
            super.writeTo(out);
            shardId.writeTo(out);
            out.writeBoolean(unallocated);
        }
    }

    public static class NodesStoreFilesMetaData extends NodesOperationResponse<NodeStoreFilesMetaData> {

        private FailedNodeException[] failures;

        NodesStoreFilesMetaData() {
        }

        public NodesStoreFilesMetaData(ClusterName clusterName, NodeStoreFilesMetaData[] nodes, FailedNodeException[] failures) {
            super(clusterName, nodes);
            this.failures = failures;
        }

        @Override
        public FailedNodeException[] failures() {
            return failures;
        }

        @Override
        public void readFrom(StreamInput in) throws IOException {
            super.readFrom(in);
            nodes = new NodeStoreFilesMetaData[in.readVInt()];
            for (int i = 0; i < nodes.length; i++) {
                nodes[i] = NodeStoreFilesMetaData.readListShardStoreNodeOperationResponse(in);
            }
        }

        @Override
        public void writeTo(StreamOutput out) throws IOException {
            super.writeTo(out);
            out.writeVInt(nodes.length);
            for (NodeStoreFilesMetaData response : nodes) {
                response.writeTo(out);
            }
        }
    }


    static class NodeRequest extends NodeOperationRequest {

        private ShardId shardId;

        private boolean unallocated;

        NodeRequest() {
        }

        NodeRequest(String nodeId, TransportNodesListShardStoreMetaData.Request request) {
            super(request, nodeId);
            this.shardId = request.shardId;
            this.unallocated = request.unallocated;
        }

        @Override
        public void readFrom(StreamInput in) throws IOException {
            super.readFrom(in);
            shardId = ShardId.readShardId(in);
            unallocated = in.readBoolean();
        }

        @Override
        public void writeTo(StreamOutput out) throws IOException {
            super.writeTo(out);
            shardId.writeTo(out);
            out.writeBoolean(unallocated);
        }
    }

    public static class NodeStoreFilesMetaData extends NodeOperationResponse {

        private StoreFilesMetaData storeFilesMetaData;

        NodeStoreFilesMetaData() {
        }

        public NodeStoreFilesMetaData(DiscoveryNode node, StoreFilesMetaData storeFilesMetaData) {
            super(node);
            this.storeFilesMetaData = storeFilesMetaData;
        }

        public StoreFilesMetaData storeFilesMetaData() {
            return storeFilesMetaData;
        }

        public static NodeStoreFilesMetaData readListShardStoreNodeOperationResponse(StreamInput in) throws IOException {
            NodeStoreFilesMetaData resp = new NodeStoreFilesMetaData();
            resp.readFrom(in);
            return resp;
        }

        @Override
        public void readFrom(StreamInput in) throws IOException {
            super.readFrom(in);
            if (in.readBoolean()) {
                storeFilesMetaData = StoreFilesMetaData.readStoreFilesMetaData(in);
            }
        }

        @Override
        public void writeTo(StreamOutput out) throws IOException {
            super.writeTo(out);
            if (storeFilesMetaData == null) {
                out.writeBoolean(false);
            } else {
                out.writeBoolean(true);
                storeFilesMetaData.writeTo(out);
            }
        }
    }
}
