/*
 * Copyright 2015 Open Networking Laboratory
 *
 * 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 org.onosproject.store.consistent.impl;

import com.google.common.collect.Sets;

import net.kuujo.copycat.cluster.ClusterConfig;
import net.kuujo.copycat.cluster.Member;
import net.kuujo.copycat.log.FileLog;
import net.kuujo.copycat.netty.NettyTcpProtocol;
import net.kuujo.copycat.protocol.Consistency;

import org.apache.felix.scr.annotations.Activate;
import org.apache.felix.scr.annotations.Component;
import org.apache.felix.scr.annotations.Deactivate;
import org.apache.felix.scr.annotations.Reference;
import org.apache.felix.scr.annotations.ReferenceCardinality;
import org.apache.felix.scr.annotations.Service;
import org.onosproject.cluster.ClusterService;
import org.onosproject.store.cluster.impl.NodeInfo;
import org.onosproject.store.service.AsyncConsistentMap;
import org.onosproject.store.service.ConsistentMap;
import org.onosproject.store.service.PartitionInfo;
import org.onosproject.store.service.Serializer;
import org.onosproject.store.service.StorageAdminService;
import org.onosproject.store.service.StorageService;
import org.onosproject.store.service.TransactionContext;
import org.slf4j.Logger;

import java.io.File;
import java.io.IOException;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.TimeUnit;
import java.util.stream.Collectors;

import static org.slf4j.LoggerFactory.getLogger;

/**
 * Database manager.
 */
@Component(immediate = true, enabled = true)
@Service
public class DatabaseManager implements StorageService, StorageAdminService {

    private final Logger log = getLogger(getClass());
    private PartitionedDatabase partitionedDatabase;
    public static final int COPYCAT_TCP_PORT = 7238; //  7238 = RAFT
    private static final String CONFIG_DIR = "../config";
    private static final String PARTITION_DEFINITION_FILE = "tablets.json";
    private static final int DATABASE_STARTUP_TIMEOUT_SEC = 60;

    private final PartitionedDatabaseConfig databaseConfig = new PartitionedDatabaseConfig();

    @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
    protected ClusterService clusterService;

    protected String nodeToUri(NodeInfo node) {
        return String.format("tcp://%s:%d", node.getIp(), COPYCAT_TCP_PORT);
    }

    @Activate
    public void activate() {

        final String logDir = System.getProperty("karaf.data", "./data");

        // load database configuration
        File file = new File(CONFIG_DIR, PARTITION_DEFINITION_FILE);
        log.info("Loading database definition: {}", file.getAbsolutePath());

        Map<String, Set<NodeInfo>> partitionMap;
        try {
            DatabaseDefinitionStore databaseDef = new DatabaseDefinitionStore(file);
            partitionMap = databaseDef.read().getPartitions();
        } catch (IOException e) {
            throw new IllegalStateException("Failed to load database config", e);
        }

        String[] activeNodeUris = partitionMap.values()
                    .stream()
                    .reduce((s1, s2) -> Sets.union(s1, s2))
                    .get()
                    .stream()
                    .map(this::nodeToUri)
                    .toArray(String[]::new);

        String localNodeUri = nodeToUri(NodeInfo.of(clusterService.getLocalNode()));

        ClusterConfig clusterConfig = new ClusterConfig()
            .withProtocol(new NettyTcpProtocol()
                    .withSsl(false)
                    .withConnectTimeout(60000)
                    .withAcceptBacklog(1024)
                    .withTrafficClass(-1)
                    .withSoLinger(-1)
                    .withReceiveBufferSize(32768)
                    .withSendBufferSize(8192)
                    .withThreads(1))
            .withElectionTimeout(3000)
            .withHeartbeatInterval(1500)
            .withMembers(activeNodeUris)
            .withLocalMember(localNodeUri);

        partitionMap.forEach((name, nodes) -> {
            Set<String> replicas = nodes.stream().map(this::nodeToUri).collect(Collectors.toSet());
            DatabaseConfig partitionConfig = new DatabaseConfig()
                            .withElectionTimeout(3000)
                            .withHeartbeatInterval(1500)
                            .withConsistency(Consistency.STRONG)
                            .withLog(new FileLog()
                                    .withDirectory(logDir)
                                    .withSegmentSize(1073741824) // 1GB
                                    .withFlushOnWrite(true)
                                    .withSegmentInterval(Long.MAX_VALUE))
                            .withDefaultSerializer(new DatabaseSerializer())
                            .withReplicas(replicas);
            databaseConfig.addPartition(name, partitionConfig);
        });

        partitionedDatabase = PartitionedDatabaseManager.create("onos-store", clusterConfig, databaseConfig);

        CountDownLatch latch = new CountDownLatch(1);
        partitionedDatabase.open().whenComplete((db, error) -> {
            if (error != null) {
                log.warn("Failed to open database.", error);
            } else {
                latch.countDown();
                log.info("Successfully opened database.");
            }
        });
        try {
            if (!latch.await(DATABASE_STARTUP_TIMEOUT_SEC, TimeUnit.SECONDS)) {
                log.warn("Timed out waiting for database to initialize.");
            }
        } catch (InterruptedException e) {
            Thread.currentThread().interrupt();
            log.warn("Failed to complete database initialization.");
        }
        log.info("Started");
    }

    @Deactivate
    public void deactivate() {
        partitionedDatabase.close().whenComplete((result, error) -> {
            if (error != null) {
                log.warn("Failed to cleanly close database.", error);
            } else {
                log.info("Successfully closed database.");
            }
        });
        log.info("Stopped");
    }

    @Override
    public <K, V> ConsistentMap<K , V> createConsistentMap(String name, Serializer serializer) {
        return new DefaultConsistentMap<K, V>(name, partitionedDatabase, serializer);
    }

    @Override
    public <K, V> AsyncConsistentMap<K , V> createAsyncConsistentMap(String name, Serializer serializer) {
        return new DefaultAsyncConsistentMap<K, V>(name, partitionedDatabase, serializer);
    }

    @Override
    public TransactionContext createTransactionContext() {
        return new DefaultTransactionContext(partitionedDatabase);
    }

    @Override
    public List<PartitionInfo> getPartitionInfo() {
        return partitionedDatabase.getRegisteredPartitions()
                .values()
                .stream()
                .map(db -> toPartitionInfo(db, databaseConfig.partitions().get(db.name())))
                .collect(Collectors.toList());
    }

    /**
     * Maps a Raft Database object to a PartitionInfo object.
     *
     * @param database database containing input data
     * @return PartitionInfo object
     */
    private static PartitionInfo toPartitionInfo(Database database, DatabaseConfig dbConfig) {
        return new PartitionInfo(database.name(),
                          database.cluster().term(),
                          database.cluster().members().stream()
                                  .map(Member::uri)
                                  .filter(uri -> dbConfig.getReplicas().contains(uri))
                                  .collect(Collectors.toList()),
                          database.cluster().leader() != null ?
                                  database.cluster().leader().uri() : null);
    }
}