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/**
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF 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.apache.kafka.common.requests;

import org.apache.kafka.common.TopicPartition;
import org.apache.kafka.common.protocol.ApiKeys;
import org.apache.kafka.common.protocol.ProtoUtils;
import org.apache.kafka.common.protocol.types.Schema;
import org.apache.kafka.common.protocol.types.Struct;
import org.apache.kafka.common.utils.CollectionUtils;

import java.nio.ByteBuffer;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

public class FetchRequest extends AbstractRequestResponse {
    public static Schema curSchema = ProtoUtils.currentRequestSchema(ApiKeys.FETCH.id);
    private static String REPLICA_ID_KEY_NAME = "replica_id";
    private static String MAX_WAIT_KEY_NAME = "max_wait_time";
    private static String MIN_BYTES_KEY_NAME = "min_bytes";
    private static String TOPICS_KEY_NAME = "topics";

    // topic level field names
    private static String TOPIC_KEY_NAME = "topic";
    private static String PARTITIONS_KEY_NAME = "partitions";

    // partition level field names
    private static String PARTITION_KEY_NAME = "partition";
    private static String FETCH_OFFSET_KEY_NAME = "fetch_offset";
    private static String MAX_BYTES_KEY_NAME = "max_bytes";

    private final int replicaId;
    private final int maxWait;
    private final int minBytes;
    private final Map fetchData;

    public static final class PartitionData {
        public final long offset;
        public final int maxBytes;

        public PartitionData(long offset, int maxBytes) {
            this.offset = offset;
            this.maxBytes = maxBytes;
        }
    }

    public FetchRequest(int replicaId, int maxWait, int minBytes, Map fetchData) {
        super(new Struct(curSchema));
        Map> topicsData = CollectionUtils.groupDataByTopic(fetchData);

        struct.set(REPLICA_ID_KEY_NAME, replicaId);
        struct.set(MAX_WAIT_KEY_NAME, maxWait);
        struct.set(MIN_BYTES_KEY_NAME, minBytes);
        List topicArray = new ArrayList();
        for (Map.Entry> topicEntry: topicsData.entrySet()) {
            Struct topicData = struct.instance(TOPICS_KEY_NAME);
            topicData.set(TOPIC_KEY_NAME, topicEntry.getKey());
            List partitionArray = new ArrayList();
            for (Map.Entry partitionEntry : topicEntry.getValue().entrySet()) {
                PartitionData fetchPartitionData = partitionEntry.getValue();
                Struct partitionData = topicData.instance(PARTITIONS_KEY_NAME);
                partitionData.set(PARTITION_KEY_NAME, partitionEntry.getKey());
                partitionData.set(FETCH_OFFSET_KEY_NAME, fetchPartitionData.offset);
                partitionData.set(MAX_BYTES_KEY_NAME, fetchPartitionData.maxBytes);
                partitionArray.add(partitionData);
            }
            topicData.set(PARTITIONS_KEY_NAME, partitionArray.toArray());
            topicArray.add(topicData);
        }
        struct.set(TOPICS_KEY_NAME, topicArray.toArray());
        this.replicaId = replicaId;
        this.maxWait = maxWait;
        this.minBytes = minBytes;
        this.fetchData = fetchData;
    }

    public FetchRequest(Struct struct) {
        super(struct);
        replicaId = struct.getInt(REPLICA_ID_KEY_NAME);
        maxWait = struct.getInt(MAX_WAIT_KEY_NAME);
        minBytes = struct.getInt(MIN_BYTES_KEY_NAME);
        fetchData = new HashMap();
        for (Object topicResponseObj : struct.getArray(TOPICS_KEY_NAME)) {
            Struct topicResponse = (Struct) topicResponseObj;
            String topic = topicResponse.getString(TOPIC_KEY_NAME);
            for (Object partitionResponseObj : topicResponse.getArray(PARTITIONS_KEY_NAME)) {
                Struct partitionResponse = (Struct) partitionResponseObj;
                int partition = partitionResponse.getInt(PARTITION_KEY_NAME);
                long offset = partitionResponse.getLong(FETCH_OFFSET_KEY_NAME);
                int maxBytes = partitionResponse.getInt(MAX_BYTES_KEY_NAME);
                PartitionData partitionData = new PartitionData(offset, maxBytes);
                fetchData.put(new TopicPartition(topic, partition), partitionData);
            }
        }
    }

    public int replicaId() {
        return replicaId;
    }

    public int maxWait() {
        return maxWait;
    }

    public int minBytes() {
        return minBytes;
    }

    public Map fetchData() {
        return fetchData;
    }

    public static FetchRequest parse(ByteBuffer buffer) {
        return new FetchRequest(((Struct) curSchema.read(buffer)));
    }
}