/*
 * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
 * or more contributor license agreements. Licensed under the "Elastic License
 * 2.0", the "GNU Affero General Public License v3.0 only", and the "Server Side
 * Public License v 1"; you may not use this file except in compliance with, at
 * your election, the "Elastic License 2.0", the "GNU Affero General Public
 * License v3.0 only", or the "Server Side Public License, v 1".
 */

package org.elasticsearch.action.support.single.shard;

import org.elasticsearch.action.ActionRequestValidationException;
import org.elasticsearch.action.IndicesRequest;
import org.elasticsearch.action.LegacyActionRequest;
import org.elasticsearch.action.ValidateActions;
import org.elasticsearch.action.support.IndicesOptions;
import org.elasticsearch.common.io.stream.StreamInput;
import org.elasticsearch.common.io.stream.StreamOutput;
import org.elasticsearch.core.Nullable;
import org.elasticsearch.index.shard.ShardId;

import java.io.IOException;
import java.util.Collections;
import java.util.List;

public abstract class SingleShardRequest<Request extends SingleShardRequest<Request>> extends LegacyActionRequest
    implements
        IndicesRequest.RemoteClusterShardRequest {

    public static final IndicesOptions INDICES_OPTIONS = IndicesOptions.strictSingleIndexNoExpandForbidClosed();

    /**
     * The concrete index name
     * <p>
     * Whether index property is optional depends on the concrete implementation. If index property is required the
     * concrete implementation should use {@link #validateNonNullIndex()} to check if the index property has been set
     */
    @Nullable
    protected String index;
    ShardId internalShardId;

    public SingleShardRequest() {}

    public SingleShardRequest(StreamInput in) throws IOException {
        super(in);
        if (in.readBoolean()) {
            internalShardId = new ShardId(in);
        }
        index = in.readOptionalString();
        // no need to pass threading over the network, they are always false when coming throw a thread pool
    }

    protected SingleShardRequest(String index) {
        this.index = index;
    }

    /**
     * @return a validation exception if the index property hasn't been set
     */
    protected ActionRequestValidationException validateNonNullIndex() {
        ActionRequestValidationException validationException = null;
        if (index == null) {
            validationException = ValidateActions.addValidationError("index is missing", validationException);
        }
        return validationException;
    }

    /**
     * @return The concrete index this request is targeted for or <code>null</code> if index is optional.
     * Whether index property is optional depends on the concrete implementation. If index property
     * is required the concrete implementation should use {@link #validateNonNullIndex()} to check
     * if the index property has been set
     */
    @Nullable
    public String index() {
        return index;
    }

    /**
     * Sets the index.
     */
    @SuppressWarnings("unchecked")
    public final Request index(String index) {
        this.index = index;
        return (Request) this;
    }

    @Override
    public String[] indices() {
        return new String[] { index };
    }

    @Override
    public List<ShardId> shards() {
        return Collections.singletonList(this.internalShardId);
    }

    @Override
    public IndicesOptions indicesOptions() {
        return INDICES_OPTIONS;
    }

    @Override
    public void writeTo(StreamOutput out) throws IOException {
        super.writeTo(out);
        out.writeOptionalWriteable(internalShardId);
        out.writeOptionalString(index);
    }
}