foreign/node/src/wire/topic/get-topic.command.ts

// Licensed to the Apache Software Foundation (ASF) under one
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// distributed with this work for additional information
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// 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
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// specific language governing permissions and limitations
// under the License.
//

import type { CommandResponse } from '../../client/client.type.js';
import { wrapCommand } from '../command.utils.js';
import { COMMAND_CODE } from '../command.code.js';
import { serializeIdentifier, type Id } from '../identifier.utils.js';
import { deserializeTopic, type Topic } from './topic.utils.js';

/**
 * Parameters for the get topic command.
 */
export type GetTopic = {
  /** Stream identifier (ID or name) */
  streamId: Id,
  /** Topic identifier (ID or name) */
  topicId: Id
}

/**
 * Get topic command definition.
 * Retrieves detailed information about a specific topic.
 */
export const GET_TOPIC = {
  code: COMMAND_CODE.GetTopic,

  serialize: ({streamId, topicId}: GetTopic) => {
    return Buffer.concat([
      serializeIdentifier(streamId),
      serializeIdentifier(topicId)
    ]);
  },

  deserialize: (r: CommandResponse) => {
    if(r.status === 0 && r.length === 0)
      return null;
    return deserializeTopic(r.data).data;
  }
};


/**
 * Executable get topic command function.
 */
export const getTopic = wrapCommand<GetTopic, Topic | null>(GET_TOPIC);