Sendbird Reply to the Latest Message in a Channel

arazzo: 1.0.1
info:
  title: Sendbird Reply to the Latest Message in a Channel
  summary: Read the most recent messages in a channel and post a reply.
  description: >-
    Fetches the most recent messages from a group channel and, when at least one
    message exists, posts a reply from a supplied sender. The flow branches on
    whether the channel has any messages so an empty channel can be handled
    gracefully instead of replying into the void. Every step spells out its
    request inline so the flow can be read and executed without opening the
    underlying OpenAPI description.
  version: 1.0.0
sourceDescriptions:
- name: messagesApi
  url: ../openapi/sendbird-messages-api-openapi.yml
  type: openapi
workflows:
- workflowId: reply-to-latest-message
  summary: Inspect recent channel messages and reply when any exist.
  description: >-
    Lists recent messages in a channel and branches: when messages are present
    it sends a reply, otherwise it ends without posting.
  inputs:
    type: object
    required:
    - apiToken
    - channelUrl
    - senderId
    - reply
    properties:
      apiToken:
        type: string
        description: Sendbird Api-Token from the dashboard.
      channelUrl:
        type: string
        description: URL of the channel to read and reply in.
      senderId:
        type: string
        description: User ID that authors the reply.
      reply:
        type: string
        description: Text content of the reply message.
  steps:
  - stepId: listRecent
    description: List the most recent messages in the channel.
    operationId: listMessages
    parameters:
    - name: Api-Token
      in: header
      value: $inputs.apiToken
    - name: channel_url
      in: path
      value: $inputs.channelUrl
    - name: prev_limit
      in: query
      value: 5
    successCriteria:
    - condition: $statusCode == 200
    outputs:
      latestMessageId: $response.body#/messages/0/message_id
    onSuccess:
    - name: hasMessages
      type: goto
      stepId: postReply
      criteria:
      - context: $response.body
        condition: $.messages.length > 0
        type: jsonpath
    - name: noMessages
      type: end
      criteria:
      - context: $response.body
        condition: $.messages.length == 0
        type: jsonpath
  - stepId: postReply
    description: Post the reply text into the channel from the sender.
    operationId: sendMessage
    parameters:
    - name: Api-Token
      in: header
      value: $inputs.apiToken
    - name: channel_url
      in: path
      value: $inputs.channelUrl
    requestBody:
      contentType: application/json
      payload:
        message_type: MESG
        user_id: $inputs.senderId
        message: $inputs.reply
    successCriteria:
    - condition: $statusCode == 200
    outputs:
      replyMessageId: $response.body#/message_id
  outputs:
    repliedToMessageId: $steps.listRecent.outputs.latestMessageId
    replyMessageId: $steps.postReply.outputs.replyMessageId