get:
  tags: [Payments]
  summary: Download billing document by operation reference
  description: |
    Returns operation-level billing document as binary content.
    The request is resolved by gateway service and operation reference.
  operationId: paymentsGetOperationDocument
  security:
    - bearerAuth: []
  parameters:
    - $ref: ../parameters/organizations_ref.yaml#/components/parameters/OrganizationsRef
    - name: gateway_service
      in: query
      required: true
      description: Gateway service identifier (`chain_gateway`, `tron_gateway`, `mntx_gateway`, `payment_gateway`, `tgsettle_gateway`).
      schema:
        type: string
    - name: operation_ref
      in: query
      required: true
      description: Operation reference for which to fetch billing document.
      schema:
        type: string
  responses:
    '200':
      description: Operation billing document file
      content:
        application/pdf:
          schema:
            type: string
            format: binary
        application/octet-stream:
          schema:
            type: string
            format: binary
    '400':
      $ref: ../response/operation.yaml#/components/responses/BadRequest
    '401':
      $ref: ../response/operation.yaml#/components/responses/Unauthorized
    '403':
      $ref: ../response/operation.yaml#/components/responses/Forbidden
    '404':
      $ref: ../response/operation.yaml#/components/responses/NotFound
    '412':
      description: Precondition failed
      content:
        application/json:
          schema:
            $ref: ../response/response.yaml#/components/schemas/ErrorResponse
    '500':
      $ref: ../response/operation.yaml#/components/responses/InternalServerError
    '503':
      description: Upstream service unavailable
      content:
        application/json:
          schema:
            $ref: ../response/response.yaml#/components/schemas/ErrorResponse