zammad/lib/sequencer/unit/import/zendesk/mixin/incremental_export.rb

# Copyright (C) 2012-2023 Zammad Foundation, https://zammad-foundation.org/

module Sequencer::Unit::Import::Zendesk::Mixin::IncrementalExport

  attr_accessor :previous_page

  def self.included(base)
    base.uses :client
    base.provides :import_job
  end

  def resource_collection
    require 'zendesk_api' # Only load this gem when it is really used.
    @resource_collection ||= "::ZendeskAPI::#{resource_klass}".constantize.incremental_export(client, 1)
  end

  def resource_iteration
    super do |record|
      # call passed/originally intended block
      yield(record)

      # add hook to check if object (e.g. ticket) count
      # update is needed because the request
      # might have changed
      update_count
    end
  end

  # The source if this is the limitation of not knowing
  # how much objects there are in total before requesting the endpoint
  # This is caused by the Zendesk API which only returns max. 1000
  # per request
  def update_count
    update_import_job

    self.previous_page = current_page
  end

  def update_import_job
    return if !update_required?

    state.provide(:import_job, updated_import_job)
  end

  def klass_key
    @klass_key ||= resource_klass.pluralize.to_sym
  end

  def updated_import_job
    import_job.result[klass_key][:total] += current_request_count
    import_job
  end

  def update_required?
    # means: still on first page
    return false if current_page.blank?

    previous_page != current_page
  end

  def current_request_count
    # access the internal instance method of the
    # Zendesk collection request to get the current
    # count of the fetched result (max. 1000)
    resource_collection.fetch.size
  end

  def current_page
    # access the internal instance method of the
    # Zendesk collection request to get the current
    # page number of the endpoint
    resource_collection.instance_variable_get(:@query)
  end
end