# Polling stack status until it's completed or failed.
class StackSynchronizer
  include PutsAndFlush
  attr_reader :out, :stack

  class SyncResult < Devops::Helpers::ResultObject
    set_result_codes(
      ok: 0,
      stack_rolled_back: 1,
      unkown_status: 2,
      timeout: 3,
      error: 5,
      stack_deleted: 6,
      stack_not_found: 7
    )
  end

  def initialize(stack, out)
    @stack, @out = stack, out
    @printed_events = []
    @sync_result = nil
  end

  def sync
    puts_and_flush "Syncing stack '#{stack.id}'..."

    sleep_times.detect do |sleep_time|
      sleep sleep_time
      stack.sync!
      print_new_events

      update_stack_status if stack_status_changed?
      stack_is_already_created_or_failed?
    end

    @sync_result ||= result(:timeout)
    print_result_message
    @sync_result
  rescue StandardError => e
    DevopsLogger.logger.error e.message
    puts_and_flush "Error: #{e.class}: #{e.message}\n#{e.backtrace.join("\n")}"
    result(:error)
  end

  private

  def stack_is_already_created_or_failed?
    case stack.stack_status
    when 'CREATE_IN_PROGRESS', 'ROLLBACK_IN_PROGRESS', 'DELETE_IN_PROGRESS'
      false
    when 'CREATE_COMPLETE', 'ROLLBACK_COMPLETE', 'DELETE_COMPLETE', 'CREATE_FAILED', 'NOT_FOUND'
      @sync_result = result_for_provider_status(stack.stack_status)
    else
      @sync_result = result(:unkown_status)
    end
  end

  def sleep_times
    [5]*5 + [10]*400
  end

  def result(reason)
    SyncResult.from_reason(reason)
  end

  def result_for_provider_status(status)
    provider_status_mapping = {
      'CREATE_COMPLETE' => :ok,
      'ROLLBACK_COMPLETE' => :stack_rolled_back,
      'DELETE_COMPLETE' => :stack_deleted,
      'NOT_FOUND' => :stack_not_found
    }
    result(provider_status_mapping.fetch(status))
  end

  def print_result_message
    puts_and_flush Devops::Messages.t("stack_synchronizer.result.#{@sync_result.reason}",
      stack_id: stack.id, status: stack.stack_status, seconds: sleep_times.inject(&:+))
  end

  def update_stack_status
    ::Devops::Db.connector.stack_update(stack)
    @last_status = stack.stack_status
  end

  def stack_status_changed?
    @last_status != stack.stack_status
  end

  def print_new_events
    stack.events.each do |event|
      unless @printed_events.include?(event["event_id"])
        @printed_events << event["event_id"]
        out.puts "#{event["timestamp"]} - #{event["status"]}: #{event["reason"]}"
      end
    end
    out.flush
  end
end