require "logger"
require "concurrent"
require "net/http"
require "sqspoller/worker_task"
require "sqspoller/common/ring_buffer"
require "sqspoller/process/task_finalizer"
require "sqspoller/common/utils"
require "sqspoller/metrics/sqs_poller_metrics"
require "sqspoller/process/task_worker"

# This manages all process task workers threads using threadpools.
# The number of thread can be configured in yaml config using concurrency:
# Refer test.yaml
module SqsPoller
  module Process
    class WorkerController

      private_class_method :new

      def initialize(worker_count, task_queue, worker_task, auto_tuning = true)
        @task_queue = task_queue
        @message_handler = worker_task
        @dynamic_scheduling = auto_tuning
        @worker_count = worker_count
        @task_workers = Concurrent::RubyThreadPoolExecutor.new(min_threads: @worker_count)
        @task_finalizer = TaskFinalizer.new(task_queue.max)
        @logger = SqsPoller::Logger.get_new_logger(self.class.name)
        @started = false
      end

      def self.get
        return @instance if @instance
        raise "WorkerController not yet started"
      end

      def self.start (worker_count, task_queue, worker_task, auto_tuning = true)
        return @instance if @instance
        @instance = new(worker_count, task_queue, worker_task, auto_tuning)
        @instance.start
        @instance
      end

      def started?
        @started
      end

      def start
        @logger.info "Starting #{@worker_count} workers"
        begin
          start_workers
          @started = true
        rescue Exception => e
          @logger.error "Task Worker killed for and restarted. Caught error: #{e.message}, #{e.backtrace.join("\n")}"
        end
      end

      def shutdown
        @logger.info "WorkerController Terminated"
      end

      private

      def start_workers
        @worker_count.times do |index|
          @task_workers.post do
            @logger.info "Starting worker #{index}"
            worker = Worker.new("Worker-#{index}", @task_queue, @task_finalizer, @message_handler)
            loop do
              begin
                worker.run
              rescue Exception => e
                @logger.error "Task Worker killed for and restarted. Caught error: #{e.message}, #{e.backtrace.join("\n")}"
              end
            end
          end
        end
      end

    end
  end
end