require 'iron_mq'
require 'fanforce/api'
require 'timeout'

class Fanforce::Worker::Runner
  include Fanforce::Worker::Utils

  MAX_EXECUTION_TIME = 3300
  class Timeout < RuntimeError; end

  def initialize(worker_data, min_execution_time=300, &code_block)
    raise "min_execution_time was set to #{min_execution_time}, which is #{min_execution_time - MAX_EXECUTION_TIME} seconds too long" if min_execution_time > MAX_EXECUTION_TIME
    log.debug 'LOADING WORKER ENV'

    @queue_id   = worker_data['queue_id'] || (raise 'worker_data must contain queue_id')
    @worker_env = worker_data['env_vars'] || {}

    @min_execution_time = min_execution_time
    @code_block = code_block

    load_env
    load_jobs
  end

  def load_jobs
    log.debug 'PROCESSING JOBS...'
    log.debug '------------------------------------------------------------------------------------'
    job_num = 0
    job_data = nil
    while job_has_enough_time_to_run and (job = Fanforce::Worker.iron_mq.queue(@queue_id).get(timeout: 3600)) do
      log.debug "- JOB #{job_num+=1}: #{job.body}"
      timeout(worker_time_remaining, Timeout) do
        job_data = nil
        job_data = Fanforce.decode_json(job.body)
        run_job(job, job_data, &@code_block)
      end
      delete_job
      log.debug '------------------------------------------------------------------------------------'
    end
    delete_job
    log.debug 'WINDING DOWN WORKER!'

  rescue Exception => e
    handle_job_loading_error(e, job, job_data)
  end

  def load_env
    if File.exists?('.developmentenv.rb')
      require '.developmentenv'
    elsif File.exists?('.stagingenv.rb')
      require '.stagingenv'
    elsif File.exists?('.productionenv.rb')
      require '.productionenv'
    end
  end

  def run_job(job, job_data, &code_block)
    @current_job = job
    @current_params  = job_data[:params]
    @current_retries = job_data[:retries]

    set_env_vars(@worker_env)
    code_block.call(job_data[:params].clone, retries: job_data[:retries], queue_id: @queue_id)
    delete_job(job)

  rescue Exception => e
    handle_job_error(e, job, job_data)
  end

  def handle_job_loading_error(e, job, job_data)
    raise($!, "#{$!}: THERE IS NO JOB", $!.backtrace) if job.nil?

    delete_job(job)
    log.debug 'REMOVED JOB FROM QUEUE, BUT COULD NOT SAVE TO ERROR CACHE...'
    raise($!, "#{$!}: #{job_data.to_json}", $!.backtrace)
  end

  def handle_job_error(e, job, job_data)
    raise($!, "#{$!}: THERE IS NO JOB", $!.backtrace) if job.nil?

    delete_job(job)
    require_relative 'errors'
    log.debug 'REMOVED JOB FROM QUEUE, AND SAVING TO ERROR CACHE...'
    Fanforce::Worker::Errors.add(@queue_id, e, job_data, @worker_env)
  end

  def worker_time_remaining
    time_since_load = Time.now - Fanforce::Worker::LOADED_AT
    MAX_EXECUTION_TIME - time_since_load
  end

  def job_has_enough_time_to_run
    time_since_load = Time.now - Fanforce::Worker::LOADED_AT
    return false if time_since_load > MAX_EXECUTION_TIME
    return false if worker_time_remaining < @min_execution_time
    return true
  end

  def set_env_vars(vars)
    vars.each {|k,v| ENV[k.to_s]=v }
  end

  def delete_job(job=nil)
    return if job.nil? and @current_job.nil?
    (job || @current_job).delete
    @current_job = nil
  end

end