require_relative 'logger'

module Remon
  class DedupedQueue

    include Logger

    def initialize
      @hash = {}
      @mutex = Mutex.new
      @queue = Queue.new
    end

    def enqueue(task)
      @mutex.synchronize do
        if @hash[task]
          logger.debug "duplicate item #{task}" if logger.debug?
          return
        end
        @hash[task] = true
      end
      @queue << task
    end

    def dequeue(non_block = false)
      task = @queue.pop(non_block)
      @mutex.synchronize do
        @hash.delete task
      end
      task
    end

    alias_method :'<<', :enqueue
    alias_method :pop, :dequeue
    alias_method :shift, :dequeue

  end
end