require "json"
require "net/http"

module Boty
  class Session
    include Boty::Logger
    attr_reader :bot

    def start(&block)
      EM.run do
        login
        @bot = initialize_bot(&block)
        stablish_connection
      end
      self
    end

    private

    def on_connect(ws)
      ws.on :message do |event|
        begin
          on_message event, @bot
        rescue StandardError => e
          logger.error "Message #{event} could not be processed. #{e.message}"
          logger.debug e.backtrace.reduce("") { |msg, line| msg << "#{line}\n" }
        end
      end
    end

    def login
      logger.debug { "Logging in against slack right now" }
      @slack_info = Slack.rtm.start
      logger.debug { "yep! logged in!" }
      @session_url = @slack_info["url"]
    end

    def initialize_bot(&block)
      Bot.new(@slack_info["self"]).tap { |bot|
        DSL.new(bot).instance_eval(&block) if block_given?
        logger.debug { "Bot is configured and ready to go!" }
      }
    end

    def on_message(event, bot)
      logger.debug { "Message arrived. Creating bot event" }
      bot.event JSON.parse(event.data)
    end

    def on_close
      logger.debug { "bye bye" }
      #todo try to reconnect (stablish_connection) unless is an em interrupt
    end

    def stablish_connection
      logger.debug { "Starting to listen on #{@session_url}" }
      ws = Faye::WebSocket::Client.new @session_url
      ws.on :close do on_close end
      on_connect ws
    end
  end
end