require "async"
require "async/io/stream"
require "async/http/endpoint"
require "async/websocket/client"
require "json"
require "nice_hash"
require "nice_http"

module SlackSocket
  class Client
    AdquisitionError = Class.new(StandardError)
    ConnectionError = Class.new(StandardError)
    AcknowledgeError = Class.new(StandardError)

    def initialize
      @token = ENV["SLACK_SOCKETS_TOKEN"]
    end

    def connect
      http = NiceHttp.new("https://slack.com")
      request = {
        headers: {
          Authorization: "Bearer #{@token}",
        },
        path: "/api/apps.connections.open",
      }
      connection_info = http.post(request)
      http.close
      result = connection_info.data.json

      raise(AdquisitionError) unless result.ok

      websocket = Async::HTTP::Endpoint.parse(result.url)

      Async do |_i|
        Async::WebSocket::Client.connect(websocket) do |connection|
          payload = connection.read

          raise(ConnectionError) unless connection_status(payload)

          puts "Listening..."
          treat(payload, connection) while (payload = connection.read)
        end
      end
    end

    private

    def connection_status(payload)
      payload.buffer.json.type == "hello"
    end

    def treat(payload, connection)
      event = payload.buffer.json.payload.event
      #send a post request with the envelope_id
      envelope_id = payload.buffer.json.envelope_id
      resp = connection.write(JSON.dump(envelope_id: envelope_id))
      raise AcknowledgeError unless resp.finished

      # call the bot supplying the event
      #
      #

    end
  end
end

client = SlackSocket::Client.new
client.connect