require "multi_json"
require "socket"
require "websocket/driver"

# Adapted from https://github.com/mackwic/slack-rtmapi

module Slacks
  class Driver
    attr_accessor :stop

    def initialize
      @has_been_init = false
      @stop = false
      @callbacks = {}
    end

    VALID = [:open, :message, :error].freeze
    def on(type, &block)
      unless VALID.include? type
        raise ArgumentError.new "Client#on accept one of #{VALID.inspect}"
      end

      callbacks[type] = block
    end

    # This init has been delayed because the SSL handshake is a blocking and
    # expensive call
    def connect_to(url)
      raise "Already been init" if @has_been_init
      url = URI(url)
      raise ArgumentError.new ":url must be a valid websocket secure url!" unless url.scheme == "wss"

      @socket = OpenSSL::SSL::SSLSocket.new(TCPSocket.new url.host, 443)
      socket.connect # costly and blocking !

      internalWrapper = (Struct.new :url, :socket do
        def write(*args)
          self.socket.write(*args)
        end
      end).new url.to_s, socket

      # this, also, is costly and blocking
      @driver = WebSocket::Driver.client internalWrapper
      driver.on :open do
        @connected = true
        unless callbacks[:open].nil?
          callbacks[:open].call
        end
      end

      driver.on :error do |event|
        @connected = false
        unless callbacks[:error].nil?
          callbacks[:error].call event
        end
      end

      driver.on :message do |event|
        data = MultiJson.load event.data
        unless callbacks[:message].nil?
          callbacks[:message].call data
        end
      end

      driver.start
      @has_been_init = true
    end

    def write(message)
      @driver.text(message)
    end

    def ping
      @driver.ping
    end

    def connected?
      @connected || false
    end

    # All the polling work is done here
    def inner_loop
      return if @stop

      data = @socket.readpartial 4096
      driver.parse data unless data.nil? or data.empty?
    end

    def main_loop
      loop do
        inner_loop
      end
    end

  private
    attr_reader :url, :socket, :driver, :callbacks

  end
end