require_relative './reactor'
module CelluloidPubsub
  # webserver to which socket connects should connect to .
  # the server will dispatch each request into a new Reactor
  # which will handle the action based on the message
  # @!attribute options
  #   @return [Hash] options used to configure the webserver
  #   @option options [String]:hostname The hostname on which the webserver runs on
  #   @option options [Integer] :port The port on which the webserver runs on
  #   @option options [String] :path The request path that the webserver accepts
  #   @option options [Boolean] :spy Enable this only if you want to enable debugging for the webserver
  #
  # @!attribute subscribers
  #   @return [Hash] The hostname on which the webserver runs on
  #
  # @!attribute backlog
  #   @return [Integer] Determines how many connections can be used
  #   Defaults to 1024
  #
  # @!attribute hostname
  #   @return [String] The hostname on which the webserver runs on
  #
  # @!attribute port
  #  @return [String] The port on which the webserver runs on
  #
  # @!attribute path
  #   @return [String] The hostname on which the webserver runs on
  #
  # @!attribute spy
  #   @return [Boolean] Enable this only if you want to enable debugging for the webserver
  class WebServer < Reel::Server::HTTP
    include Celluloid::Logger

    # The hostname on which the webserver runs on by default
    HOST = '0.0.0.0'
    # The port on which the webserver runs on by default
    PORT = 1234
    # The request path that the webserver accepts by default
    PATH = '/ws'

    attr_accessor :options, :subscribers, :backlog, :hostname, :port, :path, :spy

    #  receives a list of options that are used to configure the webserver
    #
    # @param  [Hash]  options the options that can be used to connect to webser and send additional data
    # @option options [String]:hostname The hostname on which the webserver runs on
    # @option options [Integer] :port The port on which the webserver runs on
    # @option options [String] :path The request path that the webserver accepts
    # @option options [Boolean] :spy Enable this only if you want to enable debugging for the webserver
    #
    # @return [void]
    #
    # @api public
    #
    # :nocov:
    def initialize(options = {})
      parse_options(options)
      @subscribers = {}
      info "CelluloidPubsub::WebServer example starting on #{@hostname}:#{@port}" if debug_enabled?
      super(@hostname, @port, { spy: @spy, backlog: @backlog }, &method(:on_connection))
    end
    # :nocov:

    #  receives a list of options that are used to configure the webserver
    #
    # @param  [Hash]  options the options that can be used to connect to webser and send additional data
    # @option options [String]:hostname The hostname on which the webserver runs on
    # @option options [Integer] :port The port on which the webserver runs on
    # @option options [String] :path The request path that the webserver accepts
    # @option options [Boolean] :spy Enable this only if you want to enable debugging for the webserver
    # @option options [Integer]:backlog How many connections the server accepts
    #
    # @return [void]
    #
    # @api public
    def parse_options(options)
      raise 'Options is not a hash ' unless options.is_a?(Hash)
      @options = options.stringify_keys
      @backlog = @options.fetch(:backlog, 1024)
      @hostname = @options.fetch(:hostname, CelluloidPubsub::WebServer::HOST)
      @port = @options.fetch(:port, CelluloidPubsub::WebServer::PORT)
      @path = @options.fetch(:path, CelluloidPubsub::WebServer::PATH)
      @spy = @options.fetch(:spy, false)
    end

    #  checks if debug is enabled
    #
    # @return [boolean]
    #
    # @api public
    def debug_enabled?
      self.class.debug_enabled?
    end

    #  checks if debug is enabled
    #
    # @return [boolean]
    #
    # @api public
    def self.debug_enabled?
      ENV['DEBUG_CELLULOID'].present? && (ENV['DEBUG_CELLULOID'] == 'true' || ENV['DEBUG_CELLULOID'] == true)
    end

    #  checks if debug is enabled
    #
    # @param [String] current_topic The Channel to which the reactor instance {CelluloidPubsub::Rector} will publish the message to
    # @param [Object] message
    #
    # @return [void]
    #
    # @api public
    def publish_event(current_topic, message)
      return if current_topic.blank? || message.blank?
      @subscribers[current_topic].each do |hash|
        hash[:reactor].websocket << message
      end
    end

    #  callback that will execute when receiving new conections
    # If the connections is a websocket will call method {#route_websocket}
    # and if the connection is HTTP will call method {#route_request}
    # For websocket connections , the connection is detached from the server and dispatched to another actor
    #
    # @see #route_websocket
    # @see #route_request
    #
    # @param [Reel::WebSocket] connection The connection that was made to the webserver
    #
    # @return [void]
    #
    # @api public
    def on_connection(connection)
      while request = connection.request
        if request.websocket?
          info 'Received a WebSocket connection' if debug_enabled?

          # We're going to hand off this connection to another actor (Writer/Reader)
          # However, initially Reel::Connections are "attached" to the
          # Reel::Server::HTTP actor, meaning that the server manages the connection
          # lifecycle (e.g. error handling) for us.
          #
          # If we want to hand this connection off to another actor, we first
          # need to detach it from the Reel::Server (in this case, Reel::Server::HTTP)
          connection.detach
          route_websocket(request.websocket)
          return
        else
          route_request connection, request
        end
      end
    end

    #  HTTP connections are not accepted so this method will show 404 message "Not Found"
    #
    # @param [Reel::WebSocket] connection The HTTP connection that was received
    # @param [Reel::Request] request The request that was made to the webserver and contains the type , the url, and the parameters
    #
    # @return [void]
    #
    # @api public
    def route_request(connection, request)
      info "404 Not Found: #{request.path}" if debug_enabled?
      connection.respond :not_found, 'Not found'
    end

    #  If the socket url matches with the one accepted by the server, it will dispatch the socket connection to a new reactor {CelluloidPubsub::Reactor#work}
    # The new actor is linked to the webserver
    #
    # @see CelluloidPubsub::Reactor#work
    #
    #  @param [Reel::WebSocket] socket The  web socket connection that was received
    #
    # @return [void]
    #
    # @api public
    def route_websocket(socket)
      if socket.url == @path
        info 'Reactor handles new socket connection' if debug_enabled?
        reactor = CelluloidPubsub::Reactor.new
        Actor.current.link reactor
        reactor.async.work(socket, Actor.current)
      else
        info "Received invalid WebSocket request for: #{socket.url}" if debug_enabled?
        socket.close
      end
    end

    # If the message can be parsed into a Hash it will respond to the reactor's websocket connection with the same message in JSON format
    # otherwise will try send the message how it is and escaped into JSON format
    #
    # @param [CelluloidPubsub::Reactor] reactor The  reactor that received an unhandled message
    # @param [Object] data The message that the reactor could not handle
    #
    # @return [void]
    #
    # @api public
    def handle_dispatched_message(reactor, data)
      debug "Webserver trying to dispatch message  #{data.inspect}" if debug_enabled?
      message = reactor.parse_json_data(data)
      if message.present? && message.is_a?(Hash)
        reactor.websocket << message.to_json
      else
        reactor.websocket << data.to_json
      end
    end
  end
end