# encoding: utf-8

module Hatetepe
  class Client
    USER_AGENT = 'User-Agent'.freeze
    USER_AGENT_VALUE = "hatetepe/#{Hatetepe::VERSION}".freeze
    HOST = 'Host'.freeze
    HOST_VALUE = '%s:%d'.freeze

    include Support::Handlers
    include Connection::Status

    attr_reader :config

    def initialize(config)
      @config = config
      @requests = []

      setup_connection
      setup_handlers
      notify_handlers(:setup, @config, self, @connection)
    end

    def request(*args)
      request = Request.new(*args)
      perform(request).sync
    end

    def perform(request)
      served = Promise.new
      @requests << [request, served]

      add_extra_headers(request)
      Fiber.new { perform!(request) }.resume

      served
    end

    def receive(response)
      request, served = correlate

      served.fulfill(response)
      notify_handlers(:receive, request, response)
      response.closed { finish(request) }
    end

    def finish(request)
      @requests.delete_if { |(req)| req == request }
      notify_handlers(:finish, request)
    end

    def close
      @connection.close
    end

    def teardown(reason)
      @requests.each do |_, served|
        served.reject(reason)
        if (response = served.value)
          response.reject_closed(reason)
        end
      end
    end

    private

    def add_extra_headers(request)
      host = sprintf(HOST_VALUE, config[:address], config[:port])
      request.add_extra_headers(USER_AGENT => USER_AGENT_VALUE, HOST => host)
    end

    def perform!(request)
      notify_handlers(:perform, request)
      @connection.serialize(request)
    end

    def correlate
      tuple = @requests.detect { |_, served| served.pending? }
      fail ClientError, 'Unable to correlate with request' unless tuple
      tuple
    end

    def setup_connection
      @connection =
        EM.connect(@config[:address], @config[:port], Connection::EventMachine)
      @connection.parse(method(:receive))
      @connection.closed.then(method(:teardown))
    end
  end
end