module Rogger

  require 'gelf'
  require 'yaml'

  module Config

    class ConfigurationObject

      include Errors
      include Utils
      attr_reader :protocol, :server_hostname, :server_port, :app_name, :disabled

      def initialize(file_location)
        config_file = YAML.load(ERB.new(File.read(file_location)).result)
        @env_hash    = config_file[Config.env] || @config_file['default']
        @disabled          ||= set_disabled

        # short circuit initialization if disabled:true is set for current environment
        return nil if @disabled

        @protocol          ||= set_protocol
        @server_hostname   ||= set_server_hostname
        @server_port       ||= set_server_port
        @app_name          ||= set_app_name
      end

      private

      def set_disabled
        @env_hash['disabled'] == true
      end

      def set_protocol
        case @env_hash['protocol']
          when "tcp" then GELF::Protocol::TCP
          when "udp" then GELF::Protocol::UDP
          else raise InvalidProtocolError, "Please indicate a valid protocol in rogger.yml. Valid options are 'tcp' or 'udp'"
        end
      end

      def set_server_hostname
        case @env_hash['host']
          when nil then raise InvalidHostError, "Please enter a valid server IP address or hostname in rogger.yml"
          else @env_hash['host']
        end
      end

      def set_server_port
        case @env_hash['port']
          when Integer then @env_hash['port']
          else raise InvalidPortError, "Please enter a valid server port number in rogger.yml"
        end
      end

      def set_app_name
        case @env_hash['app_name']
          when String then @env_hash['app_name']
          else raise InvalidAppNameError, "Please enter a valid application name"
        end
      end
    end

    def self.env
      return Rails.env if defined?(Rails)
      return Sinatra::Base.environment.to_s if defined?(Sinatra)
      ENV["RACK_ENV"] || raise(Errors::NoEnvironment.new)
    end
  end

  config = Config::ConfigurationObject.new('config/rogger.yml')
  unless config.disabled

    @@logger = GELF::Logger.new(
      config.server_hostname,
      config.server_port,
      'WAN',
      {
        host: config.app_name,
        environment: Config::env,
        protocol: config.protocol
      })

    Rails.logger.extend(ActiveSupport::Logger.broadcast(@@logger))

  end

end