# encoding: utf-8

require 'one_apm/frameworks/ruby'

module OneApm
  class Probe
    module Frameworks
      class Rails < OneApm::Probe::Frameworks::Ruby

        def env
          @env ||= RAILS_ENV.dup
        end

        def root
          root = rails_root.to_s
          if !root.empty?
            root
          else
            super
          end
        end

        def rails_root
          RAILS_ROOT if defined?(RAILS_ROOT)
        end

        def rails_config
          if defined?(::Rails) && ::Rails.respond_to?(:configuration)
            ::Rails.configuration
          else
            @config
          end
        end

        def init_config(options = {})
          @config = options[:config]

          if rails_config && ::Rails.configuration.respond_to?(:after_initialize)
            rails_config.after_initialize do
              LibraryDetection.detect!
            end
          end

          if !Manager.config[:agent_enabled]
            OneApm::Manager.logger.info("OneApm Agent not running.")
          else
            install_developer_mode(rails_config) if Manager.config[:developer_mode]
            install_browser_monitoring(rails_config)
            install_agent_hooks(rails_config)
          end
        end

        def agent_hooks_installed
          @@agent_hooks_installed ||= false
        end
        
        def browser_monitoring_installed
          @@browser_monitoring_installed ||= false
        end

        def developer_mode_installed
          @@developer_mode_installed ||= false
        end

        def install_agent_hooks(config)
          return if agent_hooks_installed
          @@agent_hooks_installed = true
          return if config.nil? || !config.respond_to?(:middleware)
          begin
            require 'one_apm/rack/middleware_hooks'
            return unless OneApm::Rack::MiddlewareHooks.needed?
            config.middleware.use OneApm::Rack::MiddlewareHooks
            OneApm::Manager.logger.debug("Installed OneApm Agent Hooks middleware")
          rescue => e
            OneApm::Manager.logger.warn("Error installing OneApm Agent Hooks middleware", e)
          end
        end

        def install_browser_monitoring(config)
          return if browser_monitoring_installed
          @@browser_monitoring_installed = true
          return if config.nil? || !config.respond_to?(:middleware) || !Manager.config[:'browser_monitoring.auto_instrument']
          begin
            require 'one_apm/rack/browser_monitoring'
            config.middleware.use OneApm::Rack::BrowserMonitoring
            OneApm::Manager.logger.debug("Installed OneApm Browser Monitoring middleware")
          rescue => e
            OneApm::Manager.logger.warn("Error installing OneApm Browser Monitoring middleware", e)
          end
        end

        def install_developer_mode(rails_config)
          return if env != "development"
          return if developer_mode_installed
          @@developer_mode_installed = true
          if rails_config && rails_config.respond_to?(:middleware)
            begin
              require 'one_apm/rack/developer_mode'
              rails_config.middleware.use OneApm::Rack::DeveloperMode
              OneApm::Manager.logger.info("Developer Mode enabled.")
            rescue => e
              ::OneApm::Manager.logger.warn("Error installing OneAPM Developer Mode", e)
            end
          elsif rails_config
            ::OneApm::Manager.logger.warn("Developer mode not available for Rails versions prior to 2.2")
          end
        end

        protected

        def install_shim
          super
          require 'one_apm/inst/transaction_base'
          if ActiveSupport.respond_to?(:on_load) # rails 3+
            ActiveSupport.on_load(:action_controller) { include OneApm::Agent::Instrumentation::TransactionBase::Shim }
          else
            ActionController::Base.class_eval { include OneApm::Agent::Instrumentation::TransactionBase::Shim }
          end
        end
      end
    end
  end
end