require 'logger'
require 'rack/request'
require 'active_support/core_ext/class/attribute_accessors'


module MongoRequestLogger
  class Rack
    cattr_accessor :logger
    cattr_accessor :ignore_prefixes

    def self.ignore_prefix prefix
      self.ignore_prefixes ||= []
      self.ignore_prefixes << prefix
    end

    self.ignore_prefix '/log'   # TODO: dynamically detect this?

    def initialize(app, options = {})
      @app = app
      @options = options
    end

    def logger
      self.class.logger
    end

    def call(env)
      if logger
        env['rack.logger'] = logger
      end

      if logger && logger.is_a?(MongoRequestLogger::Logger)

        #HACK: Don't log the log viewer itself
        self.class.ignore_prefixes.each do |prefix|
          if env["PATH_INFO"].to_s.start_with? prefix
            return @app.call(env)
          end
        end
        # TODO: filter parameters
        # KLUDGE: this will cause parameter parsing to happen twice: once here, once later on in Rails.
        # Or maybe it's automatically cached in env?
        logger.log_request do
          begin
            request = ::Rack::Request.new(env)
            begin
              cl = request.content_length.to_i
            rescue
              cl = 0
            end

            options = {
                path: request.path_info,
                host: request.host_with_port,
                user_agent: request.user_agent,
                ip: request.ip,
                referer: request.referrer,
                query_string: request.query_string,
                request_method: request.request_method,
                content_type: request.content_type,
                content_length: cl,
                params: filter(request.params)
            }
            logger.add_metadata options
            logger.add_metadata_set :tags, "rack"
            status, headers, body = @app.call(env)
            logger.add_metadata response: status.to_i
            [status, headers, body]
          rescue Exception => e
            logger.add_metadata response: 500
            raise
          end
        end
      else
        # No logger configured - just pass the request straight through
        @app.call(env)
      end

    end

    def filter(params)
      filtered = params.dup
      filtered.each do |key, value|
        if (key =~ /password/) && value.is_a?(String)
          filtered[key] = '*filtered*'
        end
      end
      filtered
    end
  end
end