require 'net/http'

module God
  module Conditions
    
    # Condition Symbol :http_response_code
    # Type: Poll
    # 
    # Trigger based on the response from an HTTP request.
    #
    # Paramaters
    #   Required
    #     +host+ is the hostname to connect [required]
    #     --one of code_is or code_is_not--
    #     +code_is+ trigger if the response code IS one of these
    #               e.g. 500 or '500' or [404, 500] or %w{404 500}
    #     +code_is_not+ trigger if the response code IS NOT one of these
    #                   e.g. 200 or '200' or [200, 302] or %w{200 302}
    #  Optional
    #     +port+ is the port to connect (default 80)
    #     +path+ is the path to connect (default '/')
    #     +times+ is the number of times after which to trigger (default 1)
    #             e.g. 3 (times in a row) or [3, 5] (three out of fives times)
    #     +timeout+ is the time to wait for a connection (default 60.seconds)
    #
    # Examples
    #
    # Trigger if the response code from www.example.com/foo/bar
    # is not a 200 (or if the connection is refused or times out:
    #
    #   on.condition(:http_response_code) do |c|
    #     c.host = 'www.example.com'
    #     c.path = '/foo/bar'
    #     c.code_is_not = 200
    #   end
    #
    # Trigger if the response code is a 404 or a 500 (will not
    # be triggered by a connection refusal or timeout):
    #
    #   on.condition(:http_response_code) do |c|
    #     c.host = 'www.example.com'
    #     c.path = '/foo/bar'
    #     c.code_is = [404, 500]
    #   end
    #
    # Trigger if the response code is not a 200 five times in a row:
    #
    #   on.condition(:http_response_code) do |c|
    #     c.host = 'www.example.com'
    #     c.path = '/foo/bar'
    #     c.code_is_not = 200
    #     c.times = 5
    #   end
    #
    # Trigger if the response code is not a 200 or does not respond
    # within 10 seconds:
    #
    #   on.condition(:http_response_code) do |c|
    #     c.host = 'www.example.com'
    #     c.path = '/foo/bar'
    #     c.code_is_not = 200
    #     c.timeout = 10
    #   end
    class HttpResponseCode < PollCondition
      attr_accessor :code_is,      # e.g. 500 or '500' or [404, 500] or %w{404 500}
                    :code_is_not,  # e.g. 200 or '200' or [200, 302] or %w{200 302}
                    :times,        # e.g. 3 or [3, 5]
                    :host,         # e.g. www.example.com
                    :port,         # e.g. 8080
                    :timeout,      # e.g. 60.seconds
                    :path          # e.g. '/'
      
      def initialize
        super
        self.port = 80
        self.path = '/'
        self.times = [1, 1]
        self.timeout = 60.seconds
      end
      
      def prepare
        self.code_is = Array(self.code_is).map { |x| x.to_i } if self.code_is
        self.code_is_not = Array(self.code_is_not).map { |x| x.to_i } if self.code_is_not
        
        if self.times.kind_of?(Integer)
          self.times = [self.times, self.times]
        end
        
        @timeline = Timeline.new(self.times[1])
        @history = Timeline.new(self.times[1])
      end
      
      def reset
        @timeline.clear
        @history.clear
      end
      
      def valid?
        valid = true
        valid &= complain("Attribute 'host' must be specified", self) if self.host.nil?
        valid &= complain("One (and only one) of attributes 'code_is' and 'code_is_not' must be specified", self) if
          (self.code_is.nil? && self.code_is_not.nil?) || (self.code_is && self.code_is_not)
        valid
      end
      
      def test
        response = nil
        
        Net::HTTP.start(self.host, self.port) do |http|
          http.read_timeout = self.timeout
          response = http.head(self.path)
        end
        
        actual_response_code = response.code.to_i
        if self.code_is && self.code_is.include?(actual_response_code)
          pass(actual_response_code)
        elsif self.code_is_not && !self.code_is_not.include?(actual_response_code)
          pass(actual_response_code)
        else
          fail(actual_response_code)
        end
      rescue Errno::ECONNREFUSED
        self.code_is ? fail('Refused') : pass('Refused')
      rescue Timeout::Error
        self.code_is ? fail('Timeout') : pass('Timeout')
      end
      
      private
      
      def pass(code)
        @timeline << true
        if @timeline.select { |x| x }.size >= self.times.first
          self.info = "http response abnormal #{history(code, true)}"
          true
        else
          self.info = "http response nominal #{history(code, true)}"
          false
        end
      end
      
      def fail(code)
        @timeline << false
        self.info = "http response nominal #{history(code, false)}"
        false
      end
      
      def history(code, passed)
        entry = code.to_s.dup
        entry = '*' + entry if passed
        @history << entry
        '[' + @history.join(", ") + ']'
      end
      
    end
    
  end
end