module MCollective
  # Some basic utility helper methods useful to clients, agents, runner etc.
  module Util
    # Finds out if this MCollective has an agent by the name passed
    #
    # If the passed name starts with a / it's assumed to be regex
    # and will use regex to match
    def self.has_agent?(agent)
      agent = Regexp.new(agent.gsub("\/", "")) if agent.match("^/")

      if agent.is_a?(Regexp)
        if Agents.agentlist.grep(agent).size > 0
          return true
        else
          return false
        end
      else
        return Agents.agentlist.include?(agent)
      end

      false
    end

    # On windows ^c can't interrupt the VM if its blocking on
    # IO, so this sets up a dummy thread that sleeps and this
    # will have the end result of being interruptable at least
    # once a second.  This is a common pattern found in Rails etc
    def self.setup_windows_sleeper
      Thread.new { loop { sleep 1 } } if Util.windows?
    end

    # Checks if this node has a configuration management class by parsing the
    # a text file with just a list of classes, recipes, roles etc.  This is
    # ala the classes.txt from puppet.
    #
    # If the passed name starts with a / it's assumed to be regex
    # and will use regex to match
    def self.has_cf_class?(klass)
      klass = Regexp.new(klass.gsub("\/", "")) if klass.match("^/")
      cfile = Config.instance.classesfile

      Log.debug("Looking for configuration management classes in #{cfile}")

      begin
        File.readlines(cfile).each do |k|
          if klass.is_a?(Regexp)
            return true if k.chomp.match(klass)
          else
            return true if k.chomp == klass
          end
        end
      rescue Exception => e
        Log.warn("Parsing classes file '#{cfile}' failed: #{e.class}: #{e}")
      end

      false
    end

    # Gets the value of a specific fact, mostly just a duplicate of MCollective::Facts.get_fact
    # but it kind of goes with the other classes here
    def self.get_fact(fact)
      Facts.get_fact(fact)
    end

    # Compares fact == value,
    #
    # If the passed value starts with a / it's assumed to be regex
    # and will use regex to match
    def self.has_fact?(fact, value, operator)

      Log.debug("Comparing #{fact} #{operator} #{value}")
      Log.debug("where :fact = '#{fact}', :operator = '#{operator}', :value = '#{value}'")

      fact = Facts[fact]
      return false if fact.nil?

      fact = fact.clone

      if operator == '=~'
        # to maintain backward compat we send the value
        # as /.../ which is what 1.0.x needed.  this strips
        # off the /'s wich is what we need here
        if value =~ /^\/(.+)\/$/
          value = $1
        end

        return true if fact.match(Regexp.new(value))

      elsif operator == "=="
        return true if fact == value

      elsif ['<=', '>=', '<', '>', '!='].include?(operator)
        # Yuk - need to type cast, but to_i and to_f are overzealous
        if value =~ /^[0-9]+$/ && fact =~ /^[0-9]+$/
          fact = Integer(fact)
          value = Integer(value)
        elsif value =~ /^[0-9]+.[0-9]+$/ && fact =~ /^[0-9]+.[0-9]+$/
          fact = Float(fact)
          value = Float(value)
        end

        return true if eval("fact #{operator} value")
      end

      false
    end

    # Checks if the configured identity matches the one supplied
    #
    # If the passed name starts with a / it's assumed to be regex
    # and will use regex to match
    def self.has_identity?(identity)
      identity = Regexp.new(identity.gsub("\/", "")) if identity.match("^/")

      if identity.is_a?(Regexp)
        return Config.instance.identity.match(identity)
      else
        return true if Config.instance.identity == identity
      end

      false
    end

    # Checks if the passed in filter is an empty one
    def self.empty_filter?(filter)
      filter == empty_filter || filter == {}
    end

    # Creates an empty filter
    def self.empty_filter
      {"fact"     => [],
        "cf_class" => [],
        "agent"    => [],
        "identity" => [],
        "compound" => []}
    end

    # Picks a config file defaults to ~/.mcollective
    # else /etc/mcollective/client.cfg
    def self.config_file_for_user
      # expand_path is pretty lame, it relies on HOME environment
      # which isnt't always there so just handling all exceptions
      # here as cant find reverting to default
      begin
        config = File.expand_path("~/.mcollective")

        unless File.readable?(config) && File.file?(config)
          config = "/etc/mcollective/client.cfg"
        end
      rescue Exception => e
        config = "/etc/mcollective/client.cfg"
      end

      return config
    end

    # Creates a standard options hash
    def self.default_options
      {:verbose     => false,
        :disctimeout => 2,
        :timeout     => 5,
        :config      => config_file_for_user,
        :collective  => nil,
        :filter      => empty_filter}
    end

    def self.make_subscriptions(agent, type, collective=nil)
      config = Config.instance

      raise("Unknown target type #{type}") unless [:broadcast, :directed, :reply].include?(type)

      if collective.nil?
        config.collectives.map do |c|
          {:agent => agent, :type => type, :collective => c}
        end
      else
        raise("Unknown collective '#{collective}' known collectives are '#{config.collectives.join ', '}'") unless config.collectives.include?(collective)

        [{:agent => agent, :type => type, :collective => collective}]
      end
    end

    # Helper to subscribe to a topic on multiple collectives or just one
    def self.subscribe(targets)
      connection = PluginManager["connector_plugin"]

      targets = [targets].flatten

      targets.each do |target|
        connection.subscribe(target[:agent], target[:type], target[:collective])
      end
    end

    # Helper to unsubscribe to a topic on multiple collectives or just one
    def self.unsubscribe(targets)
      connection = PluginManager["connector_plugin"]

      targets = [targets].flatten

      targets.each do |target|
        connection.unsubscribe(target[:agent], target[:type], target[:collective])
      end
    end

    # Wrapper around PluginManager.loadclass
    def self.loadclass(klass)
      PluginManager.loadclass(klass)
    end

    # Parse a fact filter string like foo=bar into the tuple hash thats needed
    def self.parse_fact_string(fact)
      if fact =~ /^([^ ]+?)[ ]*=>[ ]*(.+)/
        return {:fact => $1, :value => $2, :operator => '>=' }
      elsif fact =~ /^([^ ]+?)[ ]*=<[ ]*(.+)/
        return {:fact => $1, :value => $2, :operator => '<=' }
      elsif fact =~ /^([^ ]+?)[ ]*(<=|>=|<|>|!=|==|=~)[ ]*(.+)/
        return {:fact => $1, :value => $3, :operator => $2 }
      elsif fact =~ /^(.+?)[ ]*=[ ]*\/(.+)\/$/
        return {:fact => $1, :value => "/#{$2}/", :operator => '=~' }
      elsif fact =~ /^([^= ]+?)[ ]*=[ ]*(.+)/
        return {:fact => $1, :value => $2, :operator => '==' }
      else
        raise "Could not parse fact #{fact} it does not appear to be in a valid format"
      end
    end

    # Escapes a string so it's safe to use in system() or backticks
    #
    # Taken from Shellwords#shellescape since it's only in a few ruby versions
    def self.shellescape(str)
      return "''" if str.empty?

      str = str.dup

      # Process as a single byte sequence because not all shell
      # implementations are multibyte aware.
      str.gsub!(/([^A-Za-z0-9_\-.,:\/@\n])/n, "\\\\\\1")

      # A LF cannot be escaped with a backslash because a backslash + LF
      # combo is regarded as line continuation and simply ignored.
      str.gsub!(/\n/, "'\n'")

      return str
    end

    def self.windows?
      !!(RbConfig::CONFIG['host_os'] =~ /mswin|win32|dos|mingw|cygwin/i)
    end

    def self.eval_compound_statement(expression)
      if expression.values.first =~ /^\//
        return Util.has_cf_class?(expression.values.first)
      elsif expression.values.first =~ />=|<=|=|<|>/
        optype = expression.values.first.match(/>=|<=|=|<|>/)
        name, value = expression.values.first.split(optype[0])
        unless value.split("")[0] == "/"
          optype[0] == "=" ? optype = "==" : optype = optype[0]
        else
          optype = "=~"
        end

        return Util.has_fact?(name,value, optype).to_s
      else
        return Util.has_cf_class?(expression.values.first)
      end
    end

    # Returns the current ruby version as per RUBY_VERSION, mostly
    # doing this here to aid testing
    def self.ruby_version
      RUBY_VERSION
    end
  end
end