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       => nil,
       :timeout           => 5,
       :config            => config_file_for_user,
       :collective        => nil,
       :discovery_method  => nil,
       :discovery_options => Config.instance.default_discovery_options,
       :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

    # Return color codes, if the config color= option is false
    # just return a empty string
    def self.color(code)
      colorize = Config.instance.color

      colors = {:red => "",
                :green => "",
                :yellow => "",
                :cyan => "",
                :bold => "",
                :reset => ""}

      if colorize
        return colors[code] || ""
      else
        return ""
      end
    end

    # Helper to return a string in specific color
    def self.colorize(code, msg)
      "%s%s%s" % [ color(code), msg, color(:reset) ]
    end

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

    def self.mcollective_version
      MCollective::VERSION
    end

    # Returns an aligned_string of text relative to the size of the terminal
    # window. If a line in the string exceeds the width of the terminal window
    # the line will be chopped off at the whitespace chacter closest to the
    # end of the line and prepended to the next line, keeping all indentation.
    #
    # The terminal size is detected by default, but custom line widths can
    # passed. All strings will also be left aligned with 5 whitespace characters
    # by default.
    def self.align_text(text, console_cols = nil, preamble = 5)
      unless console_cols
        console_cols = terminal_dimensions[0]

        # if unknown size we default to the typical unix default
        console_cols = 80 if console_cols == 0
      end

      console_cols -= preamble

      # Return unaligned text if console window is too small
      return text if console_cols <= 0

      # If console is 0 this implies unknown so we assume the common
      # minimal unix configuration of 80 characters
      console_cols = 80 if console_cols <= 0

      text = text.split("\n")
      piece = ''
      whitespace = 0

      text.each_with_index do |line, i|
        whitespace = 0

        while whitespace < line.length && line[whitespace].chr == ' '
          whitespace += 1
        end

        # If the current line is empty, indent it so that a snippet
        # from the previous line is aligned correctly.
        if line == ""
          line = (" " * whitespace)
        end

        # If text was snipped from the previous line, prepend it to the
        # current line after any current indentation.
        if piece != ''
          # Reset whitespaces to 0 if there are more whitespaces than there are
          # console columns
          whitespace = 0 if whitespace >= console_cols

          # If the current line is empty and being prepended to, create a new
          # empty line in the text so that formatting is preserved.
          if text[i + 1] && line == (" " * whitespace)
            text.insert(i + 1, "")
          end

          # Add the snipped text to the current line
          line.insert(whitespace, "#{piece} ")
        end

        piece = ''

        # Compare the line length to the allowed line length.
        # If it exceeds it, snip the offending text from the line
        # and store it so that it can be prepended to the next line.
        if line.length > (console_cols + preamble)
          reverse = console_cols

          while line[reverse].chr != ' '
            reverse -= 1
          end

          piece = line.slice!(reverse, (line.length - 1)).lstrip
        end

        # If a snippet exists when all the columns in the text have been
        # updated, create a new line and append the snippet to it, using
        # the same left alignment as the last line in the text.
        if piece != '' && text[i+1].nil?
          text[i+1] = "#{' ' * (whitespace)}#{piece}"
          piece = ''
        end

        # Add the preamble to the line and add it to the text
        line = ((' ' * preamble) + line)
        text[i] = line
      end

      text.join("\n")
    end

    # Figures out the columns and lines of the current tty
    #
    # Returns [0, 0] if it can't figure it out or if you're
    # not running on a tty
    def self.terminal_dimensions(stdout = STDOUT, environment = ENV)
      return [0, 0] unless stdout.tty?

      return [80, 40] if Util.windows?

      if environment["COLUMNS"] && environment["LINES"]
        return [environment["COLUMNS"].to_i, environment["LINES"].to_i]

      elsif environment["TERM"] && command_in_path?("tput")
        return [`tput cols`.to_i, `tput lines`.to_i]

      elsif command_in_path?('stty')
        return `stty size`.scan(/\d+/).map {|s| s.to_i }
      else
        return [0, 0]
      end
    rescue
      [0, 0]
    end

    # Checks in PATH returns true if the command is found
    def self.command_in_path?(command)
      found = ENV["PATH"].split(File::PATH_SEPARATOR).map do |p|
        File.exist?(File.join(p, command))
      end

      found.include?(true)
    end

    # compare two software versions as commonly found in
    # package versions.
    #
    # returns 0 if a == b
    # returns -1 if a < b
    # returns 1 if a > b
    #
    # Code originally from Puppet but refactored to a more
    # ruby style that fits in better with this code base
    def self.versioncmp(version_a, version_b)
      vre = /[-.]|\d+|[^-.\d]+/
      ax = version_a.scan(vre)
      bx = version_b.scan(vre)

      until ax.empty? || bx.empty?
        a = ax.shift
        b = bx.shift

        next      if a == b
        next      if a == '-' && b == '-'
        return -1 if a == '-'
        return 1  if b == '-'
        next      if a == '.' && b == '.'
        return -1 if a == '.'
        return 1  if b == '.'

        if a =~ /^[^0]\d+$/ && b =~ /^[^0]\d+$/
          return Integer(a) <=> Integer(b)
        else
          return a.upcase <=> b.upcase
        end
      end

      version_a <=> version_b
    end
  end
end