require 'etc'
require 'facter'
require 'puppet/util/filetype'

Puppet::Type.newtype(:cron) do
  @doc = <<-'EOT'
    Installs and manages cron jobs.  Every cron resource requires a command
    and user attribute, as well as at least one periodic attribute (hour,
    minute, month, monthday, weekday, or special).  While the name of the cron
    job is not part of the actual job, the name is stored in a comment beginning with
    `# Puppet Name: `. These comments are used to match crontab entries created by
    Puppet with cron resources.

    If an existing crontab entry happens to match the scheduling and command of a
    cron resource that has never been synched, Puppet will defer to the existing
    crontab entry and will not create a new entry tagged with the `# Puppet Name: `
    comment.

    Example:

        cron { logrotate:
          command => "/usr/sbin/logrotate",
          user    => root,
          hour    => 2,
          minute  => 0
        }

    Note that all periodic attributes can be specified as an array of values:

        cron { logrotate:
          command => "/usr/sbin/logrotate",
          user    => root,
          hour    => [2, 4]
        }

    ...or using ranges or the step syntax `*/2` (although there's no guarantee
    that your `cron` daemon supports these):

        cron { logrotate:
          command => "/usr/sbin/logrotate",
          user    => root,
          hour    => ['2-4'],
          minute  => '*/10'
        }

    An important note: _the Cron type will not reset parameters that are
    removed from a manifest_. For example, removing a `minute => 10` parameter
    will not reset the minute component of the associated cronjob to `*`.
    These changes must be expressed by setting the parameter to
    `minute => absent` because Puppet only manages parameters that are out of
    sync with manifest entries.
  EOT
  ensurable

  # A base class for all of the Cron parameters, since they all have
  # similar argument checking going on.
  class CronParam < Puppet::Property
    class << self
      attr_accessor :boundaries, :default
    end

    # We have to override the parent method, because we consume the entire
    # "should" array
    def insync?(is)
      self.is_to_s(is) == self.should_to_s
    end

    # A method used to do parameter input handling.  Converts integers
    # in string form to actual integers, and returns the value if it's
    # an integer or false if it's just a normal string.
    def numfix(num)
      if num =~ /^\d+$/
        return num.to_i
      elsif num.is_a?(Integer)
        return num
      else
        return false
      end
    end

    # Verify that a number is within the specified limits.  Return the
    # number if it is, or false if it is not.
    def limitcheck(num, lower, upper)
      (num >= lower and num <= upper) && num
    end

    # Verify that a value falls within the specified array.  Does case
    # insensitive matching, and supports matching either the entire word
    # or the first three letters of the word.
    def alphacheck(value, ary)
      tmp = value.downcase

      # If they specified a shortened version of the name, then see
      # if we can lengthen it (e.g., mon => monday).
      if tmp.length == 3
        ary.each_with_index { |name, index|
          if tmp.upcase == name[0..2].upcase
            return index
          end
        }
      else
        return ary.index(tmp) if ary.include?(tmp)
      end

      false
    end

    def should_to_s(newvalue = @should)
      if newvalue
        newvalue = [newvalue] unless newvalue.is_a?(Array)
        if self.name == :command or newvalue[0].is_a? Symbol
          newvalue[0]
        else
          newvalue.join(",")
        end
      else
        nil
      end
    end

    def is_to_s(currentvalue = @is)
      if currentvalue
        return currentvalue unless currentvalue.is_a?(Array)

        if self.name == :command or currentvalue[0].is_a? Symbol
          currentvalue[0]
        else
          currentvalue.join(",")
        end
      else
        nil
      end
    end

    def should
      if @should and @should[0] == :absent
        :absent
      else
        @should
      end
    end

    def should=(ary)
      super
      @should.flatten!
    end

    # The method that does all of the actual parameter value
    # checking; called by all of the +param<name>=+ methods.
    # Requires the value, type, and bounds, and optionally supports
    # a boolean of whether to do alpha checking, and if so requires
    # the ary against which to do the checking.
    munge do |value|
      # Support 'absent' as a value, so that they can remove
      # a value
      if value == "absent" or value == :absent
        return :absent
      end

      # Allow the */2 syntax
      if value =~ /^\*\/[0-9]+$/
        return value
      end

      # Allow ranges
      if value =~ /^[0-9]+-[0-9]+$/
        return value
      end

      # Allow ranges + */2
      if value =~ /^[0-9]+-[0-9]+\/[0-9]+$/
        return value
      end

      if value == "*"
        return :absent
      end

      return value unless self.class.boundaries
      lower, upper = self.class.boundaries
      retval = nil
      if num = numfix(value)
        retval = limitcheck(num, lower, upper)
      elsif respond_to?(:alpha)
        # If it has an alpha method defined, then we check
        # to see if our value is in that list and if so we turn
        # it into a number
        retval = alphacheck(value, alpha)
      end

      if retval
        return retval.to_s
      else
        self.fail "#{value} is not a valid #{self.class.name}"
      end
    end
  end

  # Somewhat uniquely, this property does not actually change anything -- it
  # just calls +@resource.sync+, which writes out the whole cron tab for
  # the user in question.  There is no real way to change individual cron
  # jobs without rewriting the entire cron file.
  #
  # Note that this means that managing many cron jobs for a given user
  # could currently result in multiple write sessions for that user.
  newproperty(:command, :parent => CronParam) do
    desc "The command to execute in the cron job.  The environment
      provided to the command varies by local system rules, and it is
      best to always provide a fully qualified command.  The user's
      profile is not sourced when the command is run, so if the
      user's environment is desired it should be sourced manually.

      All cron parameters support `absent` as a value; this will
      remove any existing values for that field."

    def retrieve
      return_value = super
      return_value = return_value[0] if return_value && return_value.is_a?(Array)

      return_value
    end

    def should
      if @should
        if @should.is_a? Array
          @should[0]
        else
          devfail "command is not an array"
        end
      else
        nil
      end
    end

    def munge(value)
      value.strip
    end
  end

  newproperty(:special) do
    desc "A special value such as 'reboot' or 'annually'.
       Only available on supported systems such as Vixie Cron.
       Overrides more specific time of day/week settings.
       Set to 'absent' to make puppet revert to a plain numeric schedule."

    def specials
      %w{reboot yearly annually monthly weekly daily midnight hourly absent} +
        [ :absent ]
    end

    validate do |value|
      raise ArgumentError, "Invalid special schedule #{value.inspect}" unless specials.include?(value)
    end

    def munge(value)
      # Support value absent so that a schedule can be
      # forced to change to numeric.
      if value == "absent" or value == :absent
        return :absent
      end
      value
    end
  end

  newproperty(:minute, :parent => CronParam) do
    self.boundaries = [0, 59]
    desc "The minute at which to run the cron job.
      Optional; if specified, must be between 0 and 59, inclusive."
  end

  newproperty(:hour, :parent => CronParam) do
    self.boundaries = [0, 23]
    desc "The hour at which to run the cron job. Optional;
      if specified, must be between 0 and 23, inclusive."
  end

  newproperty(:weekday, :parent => CronParam) do
    def alpha
      %w{sunday monday tuesday wednesday thursday friday saturday}
    end
    self.boundaries = [0, 7]
    desc "The weekday on which to run the command.
      Optional; if specified, must be between 0 and 7, inclusive, with
      0 (or 7) being Sunday, or must be the name of the day (e.g., Tuesday)."
  end

  newproperty(:month, :parent => CronParam) do
    def alpha
      %w{january february march april may june july
        august september october november december}
    end
    self.boundaries = [1, 12]
    desc "The month of the year.  Optional; if specified
      must be between 1 and 12 or the month name (e.g., December)."
  end

  newproperty(:monthday, :parent => CronParam) do
    self.boundaries = [1, 31]
    desc "The day of the month on which to run the
      command.  Optional; if specified, must be between 1 and 31."
  end

  newproperty(:environment) do
    desc "Any environment settings associated with this cron job.  They
      will be stored between the header and the job in the crontab.  There
      can be no guarantees that other, earlier settings will not also
      affect a given cron job.


      Also, Puppet cannot automatically determine whether an existing,
      unmanaged environment setting is associated with a given cron
      job.  If you already have cron jobs with environment settings,
      then Puppet will keep those settings in the same place in the file,
      but will not associate them with a specific job.

      Settings should be specified exactly as they should appear in
      the crontab, e.g., `PATH=/bin:/usr/bin:/usr/sbin`."

    validate do |value|
      unless value =~ /^\s*(\w+)\s*=\s*(.*)\s*$/ or value == :absent or value == "absent"
        raise ArgumentError, "Invalid environment setting #{value.inspect}"
      end
    end

    def insync?(is)
      if is.is_a? Array
        return is.sort == @should.sort
      else
        return is == @should
      end
    end

    def is_to_s(newvalue)
      if newvalue
        if newvalue.is_a?(Array)
          newvalue.join(",")
        else
          newvalue
        end
      else
        nil
      end
    end

    def should
      @should
    end

    def should_to_s(newvalue = @should)
      if newvalue
        newvalue.join(",")
      else
        nil
      end
    end
  end

  newparam(:name) do
    desc "The symbolic name of the cron job.  This name
      is used for human reference only and is generated automatically
      for cron jobs found on the system.  This generally won't
      matter, as Puppet will do its best to match existing cron jobs
      against specified jobs (and Puppet adds a comment to cron jobs it adds),
      but it is at least possible that converting from unmanaged jobs to
      managed jobs might require manual intervention."

    isnamevar
  end

  newproperty(:user) do
    desc "The user to run the command as.  This user must
      be allowed to run cron jobs, which is not currently checked by
      Puppet.

      The user defaults to whomever Puppet is running as."

    defaultto {
      struct = Etc.getpwuid(Process.uid)
      struct.respond_to?(:name) && struct.name or 'root'
    }
  end

  # Autorequire the owner of the crontab entry.
  autorequire(:user) do
    self[:user]
  end

  newproperty(:target) do
    desc "The username that will own the cron entry. Defaults to
    the value of $USER for the shell that invoked Puppet, or root if $USER
    is empty."

    defaultto {
      if provider.is_a?(@resource.class.provider(:crontab))
        if val = @resource.should(:user)
          val
        else
          raise ArgumentError,
            "You must provide a username with crontab entries"
        end
      elsif provider.class.ancestors.include?(Puppet::Provider::ParsedFile)
        provider.class.default_target
      else
        nil
      end
    }
  end

  validate do
    return true unless self[:special]
    return true if self[:special] == :absent
    # there is a special schedule in @should, so we don't want to see
    # any numeric should values
    [ :minute, :hour, :weekday, :monthday, :month ].each do |field|
      next unless self[field]
      next if self[field] == :absent
      raise ArgumentError, "#{self.ref} cannot specify both a special schedule and a value for #{field}"
    end
  end

  # We have to reorder things so that :provide is before :target

  attr_accessor :uid

  # Marks the resource as "being purged".
  #
  # @api public
  #
  # @note This overrides the Puppet::Type method in order to handle
  #   an edge case that has so far been observed during testig only.
  #   Without forcing the should-value for the user property to be
  #   identical to the original cron file, purging from a fixture
  #   will not work, because the user property defaults to the user
  #   running the test. It is not clear whether this scenario can apply
  #   during normal operation.
  #
  # @note Also, when not forcing the should-value for the target
  #   property, unpurged file content (such as comments) can end up
  #   being written to the default target (i.e. the current login name).
  def purging
    self[:target] = provider.property_hash[:target]
    self[:user] = provider.property_hash[:target]
    super
  end

  def value(name)
    name = name.intern
    ret = nil
    if obj = @parameters[name]
      ret = obj.should

      ret ||= obj.retrieve

      if ret == :absent
        ret = nil
      end
    end

    unless ret
      case name
      when :command
        devfail "No command, somehow" unless @parameters[:ensure].value == :absent
      when :special
        # nothing
      else
        #ret = (self.class.validproperty?(name).default || "*").to_s
        ret = "*"
      end
    end

    ret
  end
end

