# bad use of metaprogramming
module MetaTimeDSL

  {:second => 1,
   :minute => 60,
   :hour => 3600,
   :day => [24,:hours],
   :week => [7,:days],
   :month => [30,:days],
   :year => [364.25, :days]}.each do |meth, amount|
    define_method "m_#{meth}" do
      amount = amount.is_a?(Array) ? amount[0].send(amount[1]) : amount
      self * amount
    end
    alias_method "m_#{meth}s".intern, "m_#{meth}"
  end

end
Numeric.send :include, MetaTimeDSL



# Rewrite
module TimeDSL

  def second
    self * 1
  end
  alias_method :seconds, :second

  def minute
    self * 60
  end
  alias_method :minutes, :minute

  def hour
    self * 3600
  end
  alias_method :hours, :hour

  def day
    self * 86400
  end
  alias_method :days, :day

  def week
    self * 604800
  end
  alias_method :weeks, :week

  def month
    self * 18144000
  end
  alias_method :months, :month

  def year
    self * 31471200
  end
  alias_method :years, :year

end
Numeric.send :include, TimeDSL

module RefaMetaTimeDSL

  {:second => 1,
   :minute => 60,
   :hour => 3600,
   :day => [24,:hours],
   :week => [7,:days],
   :month => [30,:days],
   :year => [364.25, :days]}.each do |meth, amount|
    self.class_eval <<-RUBY
      def r_#{meth}
        #{amount.is_a?(Array) ? "#{amount[0]}.#{amount[1]}" : "#{amount}"}
      end
      alias_method :r_#{meth}s, :r_#{meth}
    RUBY
  end

end
Numeric.send :include, RefaMetaTimeDSL

module EvalMetaTimeDSL
  def self.included(base)
    base.class_eval do
      [ [:e_second, 1],
        [:e_minute, 60],
        [:e_hour, 3600],
        [:e_day, [24,:e_hours]],
        [:e_week, [7,:e_days]],
        [:e_month, [30,:e_days]],
        [:e_year, [365.25, :e_days]]].each do |meth, amount|
          amount = amount.is_a?(Array) ? amount[0].send(amount[1]) : amount
          eval "def #{meth}; self*#{amount}; end"
          alias_method "#{meth}s", meth
        end
    end
  end
end
Numeric.send :include, EvalMetaTimeDSL

module GoodMetaTimeDSL

  SECOND  = 1
  MINUTE  = SECOND * 60
  HOUR    = MINUTE * 60
  DAY     = HOUR * 24
  WEEK    = DAY * 7
  MONTH   = DAY * 30
  YEAR    = DAY * 364.25

  %w[SECOND MINUTE HOUR DAY WEEK MONTH YEAR].each do |const_name|
      meth = const_name.downcase
      class_eval <<-RUBY
        def g_#{meth}
          self * #{const_name}
        end
        alias g_#{meth}s g_#{meth}
      RUBY
  end
end
Numeric.send :include, GoodMetaTimeDSL



###############################
#
#
# Benchmarks
require "rubygems"
require "rbench"

TIMES = 100_000

RBench.run(TIMES) do

  format :width => 65

  column :times
  column :bad_meta,  :title => "Bad Neta"
  column :no_meta,  :title => "No Meta"
  column :refa, :title => "Refactored"
  column :eval_meta, :title => 'Refactor 2'
  column :good_meta, :title => "Better Meta"

    group("MetaTimeDSL") do
      report "with 360.seconds" do
        bad_meta { 360.m_seconds }
        no_meta { 360.seconds }
        refa { 360.r_seconds }
        eval_meta { 360.e_seconds}
        good_meta { 360.g_seconds }
      end

      report "with 360.minutes" do
        bad_meta { 360.m_minutes }
        no_meta { 360.minutes }
        refa { 360.r_minutes }
        eval_meta { 360.e_minutes }
        good_meta { 360.g_minutes }
      end

      report "with 360.hours" do
        bad_meta  { 360.m_hours }
        no_meta   { 360.hours }
        refa      { 360.r_hours }
        eval_meta { 360.e_hours }
        good_meta { 360.g_hours }
      end

      report "with 360.days" do
        bad_meta  { 360.m_days }
        no_meta   { 360.days }
        refa      { 360.r_days }
        eval_meta { 360.e_days }
        good_meta { 360.g_days }
      end
      report "with 360.weeks" do
        bad_meta  { 360.m_weeks }
        no_meta   { 360.weeks }
        refa      { 360.r_weeks }
        eval_meta { 360.e_weeks }
        good_meta { 360.g_weeks }
      end
      report "with 18.months" do
        bad_meta  { 18.m_months }
        no_meta   { 18.months }
        refa      { 18.r_months }
        eval_meta { 18.e_months }
        good_meta { 18.g_months }
      end
      report "with 7.years" do
        bad_meta  { 7.m_years }
        no_meta   { 7.years }
        refa      { 7.r_years }
        eval_meta { 7.e_years }
        good_meta { 7.g_years }
      end

    end
end

#####
#
#                                   | Bad Neta | No Meta | Refactored | Refactor 2 | Better Meta |
#  --MetaTimeDSL----------------------------------------------------------------------------------
#  with 360.seconds         x100000 |    0.143 |   0.046 |      0.033 |      0.047 |       0.048 |
#  with 360.minutes         x100000 |    0.152 |   0.045 |      0.033 |      0.046 |       0.046 |
#  with 360.hours           x100000 |    0.127 |   0.044 |      0.032 |      0.045 |       0.048 |
#  with 360.days            x100000 |    0.144 |   0.047 |      0.070 |      0.045 |       0.048 |
#  with 360.weeks           x100000 |    0.129 |   0.044 |      0.070 |      0.046 |       0.047 |
#  with 18.months           x100000 |    0.143 |   0.045 |      0.071 |      0.045 |       0.048 |
#  with 7.years             x100000 |    0.143 |   0.046 |      0.089 |      0.054 |       0.050 |
#
####