1 files changed, 109 insertions, 2 deletions

diff --git a/activesupport/lib/active_support/duration.rb b/activesupport/lib/active_support/duration.rb
index 003f6203ef..99080e34a1 100644
--- a/activesupport/lib/active_support/duration.rb
+++ b/activesupport/lib/active_support/duration.rb
@@ -1,5 +1,8 @@
 require "active_support/core_ext/array/conversions"
+require "active_support/core_ext/module/delegation"
 require "active_support/core_ext/object/acts_like"
+require "active_support/core_ext/string/filters"
+require "active_support/deprecation"
 
 module ActiveSupport
   # Provides accurate date and time measurements using Date#advance and
@@ -7,6 +10,66 @@ module ActiveSupport
   #
   #   1.month.ago       # equivalent to Time.now.advance(months: -1)
   class Duration
+    class Scalar < Numeric #:nodoc:
+      attr_reader :value
+      delegate :to_i, :to_f, :to_s, to: :value
+
+      def initialize(value)
+        @value = value
+      end
+
+      def coerce(other)
+        [Scalar.new(other), self]
+      end
+
+      def -@
+        Scalar.new(-value)
+      end
+
+      def <=>(other)
+        if Scalar === other || Duration === other
+          value <=> other.value
+        elsif Numeric === other
+          value <=> other
+        else
+          nil
+        end
+      end
+
+      def +(other)
+        calculate(:+, other)
+      end
+
+      def -(other)
+        calculate(:-, other)
+      end
+
+      def *(other)
+        calculate(:*, other)
+      end
+
+      def /(other)
+        calculate(:/, other)
+      end
+
+      private
+        def calculate(op, other)
+          if Scalar === other
+            Scalar.new(value.public_send(op, other.value))
+          elsif Duration === other
+            Duration.seconds(value).public_send(op, other)
+          elsif Numeric === other
+            Scalar.new(value.public_send(op, other))
+          else
+            raise_type_error(other)
+          end
+        end
+
+        def raise_type_error(other)
+          raise TypeError, "no implicit conversion of #{other.class} into #{self.class}"
+        end
+    end
+
     SECONDS_PER_MINUTE = 60
     SECONDS_PER_HOUR   = 3600
     SECONDS_PER_DAY    = 86400
@@ -88,6 +151,24 @@ module ActiveSupport
       @parts.default = 0
     end
 
+    def coerce(other) #:nodoc:
+      if Scalar === other
+        [other, self]
+      else
+        [Scalar.new(other), self]
+      end
+    end
+
+    # Compares one Duration with another or a Numeric to this Duration.
+    # Numeric values are treated as seconds.
+    def <=>(other)
+      if Duration === other
+        value <=> other.value
+      elsif Numeric === other
+        value <=> other
+      end
+    end
+
     # Adds another Duration or a Numeric to this Duration. Numeric values
     # are treated as seconds.
     def +(other)
@@ -109,6 +190,28 @@ module ActiveSupport
       self + (-other)
     end
 
+    # Multiplies this Duration by a Numeric and returns a new Duration.
+    def *(other)
+      if Scalar === other || Duration === other
+        Duration.new(value * other.value, parts.map { |type, number| [type, number * other.value] })
+      elsif Numeric === other
+        Duration.new(value * other, parts.map { |type, number| [type, number * other] })
+      else
+        raise_type_error(other)
+      end
+    end
+
+    # Divides this Duration by a Numeric and returns a new Duration.
+    def /(other)
+      if Scalar === other || Duration === other
+        Duration.new(value / other.value, parts.map { |type, number| [type, number / other.value] })
+      elsif Numeric === other
+        Duration.new(value / other, parts.map { |type, number| [type, number / other] })
+      else
+        raise_type_error(other)
+      end
+    end
+
     def -@ #:nodoc:
       Duration.new(-value, parts.map { |type, number| [type, -number] })
     end
@@ -180,6 +283,7 @@ module ActiveSupport
       sum(1, time)
     end
     alias :from_now :since
+    alias :after :since
 
     # Calculates a new Time or Date that is as far in the past
     # as this Duration represents.
@@ -187,6 +291,7 @@ module ActiveSupport
       sum(-1, time)
     end
     alias :until :ago
+    alias :before :ago
 
     def inspect #:nodoc:
       parts.
@@ -210,8 +315,6 @@ module ActiveSupport
       ISO8601Serializer.new(self, precision: precision).serialize
     end
 
-    delegate :<=>, to: :value
-
     private
 
       def sum(sign, time = ::Time.current)
@@ -235,5 +338,9 @@ module ActiveSupport
       def method_missing(method, *args, &block)
         value.send(method, *args, &block)
       end
+
+      def raise_type_error(other)
+        raise TypeError, "no implicit conversion of #{other.class} into #{self.class}"
+      end
   end
 end