1 files changed, 57 insertions, 17 deletions
diff --git a/activesupport/lib/active_support/core_ext/date_and_time/calculations.rb b/activesupport/lib/active_support/core_ext/date_and_time/calculations.rb
index b85e49aca5..9525c10112 100644
--- a/activesupport/lib/active_support/core_ext/date_and_time/calculations.rb
+++ b/activesupport/lib/active_support/core_ext/date_and_time/calculations.rb
@@ -9,15 +9,26 @@ module DateAndTime
       :saturday  => 5,
       :sunday    => 6
     }
+    WEEKEND_DAYS = [ 6, 0 ]
 
     # Returns a new date/time representing yesterday.
     def yesterday
-      advance(:days => -1)
+      advance(days: -1)
+    end
+
+    # Returns a new date/time representing the previous day.
+    def prev_day
+      advance(days: -1)
     end
 
     # Returns a new date/time representing tomorrow.
     def tomorrow
-      advance(:days => 1)
+      advance(days: 1)
+    end
+
+    # Returns a new date/time representing the next day.
+    def next_day
+      advance(days: 1)
     end
 
     # Returns true if the date/time is today.
@@ -35,6 +46,11 @@ module DateAndTime
       self > self.class.current
     end
 
+    # Returns true if the date/time falls on a Saturday or Sunday.
+    def on_weekend?
+      WEEKEND_DAYS.include?(wday)
+    end
+
     # Returns a new date/time the specified number of days ago.
     def days_ago(days)
       advance(:days => -days)
@@ -111,9 +127,19 @@ module DateAndTime
     # Returns a new date/time representing the given day in the next week.
     # The +given_day_in_next_week+ defaults to the beginning of the week
     # which is determined by +Date.beginning_of_week+ or +config.beginning_of_week+
-    # when set. +DateTime+ objects have their time set to 0:00.
-    def next_week(given_day_in_next_week = Date.beginning_of_week)
-      first_hour(weeks_since(1).beginning_of_week.days_since(days_span(given_day_in_next_week)))
+    # when set. +DateTime+ objects have their time set to 0:00 unless +same_time+ is true.
+    def next_week(given_day_in_next_week = Date.beginning_of_week, same_time: false)
+      result = first_hour(weeks_since(1).beginning_of_week.days_since(days_span(given_day_in_next_week)))
+      same_time ? copy_time_to(result) : result
+    end
+
+    # Returns a new date/time representing the next weekday.
+    def next_weekday
+      if next_day.on_weekend?
+        next_week(:monday, same_time: true)
+      else
+        next_day
+      end
     end
 
     # Short-hand for months_since(1).
@@ -134,12 +160,23 @@ module DateAndTime
     # Returns a new date/time representing the given day in the previous week.
     # Week is assumed to start on +start_day+, default is
     # +Date.beginning_of_week+ or +config.beginning_of_week+ when set.
-    # DateTime objects have their time set to 0:00.
-    def prev_week(start_day = Date.beginning_of_week)
-      first_hour(weeks_ago(1).beginning_of_week.days_since(days_span(start_day)))
+    # DateTime objects have their time set to 0:00 unless +same_time+ is true.
+    def prev_week(start_day = Date.beginning_of_week, same_time: false)
+      result = first_hour(weeks_ago(1).beginning_of_week.days_since(days_span(start_day)))
+      same_time ? copy_time_to(result) : result
     end
     alias_method :last_week, :prev_week
 
+    # Returns a new date/time representing the previous weekday.
+    def prev_weekday
+      if prev_day.on_weekend?
+        copy_time_to(beginning_of_week(:friday))
+      else
+        prev_day
+      end
+    end
+    alias_method :last_weekday, :prev_weekday
+
     # Short-hand for months_ago(1).
     def prev_month
       months_ago(1)
@@ -235,17 +272,20 @@ module DateAndTime
     end
 
     private
+      def first_hour(date_or_time)
+        date_or_time.acts_like?(:time) ? date_or_time.beginning_of_day : date_or_time
+      end
 
-    def first_hour(date_or_time)
-      date_or_time.acts_like?(:time) ? date_or_time.beginning_of_day : date_or_time
-    end
+      def last_hour(date_or_time)
+        date_or_time.acts_like?(:time) ? date_or_time.end_of_day : date_or_time
+      end
 
-    def last_hour(date_or_time)
-      date_or_time.acts_like?(:time) ? date_or_time.end_of_day : date_or_time
-    end
+      def days_span(day)
+        (DAYS_INTO_WEEK[day] - DAYS_INTO_WEEK[Date.beginning_of_week]) % 7
+      end
 
-    def days_span(day)
-      (DAYS_INTO_WEEK[day] - DAYS_INTO_WEEK[Date.beginning_of_week]) % 7
-    end
+      def copy_time_to(other)
+        other.change(hour: hour, min: min, sec: sec, usec: try(:usec))
+      end
   end
 end