series.rb in groupdate-2.0.0

- old
+ new

@@ -1,19 +1,20 @@
 module Groupdate
   class Series
 
-    def initialize(relation, field, column, time_zone, time_range, week_start)
+    def initialize(relation, field, column, time_zone, time_range, week_start, day_start)
       if time_range.is_a?(Range)
         # doesn't matter whether we include the end of a ... range - it will be excluded later
         @relation = relation.where("#{column} >= ? AND #{column} <= ?", time_range.first, time_range.last)
       else
         @relation = relation.where("#{column} IS NOT NULL")
       end
       @field = field
       @time_zone = time_zone
       @time_range = time_range
       @week_start = week_start
+      @day_start = day_start
     end
 
     def build_series(count)
       utc = ActiveSupport::TimeZone["UTC"]
 
@@ -41,41 +42,46 @@
               # use first and last values
               sorted_keys = count.keys.sort
               sorted_keys.first..sorted_keys.last
             end
 
-          # determine start time
-          time = time_range.first.to_time.in_time_zone(@time_zone)
-          starts_at =
-            case @field
-            when "second"
-              time.change(:usec => 0)
-            when "minute"
-              time.change(:sec => 0)
-            when "hour"
-              time.change(:min => 0)
-            when "day"
-              time.beginning_of_day
-            when "week"
-              # same logic as MySQL group
-              weekday = (time.wday - 1) % 7
-              (time - ((7 - @week_start + weekday) % 7).days).midnight
-            when "month"
-              time.beginning_of_month
-            else # year
-              time.beginning_of_year
-            end
+          if time_range.first
+            # determine start time
+            time = time_range.first.to_time.in_time_zone(@time_zone) - @day_start.hours
+            starts_at =
+              case @field
+              when "second"
+                time.change(:usec => 0)
+              when "minute"
+                time.change(:sec => 0)
+              when "hour"
+                time.change(:min => 0)
+              when "day"
+                time.beginning_of_day
+              when "week"
+                # same logic as MySQL group
+                weekday = (time.wday - 1) % 7
+                (time - ((7 - @week_start + weekday) % 7).days).midnight
+              when "month"
+                time.beginning_of_month
+              else # year
+                time.beginning_of_year
+              end
 
-          series = [starts_at]
+            starts_at += @day_start.hours
+            series = [starts_at]
 
-          step = 1.send(@field)
+            step = 1.send(@field)
 
-          while time_range.cover?(series.last + step)
-            series << series.last + step
-          end
+            while time_range.cover?(series.last + step)
+              series << series.last + step
+            end
 
-          series.map{|s| s.to_time.utc }
+            series.map{|s| s.to_time.utc }
+          else
+            []
+          end
         end
 
       Hash[series.map do |k|
         [k, count[k] || 0]
       end]
@@ -83,9 +89,11 @@
 
     def method_missing(method, *args, &block)
       # https://github.com/rails/rails/blob/master/activerecord/lib/active_record/relation/calculations.rb
       if ActiveRecord::Calculations.method_defined?(method)
         build_series(@relation.send(method, *args, &block))
+      elsif [:joins, :includes, :where].include?(method)
+        raise NoMethodError, "#{method} must come before the group_by_#{@field} method"
       else
         raise NoMethodError, "valid methods are: #{ActiveRecord::Calculations.instance_methods.join(", ")}"
       end
     end
 