Refactor how weekly mileage is calculated.

* Add distance_in_miles column to activities table

Author: Steve Polito

app/models/activity.rb

@@ -10,6 +10,7 @@ class Activity < ApplicationRecord
     has_rich_text :description
 
     before_validation :calculate_duration
+    before_save :calculate_distance_in_miles
     before_save :calculate_pace
     after_save :create_or_update_total
     after_destroy :subract_from_total
@@ -33,24 +34,25 @@ def require_unit_if_distance_set
             errors.add(:base, "Please select a unit") if self.distance.present? && self.unit.nil? 
         end
 
-        def calculate_pace
-            if self.unit.present? && self.distance.present? && self.duration.present?
+        def calculate_distance_in_miles
+            if self.unit.present? && self.distance.present?
                 case self.unit
                 when "miles"
-                    self.calculated_pace = self.duration / self.distance
+                    self.distance_in_miles = self.distance
                 when "kilometers"
-                    converted_distance = self.distance * 0.6213712
-                    self.calculated_pace = self.duration / converted_distance
+                    self.distance_in_miles = self.distance * 0.6213712
                 when "meters"
-                    converted_distance = self.distance * 0.0006213711985
-                    self.calculated_pace = self.duration / converted_distance
+                    self.distance_in_miles = self.distance * 0.0006213711985
                 when "yards"
-                    converted_distance = self.distance * 0.0005681818239083977
-                    self.calculated_pace = self.duration / converted_distance
+                    self.distance_in_miles = self.distance * 0.0005681818239083977
                 end
             end
         end
 
+        def calculate_pace
+            self.calculated_pace = self.duration / self.distance_in_miles if self.distance_in_miles.present?
+        end
+
         def calculate_duration
             calculated_duration = 0
 
@@ -66,23 +68,11 @@ def create_or_update_total
             year = self.date.to_date.cwyear
             starting_on = Date.commercial(year, week)
 
-            original_duration = self.duration
-
-            case self.unit
-            when "miles"
-                converted_distance = self.distance
-            when "kilometers"
-                converted_distance = self.distance * 0.6213712
-            when "meters"
-                converted_distance = self.distance * 0.0006213711985
-            when "yards"
-                converted_distance = self.distance * 0.0005681818239083977
-            end
-
             @total = Total.find_or_initialize_by(user: self.user, starting_on: starting_on, range: "week")
+            @activities = Activity.where("date >= ?", starting_on).where("date <= ?", starting_on.end_of_week).where(user: self.user)
 
-            total_distance = converted_distance + @total.distance unless converted_distance.nil?
-            total_duration = original_duration + @total.duration unless original_duration.nil?
+            total_distance = @activities.sum(:distance_in_miles) unless @activities.empty?
+            total_duration = @activities.sum(:duration) unless @activities.empty?
 
             @total.distance = total_distance unless total_distance.nil?
             @total.duration = total_duration unless total_duration.nil?

db/migrate/20200826101427_add_distance_in_miles_to_activities.rb

@@ -0,0 +1,5 @@
+class AddDistanceInMilesToActivities < ActiveRecord::Migration[6.0]
+  def change
+    add_column :activities, :distance_in_miles, :decimal, precision: 5, scale: 2
+  end
+end

db/schema.rb

@@ -10,7 +10,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema.define(version: 2020_08_22_121917) do
+ActiveRecord::Schema.define(version: 2020_08_26_101427) do
 
   # These are extensions that must be enabled in order to support this database
   enable_extension "plpgsql"
@@ -60,6 +60,7 @@
     t.integer "hours"
     t.integer "minutes"
     t.integer "seconds"
+    t.decimal "distance_in_miles", precision: 5, scale: 2
     t.index ["user_id"], name: "index_activities_on_user_id"
   end
 

test/fixtures/activities.yml

@@ -9,6 +9,7 @@ confirmed_user_activity_<%= i %>:
   seconds: <%= rand(1..59) %>
   distance: <%= rand(1..26) %>
   unit: miles
+  distance_in_miles: <%= rand(1..26) %>
 <% end %>
 
 <% 1.upto(180) do |i| %>
@@ -20,6 +21,7 @@ another_confirmed_user_activity_<%= i %>:
   seconds: <%= rand(1..59) %>
   distance: <%= rand(1..26) %>
   unit: miles
+  distance_in_miles: <%= rand(1..26) %>
 <% end %>
 
 confirmed_user_with_searchable_activity_1:
@@ -29,6 +31,7 @@ confirmed_user_with_searchable_activity_1:
   minutes: <%= rand(1..59) %>
   seconds: <%= rand(1..59) %>
   distance: <%= rand(1..26) %>
+  distance_in_miles: <%= rand(1..26) %>
   unit: miles
   difficulty: easy
   category: run
@@ -40,6 +43,7 @@ confirmed_user_with_searchable_activity_2:
   minutes: <%= rand(1..59) %>
   seconds: <%= rand(1..59) %>
   distance: <%= rand(1..26) %>
+  distance_in_miles: <%= rand(1..26) %>
   unit: miles
   difficulty: moderate
   category: long_run
@@ -51,6 +55,7 @@ confirmed_user_with_searchable_activity_3:
   minutes: <%= rand(1..59) %>
   seconds: <%= rand(1..59) %>
   distance: <%= rand(1..26) %>
+  distance_in_miles: <%= rand(1..26) %>
   unit: miles
   difficulty: hard
   category: workout 
@@ -62,6 +67,7 @@ confirmed_user_with_searchable_activity_4:
   minutes: <%= rand(1..59) %>
   seconds: <%= rand(1..59) %>
   distance: <%= rand(1..26) %>
+  distance_in_miles: <%= rand(1..26) %>
   unit: miles
   difficulty: hard
   category: race   

test/models/activity_test.rb

@@ -54,26 +54,23 @@ def setup
     @activity.unit = :kilometers
     @activity.duration = 1800
     @activity.save
-    converted_distance = @activity.distance * 0.6213712
-    pace = @activity.duration / converted_distance
+    pace = @activity.duration / @activity.distance_in_miles
 
     assert_equal pace, @activity.reload.calculated_pace
 
     @activity.distance = 800
     @activity.unit = :meters
     @activity.duration = 120
     @activity.save
-    converted_distance = @activity.distance * 0.0006213711985
-    pace = @activity.duration / converted_distance
+    pace = @activity.duration / @activity.distance_in_miles
 
     assert_equal pace, @activity.reload.calculated_pace 
 
     @activity.distance = 600
     @activity.unit = :yards
     @activity.duration = 90
     @activity.save
-    converted_distance = @activity.distance * 0.0005681818239083977
-    pace = @activity.duration / converted_distance
+    pace = @activity.duration / @activity.distance_in_miles
 
     assert_equal pace, @activity.reload.calculated_pace     
   end