Refactored merge controller through merge_service

cs169 · Apr 19, 2024 · ad38df9 · ad38df9
1 parent 7fb905a
commit ad38df9
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Showing 2 changed files with 41 additions and 36 deletions.
diff --git a/app/controllers/merge_controller.rb b/app/controllers/merge_controller.rb
@@ -6,50 +6,16 @@ class MergeController < ApplicationController
   def preview
     @from_teacher = Teacher.find(params[:from])
     @into_teacher = Teacher.find(params[:into])
-    @result_teacher = merge_teachers(@from_teacher, @into_teacher)
+    @result_teacher = MergeService.get_merged_teacher(@from_teacher, @into_teacher)
   end
 
   def execute
     @from_teacher = Teacher.find(params[:from])
     @into_teacher = Teacher.find(params[:into])
-    @merged_teacher = merge_teachers(@from_teacher, @into_teacher)
+    merged_attributes = MergeService.get_merged_attributes(@from_teacher, @into_teacher)
 
-    merged_attributes = @merged_teacher.attributes.except("id")
     @into_teacher.update!(merged_attributes)
     @from_teacher.destroy
     redirect_to teachers_path, notice: "Teachers merged successfully."
   end
-
-  private
-  # Returns a merged teacher without saving it to the database.
-  # Rendered in the preview, and only saved to the DB in a call to merge.
-  def merge_teachers(from_teacher, into_teacher)
-    merged_attributes = {}
-    into_teacher.attributes.each do |attr_name, attr_value|
-      from_teacher_attr_value = from_teacher.attributes[attr_name]
-      if attr_value.blank?
-        merged_attributes[attr_name] = from_teacher_attr_value
-      elsif from_teacher_attr_value.blank?
-        merged_attributes[attr_name] = attr_value
-      else
-        case attr_name
-        when "session_count"
-          merged_attributes[attr_name] = attr_value + from_teacher_attr_value
-        when "ip_history"
-          merged_attributes[attr_name] = (attr_value + from_teacher_attr_value).uniq
-        when "last_session_at"
-          # The resulting last session time is the most recent one
-          merged_attributes[attr_name] = attr_value > from_teacher_attr_value ? attr_value : from_teacher_attr_value
-        when "created_at"
-          # The resulting record creation time is the least recent one
-          merged_attributes[attr_name] = attr_value < from_teacher_attr_value ? attr_value : from_teacher_attr_value
-        else
-          merged_attributes[attr_name] = attr_value
-        end
-      end
-    end
-
-    merged_teacher = Teacher.new(merged_attributes)
-    merged_teacher
-  end
 end
diff --git a/app/services/merge_service.rb b/app/services/merge_service.rb
@@ -0,0 +1,39 @@
+# frozen_string_literal: true
+
+class MergeService
+  # Returns a new Teacher object with merged attributes but does not save it
+  def self.get_merged_teacher(from_teacher, into_teacher)
+    merged_attributes = get_merged_attributes(from_teacher, into_teacher)
+    Teacher.new(merged_attributes)
+  end
+
+  # Returns the merged attributes hash excluding the "id" attribute
+  def self.get_merged_attributes(from_teacher, into_teacher)
+    merged_attributes = {}
+    into_teacher.attributes.each do |attr_name, attr_value|
+      next if attr_name == "id"
+
+      from_teacher_attr_value = from_teacher.attributes[attr_name]
+      if attr_value.blank?
+        merged_attributes[attr_name] = from_teacher_attr_value
+      elsif from_teacher_attr_value.blank?
+        merged_attributes[attr_name] = attr_value
+      else
+        case attr_name
+        when "session_count"
+          merged_attributes[attr_name] = attr_value + from_teacher_attr_value
+        when "ip_history"
+          merged_attributes[attr_name] = (attr_value + from_teacher_attr_value).uniq
+        when "last_session_at"
+          merged_attributes[attr_name] = [attr_value, from_teacher_attr_value].max
+        when "created_at"
+          merged_attributes[attr_name] = [attr_value, from_teacher_attr_value].min
+        else
+          merged_attributes[attr_name] = attr_value
+        end
+      end
+    end
+
+    merged_attributes
+  end
+end