Refactor: move charging logic from cb to rate

app/models/chargeback.rb

@@ -141,35 +141,14 @@ def calculate_costs(metric_rollup_records, rates, hours_in_interval)
 
     rates.each do |rate|
       rate.chargeback_rate_details.each do |r|
-        if !chargeback_fields_present && r.fixed?
-          cost = 0
-        else
-          metric_value, cost = r.metric_and_cost_by(metric_rollup_records, hours_in_interval)
+        r.charge(relevant_fields, chargeback_fields_present, metric_rollup_records, hours_in_interval).each do |field, value|
+          next unless self.class.attribute_names.include?(field)
+          self[field] = (self[field] || 0) + value
         end
-
-        accumulate_metrics_and_costs_per_rate(r, metric_value, cost)
       end
     end
   end
 
-  def accumulate_metrics_and_costs_per_rate(rate, metric, cost)
-    col_hash = {}
-
-    defined_column_for_report = (relevant_fields & [rate.metric_keys[0], rate.cost_keys[0]]).present?
-
-    if defined_column_for_report
-      rate.metric_keys.each { |col| col_hash[col] = metric }
-      rate.cost_keys.each   { |col| col_hash[col] = cost }
-    end
-
-    col_hash.each do |k, val|
-      next unless self.class.attribute_names.include?(k)
-      self[k] ||= 0
-      self[k] += val
-    end
-  end
-  private :accumulate_metrics_and_costs_per_rate
-
   def self.report_cb_model(model)
     model.gsub(/^Chargeback/, "")
   end

app/models/chargeback_rate_detail.rb

@@ -21,6 +21,21 @@ class ChargebackRateDetail < ApplicationRecord
 
   attr_accessor :hours_in_interval
 
+  def charge(relevant_fields, chargeback_fields_present, metric_rollup_records, hours_in_interval)
+    if !chargeback_fields_present && fixed?
+      cost = 0
+    else
+      metric_value, cost = metric_and_cost_by(metric_rollup_records, hours_in_interval)
+    end
+
+    result = {}
+    if (relevant_fields & [metric_keys[0], cost_keys[0]]).present?
+      metric_keys.each { |field| result[field] = metric_value }
+      cost_keys.each   { |field| result[field] = cost }
+    end
+    result
+  end
+
   def max_of_metric_from(metric_rollup_records)
     metric_rollup_records.map(&metric.to_sym).max
   end
@@ -210,6 +225,8 @@ def contiguous_tiers?
     !error
   end
 
+  private
+
   def metric_keys
     ["#{rate_name}_metric", # metric value (e.g. Storage [Used|Allocated|Fixed])
      "#{group}_metric"]     # total of metric's group (e.g. Storage Total)
@@ -227,8 +244,6 @@ def metric_and_cost_by(metric_rollup_records, hours_in_interval)
     [metric_value, hourly_cost(metric_value) * hours_in_interval]
   end
 
-  private
-
   def first_tier?(tier,tiers)
     tier == tiers.first
   end