sc-16765 Fix aggregate_state_totals patient_days calculation (#5706)

**Story card:**
[sc-16765](https://app.shortcut.com/simpledotorg/story/16765/fix-drug-stock-calculation-in-bd)

## Because

The Drug Stock table in the Bangladesh dashboard is showing incorrect
patient days.
Currently, we are summing patient days across all facilities and
districts within a division, which misrepresents the actual values.
Patient days should instead be calculated using the existing patient day
formula.

## This addresses

Patient days now reflect the proper calculation instead of a simple sum
of facilities and districts.
At the division and subtotal levels, the value is computed based on:

- The subtotal of drugs  
- The total number of patients  
- The patient day calculation formula

Key changes:
- Fixed patient day calculation in the Drug Stock table
- Removed incorrect summing of facilities and district patient days
- Ensures values at division and subtotal levels match the intended
formula

## Test instructions

- Navigate to the Drug Stock section.  
- Hover over the patient days value to view the calculation formula
being applied.

Author: Gyan-Gupta-Rtsl

app/helpers/drug_stock_helper.rb

@@ -30,7 +30,7 @@ def drug_stock_for(report, drug)
     end
   end
 
-  def aggregate_state_totals(districts, drugs_by_category)
+  def aggregate_state_totals(districts, drugs_by_category, state = nil)
     totals = Hash.new(0)
     patient_days = Hash.new(0)
     patient_count = 0
@@ -43,14 +43,56 @@ def aggregate_state_totals(districts, drugs_by_category)
         drugs.each do |drug|
           totals[drug.rxnorm_code] += drug_stock_for(report, drug)
         end
+      end
+    end
 
-        if report.dig(:total_patient_days, drug_category, :patient_days)
-          patient_days[drug_category] += report.dig(:total_patient_days, drug_category, :patient_days).to_i
-        end
+    patient_days_report = {}
+    drugs_by_category.each do |drug_category, drugs|
+      state_coeffs = state ? Reports::DrugStockCalculation.new(
+        state: state,
+        protocol_drugs: drugs,
+        drug_category: drug_category,
+        current_drug_stocks: districts.map { |_, d| d[:report][:drugs] }.flatten,
+        patient_count: patient_count
+      ).patient_days_coefficients(state) : {}
+
+      load_coefficient = state_coeffs[:load_coefficient] || 1
+      new_patient_coefficient = state_coeffs.dig(:drug_categories, drug_category, :new_patient_coefficient) || 1
+
+      adjusted_stock_sum = drugs.sum do |drug|
+        coefficient = state_coeffs.dig(:drug_categories, drug_category, drug.rxnorm_code) || 1
+        totals[drug.rxnorm_code].to_f * coefficient
+      end
+
+      patient_days[drug_category] = if patient_count.positive?
+        (adjusted_stock_sum / (patient_count * load_coefficient * new_patient_coefficient)).to_i
+      else
+        0
       end
+
+      stocks = drugs.map do |drug|
+        {
+          protocol_drug: drug,
+          in_stock: totals[drug.rxnorm_code].to_i,
+          coefficient: state_coeffs.dig(:drug_categories, drug_category, drug.rxnorm_code) || 1
+        }
+      end
+
+      patient_days_report[drug_category] = {
+        stocks_on_hand: stocks,
+        patient_count: patient_count,
+        load_coefficient: load_coefficient,
+        new_patient_coefficient: new_patient_coefficient,
+        patient_days: patient_days[drug_category]
+      }
     end
 
-    {totals: totals, patient_days: patient_days, patient_count: patient_count}
+    {
+      totals: totals,
+      patient_days: patient_days,
+      patient_count: patient_count,
+      patient_days_report: patient_days_report
+    }
   end
 
   def grouped_district_reports(district_reports)

app/views/my_facilities/drug_stocks/_all_district_drug_stock_table.html.erb

@@ -83,7 +83,7 @@
       </thead>
 
       <% grouped.each do |state, districts| %>
-        <% state_data = aggregate_state_totals(districts, first_drugs_by_category) %>
+        <% state_data = aggregate_state_totals(districts, first_drugs_by_category, state) %>
         <% state_totals = state_data[:totals] %>
         <% state_patient_days = state_data[:patient_days] %>
         <% state_patient_count = state_data[:patient_count] %>
@@ -105,9 +105,19 @@
               <% end %>
               <% unless drug_category == "diabetes" %>
                 <% if state_patient_days[drug_category].present? %>
-                  <td class="type-percent">
-                    <em class="<%= patient_days_css_class(state_patient_days[drug_category]) %>"><%= state_patient_days[drug_category] %></em>
-                  </td>
+                <td class="type-percent"
+                  data-html="true"
+                  data-toggle="tooltip"
+                  data-placement="top"
+                  data-trigger="hover focus"
+                  data-template="<%= render 'wide_tooltip_template' %>"
+                  data-original-title="<%= render 'drug_stocks_tooltip', report: state_data[:patient_days_report][drug_category] %>"
+                  data-sort-value="<%= state_patient_days[drug_category] %>">
+                <em class="<%= patient_days_css_class(state_patient_days[drug_category]) %>">
+                  <%= state_patient_days[drug_category] %>
+                </em>
+              </td>
+
                 <% else %>
                   <td class="type-blank"><span>&#8212;</span></td>
                 <% end %>

spec/helpers/drug_stock_helper_spec.rb

@@ -65,19 +65,28 @@
           report: {
             total_drugs_in_stock: {"979467" => 10, "316764" => 0, "329528" => 5},
             total_patient_days: {"hypertension_arb" => {patient_days: 3}, "hypertension_ccb" => {patient_days: 1}},
-            district_patient_count: 7
+            district_patient_count: 7,
+            patient_days_report: {
+              "hypertension_arb" => {patient_days: 1},
+              "hypertension_ccb" => {patient_days: 0}
+            }
           }
         }
       }
     end
 
-    it "aggregates totals, patient_days, and patient_count correctly" do
+    it "aggregates totals, patient_days, patient_count, and patient_days_report correctly" do
       result = helper.aggregate_state_totals(districts, drugs_by_category)
-      expect(result).to eq(
-        totals: {"979467" => 10, "316764" => 0, "329528" => 5},
-        patient_days: {"hypertension_arb" => 3, "hypertension_ccb" => 1},
-        patient_count: 7
-      )
+
+      expect(result[:totals]).to eq({"979467" => 10, "316764" => 0, "329528" => 5})
+      expect(result[:patient_count]).to eq(7)
+      expect(result[:patient_days]).to eq({"hypertension_arb" => 1, "hypertension_ccb" => 0})
+
+      report_arb = result[:patient_days_report]["hypertension_arb"]
+      report_ccb = result[:patient_days_report]["hypertension_ccb"]
+
+      expect(report_arb[:patient_days]).to eq(1)
+      expect(report_ccb[:patient_days]).to eq(0)
     end
   end