SIMPLEBACK-36: fix ltfu toggle bug

app/models/reports/region_summary_schema.rb

@@ -20,8 +20,19 @@ def self.cache_version
     def initialize(regions, periods:)
       @regions = regions
       @regions_by_type = regions.group_by { |region| region.region_type }
-      @periods = periods
-      @period_hash = lambda { |month_date, count| [Period.month(month_date), count] }
+
+      @original_periods =
+        case periods
+        when Range
+          periods
+        when Array
+          (periods.min..periods.max)
+        else
+          (periods..periods)
+        end
+
+      @periods = @original_periods
+      @period_hash = ->(month_date, count) { [Period.month(month_date), count] }
     end
 
     # Returns the earliest patient record for a Region from either assigned or registered patients. Note that this *ignores*
@@ -41,21 +52,11 @@ def initialize(regions, periods:)
     # Adjusted patient counts are the patient counts from three months ago (the adjusted period) that
     # are the basis for control rates. These counts DO include lost to follow up.
     memoize def adjusted_patients_with_ltfu
-      cumulative_assigned_patients.each_with_object({}) do |(entry, result), results|
-        values = periods.each_with_object(Hash.new(0)) { |period, region_result|
-          region_result[period] = result[period.adjusted_period]
-        }
-        results[entry] = values
-      end
+      adjusted_patients_with_ltfu_for("cumulative_assigned_patients")
     end
 
     memoize def adjusted_diabetes_patients_with_ltfu
-      cumulative_assigned_diabetic_patients.each_with_object({}) do |(entry, result), results|
-        values = periods.each_with_object(Hash.new(0)) { |period, region_result|
-          region_result[period] = result[period.adjusted_period]
-        }
-        results[entry] = values
-      end
+      adjusted_patients_with_ltfu_for("cumulative_assigned_diabetic_patients")
     end
 
     # Adjusted patient counts are the patient counts from three months ago (the adjusted period) that
@@ -779,6 +780,33 @@ def diabetes_patients_by_risk_state_and_type(risk_state:, types:)
 
     private
 
+    def adjusted_patients_with_ltfu_for(field_name)
+      extended_begin = @original_periods.begin.advance(
+        months: -Reports::REGISTRATION_BUFFER_IN_MONTHS
+      )
+      extended_range = (extended_begin..@original_periods.end)
+
+      extended_data = regions_by_type.each_with_object({}) do |(_, regions), result|
+        result.merge! RegionSummary.call(regions, range: extended_range)
+      end
+
+      cumulative_data = extended_data.transform_values do |period_values|
+        period_values.transform_values do |v|
+          v.fetch(field_name, 0)
+        end
+      end
+
+      regions.each_with_object({}) do |region, results|
+        counts = cumulative_data[region.slug] || {}
+
+        values = @original_periods.each_with_object(Hash.new(0)) do |period, h|
+          h[period] = counts.fetch(period.adjusted_period, 0)
+        end
+
+        results[region.slug] = values
+      end
+    end
+
     def appts_scheduled_rates(entry)
       rounded_percentages({
         appts_scheduled_0_to_14_days_rates: appts_scheduled_0_to_14_days[entry.region.slug][entry.period],

spec/models/reports/repository_spec.rb

@@ -934,4 +934,128 @@
       expect(described_class::DELEGATED_RATES).to match_array(expected_keys)
     end
   end
+
+  context "period extension for 3-month lookback (18 month UI window + 3 month buffer)" do
+    let(:facility) { create(:facility, facility_group: facility_group_1) }
+
+    let(:end_period) { Period.month("February 2026") }
+    let(:start_period) { end_period.advance(months: -(Reports::MAX_MONTHS_OF_DATA - 1)) }
+    let(:original_range) { (start_period..end_period) }
+
+    let(:repo) { Reports::Repository.new(facility.region, periods: original_range) }
+
+    before do
+      allow(Reports::PatientState).to receive(:get_refresh_months).and_return(
+        ReportingHelpers.get_refresh_months_between_dates(
+          start_period.advance(months: -Reports::REGISTRATION_BUFFER_IN_MONTHS).to_date,
+          end_period.to_date
+        )
+      )
+    end
+
+    it "keeps original UI period window as 18 months" do
+      expect(repo.periods).to eq(original_range)
+      expect(repo.periods.count).to eq(18)
+    end
+
+    [:adjusted_diabetes_patients_with_ltfu, :adjusted_patients_with_ltfu].each do |method|
+      it "does not expose buffer months for #{method}" do
+        refresh_views
+        result = repo.send(method)[facility.region.slug]
+
+        expect(result.keys.min).to eq(start_period)
+        expect(result.keys.max).to eq(end_period)
+        expect(result.keys).not_to include(start_period.advance(months: -1))
+        expect(result.keys).not_to include(start_period.advance(months: -2))
+        expect(result.keys).not_to include(start_period.advance(months: -3))
+      end
+    end
+
+    it "ensures first visible month has access to 3-month back denominator data" do
+      patients = create_list(:patient, 3, :diabetes,
+        recorded_at: start_period.advance(months: -3).to_date,
+        assigned_facility: facility,
+        registration_user: user)
+
+      patients.each do |patient|
+        create(:blood_sugar, :with_encounter, patient: patient, facility: facility, recorded_at: start_period.to_date, user: user)
+      end
+
+      refresh_views
+      result = repo.adjusted_diabetes_patients_with_ltfu[facility.region.slug]
+      expect(result[start_period]).to eq(3)
+    end
+
+    it "works correctly for single period input with 3-month lookback data" do
+      single_period = Period.month("February 2026")
+
+      patients = create_list(:patient, 2, :diabetes,
+        recorded_at: single_period.advance(months: -3).to_date,
+        assigned_facility: facility,
+        registration_user: user)
+
+      patients.each do |patient|
+        create(:blood_sugar, :with_encounter,
+          patient: patient,
+          facility: facility,
+          recorded_at: single_period.to_date,
+          user: user)
+      end
+
+      repo = Reports::Repository.new(facility.region, periods: single_period)
+
+      refresh_views
+      result = repo.adjusted_diabetes_patients_with_ltfu[facility.region.slug]
+      expect(repo.periods).to eq(single_period..single_period)
+      expect(result.keys).to eq([single_period])
+      expect(result[single_period]).to eq(2)
+    end
+
+    it "ensures first visible month has access to 3-month back denominator data for hypertension" do
+      patients = create_list(:patient, 3, :hypertension,
+        recorded_at: start_period.advance(months: -3).to_date,
+        assigned_facility: facility,
+        registration_user: user)
+
+      patients.each do |patient|
+        create(:bp_with_encounter, patient: patient, facility: facility, recorded_at: start_period.to_date, user: user)
+      end
+
+      refresh_views
+      result = repo.adjusted_patients_with_ltfu[facility.region.slug]
+      expect(result[start_period]).to eq(3)
+    end
+
+    it "works correctly for single period input with 3-month lookback data for hypertension" do
+      single_period = Period.month("February 2026")
+
+      allow(Reports::PatientState).to receive(:get_refresh_months).and_return(
+        ReportingHelpers.get_refresh_months_between_dates(
+          single_period.advance(months: -Reports::REGISTRATION_BUFFER_IN_MONTHS).to_date,
+          single_period.to_date
+        )
+      )
+
+      patients = create_list(:patient, 2, :hypertension,
+        recorded_at: single_period.advance(months: -3).to_date,
+        assigned_facility: facility,
+        registration_user: user)
+
+      patients.each do |patient|
+        create(:bp_with_encounter,
+          patient: patient,
+          facility: facility,
+          recorded_at: single_period.to_date,
+          user: user)
+      end
+
+      repo = Reports::Repository.new(facility.region, periods: single_period)
+
+      refresh_views
+      result = repo.adjusted_patients_with_ltfu[facility.region.slug]
+      expect(repo.periods).to eq(single_period..single_period)
+      expect(result.keys).to eq([single_period])
+      expect(result[single_period]).to eq(2)
+    end
+  end
 end