Derive household variables for sales logs

app/models/derived_variables/sales_log_variables.rb

@@ -16,5 +16,74 @@ module DerivedVariables::SalesLogVariables
       self.mscharge = 0
     end
     self.pcode1, self.pcode2 = postcode_full.split(" ") if postcode_full.present?
+    self.totchild = total_child
+    self.totadult = total_adult + total_elder
+    self.hhmemb = totchild + totadult
+    self.hhtype = household_type
+  end
+
+private
+
+  def total_elder
+    ages = [age1, age2, age3, age4, age5, age6]
+    ages.count { |x| !x.nil? && x >= 60 }
+  end
+
+  def total_child
+    relationships = [relat2, relat3, relat4, relat5, relat6]
+    relationships.count("C")
+  end
+
+  def total_adult
+    total = !age1.nil? && age1 >= 16 && age1 < 60 ? 1 : 0
+    total + (2..6).count do |i|
+      age = public_send("age#{i}")
+      relat = public_send("relat#{i}")
+      !age.nil? && ((age >= 16 && age < 18 && %w[P X].include?(relat)) || age >= 18 && age < 60)
+    end
+  end
+
+  def household_type
+    return unless total_elder && total_adult && totchild
+
+    if only_one_elder?
+      1
+    elsif two_adults_including_elders?
+      2
+    elsif only_one_adult?
+      3
+    elsif only_two_adults?
+      4
+    elsif one_adult_with_at_least_one_child?
+      5
+    elsif two_adults_with_at_least_one_child?
+      6
+    else
+      9
+    end
+  end
+
+  def two_adults_with_at_least_one_child?
+    total_elder.zero? && total_adult >= 2 && totchild >= 1
+  end
+
+  def one_adult_with_at_least_one_child?
+    total_elder.zero? && total_adult == 1 && totchild >= 1
+  end
+
+  def only_two_adults?
+    total_elder.zero? && total_adult == 2 && totchild.zero?
+  end
+
+  def only_one_adult?
+    total_elder.zero? && total_adult == 1 && totchild.zero?
+  end
+
+  def two_adults_including_elders?
+    (total_elder + total_adult) == 2 && total_elder >= 1
+  end
+
+  def only_one_elder?
+    total_elder == 1 && total_adult.zero? && totchild.zero?
   end
 end

spec/models/sales_log_spec.rb

@@ -232,6 +232,44 @@ RSpec.describe SalesLog, type: :model do
     end
   end
 
+  context "when deriving household variables" do
+    let!(:household_lettings_log) do
+      described_class.create!({
+        jointpur: 1,
+        hholdcount: 3,
+        relat2: "X",
+        relat3: "C",
+        relat4: "X",
+        relat5: "C",
+        age1: 22,
+        age2: 60,
+        age3: 15,
+        age4: 88,
+        age5: 14,
+      })
+    end
+
+    it "correctly derives and saves hhmemb" do
+      record_from_db = ActiveRecord::Base.connection.execute("select hhmemb from sales_logs where id=#{household_lettings_log.id}").to_a[0]
+      expect(record_from_db["hhmemb"]).to eq(5)
+    end
+
+    it "correctly derives and saves totchild" do
+      record_from_db = ActiveRecord::Base.connection.execute("select totchild from sales_logs where id=#{household_lettings_log.id}").to_a[0]
+      expect(record_from_db["totchild"]).to eq(2)
+    end
+
+    it "correctly derives and saves totadult" do
+      record_from_db = ActiveRecord::Base.connection.execute("select totadult from sales_logs where id=#{household_lettings_log.id}").to_a[0]
+      expect(record_from_db["totadult"]).to eq(3)
+    end
+
+    it "correctly derives and saves hhtype" do
+      record_from_db = ActiveRecord::Base.connection.execute("select hhtype from sales_logs where id=#{household_lettings_log.id}").to_a[0]
+      expect(record_from_db["hhtype"]).to eq(9)
+    end
+  end
+
   context "when saving previous address" do
     def check_previous_postcode_fields(postcode_field)
       record_from_db = ActiveRecord::Base.connection.execute("select #{postcode_field} from sales_logs where id=#{address_sales_log.id}").to_a[0]