Net worth calculation (#508)

* Add classification generated column to account

* Add basic net worth calculation

* Add net worth tests

* Fix lint errors

app/models/account.rb

@@ -9,24 +9,8 @@ class Account < ApplicationRecord
 
   delegated_type :accountable, types: Accountable::TYPES, dependent: :destroy
 
-  delegate :type_name, to: :accountable
   before_create :check_currency
 
-  def classification
-    classifications = {
-      "Account::Depository" => :asset,
-      "Account::Investment" => :asset,
-      "Account::Property" => :asset,
-      "Account::Vehicle" => :asset,
-      "Account::OtherAsset" => :asset,
-      "Account::Loan" => :liability,
-      "Account::Credit" => :liability,
-      "Account::OtherLiability" => :liability
-    }
-
-    classifications[accountable_type]
-  end
-
   def balance_series(period)
     MoneySeries.new(
       balances.in_period(period).order(:date),

app/models/account/balance_calculator.rb

@@ -11,7 +11,7 @@ class Account::BalanceCalculator
       oldest_entry = [ valuations.first, transactions.first ].compact.min_by(&:date)
 
       net_transaction_flows = transactions.sum(&:amount)
-      net_transaction_flows *= -1 if @account.classification == :liability
+      net_transaction_flows *= -1 if @account.classification == "liability"
       implied_start_balance = oldest_entry.is_a?(Valuation) ? oldest_entry.value : @account.balance + net_transaction_flows
 
       prior_balance = implied_start_balance
@@ -22,7 +22,7 @@ class Account::BalanceCalculator
             current_balance = valuation.value
         else
             current_day_net_transaction_flows = transactions.select { |t| t.date == date }.sum(&:amount)
-            current_day_net_transaction_flows *= -1 if @account.classification == :liability
+            current_day_net_transaction_flows *= -1 if @account.classification == "liability"
             current_balance = prior_balance - current_day_net_transaction_flows
         end
 

app/models/family.rb

@@ -2,4 +2,66 @@ class Family < ApplicationRecord
   has_many :users, dependent: :destroy
   has_many :accounts, dependent: :destroy
   has_many :transactions, through: :accounts
+
+  def net_worth
+    accounts.sum("CASE WHEN classification = 'asset' THEN balance ELSE -balance END")
+  end
+
+  def assets
+    accounts.where(classification: "asset").sum(:balance)
+  end
+
+  def liabilities
+    accounts.where(classification: "liability").sum(:balance)
+  end
+
+  def net_worth_series(period = nil)
+    query = accounts.joins(:balances)
+      .select("account_balances.date, SUM(CASE WHEN accounts.classification = 'asset' THEN account_balances.balance ELSE -account_balances.balance END) AS balance, 'USD' as currency")
+      .group("account_balances.date")
+      .order("account_balances.date ASC")
+
+    if period && period.date_range
+      query = query.where("account_balances.date BETWEEN ? AND ?", period.date_range.begin, period.date_range.end)
+    end
+
+    MoneySeries.new(
+      query,
+      { trend_type: "asset" }
+    )
+  end
+
+  def asset_series(period = nil)
+    query = accounts.joins(:balances)
+      .select("account_balances.date, SUM(account_balances.balance) AS balance, 'asset' AS classification, 'USD' AS currency")
+      .group("account_balances.date")
+      .order("account_balances.date ASC")
+      .where(classification: "asset")
+
+    if period && period.date_range
+      query = query.where("account_balances.date BETWEEN ? AND ?", period.date_range.begin, period.date_range.end)
+    end
+
+    MoneySeries.new(
+      query,
+      { trend_type: "asset" }
+    )
+  end
+
+  def liability_series(period = nil)
+    query = accounts.joins(:balances)
+      .select("account_balances.date, SUM(account_balances.balance) AS balance, 'liability' AS classification, 'USD' AS currency")
+      .group("account_balances.date")
+      .order("account_balances.date ASC")
+      .where(classification: "liability")
+
+    if period && period.date_range
+      query = query.where("account_balances.date BETWEEN ? AND ?", period.date_range.begin, period.date_range.end)
+    end
+
+    MoneySeries.new(
+      query,
+      { trend_type: "liability" }
+    )
+  end
 end

app/models/money_series.rb

@@ -1,6 +1,6 @@
 class MoneySeries
     def initialize(series, options = {})
-        @trend_type = options[:trend_type] || :asset # Defines whether a positive trend is good or bad
+        @trend_type = options[:trend_type] || "asset" # Defines whether a positive trend is good or bad
         @accessor = options[:amount_accessor] || :balance
         @series = series
     end

app/models/trend.rb

@@ -1,10 +1,10 @@
 class Trend
   attr_reader :current, :previous, :type
 
-  def initialize(current:, previous: nil, type: :asset)
+  def initialize(current:, previous: nil, type: "asset")
     @current = current
     @previous = previous
-    @type = type # :asset means positive trend is good, :liability means negative trend is good
+    @type = type # asset means positive trend is good, liability means negative trend is good
   end
 
   def direction