Multi-currency support: Money + Currency class improvements (#553)

* Money improvements

* Replace all old money usage

app/models/account.rb

@@ -1,5 +1,6 @@
 class Account < ApplicationRecord
   include Syncable
+  include Monetizable
 
   validates :family, presence: true
 
@@ -9,6 +10,8 @@ class Account < ApplicationRecord
   has_many :valuations
   has_many :transactions
 
+  monetize :balance
+
   enum :status, { ok: "ok", syncing: "syncing", error: "error" }, validate: true
 
   scope :active, -> { where(is_active: true) }

app/models/account/balance_calculator.rb

@@ -6,8 +6,8 @@ class Account::BalanceCalculator
     def daily_balances(start_date = nil)
       calc_start_date = [ start_date, @account.effective_start_date ].compact.max
 
-      valuations = @account.valuations.where("date >= ?", calc_start_date).order(:date).select(:date, :value)
-      transactions = @account.transactions.where("date > ?", calc_start_date).order(:date).select(:date, :amount)
+      valuations = @account.valuations.where("date >= ?", calc_start_date).order(:date).select(:date, :value, :currency)
+      transactions = @account.transactions.where("date > ?", calc_start_date).order(:date).select(:date, :amount, :currency)
       oldest_entry = [ valuations.first, transactions.first ].compact.min_by(&:date)
 
       net_transaction_flows = transactions.sum(&:amount)

app/models/account_balance.rb

@@ -1,7 +1,9 @@
 class AccountBalance < ApplicationRecord
-  belongs_to :account
+  include Monetizable
 
+  belongs_to :account
   validates :account, :date, :balance, presence: true
+  monetize :balance
 
   scope :in_period, ->(period) { period.date_range.nil? ? all : where(date: period.date_range) }
 

app/models/concerns/monetizable.rb

@@ -0,0 +1,14 @@
+module Monetizable
+    extend ActiveSupport::Concern
+
+    class_methods do
+      def monetize(*fields)
+        fields.each do |field|
+          define_method("#{field}_money") do
+            value = self.send(field)
+            value.nil? ? nil : Money.new(value, currency)
+          end
+        end
+      end
+    end
+end

app/models/family.rb

@@ -1,9 +1,13 @@
 class Family < ApplicationRecord
+  include Monetizable
+
   has_many :users, dependent: :destroy
   has_many :accounts, dependent: :destroy
   has_many :transactions, through: :accounts
   has_many :transaction_categories, dependent: :destroy, class_name: "Transaction::Category"
 
+  monetize :net_worth, :assets, :liabilities
+
   def snapshot(period = Period.all)
     query = accounts.active.joins(:balances)
       .where("account_balances.currency = ?", self.currency)
@@ -35,7 +39,7 @@ class Family < ApplicationRecord
   end
 
   def assets
-   accounts.active.assets.sum(:balance)
+    accounts.active.assets.sum(:balance)
   end
 
   def liabilities

app/models/money.rb

@@ -1,32 +0,0 @@
-class Money
-    attr_reader :amount, :currency
-
-    def self.from_amount(amount, currency = "USD")
-        Money.new(amount, currency)
-    end
-
-    def initialize(amount, currency = :USD)
-        @amount = amount
-        @currency = currency
-    end
-
-    def cents(precision: nil)
-        _precision = precision || CURRENCY_OPTIONS[@currency.to_sym][:precision]
-        return "" unless _precision.positive?
-
-        fractional_part = @amount.to_s.split(".")[1] || ""
-        fractional_part = fractional_part[0, _precision].ljust(_precision, "0")
-    end
-
-    def symbol
-        CURRENCY_OPTIONS[@currency.to_sym][:symbol]
-    end
-
-    def separator
-        CURRENCY_OPTIONS[@currency.to_sym][:separator]
-    end
-
-    def precision
-        CURRENCY_OPTIONS[@currency.to_sym][:precision]
-    end
-end

app/models/money_series.rb

@@ -14,7 +14,7 @@ class MoneySeries
             {
                 raw: current,
                 date: current.date,
-                value: Money.from_amount(current.send(@accessor), current.currency),
+                value: Money.new(current.send(@accessor), current.currency),
                 trend: Trend.new(
                     current: current.send(@accessor),
                     previous: previous&.send(@accessor),

app/models/transaction.rb

@@ -1,4 +1,6 @@
 class Transaction < ApplicationRecord
+  include Monetizable
+
   belongs_to :account
   belongs_to :category, optional: true
 
@@ -6,6 +8,12 @@ class Transaction < ApplicationRecord
 
   after_commit :sync_account
 
+  monetize :amount
+
+  scope :inflows, -> { where("amount > 0") }
+  scope :outflows, -> { where("amount < 0") }
+  scope :active, -> { where(excluded: false) }
+
   def self.ransackable_attributes(auth_object = nil)
     %w[name amount date]
   end

app/models/valuation.rb

@@ -1,9 +1,10 @@
 class Valuation < ApplicationRecord
+  include Monetizable
+
   belongs_to :account
-
   validates :account, :date, :value, presence: true
-
   after_commit :sync_account
+  monetize :value
 
   scope :in_period, ->(period) { period.date_range.nil? ? all : where(date: period.date_range) }