Add Money and Money Series (#505)

* Add Money class

* Standardize creation of money series

* Formatting

* Fix test

app/controllers/accounts_controller.rb

@@ -1,4 +1,6 @@
 class AccountsController < ApplicationController
+  include Filterable
+
   before_action :authenticate_user!
 
   def new
@@ -10,19 +12,6 @@ class AccountsController < ApplicationController
 
   def show
     @account = Current.family.accounts.find(params[:id])
-
-    @period = Period.find_by_name(params[:period])
-    if @period.nil?
-      start_date = params[:start_date].presence&.to_date
-      end_date = params[:end_date].presence&.to_date
-      if start_date.is_a?(Date) && end_date.is_a?(Date) && start_date <= end_date
-        @period = Period.new(name: "custom", date_range: start_date..end_date)
-      else
-        params[:period] = "last_30_days"
-        @period = Period.find_by_name(params[:period])
-      end
-    end
-
     @balance_series = @account.balance_series(@period)
     @valuation_series = @account.valuation_series
   end

app/controllers/concerns/filterable.rb

@@ -0,0 +1,23 @@
+module Filterable
+    extend ActiveSupport::Concern
+
+    included do
+        before_action :set_period
+    end
+
+    private
+
+      def set_period
+        @period = Period.find_by_name(params[:period])
+        if @period.nil?
+          start_date = params[:start_date].presence&.to_date
+          end_date = params[:end_date].presence&.to_date
+          if start_date.is_a?(Date) && end_date.is_a?(Date) && start_date <= end_date
+            @period = Period.new(name: "custom", date_range: start_date..end_date)
+          else
+            params[:period] = "last_30_days"
+            @period = Period.find_by_name(params[:period])
+          end
+        end
+      end
+end

app/javascript/controllers/line_chart_controller.js

@@ -4,7 +4,7 @@ import * as d3 from "d3";
 
 // Connects to data-controller="line-chart"
 export default class extends Controller {
-  static values = { series: Array };
+  static values = { series: Object };
 
   connect() {
     this.renderChart(this.seriesValue);
@@ -36,26 +36,26 @@ export default class extends Controller {
     }[trendDirection];
   }
 
-  drawChart(balances) {
-    const data = balances.map((b) => ({
-      date: new Date(b.data.date + "T00:00:00"),
-      value: +b.data.balance,
+  drawChart(series) {
+    const data = series.data.map((b) => ({
+      date: new Date(b.date + "T00:00:00"),
+      value: +b.amount,
       styles: this.trendStyles(b.trend.direction),
       trend: b.trend,
       formatted: {
         value: Intl.NumberFormat("en-US", {
           style: "currency",
-          currency: b.data.currency || "USD",
-        }).format(b.data.balance),
+          currency: b.currency || "USD",
+        }).format(b.amount),
         change: Intl.NumberFormat("en-US", {
           style: "currency",
-          currency: b.data.currency || "USD",
+          currency: b.currency || "USD",
           signDisplay: "always",
         }).format(b.trend.amount),
       },
     }));
 
-    const chartContainer = d3.select("#lineChart");
+    const chartContainer = d3.select(this.element);
 
     // Clear any existing chart
     chartContainer.selectAll("svg").remove();

app/models/account.rb

@@ -28,29 +28,17 @@ class Account < ApplicationRecord
   end
 
   def balance_series(period)
-    filtered_balances = balances.in_period(period).order(:date)
-    return nil if filtered_balances.empty?
-
-    series_data = [ nil, *filtered_balances ].each_cons(2).map do |previous, current|
-      trend = current&.trend(previous)
-      { data: current, trend: { amount: trend&.amount, direction: trend&.direction, percent: trend&.percent } }
-    end
-
-    last_balance = series_data.last[:data]
-
-    {
-      series_data: series_data,
-      last_balance: last_balance.balance,
-      trend: last_balance.trend(series_data.first[:data])
-    }
+    MoneySeries.new(
+      balances.in_period(period).order(:date),
+      { trend_type: classification }
+    )
   end
 
   def valuation_series
-    series_data = [ nil, *valuations.order(:date) ].each_cons(2).map do |previous, current|
-      { value: current, trend: current&.trend(previous) }
-    end
-
-    series_data.reverse_each
+    MoneySeries.new(
+      valuations.order(:date),
+      { trend_type: classification, amount_accessor: :value }
+    )
   end
 
   def check_currency

app/models/money.rb

@@ -0,0 +1,32 @@
+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

@@ -0,0 +1,60 @@
+class MoneySeries
+    def initialize(series, options = {})
+        @trend_type = options[:trend_type] || :asset # Defines whether a positive trend is good or bad
+        @accessor = options[:amount_accessor] || :balance
+        @series = series
+    end
+
+    def valid?
+        @series.length > 1
+    end
+
+    def data
+        [ nil, *@series ].each_cons(2).map do |previous, current|
+            {
+                raw: current,
+                date: current.date,
+                value: Money.from_amount(current.send(@accessor), current.currency),
+                trend: Trend.new(
+                    current: current.send(@accessor),
+                    previous: previous&.send(@accessor),
+                    type: @trend_type
+                )
+            }
+        end
+    end
+
+    def trend
+        return Trend.new(current: 0, type: @trend_type) unless valid?
+
+        Trend.new(
+            current: @series.last.send(@accessor),
+            previous: @series.first&.send(@accessor),
+            type: @trend_type
+        )
+    end
+
+    def serialize_for_d3_chart
+        {
+            data: data.map do |datum|
+                {
+                    date: datum[:date],
+                    amount: datum[:value].amount,
+                    currency: datum[:value].currency,
+                    trend: {
+                        amount: datum[:trend].amount,
+                        percent: datum[:trend].percent,
+                        direction: datum[:trend].direction,
+                        type: datum[:trend].type
+                    }
+                }
+            end,
+            trend: {
+                amount: trend.amount,
+                percent: trend.percent,
+                direction: trend.direction,
+                type: trend.type
+            }
+        }.to_json
+    end
+end

app/models/trend.rb

@@ -1,26 +1,27 @@
 class Trend
-    attr_reader :current, :previous
+  attr_reader :current, :previous, :type
 
-    def initialize(current, previous)
-        @current = current
-        @previous = previous
-    end
+  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
+  end
 
-    def direction
-        return "flat" unless @previous
-        return "up" if @current > @previous
-        return "down" if @current < @previous
-        "flat"
-    end
+  def direction
+    return "flat" unless @previous
+    return "up" if @current > @previous
+    return "down" if @current < @previous
+    "flat"
+  end
 
-    def amount
-      return 0 if @previous.nil?
-      @current - @previous
-    end
+  def amount
+    return 0 if @previous.nil?
+    @current - @previous
+  end
 
-    def percent
-      return 0 if @previous.nil?
-      return Float::INFINITY if @previous == 0
-      ((@current - @previous).abs / @previous.to_f * 100).round(1)
-    end
+  def percent
+    return 0 if @previous.nil?
+    return Float::INFINITY if @previous == 0
+    ((@current - @previous).abs / @previous.to_f * 100).round(1)
+  end
 end

app/models/valuation.rb

@@ -4,7 +4,7 @@ class Valuation < ApplicationRecord
   after_commit :sync_account
 
   def trend(previous)
-    Trend.new(value, previous&.value)
+    Trend.new(current: value, previous: previous&.value, type: account.classification)
   end
 
   private

app/views/accounts/_account_valuation_list.html.erb

@@ -1,6 +1,6 @@
 <%# locals: (valuation_series:, classification:) %>
-<% valuation_series.with_index do |valuation_item, index| %>
-  <% valuation, trend = valuation_item.values_at(:value, :trend) %>
+<% valuation_series.data.reverse_each.with_index do |valuation_item, index| %>
+  <% valuation, trend = valuation_item.values_at(:raw, :trend) %>
   <% valuation_styles = trend_styles(valuation_item[:trend], mode: classification) %>
   <%= turbo_frame_tag dom_id(valuation) do %>
     <div class="p-4 flex items-center">
@@ -41,7 +41,7 @@
         </div>
       </div>
     </div>
-    <% unless index == valuation_series.size - 1 %>
+    <% unless index == valuation_series.data.size - 1 %>
       <div class="h-px bg-alpha-black-50 ml-20 mr-4"></div>
     <% end %>
   <% end %>

app/views/accounts/show.html.erb

@@ -1,5 +1,6 @@
 <%= turbo_stream_from @account %>
-<% balance_trend_styles = @balance_series.nil? ? {} : trend_styles(@balance_series[:trend], mode: @account.classification) %>
+<% balance_trend_styles = trend_styles(@balance_series.trend, mode: @account.classification) %>
+<% balance = Money.from_amount(@account.balance, @account.currency) %>
 <div class="space-y-4">
   <div class="flex justify-between items-center">
     <div class="flex items-center gap-3">
@@ -11,7 +12,7 @@
     <div class="flex items-center gap-3">
       <div class="relative cursor-not-allowed">
         <div class="flex items-center gap-2 px-3 py-2">
-          <span class="text-gray-900"><%= @account.currency %> <%= @account.currency.unit %></span>
+          <span class="text-gray-900"><%= balance.currency %> <%= balance.symbol %></span>
           <%= lucide_icon("chevron-down", class: "w-5 h-5 text-gray-500") %>
         </div>
       </div>
@@ -27,22 +28,21 @@
     <div class="p-4 flex justify-between">
       <div class="space-y-2">
         <p class="text-sm text-gray-500">Total Value</p>
-        <%# TODO: Will need a better way to split a formatted monetary value into these 3 parts %>
         <p class="text-gray-900">
-          <span class="text-gray-500"><%= @account.currency.unit %></span>
-          <span class="text-xl font-medium"><%= format_currency(@account.balance, precision: 0, unit: '') %></span>
-          <%- if @account.currency.precision.positive? -%>
-            <span class="text-gray-500"><%= @account.currency.separator %><%= @account.balance.cents(precision: @account.currency.precision) %></span>
+          <span class="text-gray-500"><%= balance.symbol %></span>
+          <span class="text-xl font-medium"><%= format_currency(balance.amount, precision: 0, unit: '') %></span>
+          <%- if balance.precision.positive? -%>
+            <span class="text-gray-500"><%= balance.separator %><%= balance.cents %></span>
           <% end %>
         </p>
         <% if @balance_series.nil? %>
           <p class="text-sm text-gray-500">Data not available for the selected period</p>
-        <% elsif @balance_series[:trend].amount == 0 %>
+        <% elsif @balance_series.trend.amount == 0 %>
           <p class="text-sm text-gray-500">No change vs. prior period</p>
         <% else %>
           <p class="text-sm <%= balance_trend_styles[:text_class] %>">
-            <span><%= balance_trend_styles[:symbol] %><%= number_to_currency(@balance_series[:trend].amount.abs, precision: 2) %></span>
-            <span>(<%= lucide_icon(@balance_series[:trend].amount > 0 ? 'arrow-up' : 'arrow-down', class: "w-4 h-4 align-text-bottom inline") %> <%= @balance_series[:trend].percent %>%)</span>
+            <span><%= balance_trend_styles[:symbol] %><%= number_to_currency(@balance_series.trend.amount.abs, precision: 2) %></span>
+            <span>(<%= lucide_icon(@balance_series.trend.amount > 0 ? 'arrow-up' : 'arrow-down', class: "w-4 h-4 align-text-bottom inline") %> <%= @balance_series.trend.percent %>%)</span>
             <span class="text-gray-500"><%= trend_label(@period) %></span>
           </p>
         <% end %>
@@ -53,7 +53,7 @@
     </div>
     <div class="h-96 flex items-center justify-center text-2xl font-bold">
       <% if @balance_series %>
-        <div data-controller="line-chart" id="lineChart" class="w-full h-full" data-line-chart-series-value="<%= @balance_series[:series_data].to_json %>"></div>
+        <div data-controller="line-chart" id="lineChart" class="w-full h-full" data-line-chart-series-value="<%= @balance_series.serialize_for_d3_chart %>"></div>
       <% else %>
         <div class="w-full h-full flex items-center justify-center">
           <p class="text-gray-500">No data available for the selected period.</p>

config/initializers/constants.rb

@@ -1,18 +1,18 @@
-default_currency_options = { unit: "$", precision: 2, delimiter: ",", separator: "." }
+default_currency_options = { symbol: "$", precision: 2, delimiter: ",", separator: "." }
 
 CURRENCY_OPTIONS = Hash.new { |hash, key| hash[key] = default_currency_options.dup }.merge(
-  "USD": { unit: "$", precision: 2, delimiter: ",", separator: "." },
-  "EUR": { unit: "€", precision: 2, delimiter: ".", separator: "," },
-  "GBP": { unit: "£", precision: 2, delimiter: ",", separator: "." },
-  "CAD": { unit: "C$", precision: 2, delimiter: ",", separator: "." },
-  "MXN": { unit: "MX$", precision: 2, delimiter: ",", separator: "." },
-  "HKD": { unit: "HK$", precision: 2, delimiter: ",", separator: "." },
-  "CHF": { unit: "CHF", precision: 2, delimiter: ".", separator: "," },
-  "SGD": { unit: "S$", precision: 2, delimiter: ",", separator: "." },
-  "NZD": { unit: "NZ$", precision: 2, delimiter: ",", separator: "." },
-  "AUD": { unit: "A$", precision: 2, delimiter: ",", separator: "." },
-  "KRW": { unit: "₩", precision: 0, delimiter: ",", separator: "." },
-  "INR": { unit: "₹", precision: 2, delimiter: ",", separator: "." }
+  "USD": { symbol: "$", precision: 2, delimiter: ",", separator: "." },
+  "EUR": { symbol: "€", precision: 2, delimiter: ".", separator: "," },
+  "GBP": { symbol: "£", precision: 2, delimiter: ",", separator: "." },
+  "CAD": { symbol: "C$", precision: 2, delimiter: ",", separator: "." },
+  "MXN": { symbol: "MX$", precision: 2, delimiter: ",", separator: "." },
+  "HKD": { symbol: "HK$", precision: 2, delimiter: ",", separator: "." },
+  "CHF": { symbol: "CHF", precision: 2, delimiter: ".", separator: "," },
+  "SGD": { symbol: "S$", precision: 2, delimiter: ",", separator: "." },
+  "NZD": { symbol: "NZ$", precision: 2, delimiter: ",", separator: "." },
+  "AUD": { symbol: "A$", precision: 2, delimiter: ",", separator: "." },
+  "KRW": { symbol: "₩", precision: 0, delimiter: ",", separator: "." },
+  "INR": { symbol: "₹", precision: 2, delimiter: ",", separator: "." }
 )
 
 EXCHANGE_RATE_ENABLED = ENV["OPEN_EXCHANGE_APP_ID"].present?

config/initializers/numeric_extensions.rb

@@ -1,11 +0,0 @@
-class Numeric
-  def cents(precision: 2)
-    return "" unless precision.positive?
-
-    cents = self.to_s.split(".")[1]
-    cents = "" unless cents.to_i.positive?
-
-    zero_padded_cents = cents.ljust(precision, "0")
-    zero_padded_cents[0..precision - 1]
-  end
-end

config/initializers/string_extensions.rb

@@ -1,13 +0,0 @@
-class String
-  def unit
-    CURRENCY_OPTIONS[self.to_sym][:unit]
-  end
-
-  def separator
-    CURRENCY_OPTIONS[self.to_sym][:separator]
-  end
-
-  def precision
-    CURRENCY_OPTIONS[self.to_sym][:precision]
-  end
-end

test/initializers/numeric_extensions_test.rb

@@ -1,28 +0,0 @@
-# test/initializers/big_decimal_extensions_test.rb
-require "test_helper"
-
-class NumericExtensionsTest < ActiveSupport::TestCase
-  test "#cents returns the cents part with 2 precisions by default" do
-    amount = 123.45
-    assert_equal "45", amount.cents
-  end
-
-  test "#cents returns empty when precision is 0" do
-    amount = 123.45
-    assert_equal "", amount.cents(precision: 0)
-  end
-
-  test "#cents returns the cents part of the string with given precision" do
-    amount = 123.4862
-    assert_equal "4", amount.cents(precision: 1)
-    assert_equal "486", amount.cents(precision: 3)
-  end
-
-  test "#cents pads the cents part with zeros up to the specified precision" do
-    amount_without_decimal = 123
-    amount_with_decimal = 123.4
-
-    assert_equal "00", amount_without_decimal.cents
-    assert_equal "40", amount_with_decimal.cents
-  end
-end

test/initializers/string_extensions_test.rb

@@ -1,19 +0,0 @@
-# test/string_extensions_test.rb
-require "test_helper"
-
-class StringExtensionsTest < ActiveSupport::TestCase
-  test "#unit returns the currency unit for a given currency code" do
-    assert_equal "$", "USD".unit
-    assert_equal "€", "EUR".unit
-  end
-
-  test "#separator returns the currency separator for a given currency code" do
-    assert_equal ".", "USD".separator
-    assert_equal ",", "EUR".separator
-  end
-
-  test "#precision returns the currency's precision for a given currency code" do
-    assert_equal 2, "USD".precision
-    assert_equal 0, "KRW".precision
-  end
-end

test/models/money_test.rb

@@ -0,0 +1,45 @@
+require "test_helper"
+
+class MoneyTest < ActiveSupport::TestCase
+    test "#symbol returns the currency symbol for a given currency code" do
+        assert_equal "$", Money.from_amount(0, "USD").symbol
+        assert_equal "€", Money.from_amount(0, "EUR").symbol
+    end
+
+    test "#separator returns the currency separator for a given currency code" do
+        assert_equal ".", Money.from_amount(0, "USD").separator
+        assert_equal ",", Money.from_amount(0, "EUR").separator
+    end
+
+    test "#precision returns the currency's precision for a given currency code" do
+        assert_equal 2, Money.from_amount(0, "USD").precision
+        assert_equal 0, Money.from_amount(123.45, "KRW").precision
+    end
+
+    test "#cents returns the cents part with 2 precisions by default" do
+        assert_equal "45", Money.from_amount(123.45, "USD").cents
+    end
+
+    test "#cents returns empty when precision is 0" do
+        assert_equal "", Money.from_amount(123.45, "USD").cents(precision: 0)
+    end
+
+    test "#cents returns the cents part of the string with given precision" do
+        amount = Money.from_amount(123.4862, "USD")
+        assert_equal "4", amount.cents(precision: 1)
+        assert_equal "486", amount.cents(precision: 3)
+    end
+
+    test "#cents pads the cents part with zeros up to the specified precision" do
+        amount_without_decimal = Money.from_amount(123, "USD")
+        amount_with_decimal = Money.from_amount(123.4, "USD")
+
+        assert_equal "00", amount_without_decimal.cents
+        assert_equal "40", amount_with_decimal.cents
+    end
+
+    test "works with BigDecimal" do
+        amount = Money.from_amount(BigDecimal("123.45"), "USD")
+        assert_equal "45", amount.cents
+    end
+end