port_stock.rb

# == Schema Information
#
# Table name: port_stocks
#
#  id                :bigint(8)        not null, primary key
#  portfolio_id      :integer
#  stock_id          :integer
#  volume            :integer
#  transaction_price :float
#  current_price     :float
#  percent_change    :float
#  created_at        :datetime         not null
#  updated_at        :datetime         not null
#  current_value     :float
#  dollar_change     :float
#  total_spend       :float
#  transaction_date  :datetime
#  action            :integer
#  position          :integer          default("open")
#  ticker            :string
#  slug              :string
#

class PortStock < ApplicationRecord
  extend FriendlyId
  friendly_id :slug_candidates, use: :slugged

  belongs_to :portfolio
  belongs_to :stock
  has_many :closed_positions, dependent: :destroy
  accepts_nested_attributes_for :closed_positions, allow_destroy: true
  has_many :order_histories, dependent: :destroy

  enum action: [ :buy, :sell ]
  enum position: [ :open, :closed ]

  before_save :calculate_percent_change
  before_save :calculate_dollar_change
  before_save :calculate_current_value
  before_save :calculate_total_spend
  after_save :calculate_portfolio_initial_dollar_value
  after_save :calculate_portfolio_num_winners
  after_save :calculate_portfolio_num_losers
  after_save :update_portfolio_current_dollar_value
  after_save :update_portfolio_initial_dollar_value, if: (:total_spend_previously_changed? || :volume_previously_changed?)
  after_save :calculate_portfolio_percent_change
  after_save :calculate_portfolio_dollar_change

  after_destroy :update_portfolio_values_on_delete

  def slug_candidates
    [
      :ticker,
      [:ticker, :volume],
      [:ticker, :volume, :transaction_price],
      [:ticker, :volume, :transaction_price, :created_at]
    ]
  end

  def calculate_percent_change
    self.percent_change = ((self.current_price - self.transaction_price)/self.transaction_price)*100
  end

  def calculate_dollar_change
    self.dollar_change = (self.current_price - self.transaction_price) * self.volume
  end

  def calculate_current_value
    self.current_value = self.current_price * self.volume
  end

  def calculate_total_spend
    self.total_spend = self.transaction_price * self.volume
  end

# ========= Update Associated Portfolio Values

  def calculate_portfolio_num_winners
    self.portfolio.num_winners = self.portfolio.port_stocks.open.where("percent_change > 0").count
    self.portfolio.save!
  end

  def calculate_portfolio_num_losers
    self.portfolio.num_losers = self.portfolio.port_stocks.open.where("percent_change < 0").count
    self.portfolio.save!
  end

  def update_portfolio_current_dollar_value
    self.portfolio.current_dollar_value = self.portfolio.port_stocks.open.map(&:current_value).sum
    self.portfolio.save!
  end

  def update_portfolio_initial_dollar_value
    self.portfolio.initial_dollar_value = self.portfolio.port_stocks.open.map { |ps| ps.volume * ps.transaction_price }.sum
    self.portfolio.save!
  end

  def update_portfolio_values_on_delete
    if self.portfolio.port_stocks.open.count > 0
      self.portfolio.current_dollar_value = self.portfolio.port_stocks.open.map(&:current_value).sum
      self.portfolio.initial_dollar_value = self.portfolio.port_stocks.open.map { |ps| ps.volume * ps.transaction_price }.sum
      self.portfolio.dollar_change = self.portfolio.current_dollar_value - self.portfolio.initial_dollar_value
      self.portfolio.percent_change = ((self.portfolio.current_dollar_value - self.portfolio.initial_dollar_value)/self.portfolio.initial_dollar_value)*100
      self.portfolio.num_winners, self.portfolio.num_losers = self.portfolio.port_stocks.open.where("percent_change > 0").count, self.portfolio.port_stocks.open.where("percent_change < 0").count
      self.portfolio.save!
    else
      self.portfolio.current_dollar_value, self.portfolio.initial_dollar_value, self.portfolio.dollar_change, self.portfolio.percent_change = 0.0, 0.0, 0.0, 0.0
      self.portfolio.num_winners, self.portfolio.num_losers = 0, 0
      self.portfolio.save!
    end
  end

  def calculate_portfolio_initial_dollar_value
    if self.portfolio.initial_dollar_value.nil?
      self.portfolio.initial_dollar_value = 0.0
    end
    self.portfolio.initial_dollar_value += (self.transaction_price * self.volume)
    self.portfolio.save!
  end

  def calculate_portfolio_percent_change
    self.portfolio.percent_change = ((self.portfolio.current_dollar_value - self.portfolio.initial_dollar_value)/self.portfolio.initial_dollar_value)*100
    self.portfolio.save!
  end

  def calculate_portfolio_dollar_change
    self.portfolio.dollar_change = self.portfolio.current_dollar_value - self.portfolio.initial_dollar_value
    self.portfolio.save!
  end

end

port_stock_spec.rb

# == Schema Information
#
# Table name: port_stocks
#
#  id                :bigint(8)        not null, primary key
#  portfolio_id      :integer
#  stock_id          :integer
#  volume            :integer
#  transaction_price :float
#  current_price     :float
#  percent_change    :float
#  created_at        :datetime         not null
#  updated_at        :datetime         not null
#  current_value     :float
#  dollar_change     :float
#  total_spend       :float
#  transaction_date  :datetime
#  action            :integer
#  position          :integer          default("open")
#  ticker            :string
#  slug              :string
#

require 'rails_helper'

RSpec.describe PortStock, type: :model do
  let(:stock) { create(:stock, price: 10.00) }
  let(:portfolio) { create(:portfolio) }
  let(:port_stock_1) { create(:port_stock, stock: stock, portfolio: portfolio, transaction_price: stock.price, action: :buy, volume: 100) }

  context "associations" do
    it { should belong_to(:portfolio) }
    it { should belong_to (:stock) }
  end

  context "methods" do
    it "should accurately calculate the positive percent_change of the current PortStock" do
      port_stock_1.current_price = 20.00
      expect(port_stock_1.calculate_percent_change).to eql 100.00
    end

    it "should accurately calculate the negative percent_change of the current PortStock" do
      port_stock_1.current_price = 5.00
      expect(port_stock_1.calculate_percent_change).to eql(-50.00)
    end

    it "should accurately calculate the positive dollar_change of the current PortStock" do
      port_stock_1.current_price = 15.00
      port_stock_1.volume = 1000
      expect(port_stock_1.calculate_dollar_change).to eql 5000.00
    end

    it "should accurately calculate the negative dollar_change of the current PortStock" do
      port_stock_1.current_price = 5.00
      port_stock_1.volume = 1000
      expect(port_stock_1.calculate_dollar_change).to eql (-5000.00)
    end

    it "should accurately calculate the current_value of the PortStock when the price increases" do
      port_stock_1.current_price = 15.00
      port_stock_1.volume = 1000
      expect(port_stock_1.calculate_current_value).to eql 15000.00
    end

    it "should accurately calculate the negative current_value of the PortStock when the price decreases" do
      port_stock_1.current_price = 5.00
      port_stock_1.volume = 1000
      expect(port_stock_1.calculate_current_value).to eql 5000.00
    end

    it "should accurately calculate the total_spend of the current PortStock on original purchase" do
      expect(port_stock_1.calculate_total_spend).to eql 1000.00
    end

    it "should accurately calculate the portfolio's initial_dollar_value" do
      binding.pry
      expect(portfolio.initial_dollar_value).to eql 1000.00
    end


    it "should accurately calculate the portfolio's number of winners"
    it "should accurately calculate the portfolio's number of losers"
    it "should accurately update the portfolio's current_dollar_value"
    it "should accurately update the portfolio's initial_dollar_value"
    it "should accurately calculate the portfolio's percent_change"
    it "should accurately calculate the portfolio's dollar_change"
    it "should accurately update all portfolio values when PortStock is deleted"
  end

  context "callbacks" do
    it "should accurately calculate the percent_change of the current PortStock BEFORE SAVING"
    it "should accurately calculate the dollar_change of the current PortStock BEFORE SAVING"
    it "should accurately calculate the current_value of the current PortStock BEFORE SAVING"
    it "should accurately calculate the total_spend of the current PortStock BEFORE SAVING"
    it "should accurately calculate the portfolio's initial_dollar_value AFTER SAVING"
    it "should accurately calculate the portfolio's number of winners AFTER SAVING"
    it "should accurately calculate the portfolio's number of losers AFTER SAVING"
    it "should accurately update the portfolio's current_dollar_value AFTER SAVING"
    it "should accurately update the portfolio's initial_dollar_value AFTER SAVING"
    it "should accurately calculate the portfolio's percent_change AFTER SAVING"
    it "should accurately calculate the portfolio's dollar_change AFTER SAVING"
    it "should accurately update all portfolio values when PortStock is deleted"
  end

end