Add main program file. Save product details to database. Implement show basket.

Author: John Ollier

.gitignore

@@ -1,3 +1,5 @@
 .idea
 .rspec
 .DS_Store
+/supermarket.db
+*.db

Lib/basket.rb

@@ -8,40 +8,82 @@ def initialize(catalogue)
     @catalogue.products_by_code.each_key { |p_code| @purchases[p_code] = 0 }
   end
 
-  def show_basket
-    # #{@basket} will call to_s method of Basket
+  def show
+    # #{@basket} will call to_s method of Basket - that's good for debugging, but not user friendly.
+    message_lines = Array.new
+    @purchases.each do |code, quantity|
+      if quantity > 0
+        product = @catalogue.products_by_code[code]
+        price = product.price * quantity
+        message_lines << checkout_line(product.name, quantity, price)
+      end
+    end
+    message_lines << total_line(total)
+    message_lines
   end
 
   def total
     running_total = 0
     @purchases.each do |code, quantity|
       running_total = running_total + quantity * @catalogue.products_by_code[code].price
     end
-    return running_total
+    running_total
   end
 
   # give our parameter a descriptive name
   def add(product_code)
     # what if the user passes a non existant product code
     if @purchases.key?(product_code)
       @purchases[product_code] = @purchases[product_code] + 1
+      product = @catalogue.products_by_code[product_code]
+      return add_line(product.name, product.price)
     else
-      # TODO can do better than this
-      print("Error: no product with code: #{product_code}")
+      return "Error: no product with code: #{product_code}"
     end
   end
 
   def remove(product_code)
     if @purchases.key?(product_code)
       if purchases[product_code] > 0
         purchases[product_code] = purchases[product_code] - 1
+        product = @catalogue.products_by_code[product_code]
+        return removed_line(product.name)
       else
-        print("Warning: no product with code #{product_code} in basket")
+        return "Warning: no product with code #{product_code} in basket"
       end
     else
-      # TODO can do better than this
-      print("Error: no product with code: #{product_code}")
+      return "Error: no product with code: #{product_code} in catalogue"
+    end
+  end
+
+  private
+
+  def format_price(price_in_p)
+    price_in_pounds = price_in_p / 100.0
+    if price_in_p % 10 == 0
+      price_in_pounds.to_s + '0'
+    else
+      price_in_pounds.to_s
     end
   end
 
+  def checkout_line(name, quantity, price)
+    price_in_pounds = format_price(price)
+    "#{quantity} x #{name} £#{price_in_pounds}"
+  end
+
+  def add_line(name, price)
+    price_in_pounds = format_price(price)
+    "Added #{name} £#{price_in_pounds}"
+  end
+
+  def removed_line(name)
+    "Removed #{name}"
+  end
+
+  def total_line(total_pence)
+    total = format_price(total_pence)
+    "Total #{total}"
+  end
+
 end

Lib/catalogue.rb

@@ -1,14 +1,31 @@
-require 'product'
+require 'sqlite3'
+require_relative 'product'
 
 class Catalogue
 
   attr_reader :products_by_code
 
-  def initialize()
-    fruit_tea = Product.new('FR1','Fruit Tea', 311)
-    strawberries = Product.new('SR1','Strawberries', 500)
-    coffee = Product.new('CF1','Coffee', 1123)
-    @products_by_code = {'FR1' => fruit_tea, 'SR1' => strawberries, 'CF1' => coffee}
+  def initialize(db)
+
+      product_table = db.get_first_value "SELECT name FROM sqlite_master WHERE type='table' AND name='product';"
+
+      if product_table
+        @products_by_code = {}
+        product_results = db.execute "SELECT code, name, price FROM product;"
+        product_results.each do |result|
+          @products_by_code[result[0]] = Product.new(result[0], result[1], result[2])
+        end
+      else
+        fruit_tea = Product.new('FR1', 'Fruit Tea', 311)
+        strawberries = Product.new('SR1', 'Strawberries', 500)
+        coffee = Product.new('CF1', 'Coffee', 1123)
+        @products_by_code = {'FR1' => fruit_tea, 'SR1' => strawberries, 'CF1' => coffee}
+        db.execute "CREATE TABLE IF NOT EXISTS product (code VARCHAR PRIMARY KEY, name VARCHAR NOT NULL, price INT NOT NULL);"
+        @products_by_code.each do |product_code, product|
+          db.execute "INSERT INTO product VALUES ('#{product_code}','#{product.name}', #{product.price.to_i} );"
+        end
+
+      end
   end
 
 end

Lib/main.rb

@@ -1,12 +1,40 @@
-puts "Welcome to the GDS supermarket"
+require './basket'
+require './catalogue'
 
-finish = false
+def print_message(lines)
+  lines.each { |line| puts line }
+end
+
+begin
+  db = SQLite3::Database.new 'supermarket.db'
+
+  puts "Welcome to the GDS supermarket"
+
+  finish = false
+
+  catalogue = Catalogue.new(db)
+  basket = Basket.new(catalogue)
+
+  while !finish
+    puts "Please enter command from: add [product code], remove [product_code], checkout"
+    command = gets.strip
+    if command == 'checkout'
+      puts basket.show
+      finish = true
+    elsif command =~ /add \w{3}/
+      product_code = command.split(" ")[1]
+      puts basket.add(product_code)
+    elsif command =~ /remove \w{3}/
+      product_code = command.split(" ")[1]
+      puts basket.remove(product_code)
+    else
+      puts "You did not enter a valid command!"
+    end
 
-while !finish
-  puts "Please enter command"
-  command = gets
-  if command == 'checkout':
-    finish = true
   end
 
+rescue SQLite3::Exception => e
+  puts e
+ensure
+  db.close if db
 end

Spec/basket_spec.rb

@@ -1,8 +1,21 @@
 require 'basket'
 require 'catalogue'
 
+# here's a simple mock class, but for anything more complex use a mocking framework
+class MockDB
+  def execute(s)
+    # do nothing
+  end
+
+  def get_first_value(s)
+    nil
+  end
+end
+
+db = MockDB.new
+
 describe Basket do
-  catalogue = Catalogue.new
+  catalogue = Catalogue.new(db)
   describe '#initialize' do
     it "is empty initially" do
       basket = Basket.new(catalogue)
@@ -59,5 +72,16 @@
       expect(basket.total).to eq(1745)
     end
   end
+  describe '#show' do
+    it "will show product names and quantities" do
+      basket = Basket.new(catalogue)
+      basket.add("FR1")
+      basket.add("FR1")
+      basket.add("CF1")
+      message = basket.show
+      expect(message[0]).to eq("2 x Fruit Tea £6.22")
+      expect(message[1]).to eq("1 x Coffee £11.23")
+    end
+  end
 end
 

Spec/catalogue_spec.rb

@@ -1,9 +1,21 @@
 require 'catalogue'
 
+class MockDB
+  def execute(s)
+    # do nothing
+  end
+
+  def get_first_value(s)
+    return nil
+  end
+end
+
+db = MockDB.new
+
 describe Catalogue do
   describe '#initialize' do
     it "has all products" do
-      catalogue = Catalogue.new
+      catalogue = Catalogue.new(db)
       # when testing methods test the data not a formatted message containing the data
       expect(catalogue.products_by_code['FR1'].code).to eq('FR1')
     end

readme.md

@@ -0,0 +1,10 @@
+## Supermarket checkout
+
+We now need a database. You should install sqlite and the ruby driver for it.
+
+    brew install sqlite
+
+    gem install sqlite3
+    
+
+