interface.rb

$products = [
  {
    name: "kiwi",
    price: 5,
    stock: 20
  },
  {
    name: "banane",
    price: 3,
    stock: 3
  },
  {
    name: "orange",
    price: 2,
    stock: 150
  }
]

$cart = []

def display_menu
  puts "---------- INSTACART ----------"
  puts "1. Lister le catalogue"
  puts "2. Ajouter un produit"
  puts "3. Retirer un produit"
  puts "4. Imprimer la facture"
  puts "5. Exit"
end

def list_products
  puts "-" * 30
  $products.each_with_index do |product, index|
    puts "#{index + 1}) #{product[:name]} - #{product[:price]}€ (#{product[:stock]})"
  end
end

def add_product
  print "product index?> "
  product_index = gets.to_i - 1 

  selected_product = $products[product_index].clone
  return puts "Ce produit n'existe pas" unless selected_product

  print "how many?> "
  quantity = gets.to_i

  if quantity > selected_product[:stock]
    quantity = selected_product[:stock]
    puts "On t'a tout mis"
  end
  selected_product[:quantity] = quantity

  selected_product.delete(:stock)
  $cart << selected_product

  $products[product_index][:stock] -= quantity
end

def print_bill
  $cart.each_with_index do |product, index|
    puts "#{index + 1}) #{product[:name]} - #{product[:price]}€ x #{product[:quantity]}"
  end

  total = $cart.reduce(0) do |sum, product|
    sum += product[:quantity] * product[:price]
  end

  puts "TOTAL:...........#{total}€"
end

def remove_product
  print "product index?>"
  product_index = gets.to_i - 1

  $cart.delete_at(product_index)
end

loop do
  display_menu

  print "action?> "
  user_action = gets.to_i

  case user_action
  when 1 then list_products
  when 2 then add_product
  when 3 then remove_product
  when 4 then print_bill
  when 5 then break
  end
end