#297 Running JavaScript in Ruby pro

class Member < ActiveRecord::Base
  validate :check_membership_number
  
  def check_membership_number
    source = File.read(Rails.root.join("app/assets/javascripts/membership_number.js"))
    context = ExecJS.compile(source)
    unless context.call("isValidMembershipNumber", membership_number)
      errors.add :membership_number, "is an invalid number"
    end
  end
end

gem 'therubyracer', require: 'v8'

c = V8::Context.new
c.eval('1 + 2')
c[:num] = 3
c.eval('num * num')
c.eval('math = {square: function(n) { return n*n }}')
c[:math].square(5)
c[:square] = lambda { |n| n*n }
c.eval('square(4)')

<%= render "product", :mustache => product.for_mustache %>

def for_mustache
  Thread.current[:product_v8] ||= V8::Context.new.tap do |context|
    coffee = File.read(Rails.root.join("app/assets/javascripts/product.js.coffee"))
    javascript = CoffeeScript.compile(coffee)
    context.eval(javascript)
  end
  Thread.current[:product_v8].eval("new Product(#{to_json})")
end

product = new Product(product_attributes)

class Product
  constructor: (@attributes) ->
  id: -> @attributes.id
  name: -> @attributes.name

  price: ->
    digits = String(Math.round(@attributes.price * 100)).split("").reverse()
    formatted = [digits.shift(), digits.shift(), "."]
    for digit, index in digits
      formatted.push(digit)
      if (index+1) % 3 == 0 && index+1 < digits.length
        formatted.push(",")
    "$" + formatted.reverse().join("")

  released_at: ->
    months = ["January", "February", "March", "April", "May", "June", "July", "August", "September", "October", "November", "December"]
    date = new Date(@attributes.released_at)
    day = date.getDate()
    month = months[date.getMonth()]
    year = date.getFullYear()
    "#{month} #{day}, #{year}"

@Product = Product