#403 Dynamic Forms pro

rails g scaffold ProductType name --skip-stylesheets
rails g model ProductField name field_type required:boolean product_type:belongs_to
rails g migration add_type_to_products product_type_id:integer properties:text
rake db:migrate

class ProductType < ActiveRecord::Base
  attr_accessible :name, :fields_attributes
  has_many :fields, class_name: "ProductField"
  accepts_nested_attributes_for :fields, allow_destroy: true
end

class Product < ActiveRecord::Base
  attr_accessible :name, :price, :product_type_id, :properties
  belongs_to :product_type
  serialize :properties, Hash
  
  validate :validate_properties
  
  def validate_properties
    product_type.fields.each do |field|
      if field.required? && properties[field.name].blank?
        errors.add field.name, "must not be blank"
      end
    end
  end
end

<%= f.fields_for :fields do |builder| %>
  <%= render 'field_fields', f: builder %>
<% end %>
<%= link_to_add_fields "Add Field", f, :fields %>

<fieldset>
  <%= f.select :field_type, %w[text_field check_box shirt_sizes] %>
  <%= f.text_field :name, placeholder: "field_name" %>
  <%= f.check_box :required %> <%= f.label :required %>
  <%= f.hidden_field :_destroy %>
  <%= link_to "remove", '#', class: "remove_fields" %>
</fieldset>

<%= form_tag new_product_path, method: :get do %>
  <%= select_tag :product_type_id, options_from_collection_for_select(ProductType.all, :id, :name) %>
  <%= submit_tag "New Product", name: nil %>
<% end %>

def new
  @product = Product.new(product_type_id: params[:product_type_id])
end

<%= f.hidden_field :product_type_id %>

<%= f.fields_for :properties, OpenStruct.new(@product.properties) do |builder| %>
  <% @product.product_type.fields.each do |field| %>
    <%= render "products/fields/#{field.field_type}", field: field, f: builder %>
  <% end %>
<% end %>

<div class="field">
  <%= f.label field.name %><br />
  <%= f.text_field field.name %>
</div>

<div class="field">
  <%= f.check_box field.name %>
  <%= f.label field.name %>
</div>

<div class="field">
  <%= f.label field.name %><br />
  <%= f.select field.name, %w[S M L XL], {}, {multiple: true} %>
</div>

module ApplicationHelper
  def link_to_add_fields(name, f, association)
    new_object = f.object.send(association).klass.new
    id = new_object.object_id
    fields = f.fields_for(association, new_object, child_index: id) do |builder|
      render(association.to_s.singularize + "_fields", f: builder)
    end
    link_to(name, '#', class: "add_fields", data: {id: id, fields: fields.gsub("\n", "")})
  end
end

$(document).on 'click', 'form .remove_fields', (event) ->
  $(this).prev('input[type=hidden]').val('1')
  $(this).closest('fieldset').hide()
  event.preventDefault()

$(document).on 'click', 'form .add_fields', (event) ->
  time = new Date().getTime()
  regexp = new RegExp($(this).data('id'), 'g')
  $(this).before($(this).data('fields').replace(regexp, time))
  event.preventDefault()