Rails 3 array - add items with category then list items in category - arrays

Question

As part of my Rails 3 app, I want the User to be able to click on links on other profiles/pages and have the string value of the link be added to an array belonging to that User's profile.
Specifically, what I am looking to do is populate a list of :todos for each profile depending on which todo they click. The idea is that each todo will fall within one of two categories: inside and outside. So clicking the links will push the value of the todo to either inside or outside. Then the User's profile will display a list of :todos inside and outside, and count the total of todos for that User's profile.
Since I'm a beginner to programming, I got some help here on SO about setting this up; however I need some help finishing it. I can't quite seem to connect all the dots. I've set up a join model but am not able to add the todo's string value, then list/count it in the profile. Here is my code:
profile.rb Model:
class Profile < ActiveRecord::Base
belongs_to :user
accepts_nested_attributes_for :user
has_many :profile_todos
has_many :todos, :through => :profile_todos
def add_todo_inside_item(item)
self.profile_todos.build :category => 'inside'
end
def add_todo_outside_item(item)
self.profile_todos.build :category => 'outside'
end
end
todo.rb Model:
class Todo < ActiveRecord::Base
belongs_to :profile
end
profile_todo.rb Model:
class ProfileTodo < ActiveRecord::Base
belongs_to :profile
belongs_to :todo
end
_create_todos.rb Migration:
class CreateTodos < ActiveRecord::Migration
def self.up
create_table :todos do |t|
t.string :name
t.timestamps
end
end
_create_profile_todos.rb Migration:
class CreateProfileTodos < ActiveRecord::Migration
def self.up
create_table :profile_todos do |t|
t.string :category
t.integer :profile_id
t.timestamps
end
end
Listing the todos in a User's Profile:
<div id="todos">
<p><%= #profile.first_name %> has <%= pluralize(#profile.profile_todos.count, 'goal') %>.</p>
<div id="todo-list">
<div class="todos_inside">
<p><%= #profile.profile_todos(:category => 'inside' %>.</p>
</div>
<div class="todos_outside">
<p><%= #profile.profile_todos(:category => 'outside' %>.</p>
</div>
</div>
</div>
add_item to #profile.todos:
<li><%= link_to "#", :class => 'button white' do %><%= #user.profile.stringtoadd %><% end %></li>

Answer 1

As #socjopata mentioned, you're going to need some sort of controller action to manage the creation and building of your ProfileTodo records. Since you already created a ProfileTodo join model, go ahead and create a ProfileTodosController.
More on controllers:
http://guides.rubyonrails.org/action_controller_overview.html
Your link_to tag should then make a remote call to the create action. In order to get everything to work properly, you'd most likely need to supply the controller with both the profile_id and topic_id in order to make the correct RESTful transaction, which means you'll have to supply a parameter hash to your link_to tag, which can get kinda messy if you use the url_options.
Look at passing in url_options:
http://api.rubyonrails.org/classes/ActionView/Helpers/UrlHelper.html#method-i-link_to
Ultimately, you are creating a new ProfileTodo record, so I think it would be a better description of the work being done if you used a form_for tag that has hidden fields for the profile_id and the topic_id. You can also make forms remote in rails by supplying them with :remote => true
Assuming you make an accompanying controller and add RESTful resources to your config/routes.rb file, your form for each individual topic would look something like this:
<%= form_for(profile_todo_path, :remote=> true) do |f| %>
<%= f.hidden_field_tag :profile_id, :value => #user.profile.id %>
<%= f.hidden_field_tag :topic_id, :value => topic.id %>
<%= f.submit_tag topic.name %>
<% end %>
You can always style your forms, so if you only want a link to be displayed, that should be doable :)

Answer 2

You rather need a remote link pointing to some action, so you can manipulate your todos without refreshing the page. From the docs:
:remote => true - This will allow the unobtrusive JavaScript driver to
make an Ajax request to the URL in question instead of following the
link. The drivers each provide mechanisms for listening for the
completion of the Ajax request and performing JavaScript operations
once they’re complete
As for the other question, you can define scopes you'll use for displaying and counting objects:
http://api.rubyonrails.org/classes/ActiveRecord/NamedScope/ClassMethods.html