Vfrdtyky

I'm writing a quiz app with rails 5. I have got a multi-step form for question building.

Models:

class Mcq < ApplicationRecord

  attr_accessor :option_count

  has_many :options, dependent: :destroy

  belongs_to :quiz



  accepts_nested_attributes_for :options

  validates :question_text, presence: true

end



class Option < ApplicationRecord

  belongs_to :mcq, optional: true

  validates :option_text, presence: true

end

Schema:

create_table "mcqs", force: :cascade do |t|

  t.string   "question_text"

  t.boolean  "required"

  t.boolean  "multiselect"

  t.integer  "quiz_id"

  t.datetime "created_at",    null: false

  t.datetime "updated_at",    null: false

end





create_table "options", force: :cascade do |t|

  t.string   "option_text"

  t.integer  "mcq_id"

  t.datetime "created_at",  null: false

  t.datetime "updated_at",  null: false

end

The first page is for question setup and has the following fields:

1. Option Count


2. Required (Yes / No)


3. No of options that can be selected (Single / Multiple)

The second page is for options and has the following fields:

1. Question Text


2. Nested Form for Options

Controller:

class McqsController < ApplicationController

  def new

    session[:current_step] ||= 'setup'

    session[:mcq_params] ||= {}



    @current_step = session[:current_step]

    @quiz = Quiz.find(params[:quiz_id])

    @mcq = Mcq.new(session[:mcq_params])



    if session[:current_step] == 'options'

      @option_count = session[:mcq_params]['option_count']

      @option_count.times { @mcq.options.build }

    end

  end



  def create

    if params[:previous_button]

      session[:current_step] = 'setup'

      redirect_to new_quiz_mcq_path

    elsif session[:current_step] == 'setup'

      save_session(params[:mcq])

      redirect_to new_quiz_mcq_path

    elsif session[:current_step] == 'options'

      @mcq = Mcq.new(whitelisted_mcq_params)

      @mcq.quiz_id = params[:quiz_id]

      @quiz = Quiz.find(params[:quiz_id])

      if @mcq.save

        session[:current_step] = session[:mcq_params] = nil

        redirect_to quiz_new_question_path(@mcq.quiz_id)

      else

        @current_step = session[:current_step]

        render :new

      end

    end

  end



  private



  def whitelisted_mcq_params

    params.require(:mcq)

        .permit(:question_text, :multiselect, :required,    options_attributes: [:option_text])

  end



  def save_session(mcq_params)

     session[:mcq_params][:option_count] = mcq_params[:option_count].to_i

     session[:mcq_params][:required] = mcq_params[:required]

     session[:mcq_params][:multiselect] = mcq_params[:multiselect]

     session[:current_step] = 'options'

  end

end

The above solution works, but the code is messy and difficult to understand. I came across this railscasts episode which does something similar in a cleaner way. I've updated my code as follows:

class Mcq < ApplicationRecord

  has_many :options, dependent: :destroy

  belongs_to :quiz



  attr_writer :current_step

  attr_accessor :option_count



  accepts_nested_attributes_for :options

  validates :question_text, presence: true



  def current_step

    @current_step || steps.first

  end



  def steps

    %w[setup options]

  end



  def next_step

    self.current_step = steps[steps.index(current_step)+1]

  end



  def previous_step

    self.current_step = steps[steps.index(current_step)-1]

  end



  def last_step?

    current_step == steps.last

  end

end



class McqsController < ApplicationController

  def new

    session[:mcq_params] ||= {}

    @quiz = Quiz.find(params[:quiz_id])

    @mcq = Mcq.new(session[:mcq_params])

    @mcq.current_step = session[:mcq_step]

  end



  def create

    @quiz = Quiz.find(params[:quiz_id])

    session[:mcq_params].deep_merge!(params[:mcq]) if params[:mcq]

    @mcq = Mcq.new(session[:mcq_params])



    @option_count = session[:mcq_params]['option_count']

    @option_count.times { @mcq.options.build }



    @mcq.quiz_id = params[:quiz_id]

    @mcq.current_step = session[:mcq_step]



    if params[:previous_button]

      @mcq.previous_step

    elsif @mcq.last_step?

      @mcq.save if @mcq.valid?

    else

      @mcq.next_step

    end

    session[:mcq_step] = @mcq.current_step



    if @mcq.new_record?

      render "new"

    else

      session[:mcq_step] = session[:mcq_params] = nil

      redirect_to edit_quiz_path(@mcq.quiz_id)

    end

  end

end

But each time the second page is shown, the no of fields for options doubles or in case of invalid entry only the field for question_text is shown. How do I show the options correctly? Should I just go with my first solution? I'm new to rails and don't know much about the best practices.

Edited :

new.html.erb

<div class="sub-heading">Add a Multiple Choice Question:</div>



<%= render "mcq_#{@mcq.current_step}", quiz: @quiz, mcq: @mcq %>

_mcq_setup.html.erb

<div class="form-container">

  <%= form_for [quiz, mcq] do |f| %>



    <div class="form-row">

      <div class="response-count">How many options should the question have?</div>

      <%= f.select(:option_count, (2..5)) %>

    </div>



    <div class="form-row">

      <div class="response-count">How many options can be selected?</div>



      <div class="option">

        <%= f.radio_button :multiselect, 'false', checked: true %>

        <%= f.label :multiselect, 'Just One', value: 'false' %>

      </div>



      <div class="option">

        <%= f.radio_button :multiselect, 'true' %>

        <%= f.label :multiselect, 'Multiple', value: 'true' %>

      </div>

    </div>



    <div class="form-row">

      <div class="response-count">Is the question required?</div>



      <div class="option">

        <%= f.radio_button :required, 'true', checked: true %>

        <%= f.label :required, 'Yes', value: 'true' %>

      </div>



      <div class="option">

        <%= f.radio_button :required, 'false' %>

        <%= f.label :required, 'No', value: 'false' %>

      </div>



    </div>

    <%= f.submit "Continue to the Next Step" %>

  <% end %>

</div>

_mcq_options.html.erb

<%= form_for [quiz, mcq] do |f| %>



  <%= f.label :question_text, 'What is your question?' %>

  <%= f.text_field :question_text %>



  <%= f.fields_for :options do |option_fields| %>

    <%= option_fields.label :option_text, "Option #{option_fields.options[:child_index] + 1}:" %>

    <%= option_fields.text_field :option_text %>

  <% end %>



  <%= f.hidden_field :multiselect %>

  <%= f.hidden_field :required %>



  <%= f.submit "Add Question" %>

  <%= f.submit "Back to previous step", name: 'previous_button' %>

<% end %>

You may look in direction of state_machine. By using that you can use your steps as states of state machine and use its ability to define validations that only active for given states (look here in state :first_gear, :second_gear do) so fields that required on second step will be not required on first. Also, it'll allow you to avoid complex checks for the step you currently on (because the state will be persisted in a model) and will be pretty easy to extend with more steps in a future.