split login/welcome and added direct link welcome

app/controllers/application_controller.rb

@@ -30,6 +30,6 @@ class ApplicationController < ActionController::Base
     end
 
     def authorize_candidate
-      redirect_to welcome_path unless current_candidate
+      redirect_to login_path unless current_candidate
     end
 end

app/controllers/candidate_controller.rb

@@ -1,5 +1,14 @@
 class CandidateController < ApplicationController
-  before_action :authorize_candidate, except: [:welcome, :validate, :live_coder]
+  before_action :authorize_candidate, except: [:login, :validate, :live_coder]
+  before_action :send_to_oops, only: [:login]
+
+  def login
+    login_candidate
+    redirect_to :thankyou and return if current_candidate && current_candidate.completed?
+    redirect_to :welcome if current_candidate
+
+    flash[:error] = "Sorry, incorrect test id" if params[:test_hash].present?
+  end
 
   def welcome
   end
@@ -7,6 +16,9 @@ class CandidateController < ApplicationController
   def saved
   end
 
+  def oops
+  end
+
   def thankyou
     redirect_to root_path if session[:test_id].nil?
     reset_session
@@ -52,11 +64,22 @@ class CandidateController < ApplicationController
 
     session[:test_id] = candidate.test_hash
     redirect_to :thankyou and return if candidate.completed?
-    redirect_to :question
+    redirect_to :welcome
   end
 
   private
 
+    def login_candidate
+      candidate = Candidate.find_by(test_hash: params['test_id'])
+      return false if candidate.nil?
+
+      session[:test_id] = candidate.test_hash
+    end
+
+    def send_to_oops
+      redirect_to oops_path if current_candidate
+    end
+
     def prep_question qid
       @question = current_candidate.fetch_question(qid)
     end