One login account recovery feature

When going live with one login, a candidate can sign up with a different
email address, not the magic link email address.

For this, we need to allow our candidates to recover their 'old'
account. This commit adds this feature.

We show a banner which the candidate can dismiss or they can click to
recover their old account. They will be asked to input their old email
and a code will be sent to their email. The code is encrypted with
bcrypt.

.erb_lint.yml

@@ -2,6 +2,9 @@
 EnableDefaultLinters: true
 exclude:
   - '**/node_modules/**/*'
+  - 'app/views/candidate_interface/account_recovery/new.html.erb'
+  - 'app/views/candidate_interface/application_choices/index.html.erb'
+  - 'app/views/candidate_interface/shared/_details.html.erb'
 linters:
   Rubocop:
     enabled: true

app/controllers/candidate_interface/account_recovery_controller.rb

@@ -0,0 +1,46 @@
+module CandidateInterface
+  class AccountRecoveryController < CandidateInterfaceController
+    before_action :check_if_user_recovered
+    before_action :check_if_user_has_account_recovery_request
+
+    def new
+      @account_recovery = CandidateInterface::AccountRecoveryForm.new(current_candidate:)
+    end
+
+    def create
+      @account_recovery = CandidateInterface::AccountRecoveryForm.new(
+        current_candidate:,
+        code: permitted_params[:code],
+      )
+
+      if @account_recovery.call
+        terminate_session
+        start_new_session_for(
+          candidate: @account_recovery.old_candidate,
+          id_token_hint: @account_recovery.id_token_hint,
+        )
+
+        flash[:success] = I18n.t('.authentication.successful_account_recovery_html')
+        redirect_to candidate_interface_interstitial_path
+      else
+        render :new
+      end
+    end
+
+  private
+
+    def permitted_params
+      strip_whitespace(
+        params.require(:candidate_interface_account_recovery_form).permit(:code),
+      )
+    end
+
+    def check_if_user_recovered
+      redirect_to candidate_interface_details_path if current_candidate.account_recovery_status_recovered?
+    end
+
+    def check_if_user_has_account_recovery_request
+      redirect_to candidate_interface_details_path if current_candidate.account_recovery_request.nil?
+    end
+  end
+end

app/controllers/candidate_interface/account_recovery_requests_controller.rb

@@ -0,0 +1,37 @@
+module CandidateInterface
+  class AccountRecoveryRequestsController < CandidateInterfaceController
+    before_action :check_if_user_recovered
+
+    def new
+      @account_recovery_request = CandidateInterface::AccountRecoveryRequestForm
+        .build_from_candidate(current_candidate)
+    end
+
+    def create
+      @account_recovery_request = CandidateInterface::AccountRecoveryRequestForm.new(
+        current_candidate:,
+        previous_account_email_address: permitted_params[:previous_account_email_address],
+      )
+
+      if @account_recovery_request.save_and_email_candidate
+        redirect_to candidate_interface_account_recovery_new_path
+      else
+        render :new
+      end
+    end
+
+  private
+
+    def permitted_params
+      strip_whitespace(
+        params.require(:candidate_interface_account_recovery_request_form).permit(
+          :previous_account_email_address,
+        ),
+      )
+    end
+
+    def check_if_user_recovered
+      redirect_to candidate_interface_details_path if current_candidate.account_recovery_status_recovered?
+    end
+  end
+end

app/controllers/candidate_interface/dismiss_account_recovery_controller.rb

@@ -0,0 +1,8 @@
+module CandidateInterface
+  class DismissAccountRecoveryController < CandidateInterfaceController
+    def create
+      current_candidate.account_recovery_status_dismissed!
+      redirect_to candidate_interface_details_path
+    end
+  end
+end

app/controllers/concerns/authentication.rb

@@ -53,6 +53,7 @@ def start_new_session_for(candidate:, id_token_hint: nil)
 
   def terminate_session
     Current.session&.destroy
+    Current.session = nil
     cookies.delete(:session_id)
     reset_session
   end

app/forms/candidate_interface/account_recovery_form.rb

@@ -0,0 +1,54 @@
+module CandidateInterface
+  class AccountRecoveryForm
+    include ActiveModel::Model
+
+    attr_accessor :code
+    attr_reader :valid_account_recovery_request, :current_candidate, :old_candidate, :id_token_hint
+
+    validates :code, presence: true
+    validates :code, numericality: { only_integer: true }, length: { is: 6 }
+
+    validate :account_recovery, unless: -> { valid_account_recovery_request && old_candidate }
+    validate :previous_account_has_no_one_login, if: -> { valid_account_recovery_request && old_candidate }
+
+    def initialize(current_candidate:, code: nil)
+      self.code = code
+      @current_candidate = current_candidate
+      @id_token_hint = current_candidate.sessions.last.id_token_hint
+    end
+
+    def call
+      valid_request_code = current_candidate.account_recovery_request.codes.not_expired.find do |requested_code|
+        requested_code.authenticate_code(code)
+      end
+
+      @valid_account_recovery_request = valid_request_code&.account_recovery_request
+      @old_candidate = Candidate.find_by(email_address: valid_account_recovery_request&.previous_account_email_address)
+
+      return false unless valid?
+
+      ActiveRecord::Base.transaction do
+        old_candidate.account_recovery_status_recovered!
+        current_candidate.one_login_auth.update!(candidate: old_candidate)
+        current_candidate.reload
+        current_candidate.destroy!
+      end
+    end
+
+    def requested_new_code?
+      current_candidate.account_recovery_request.codes.not_expired.count > 1
+    end
+
+  private
+
+    def account_recovery
+      errors.add(:code, :invalid)
+    end
+
+    def previous_account_has_no_one_login
+      if old_candidate.one_login_auth.present?
+        errors.add(:code, :one_login_already_present)
+      end
+    end
+  end
+end

app/forms/candidate_interface/account_recovery_request_form.rb

@@ -0,0 +1,60 @@
+module CandidateInterface
+  class AccountRecoveryRequestForm
+    include ActiveModel::Model
+
+    attr_accessor :previous_account_email_address
+    attr_reader :current_candidate, :previous_candidate
+
+    validates :previous_account_email_address, presence: true, format: { with: URI::MailTo::EMAIL_REGEXP }
+    validate :email_different_from_current_candidate, if: -> { previous_candidate.present? }
+
+    def initialize(current_candidate:, previous_account_email_address: nil)
+      self.previous_account_email_address = previous_account_email_address&.downcase&.strip
+      @current_candidate = current_candidate
+    end
+
+    def self.build_from_candidate(candidate)
+      new(
+        current_candidate: candidate,
+        previous_account_email_address: candidate.account_recovery_request&.previous_account_email_address,
+      )
+    end
+
+    def save_and_email_candidate
+      @previous_candidate = Candidate.find_by(email_address: previous_account_email_address)
+      return false unless valid?
+
+      ActiveRecord::Base.transaction do
+        account_recovery_request = find_or_create_account_recovery_request
+
+        account_recovery_request_code = account_recovery_request.codes.create(
+          code: AccountRecoveryRequestCode.generate_code,
+        )
+
+        if Candidate.find_by(email_address: previous_account_email_address).present?
+          AccountRecoveryMailer.send_code(
+            email: previous_account_email_address,
+            code: account_recovery_request_code.code,
+          ).deliver_later
+        else
+          true # We still want the user to progress to the next page
+        end
+      end
+    end
+
+  private
+
+    def find_or_create_account_recovery_request
+      AccountRecoveryRequest.find_by(
+        candidate: current_candidate,
+        previous_account_email_address:,
+      ) || current_candidate.create_account_recovery_request(previous_account_email_address:)
+    end
+
+    def email_different_from_current_candidate
+      if current_candidate.email_address == previous_account_email_address
+        errors.add(:previous_account_email_address, :email_same_as_current_candidate)
+      end
+    end
+  end
+end

app/frontend/styles/_button.scss

@@ -0,0 +1,15 @@
+.govuk-link-button {
+  padding: 0;
+
+  font-size: inherit;
+  color: $govuk-link-colour;
+
+  cursor: pointer;
+
+  background: none;
+  border: none;
+}
+
+form:has(.govuk-link-button) {
+  display: contents;
+}

app/frontend/styles/application.scss

@@ -52,6 +52,7 @@ $govuk-new-link-styles: true;
 @import "autocomplete";
 @import "banner";
 @import "box";
+@import "button";
 @import "notification_banner";
 @import "card";
 @import "conditions-list";

app/mailers/account_recovery_mailer.rb

@@ -0,0 +1,14 @@
+class AccountRecoveryMailer < ApplicationMailer
+  helper UtmLinkHelper
+
+  def send_code(email:, code:)
+    @code = code
+    @account_recovery_url = candidate_interface_account_recovery_new_url
+
+    mailer_options = {
+      to: email,
+      subject: t('.subject'),
+    }
+    notify_email(mailer_options)
+  end
+end

app/models/account_recovery_request.rb

@@ -1,4 +1,6 @@
 class AccountRecoveryRequest < ApplicationRecord
   belongs_to :candidate
-  has_many :account_recovery_request_codes, dependent: :destroy
+  has_many :codes, class_name: 'AccountRecoveryRequestCode', dependent: :destroy
+
+  normalizes :previous_account_email_address, with: ->(email) { email.downcase.strip }
 end

app/models/account_recovery_request_code.rb

@@ -1,3 +1,12 @@
 class AccountRecoveryRequestCode < ApplicationRecord
   belongs_to :account_recovery_request
+  has_secure_password :code, validations: false
+
+  validates :code, presence: true
+
+  scope :not_expired, -> { where('created_at >= ?', 1.hour.ago) }
+
+  def self.generate_code
+    Array.new(6) { rand(0..9) }.join
+  end
 end

app/models/candidate.rb

@@ -27,6 +27,12 @@ class Candidate < ApplicationRecord
 
   PUBLISHED_FIELDS = %w[email_address].freeze
 
+  enum :account_recovery_status, {
+    not_started: 'not_started',
+    recovered: 'recovered',
+    dismissed: 'dismissed',
+  }, prefix: true
+
   after_create do
     update!(candidate_api_updated_at: Time.zone.now)
   end
@@ -37,6 +43,8 @@ class Candidate < ApplicationRecord
     end
   end
 
+  delegate :previous_account_email_address, to: :account_recovery_request, allow_nil: true
+
   def touch_application_choices_and_forms
     return unless application_choices.any?
 

app/presenters/candidate_interface/application_form_presenter.rb

@@ -340,6 +340,12 @@ def can_submit_more_applications?
         CycleTimetable.can_add_course_choice?(application_form) # The apply deadline for this form has not passed
     end
 
+    def show_account_recovery_banner?
+      return false if OneLogin.bypass?
+
+      application_form.candidate.account_recovery_status_not_started? && !submitted_applications?
+    end
+
   private
 
     def show_review_volunteering?

app/views/account_recovery_mailer/send_code.text.erb

@@ -0,0 +1,9 @@
+Hello
+
+You requested a code to get your details back in Apply for teacher training.
+
+^<%= @code %>
+
+Enter this code in [Apply for teacher training](<%= @account_recovery_url %>). It will expire in 1 hour.
+
+If you did not request a code you can ignore this email.

app/views/candidate_interface/account_recovery/new.html.erb

@@ -0,0 +1,40 @@
+<% page_title = if @account_recovery.requested_new_code?
+                  I18n.t('page_titles.account_recovery_resend_email', email: current_candidate.previous_account_email_address)
+                else
+                  I18n.t('page_titles.account_recovery', email: current_candidate.previous_account_email_address)
+                end %>
+
+<% content_for :title, page_title %>
+<% content_for :before_content do %>
+  <%= govuk_back_link(
+    text: 'Back',
+    href: new_candidate_interface_account_recovery_request_path,
+  ) %>
+<% end %>
+
+<h1 class="govuk-heading-l">
+  <%= page_title %>
+</h1>
+
+<div class="govuk-grid-row">
+  <div class="govuk-grid-column-two-thirds">
+    <%= form_with model: @account_recovery, url: candidate_interface_account_recovery_create_path do |f| %>
+      <%= f.govuk_error_summary %>
+      <%= f.govuk_text_field :code, label: { text: t('.form.code.label'), size: 'm' }, width: 20 %>
+
+      <%= f.govuk_submit %>
+    <% end %>
+
+    <%= button_to(
+      t('.form.request_a_new_code'),
+      candidate_interface_account_recovery_requests_path(
+        params: {
+          candidate_interface_account_recovery_request_form: {
+            previous_account_email_address: current_candidate.previous_account_email_address,
+          },
+        },
+      ),
+      class: 'govuk-link govuk-link-button',
+    ) %>
+  </div>
+</div>