extract checkout/checking functionality

resolves #1608

--create manage route for managing users' reservations
--extract checkin/checkout functionality to manage controller
--extract as much functionality to checkoutHelper service object as possible

--replace set_reservation before action with ||=

--put repeated before_action into application controller

Author: zeffman

app/controllers/application_controller.rb

@@ -143,6 +143,13 @@ def skip_authentication?
       .include?(params[:action]) && !guests_disabled?)
   end
 
+  def set_user
+    @user = User.find(params[:user_id])
+    return unless @user.role == 'banned'
+    flash[:error] = 'This user is banned and cannot check out equipment.'
+    params[:banned] = true
+  end
+
   #-------- end before_filter methods --------#
 
   def update_cart # rubocop:disable MethodLength, AbcSize

app/controllers/manage_controller.rb

@@ -0,0 +1,165 @@
+# frozen_string_literal: true
+# rubocop:disable ClassLength
+class ManageController < ApplicationController
+  load_and_authorize_resource
+  before_action :set_user, only: [:show, :checkout]
+  before_action :set_reservation, only: [:send_receipt]
+
+  private
+
+  def set_reservation
+    @reservation = Reservation.find(params[:receipt_id])
+  end
+
+  def check_for_banned_user
+    if @user.role == 'banned'
+      flash[:error] = 'Banned users cannot check out equipment.'
+      redirect_to(root_path) && return
+    end
+    true
+  end
+
+  def check_terms_of_service
+    unless @user.terms_of_service_accepted ||
+           params[:terms_of_service_accepted].present?
+      flash[:error] = 'You must confirm that the user accepts the Terms of '\
+        'Service.'
+      redirect_to(:back) && return
+    end
+    true
+  end
+
+  def handle_overdue_reservations
+    if @user.overdue_reservations?
+      if can? :override, :checkout_errors
+        # Admins can ignore this
+        flash[:notice] = 'Admin Override: Equipment has been checked out '\
+          'successfully, even though the reserver has overdue equipment.'
+      else
+        # Everyone else is redirected
+        flash[:error] = 'Could not check out the equipment, because the '\
+          'reserver has reservations that are overdue.'
+        redirect_to(:back) && return
+      end
+    end
+    true
+  end
+
+  def approve_checkout
+    # check for banned user
+    return unless check_for_banned_user
+
+    # check terms of service
+    return unless check_terms_of_service
+
+    # Overdue validation
+    return unless handle_overdue_reservations
+    true
+  end
+
+  def check_nonemptiness_of(checked_out_reservations)
+    if checked_out_reservations.empty?
+      flash[:error] = 'No reservation selected.'
+      redirect_to(:back) && return
+    end
+    true
+  end
+
+  def check_validity_of(checked_in_reservations)
+    unless checked_in_reservations
+      flash[:error] = 'One of the items you tried to check in has already '\
+        'been checked in.'
+      redirect_to(:back) && return
+    end
+    true
+  end
+
+  def check_uniqueness_of(checked_out_reservations)
+    unless Reservation.unique_equipment_items?(checked_out_reservations)
+      flash[:error] = 'The same equipment item cannot be simultaneously '\
+        'checked out in multiple reservations.'
+      redirect_to(:back) && return
+    end
+    true
+  end
+
+  def prep_receipt_page(check_in_set:, check_out_set:, user: nil)
+    @check_in_set = check_in_set
+    @check_out_set = check_out_set
+    @user = user if user
+    render('receipt', layout: 'application_with_search_sidebar') && return
+  end
+
+  public
+
+  def show # initializer
+    @check_out_set = @user.due_for_checkout.includes(:equipment_model)
+    @check_in_set = @user.due_for_checkin.includes(:equipment_model)
+
+    render :show, layout: 'application'
+  end
+
+  def checkout
+    return unless approve_checkout
+
+    checked_out_reservations =
+      CheckoutHelper.preprocess_checkout(params[:reservations],
+                                         @user, current_user)
+
+    return unless check_nonemptiness_of(checked_out_reservations)
+    return unless check_uniqueness_of(checked_out_reservations)
+
+    ## Save reservations
+    Reservation.transaction do
+      begin
+        checked_out_reservations.each do |r|
+          CheckoutHelper.checkout_reservation(r, params[:reservations])
+        end
+      rescue ActiveRecord::RecordNotSaved, ActiveRecord::RecordInvalid => e
+        flash[:error] = "Checking out your reservation failed: #{e.message}"
+        redirect_to manage_reservations_for_user_path(@user)
+        raise ActiveRecord::Rollback
+      end
+    end
+
+    CheckoutHelper.update_tos(@user)
+    CheckoutHelper.send_checkout_receipts(checked_out_reservations)
+    prep_receipt_page(check_in_set: [], check_out_set: checked_out_reservations)
+  end
+
+  def checkin
+    # see comments for checkout, this method proceeds in a similar way
+    checked_in_reservations =
+      CheckoutHelper.preproccess_checkins(params[:reservations], current_user)
+
+    return unless check_validity_of(checked_in_reservations)
+
+    return unless check_nonemptiness_of(checked_in_reservations)
+    ## Save reservations
+    Reservation.transaction do
+      begin
+        checked_in_reservations.each do |r|
+          CheckoutHelper.checkin_reservation(r, params[:reservations])
+        end
+      rescue ActiveRecord::RecordNotSaved, ActiveRecord::RecordInvalid => e
+        flash[:error] = "Checking in your reservation failed: #{e.message}"
+        redirect_to :back
+        raise ActiveRecord::Rollback
+      end
+    end
+
+    prep_receipt_page(check_in_set: checked_in_reservations, check_out_set: [],
+                      user: checked_in_reservations.first.reserver)
+  end
+
+  def send_receipt
+    if UserMailer.reservation_status_update(@reservation, 'checked out')
+                 .deliver_now
+      flash[:notice] = 'Successfully delivered receipt email.'
+    else
+      flash[:error] = 'Unable to deliver receipt email. Please contact '\
+        'administrator for more support.'
+    end
+    redirect_to @reservation
+  end
+end