Visitor creates crank user

app/controllers/crank_users_controller.rb

@@ -0,0 +1,15 @@
+class CrankUsersController < ApplicationController
+  skip_before_action :ensure_admin
+
+  expose(:crank_user, build: -> { CrankUser.new_with_code }, find_by: :code, id: :code)
+
+  def create
+    if crank_user.save
+      flash.notice = "Crank User created"
+      redirect_to crank_user_path(crank_user)
+    else
+      flash.alert = crank_user.errors.full_messages.to_sentence
+      redirect_to new_crank_user_path
+    end
+  end
+end

app/models/crank_user.rb

@@ -0,0 +1,19 @@
+class CrankUser < ApplicationRecord
+  validates :code, presence: true, uniqueness: true
+
+  def self.generate_codes
+    3.times.lazy.map do
+      candidate = SecureRandom.hex(4)
+      candidate unless CrankUser.where(code: candidate).exists?
+    end.compact
+  end
+
+  def self.new_with_code
+    code = generate_codes.first
+    new(code: code)
+  end
+
+  def to_param
+    code
+  end
+end

app/views/crank_users/new.html.haml

@@ -0,0 +1,6 @@
+%h1 Create Crank User
+
+%p Wow you seem like you can really crank - click the create button to get started!
+
+= form_with model: crank_user do |f|
+  = f.button "create"

app/views/crank_users/show.html.haml

@@ -0,0 +1,3 @@
+%h1 Crank User #{crank_user.code}
+
+%p OMG you did it!

config/routes.rb

@@ -24,6 +24,8 @@
 
   resources :gift_ideas, only: %i[update]
 
+  resources :crank_users, only: %i[create new show], param: :code
+
   namespace :crud do
     resources :books, only: %i[create edit new update]
     resources :csv_uploads

db/migrate/20240305034656_create_crank_users.rb

@@ -0,0 +1,10 @@
+class CreateCrankUsers < ActiveRecord::Migration[7.1]
+  def change
+    create_table :crank_users do |t|
+      t.string :code, null: false
+      t.timestamps
+    end
+
+    add_index :crank_users, :code, unique: true
+  end
+end

spec/factories/crank_user.rb

@@ -0,0 +1,5 @@
+FactoryBot.define do
+  factory :crank_user do
+    code { "abcd1234" }
+  end
+end

spec/models/crank_user_spec.rb

@@ -0,0 +1,78 @@
+require "rails_helper"
+
+describe CrankUser do
+  describe ".new_with_code" do
+    let!(:existing_crank_user) do
+      CrankUser.create(code: "existing code")
+    end
+
+    context "unique code on first try" do
+      let(:codes) do
+        [
+          "unique code"
+        ]
+      end
+
+      it "is valid" do
+        expect(SecureRandom).to receive(:hex).with(4).exactly(1).and_return(*codes)
+        crank_user = CrankUser.new_with_code
+
+        expect(crank_user).to be_valid
+        expect(crank_user.code).to eq "unique code"
+      end
+    end
+
+    context "unique code on second try" do
+      let(:codes) do
+        [
+          "existing code",
+          "unique code"
+        ]
+      end
+
+      it "is valid" do
+        expect(SecureRandom).to receive(:hex).with(4).exactly(2).and_return(*codes)
+        crank_user = CrankUser.new_with_code
+
+        expect(crank_user).to be_valid
+        expect(crank_user.code).to eq "unique code"
+      end
+    end
+
+    context "unique code on third try" do
+      let(:codes) do
+        [
+          "existing code",
+          "existing code",
+          "unique code"
+        ]
+      end
+
+      it "is valid" do
+        expect(SecureRandom).to receive(:hex).with(4).exactly(3).and_return(*codes)
+        crank_user = CrankUser.new_with_code
+
+        expect(crank_user).to be_valid
+        expect(crank_user.code).to eq "unique code"
+      end
+    end
+
+    context "fails to find unique code" do
+      let(:codes) do
+        [
+          "existing code",
+          "existing code",
+          "existing code"
+        ]
+      end
+
+      it "is not valid" do
+        expect(SecureRandom).to receive(:hex).with(4).exactly(3).and_return(*codes)
+        crank_user = CrankUser.new_with_code
+
+        expect(crank_user).to_not be_valid
+        expect(crank_user.code).to eq nil
+      end
+    end
+  end
+end

spec/system/crank_users/visitor_creates_crank_user_spec.rb

@@ -0,0 +1,12 @@
+require "rails_helper"
+
+describe "visitor creates crank user" do
+  scenario "create successfully" do
+    visit "/crank_users/new"
+    click_on "create"
+    expect(page).to have_content "Crank User created"
+    crank_user = CrankUser.last
+    expect(page).to have_content crank_user.code
+    expect(page.current_path).to eq crank_user_path(crank_user)
+  end
+end

spec/system/model_counts/admin_views_model_counts_spec.rb

@@ -11,6 +11,7 @@
     expected_rows = [
       "Artwork 0",
       "Book 0",
+      "CrankUser 0",
       "CsvUpload 0",
       "FinancialAccount 0",
       "FinancialStatement 0",
@@ -32,6 +33,7 @@
 
   scenario "with some models" do
     FactoryBot.create(:book)
+    FactoryBot.create(:crank_user)
     FactoryBot.create(:csv_upload)
     FactoryBot.create(:gift_idea)
     FactoryBot.create(:killswitch)
@@ -63,6 +65,7 @@
     expected_rows = [
       "Artwork 1",
       "Book 1",
+      "CrankUser 1",
       "CsvUpload 1",
       "FinancialAccount 1",
       "FinancialStatement 1",
@@ -81,6 +84,6 @@
 
     expect(actual_rows).to match_array(expected_rows)
 
-    expect(page.find("tfoot tr").text).to eq "Total 16"
+    expect(page.find("tfoot tr").text).to eq "Total 17"
   end
 end