Adding automatic permalink generation on enterprise creation

app/models/enterprise.rb

@@ -63,6 +63,7 @@ class Enterprise < ActiveRecord::Base
 
   before_save :confirmation_check, if: lambda { email_changed? }
 
+  before_validation :initialize_permalink, if: lambda { permalink.nil? }
   before_validation :ensure_owner_is_manager, if: lambda { owner_id_changed? && !owner_id.nil? }
   before_validation :set_unused_address_fields
   after_validation :geocode_address
@@ -295,6 +296,21 @@ class Enterprise < ActiveRecord::Base
     shipping_methods.any? && payment_methods.available.any?
   end
 
+  def self.find_available_permalink(test_permalink)
+    test_permalink = test_permalink.parameterize
+    existing = Enterprise.select(:permalink).order(:permalink).where("permalink LIKE ?", "#{test_permalink}%").map(&:permalink)
+    if existing.empty?
+      test_permalink
+    else
+      used_indices = existing.map do |p|
+        p.slice!(/^#{test_permalink}/)
+        p.match(/^\d+$/).to_s.to_i
+      end.select{ |p| p }
+      options = (1..existing.length).to_a - used_indices
+      test_permalink + options.first.to_s
+    end
+  end
+
   protected
 
   def devise_mailer
@@ -370,4 +386,8 @@ class Enterprise < ActiveRecord::Base
     # If the permalink has errors, reset it to it's original value, so we can update the form
     self.permalink = permalink_was if permalink_changed? && errors[:permalink].present?
   end
+
+  def initialize_permalink
+    self.permalink = Enterprise.find_available_permalink(name)
+  end
 end

spec/models/enterprise_spec.rb

@@ -802,4 +802,42 @@ describe Enterprise do
       non_producer_sell_none.category.should == :hub_profile
     end
   end
+
+  describe "finding and automatically assigning a permalink" do
+    let(:enterprise) { build(:enterprise, name: "Name To Turn Into A Permalink") }
+    it "assigns permalink when initialized" do
+      allow(Enterprise).to receive(:find_available_permalink).and_return("available_permalink")
+      Enterprise.should_receive(:find_available_permalink).with("Name To Turn Into A Permalink")
+      expect(
+        lambda { enterprise.send(:initialize_permalink) }
+      ).to change{
+        enterprise.permalink
+      }.to(
+        "available_permalink"
+      )
+    end
+
+    describe "finding a permalink" do
+      let!(:enterprise1) { create(:enterprise, permalink: "permalink") }
+      let!(:enterprise2) { create(:enterprise, permalink: "permalink1") }
+
+      it "parameterizes the value provided" do
+        expect(Enterprise.find_available_permalink("Some Unused Permalink")).to eq "some-unused-permalink"
+      end
+
+      it "finds and index value based on existing permalinks" do
+        expect(Enterprise.find_available_permalink("permalink")).to eq "permalink2"
+      end
+
+      it "ignores permalinks with characters after the index value" do
+        create(:enterprise, permalink: "permalink2xxx")
+        expect(Enterprise.find_available_permalink("permalink")).to eq "permalink2"
+      end
+
+      it "finds gaps in the indices of existing permalinks" do
+        create(:enterprise, permalink: "permalink3")
+        expect(Enterprise.find_available_permalink("permalink")).to eq "permalink2"
+      end
+    end
+  end
 end