hacketyhack · coreypurcell · Nov 2, 2011 · Nov 2, 2011
diff --git a/app/models/program.rb b/app/models/program.rb
@@ -8,6 +8,15 @@ class Program
 
   scope :by_username,  lambda { |username| where(:author_username => username) }
 
+  before_create :make_slug
+
+  def make_slug
+    unless slug
+      all_slugs = Program.where(:author_username => author_username).map(&:slug)
+      self.slug = Sluggifier.generate(title)
+    end
+  end
+
   def to_param
     slug
   end

diff --git a/lib/sluggifier.rb b/lib/sluggifier.rb
@@ -0,0 +1,24 @@
+class Sluggifier
+  def self.generate(title, all_slugs=[])
+    slug = title.parameterize
+    while self.conflict?(slug,all_slugs)
+      slug = self.next(slug, all_slugs)
+    end
+    slug
+  end
+
+  def self.next(slug,all_slugs)
+    sequence = self.conflict(slug,all_slugs).split('-')[1].to_i
+    next_sequence = sequence == 0 ? 2 : sequence.next
+    "#{slug.gsub(/(\-\d+)/,'')}-#{next_sequence}"
+  end
+
+  def self.conflict?(slug,all_slugs)
+    !! self.conflict(slug,all_slugs)
+  end
+
+  def self.conflict(slug, all_slugs)
+    all_slugs.select { |s| s == slug }.first
+  end
+
+end
diff --git a/spec/unit/sluggifier_spec.rb b/spec/unit/sluggifier_spec.rb
@@ -0,0 +1,28 @@
+# encoding: utf-8
+
+require 'active_support/all'
+require_relative '../../lib/sluggifier'
+
+describe Sluggifier do
+  describe '.generate' do
+    it "makes a slug from a title" do
+      Sluggifier.generate('test a slug').should == 'test-a-slug'
+    end
+
+
+    context "doesn't allow multiple slugs to be the same" do
+        let(:all_slugs) { ['test'] }
+
+      it "appends a one if there is one repeated slug" do
+        Sluggifier.generate('test',all_slugs).should == 'test-2'
+      end
+
+      it "appends the next sequential number for repeats" do
+        all_slugs << 'test-2'
+        Sluggifier.generate('test',all_slugs).should == 'test-3'
+      end
+    end
+  end
+
+
+end