Fix short agent description parsing

We used to use the first line of agent description in the agent
selection cards verbatim (as html_safe).

Agent description (being markdown) can start with peculiar things:
headers, paragraphs, images, links and even html comments. When you
include it in the template as html_safe it breaks everything down the
page.

Now we find the first paragraph or header (h1, h2 or h3) and include its
text stripped of any formatting.

Author: Vidas P

app/helpers/agent_helper.rb

@@ -82,20 +82,26 @@ def agent_type_icon(agent, agents)
     end
   end
 
-  def agent_type_select_options
-    Rails.cache.fetch('agent_type_select_options') do
-      [['Select an Agent Type', 'Agent', { title: '' }]] + Agent.types.map { |type| [agent_type_to_human(type), type, { title: h(Agent.build_for_type(type.name, User.new(id: 0), {}).html_description.lines.first.strip) }] }
-    end
+  def agent_short_description(agent)
+    html = agent.html_description
+    doc = Nokogiri::HTML::Document.parse(html)
+    text = doc.xpath('(//*[self::h1 or self::h2 or self::h3 or self::p])[1]/descendant-or-self::*/text()').to_s
+    return 'No description' if text.blank?
+    text
   end
+  module_function :agent_short_description
 
   def agent_types
-    Agent.types.map do |type|
-      agent = Agent.build_for_type(type.name, User.new(id: 0), {})
-      {
-        type: type,
-        name: agent_type_to_human(type),
-        description: agent.html_description
-      }
+    Rails.cache.fetch('agent_types') do
+      Agent.types.map do |type|
+        agent = Agent.build_for_type(type.name, User.new(id: 0), {})
+        {
+          type: type,
+          name: agent_type_to_human(type),
+          short_description: agent_short_description(agent),
+          description: agent.html_description
+        }
+      end
     end
   end
 

app/views/agents/_form.html.erb

@@ -31,7 +31,7 @@
               <%= type[:name] %>
             </div>
             <div class="card-body d-flex flex-column">
-              <%= type[:description].lines.first.html_safe %>
+              <p><%= type[:short_description] %></p>
               <button class="btn btn-primary select_agent_type align-self-end mt-auto"
                       data-type="<%= type[:type] %>"
                       data-name="<%= type[:name] %>">Create</button>

spec/helpers/agent_helper_spec.rb

@@ -0,0 +1,45 @@
+require 'rails_helper'
+
+describe AgentHelper do
+  describe '#agent_short_description' do
+    subject(:short_description) do
+      AgentHelper.agent_short_description(agent)
+    end
+
+    let(:agent) do
+      Agent.new.tap do |a|
+        stub(a).description { description }
+      end
+    end
+
+    context 'when description is simple text' do
+      let(:description) { 'Good!' }
+      it { is_expected.to eq 'Good!' }
+    end
+
+    context 'When description is multi paragraph text' do
+      let(:description) { "Good!\n\nLong text." }
+      it { is_expected.to eq 'Good!' }
+    end
+
+    context 'When description starts with header' do
+      let(:description) { "# Good!\n\nLong text." }
+      it { is_expected.to eq 'Good!' }
+    end
+
+    context 'When description starts with h2' do
+      let(:description) { "## Good!\n\nLong text." }
+      it { is_expected.to eq 'Good!' }
+    end
+
+    context 'When description starts with a comment' do
+      let(:description) { "<!-- Comment -->\nGood!" }
+      it { is_expected.to eq 'Good!' }
+    end
+
+    context 'When description includes formatting/subtags' do
+      let(:description) { "Good `agent` **here**!" }
+      it { is_expected.to eq 'Good agent here!' }
+    end
+  end
+end