introduce preview; wire up list of previews and prompts

Gemfile

@@ -13,4 +13,4 @@ gem "sprockets-rails"
 gem "rubocop-rails-omakase", require: false
 
 # Start debugger with binding.b [https://github.com/ruby/debug]
-# gem "debug", ">= 1.0.0"
+gem "debug"

Gemfile.lock

@@ -85,6 +85,9 @@ GEM
     connection_pool (2.4.1)
     crass (1.0.6)
     date (3.3.4)
+    debug (1.9.2)
+      irb (~> 1.10)
+      reline (>= 0.3.8)
     drb (2.2.1)
     erubi (1.13.0)
     globalid (1.2.1)
@@ -266,6 +269,7 @@ PLATFORMS
 
 DEPENDENCIES
   action_prompt!
+  debug
   puma
   rubocop-rails-omakase
   sprockets-rails

app/controllers/action_prompt/previews_controller.rb

@@ -4,7 +4,7 @@ class ActionPrompt::PreviewsController < Rails::ApplicationController
 
   def index
     @page_title = "Action Prompt Previews"
-    @previews = []
+    @previews = ActionPrompt::Preview.all
   end
 
   def show

app/views/action_prompt/previews/index.html.erb

@@ -1,13 +1,11 @@
-<h1><%= @page_title %></h1>
+<h1>Action Prompt Previews</h1>
 
 <% if @previews.any? %>
   <% @previews.each do |preview| %>
-  <h3><%= link_to preview.preview_name.titleize, url_for(controller: "rails/mailers", action: "preview", path: preview.preview_name) %></h3>
-  <ul>
-  <% preview.emails.each do |email| %>
-  <li><%= link_to email, url_for(controller: "rails/mailers", action: "preview", path: "#{preview.preview_name}/#{email}") %></li>
-  <% end %>
-  </ul>
+    <h3><%= preview.preview_name %></h3>
+    <% preview.prompts.each do |prompt| %>
+      <p><%= link_to prompt, "/action_prompt/preview/#{prompt}" %></p>
+    <% end %>
   <% end %>
 <% else %>
   <p>You have not defined any Action Prompt Previews.</p>

lib/action_prompt.rb

@@ -1,7 +1,7 @@
 require "action_prompt/version"
 require "action_prompt/engine"
 require "action_prompt/railtie"
-
+require "action_prompt/preview"
 module ActionPrompt
   def self.render(template_name, locals: {})
     controller = ApplicationController.new

lib/action_prompt/preview.rb

@@ -0,0 +1,33 @@
+require "active_support/descendants_tracker"
+
+module ActionPrompt
+  class Preview
+    # We need to be able to do the following:
+    # - find all the preview objects
+    # - find all the preview methods on those objects
+    # - render a preview
+    #
+    class << self
+      def all
+        load_previews if descendants.empty?
+        descendants.sort_by(&:name)
+      end
+
+      def load_previews
+        # TODO: this preview path could be made configurable in order to have equivalent
+        # functionality to Rails mailer previews
+        Dir[Rails.root.join("test", "prompts", "**", "*_preview.rb")].each do |path|
+          require path
+        end
+      end
+
+      def preview_name
+        name.delete_suffix("Preview").underscore
+      end
+
+      def prompts
+        public_instance_methods(false).map(&:to_s).sort
+      end
+    end
+  end
+end

lib/action_prompt/railtie.rb

@@ -5,8 +5,8 @@ class Railtie < Rails::Railtie
     config.after_initialize do |app|
       if Rails.env.development? || Rails.env.test?
         app.routes.prepend do
-          get "/action_prompt/previews", to: "action_prompt/previews#index", internal: true
-          get "/action_prompt/preview/:prompt_id", to: "action_prompt/previews#show", internal: true
+          get "/action_prompt/previews", to: "action_prompt/previews#index" # , internal: true
+          get "/action_prompt/preview/:prompt", to: "action_prompt/previews#show" # , internal: true
         end
       end
     end

test/action_prompt/preview_test.rb

@@ -0,0 +1,14 @@
+require "test_helper"
+
+class ActionPrompt::PreviewTest < ActiveSupport::TestCase
+  test "all" do
+    previews =  ActionPrompt::Preview.all
+    assert_equal 1, previews.count
+  end
+
+  test "preview_name" do
+    preview = ActionPrompt::Preview.all.first
+
+    assert_equal "hello_world", preview.preview_name
+  end
+end

test/dummy/test/prompts/hello_world_preview.rb

@@ -0,0 +1,9 @@
+class HelloWorldPreview < ActionPrompt::Preview
+  def hello_world
+    ActivePrompt.render("hello_world")
+  end
+
+  def hello_somebody
+    ActivePrompt.render("hello_somebody", locals: { name: "Lenny" })
+  end
+end