WIP: Part 2

Continuing to delve into this.

Collected notes in the wiki on GH.

I think I have a better or at least different way to prepend the
mailer_controller preview method for our purposes.

We want to check if the email is going to be delivered by Notify and
render a different preview when that is the case.

The main blocker right now is not having a real Notify account to test
with - we call the api to generate a preview, which is what we want to
show in the Rails preview, but without a real API key I can't get a
handle on that.

lib/mail/notify/delivery_method.rb

@@ -18,9 +18,11 @@ def deliver!(mail)
       end
 
       def preview(mail)
+        debugger
         personalisation = Personalisation.new(mail).to_h
         template_id = mail[:template_id].to_s
-        client.generate_template_preview(template_id, personalisation: personalisation)
+        #client.generate_template_preview(template_id, personalisation: personalisation)
+        OpenStruct.new(html: "<h1>Hej!</h1>")
       end
 
       private

lib/mail/notify/mailers_controller.rb

@@ -4,16 +4,26 @@ module Mail
   module Notify
     module MailersController
       def preview
-        @email_action = File.basename(params[:path])
-        return super unless @preview.email_exists?(@email_action)
 
+        # this methods overides the built in one
+        # https://www.rubydoc.info/docs/rails/Rails/MailersController#preview-instance_method
+        #
+        # what kind of mailer is trying to be previewed
+        # if it is a Notify one, we need to do something different
+        @email_action = File.basename(params[:path])
         @email = @preview.call(@email_action, params)
 
-        return super unless notify?
-
-        return render_part if params[:part]
-
-        render_preview_wrapper
+        if @email.delivery_method.is_a?(Mail::Notify::DeliveryMethod)
+          # because we have two types, a view or template, we have to do different
+          # things
+          debugger
+          response.content_type = "text/html"
+          debugger
+          @part = @email.find_first_mime_type(:html)
+        render action: "email", layout: false, formats: %i[html]
+        else
+          super
+        end
       end
 
       private
@@ -23,8 +33,6 @@ def render_part
         # the `govuk_notify_layout` layout
         append_view_path(__dir__)
 
-        response.content_type = "text/html"
-        render html: @email.preview.html.html_safe, layout: "govuk_notify_layout"
       end
 
       def render_preview_wrapper

lib/mail/notify/rails/mailers/notify_email.html.erb

@@ -0,0 +1 @@
+My Email

lib/mail/notify/railtie.rb

@@ -8,6 +8,12 @@ class Railtie < Rails::Engine
       initializer "mail-notify.add_delivery_method", before: "action_mailer.set_configs" do
         ActionMailer::Base.add_delivery_method(:notify, Mail::Notify::DeliveryMethod)
       end
+
+      initializer "mail-notify.action_controller" do
+        ActiveSupport.on_load(:action_controller, run_once: true) do
+          Rails::MailersController.prepend(Mail::Notify::MailersController)
+        end
+      end
     end
   end
 end