From 90c5b26f59b5e7b855d02cb7100c6b4f02eef40d Mon Sep 17 00:00:00 2001
From: Samuel Culley <samuel.culley@digital.cabinet-office.gov.uk>
Date: Thu, 16 Jul 2026 12:09:26 +0100
Subject: [PATCH] Add rake task to retrieve form documents

The task retrieves form documents for a given form based on the provided
form_id, tag and language. One form document is retrieved at a time so
that the output is always limited to a single JSON form document.

If no language is provided, it defaults to using 'en'.
---
 lib/tasks/forms.rake              | 18 ++++++++++
 spec/lib/tasks/forms.rake_spec.rb | 55 +++++++++++++++++++++++++++++++
 2 files changed, 73 insertions(+)

diff --git a/lib/tasks/forms.rake b/lib/tasks/forms.rake
index c49831887..4c580fe8b 100644
--- a/lib/tasks/forms.rake
+++ b/lib/tasks/forms.rake
@@ -174,6 +174,24 @@ namespace :forms do
       Rails.logger.info "Form #{form.id} (\"#{form.name}\") created by #{creator&.name || 'No creator'} with organisation #{creator&.organisation&.name || 'N/A'}"
     end
   end
+
+  desc "Show a form's form_document as JSON"
+  task :show_form_document, %i[form_id tag language] => :environment do |_, args|
+    usage_message = "usage: rake forms:show_form_document[<form_id>, <tag>, <language>]".freeze
+
+    abort usage_message if args[:form_id].blank? || args[:tag].blank?
+    language = args[:language].presence || "en"
+
+    abort "tag must be one of draft, live or archived" unless %w[draft live archived].include?(args[:tag])
+    abort "language must be en or cy" unless %w[en cy].include?(language)
+
+    form = Form.find(args[:form_id])
+
+    form_document = form.form_documents.find_by(tag: args[:tag], language:)
+    abort "#{fmt_form(form)} does not have a #{args[:tag]} #{language} form document" if form_document.blank?
+
+    puts JSON.pretty_generate(form_document.as_json)
+  end
 end
 
 def move_forms(form_ids, group_id)
diff --git a/spec/lib/tasks/forms.rake_spec.rb b/spec/lib/tasks/forms.rake_spec.rb
index 3c778e0cd..81f159299 100644
--- a/spec/lib/tasks/forms.rake_spec.rb
+++ b/spec/lib/tasks/forms.rake_spec.rb
@@ -807,4 +807,59 @@
       end
     end
   end
+
+  describe "forms:show_form_document" do
+    subject(:task) do
+      Rake::Task["forms:show_form_document"]
+    end
+
+    let(:form) { create(:form) }
+
+    it "prints the requested form document as JSON" do
+      expect { task.invoke(form.id, "draft", "en") }
+        .to output(/"id": #{form.draft_form_document.id}/).to_stdout
+    end
+
+    it "prints the requested English form document when no language is given" do
+      expect { task.invoke(form.id, "draft") }
+        .to output(/"id": #{form.draft_form_document.id}/).to_stdout
+    end
+
+    it "aborts with a usage message when arguments are missing" do
+      expect {
+        task.invoke(form.id)
+      }.to raise_error(SystemExit)
+         .and output(/usage: rake forms:show_form_document\[<form_id>, <tag>, <language>\]/).to_stderr
+    end
+
+    it "aborts when the tag is invalid" do
+      expect {
+        task.invoke(form.id, "invalid", "en")
+      }.to raise_error(SystemExit)
+         .and output(/tag must be one of draft, live or archived/).to_stderr
+    end
+
+    it "aborts when the language is invalid" do
+      expect {
+        task.invoke(form.id, "draft", "invalid")
+      }.to raise_error(SystemExit)
+         .and output(/language must be en or cy/).to_stderr
+    end
+
+    it "aborts when the requested form document is missing" do
+      expect {
+        task.invoke(form.id, "draft", "cy")
+      }.to raise_error(SystemExit)
+         .and output(/form #{form.id} \("#{form.name}"\) does not have a draft cy form document/).to_stderr
+    end
+
+    context "when a form has a Welsh translation" do
+      let(:form) { create(:form, :with_welsh_translation) }
+
+      it "prints the requested form document as JSON" do
+        expect { task.invoke(form.id, "draft", "cy") }
+          .to output(/"id": #{form.draft_welsh_form_document.id}/).to_stdout
+      end
+    end
+  end
 end