for using ActiveAdmin v4 without node/yarn on Rails 7

active_admin.rake

namespace :active_admin do
  COMMAND = [
    Rails.root.join("bin/tailwindcss").to_s,
    "-i", Rails.root.join("app/assets/stylesheets/active_admin.css").to_s,
    "-o", Rails.root.join("app/assets/builds/active_admin.css").to_s,
    "-c", Rails.root.join("config/tailwind-active_admin.config.js").to_s,
    "-m" # minify
  ]

  desc "Build Active Admin Tailwind stylesheets"
  task build: :environment do
    system(*COMMAND, exception: true)
  end

  desc "Watch Active Admin Tailwind stylesheets"
  task watch: :environment do
    command = COMMAND.push("--watch")
    system(*command)
  end
end

Rake::Task["assets:precompile"].enhance(["active_admin:build"])

Rake::Task["test:prepare"].enhance(["active_admin:build"]) if Rake::Task.task_defined?("test:prepare")
Rake::Task["spec:prepare"].enhance(["tailwindcss:build"]) if Rake::Task.task_defined?("spec:prepare")
Rake::Task["db:test:prepare"].enhance(["tailwindcss:build"]) if Rake::Task.task_defined?("db:test:prepare")