From f9f8638a599591f1a646f1df873414b1c35fe816 Mon Sep 17 00:00:00 2001
From: Alex Evanczuk <alexevanczuk@gmail.com>
Date: Thu, 21 Oct 2021 17:00:26 -0400
Subject: [PATCH] generate binstub along with other commands

---
 lib/packwerk.rb                            |  1 +
 lib/packwerk/cli.rb                        |  3 +-
 lib/packwerk/generators/binstub.rb         | 42 ++++++++++++++++++++++
 lib/packwerk/generators/templates/packwerk | 21 +++++++++++
 test/unit/generators/binstub_test.rb       | 36 +++++++++++++++++++
 5 files changed, 102 insertions(+), 1 deletion(-)
 create mode 100644 lib/packwerk/generators/binstub.rb
 create mode 100644 lib/packwerk/generators/templates/packwerk
 create mode 100644 test/unit/generators/binstub_test.rb

diff --git a/lib/packwerk.rb b/lib/packwerk.rb
index 89c439979..769251fc4 100644
--- a/lib/packwerk.rb
+++ b/lib/packwerk.rb
@@ -73,6 +73,7 @@ module Generators
     autoload :ConfigurationFile
     autoload :InflectionsFile
     autoload :RootPackage
+    autoload :Binstub
   end
 
   module ReferenceChecking
diff --git a/lib/packwerk/cli.rb b/lib/packwerk/cli.rb
index 1d5fa6d49..ade013a30 100644
--- a/lib/packwerk/cli.rb
+++ b/lib/packwerk/cli.rb
@@ -92,8 +92,9 @@ def generate_configs
       )
       inflections_file = Packwerk::Generators::InflectionsFile.generate(root: @configuration.root_path, out: @out)
       root_package = Packwerk::Generators::RootPackage.generate(root: @configuration.root_path, out: @out)
+      binstub = Packwerk::Generators::Binstub.generate(root: @configuration.root_path, out: @out)
 
-      success = configuration_file && inflections_file && root_package
+      success = configuration_file && inflections_file && root_package && binstub
 
       result = if success
         <<~EOS
diff --git a/lib/packwerk/generators/binstub.rb b/lib/packwerk/generators/binstub.rb
new file mode 100644
index 000000000..7db3fb00e
--- /dev/null
+++ b/lib/packwerk/generators/binstub.rb
@@ -0,0 +1,42 @@
+# typed: true
+# frozen_string_literal: true
+
+module Packwerk
+  module Generators
+    class Binstub
+      class << self
+        def generate(root: ".", out: $stdout)
+          new(root, out: out).generate
+        end
+      end
+
+      def initialize(root, out: $stdout)
+        @root = root
+        @out = out
+      end
+
+      def generate
+        @out.puts("📦 Generating binstub...")
+        generate_packwerk_validate_script
+      end
+
+      private
+
+      def generate_packwerk_validate_script
+        destination_file_path = File.join(@root, "bin")
+        FileUtils.mkdir_p(destination_file_path)
+
+        if File.exist?(File.join(destination_file_path, "packwerk"))
+          @out.puts("⚠️  Packwerk binstub already exists.")
+          return true
+        end
+
+        source_file_path = File.expand_path("templates/packwerk", __dir__)
+        FileUtils.cp(source_file_path, destination_file_path)
+
+        @out.puts("✅ Packwerk binstub generated in #{destination_file_path}")
+        true
+      end
+    end
+  end
+end
diff --git a/lib/packwerk/generators/templates/packwerk b/lib/packwerk/generators/templates/packwerk
new file mode 100644
index 000000000..dfd517c0c
--- /dev/null
+++ b/lib/packwerk/generators/templates/packwerk
@@ -0,0 +1,21 @@
+#!/usr/bin/env ruby
+# frozen_string_literal: true
+
+# This file was auto-generated by Packwerk through `packwerk init`
+
+# Needs to be run in test environment in order to have test helper paths available in the autoload paths
+ENV["RAILS_ENV"] = "test"
+
+# Command line arguments needs to be duplicated because spring modifies it
+packwerk_argv = ARGV.dup
+
+begin
+  load(File.expand_path("spring", __dir__))
+rescue LoadError => e
+  raise unless e.message.include?("spring")
+end
+
+require "packwerk"
+
+cli = Packwerk::Cli.new
+cli.run(packwerk_argv)
diff --git a/test/unit/generators/binstub_test.rb b/test/unit/generators/binstub_test.rb
new file mode 100644
index 000000000..c5f7cc0c2
--- /dev/null
+++ b/test/unit/generators/binstub_test.rb
@@ -0,0 +1,36 @@
+# typed: false
+# frozen_string_literal: true
+
+require "test_helper"
+
+module Packwerk
+  module Generators
+    class BinstubTest < Minitest::Test
+      setup do
+        @string_io = StringIO.new
+        @temp_dir = Dir.mktmpdir
+        FileUtils.mkdir_p(Pathname.new(@temp_dir).join("bin"))
+        @generated_file_path = File.join(@temp_dir, "bin", "packwerk")
+      end
+
+      teardown do
+        FileUtils.remove_entry(@temp_dir)
+      end
+
+      test ".generate creates a bin/packwerk file" do
+        success = Packwerk::Generators::Binstub.generate(root: @temp_dir, out: @string_io)
+        assert(File.exist?(@generated_file_path))
+        assert success
+        assert_includes @string_io.string, "binstub generated"
+      end
+
+      test ".generate does not create a bin/packwerk file if bin/packwerk already exists" do
+        File.open(File.join(@temp_dir, "bin/packwerk"), "w") do |_f|
+          success = Packwerk::Generators::Binstub.generate(root: @temp_dir, out: @string_io)
+          assert success
+          assert_includes @string_io.string, "binstub already exists"
+        end
+      end
+    end
+  end
+end