add a compiler for flag shih tzu

Author: stathis-alexander

Gemfile

@@ -11,6 +11,7 @@ group :development do
   gem "minitest-reporters"
 
   gem "attr_json"
+  gem "flag_shih_tzu"
   gem "kaminari-activerecord"
   gem "money-rails"
   gem "paperclip"

Gemfile.lock

@@ -93,6 +93,7 @@ GEM
     date (3.3.4)
     drb (2.2.1)
     erubi (1.13.1)
+    flag_shih_tzu (0.3.23)
     globalid (1.2.1)
       activesupport (>= 6.1)
     i18n (1.14.6)
@@ -292,6 +293,7 @@ PLATFORMS
 DEPENDENCIES
   attr_json
   boba!
+  flag_shih_tzu
   kaminari-activerecord
   minitest
   minitest-hooks

lib/tapioca/dsl/compilers/flag_shih_tzu.rb

@@ -0,0 +1,118 @@
+# typed: strict
+# frozen_string_literal: true
+
+return unless defined?(FlagShihTzu)
+
+module Tapioca
+  module Dsl
+    module Compilers
+      # `Tapioca::Dsl::Compilers::FlagShihTzu` decorates RBI files for models
+      # using FlagShihTzu.
+      #
+      # For example, with FlagShihTzu installed and the following `ActiveRecord::Base` subclass:
+      #
+      # ~~~rb
+      # class Post < ApplicationRecord
+      #   has_flags(
+      #     1 => :published,
+      #     2 => :deleted,
+      #   )
+      # end
+      # ~~~
+      #
+      # This compiler will produce the RBI file `post.rbi` with the following content:
+      #
+      # ~~~rbi
+      # # post.rbi
+      # # typed: true
+      # class Post
+      #   include FlagShihTzu
+      #   include FlagShihTzuGeneratedMethods
+      #
+      #   module FlagShihTzuGeneratedMethods
+      #     sig { returns(T::Boolean) }
+      #     def published; end
+      #     sig { params(value: T::Boolean).returns(T::Boolean) }
+      #     def published=(value); end
+      #     sig { returns(T::Boolean) }
+      #     def published?; end
+      #
+      #     sig { returns(T::Boolean) }
+      #     def deleted; end
+      #     sig { params(value: T::Boolean).returns(T::Boolean) }
+      #     def deleted=(value); end
+      #     sig { returns(T::Boolean) }
+      #     def deleted?; end
+      #   end
+      # end
+      # ~~~
+      class FlagShihTzu < Tapioca::Dsl::Compiler
+        extend T::Sig
+
+        ConstantType = type_member { { fixed: T.all(T.class_of(::FlagShihTzu), ::FlagShihTzu::GeneratedClassMethods) } }
+
+        InstanceMethodsModuleName = "FlagShihTzuGeneratedMethods"
+        ClassMethodsModuleName = "::FlagShihTzu"
+
+        class << self
+          extend T::Sig
+
+          sig { override.returns(T::Enumerable[Module]) }
+          def gather_constants
+            all_classes.select { |c| c < ::FlagShihTzu }
+          end
+        end
+
+        sig { override.void }
+        def decorate
+          return if constant.flag_mapping.blank?
+
+          root.create_path(constant) do |klass|
+            instance_module = RBI::Module.new(InstanceMethodsModuleName)
+
+            # has_flags(
+            #   1 => :warpdrive,
+            #   2 => shields,
+            #   column: 'features',
+            # )
+            constant.flag_mapping.each do |_, flags|
+              # column: 'features', flags: { warpdrive: ..., shields: ... }
+              flags.each do |flag_key, _|
+                # .warpdrive
+                # .warpdrive=
+                # .warpdrive?
+                # .warpdrive_changed?
+                instance_module.create_method(flag_key.to_s, return_type: "T::Boolean")
+                instance_module.create_method(
+                  "#{flag_key}=",
+                  parameters: [create_param("value", type: "T::Boolean")],
+                  return_type: "T::Boolean",
+                )
+                instance_module.create_method("#{flag_key}?", return_type: "T::Boolean")
+                instance_module.create_method("#{flag_key}_changed?", return_type: "T::Boolean")
+
+                # .not_warpdrive
+                # .not_warpdrive=
+                # .not_warpdrive?
+                instance_module.create_method("not_#{flag_key}", return_type: "T::Boolean")
+                instance_module.create_method("not_#{flag_key}?", return_type: "T::Boolean")
+                instance_module.create_method(
+                  "not_#{flag_key}=",
+                  parameters: [create_param("value", type: "T::Boolean")],
+                  return_type: "T::Boolean",
+                )
+
+                # .has_warpdrive?
+                instance_module.create_method("has_#{flag_key}?", return_type: "T::Boolean")
+              end
+            end
+
+            klass << instance_module
+            klass.create_include(ClassMethodsModuleName)
+            klass.create_include(InstanceMethodsModuleName)
+          end
+        end
+      end
+    end
+  end
+end