[Tapioca Add-on] Trigger DSL generation upon file changes

lib/ruby_lsp/tapioca/addon.rb

@@ -23,15 +23,15 @@ class Addon < ::RubyLsp::Addon
       def initialize
         super
 
-        @global_state = T.let(nil, T.nilable(RubyLsp::GlobalState))
         @rails_runner_client = T.let(nil, T.nilable(RubyLsp::Rails::RunnerClient))
+        @index = T.let(nil, T.nilable(RubyIndexer::Index))
       end
 
       sig { override.params(global_state: RubyLsp::GlobalState, outgoing_queue: Thread::Queue).void }
       def activate(global_state, outgoing_queue)
-        @global_state = global_state
-        return unless @global_state.experimental_features
+        return unless global_state.experimental_features
 
+        @index = global_state.index
         Thread.new do
           # Get a handle to the Rails add-on's runtime client. The call to `rails_runner_client` will block this thread
           # until the server has finished booting, but it will not block the main LSP. This has to happen inside of a
@@ -60,6 +60,22 @@ def version
 
       sig { params(changes: T::Array[{ uri: String, type: Integer }]).void }
       def workspace_did_change_watched_files(changes)
+        constants = changes.filter_map do |change|
+          path = change[:uri].gsub("file://", "")
+
+          entries = T.must(@index).entries_for(path, RubyIndexer::Entry::Class, RubyIndexer::Entry::Module)
+          next unless entries
+        end.flatten
+
+        return if constants.empty?
+
+        T.must(@rails_runner_client).send_notification("reload", {})
+        T.must(@rails_runner_client).send_notification(
+          "server_addon/delegate",
+          request_name: "dsl",
+          server_addon_name: "Tapioca",
+          constants: constants,
+        )
       end
     end
   end