From 48bd1a73017a1c8a5e388a5898780cb13221998b Mon Sep 17 00:00:00 2001
From: robmckinnon <rob@movingflow>
Date: Mon, 20 Mar 2023 09:08:25 +0000
Subject: [PATCH] Add extract function as an execute command

---
 .../code_mod/refactor_extract_function.ex     | 18 +++++++++
 .../providers/execute_command.ex              |  1 +
 .../execute_command/extract_function.ex       | 39 +++++++++++++++++++
 3 files changed, 58 insertions(+)
 create mode 100644 apps/language_server/lib/language_server/experimental/code_mod/refactor_extract_function.ex
 create mode 100644 apps/language_server/lib/language_server/providers/execute_command/extract_function.ex

diff --git a/apps/language_server/lib/language_server/experimental/code_mod/refactor_extract_function.ex b/apps/language_server/lib/language_server/experimental/code_mod/refactor_extract_function.ex
new file mode 100644
index 000000000..128d7d781
--- /dev/null
+++ b/apps/language_server/lib/language_server/experimental/code_mod/refactor_extract_function.ex
@@ -0,0 +1,18 @@
+defmodule ElixirLS.LanguageServer.Experimental.CodeMod.RefactorExtractFunction do
+  alias ElixirLS.LanguageServer.Experimental.CodeMod.Diff
+  alias ElixirLS.LanguageServer.Experimental.CodeMod.ExtractFunction
+
+  alias Sourceror.Zipper
+
+  require Logger
+
+  def text_edits(original_text, tree, start_line, end_line, new_function_name) do
+    result =
+      tree
+      |> Zipper.zip()
+      |> ExtractFunction.extract_function(start_line + 1, end_line + 1, new_function_name)
+      |> Sourceror.to_string()
+
+    {:ok, Diff.diff(original_text, result)}
+  end
+end
diff --git a/apps/language_server/lib/language_server/providers/execute_command.ex b/apps/language_server/lib/language_server/providers/execute_command.ex
index 414759acc..9acec43b3 100644
--- a/apps/language_server/lib/language_server/providers/execute_command.ex
+++ b/apps/language_server/lib/language_server/providers/execute_command.ex
@@ -8,6 +8,7 @@ defmodule ElixirLS.LanguageServer.Providers.ExecuteCommand do
   @handlers %{
     "spec" => ExecuteCommand.ApplySpec,
     "expandMacro" => ExecuteCommand.ExpandMacro,
+    "extractFunction" => ExecuteCommand.ExtractFunction,
     "manipulatePipes" => ExecuteCommand.ManipulatePipes,
     "restart" => ExecuteCommand.Restart,
     "mixClean" => ExecuteCommand.MixClean,
diff --git a/apps/language_server/lib/language_server/providers/execute_command/extract_function.ex b/apps/language_server/lib/language_server/providers/execute_command/extract_function.ex
new file mode 100644
index 000000000..22d1f6e45
--- /dev/null
+++ b/apps/language_server/lib/language_server/providers/execute_command/extract_function.ex
@@ -0,0 +1,39 @@
+defmodule ElixirLS.LanguageServer.Providers.ExecuteCommand.ExtractFunction do
+  @moduledoc """
+  This module implements a custom command extract function.
+  Sends applyEdit request.
+  """
+
+  alias ElixirLS.LanguageServer.JsonRpc
+  alias ElixirLS.LanguageServer.Server
+  alias ElixirLS.LanguageServer.Experimental.CodeMod.Ast
+  alias ElixirLS.LanguageServer.Experimental.CodeMod.RefactorExtractFunction
+
+  require Logger
+
+  @behaviour ElixirLS.LanguageServer.Providers.ExecuteCommand
+
+  @impl ElixirLS.LanguageServer.Providers.ExecuteCommand
+  def execute([uri, start_line, end_line, new_function_name], state) do
+    with source_file <- Server.get_source_file(state, uri),
+         {:ok, tree} <- Ast.from(source_file.text, include_comments: true),
+         {:ok, text_edits} <-
+           RefactorExtractFunction.text_edits(
+             source_file.text,
+             tree,
+             start_line,
+             end_line,
+             new_function_name
+           ) do
+      apply_edits(uri, text_edits)
+      {:ok, nil}
+    end
+  end
+
+  def apply_edits(uri, text_edits) do
+    JsonRpc.send_request("workspace/applyEdit", %{
+      "label" => "Extract function",
+      "edit" => %{"changes" => %{uri => text_edits}}
+    }) |> IO.inspect(label: :rpc_response, limit: :infinity)
+  end
+end