From 54d00d953a04f88e2facb4eb80e51019b77c80d0 Mon Sep 17 00:00:00 2001
From: Hakan Nilsson <hanilsso@cisco.com>
Date: Tue, 15 Oct 2024 10:12:50 +0200
Subject: [PATCH] Add code action to export function

---
 apps/els_lsp/src/els_code_action_provider.erl |  2 +
 apps/els_lsp/src/els_code_actions.erl         | 27 ++++++++++
 apps/els_lsp/test/els_code_action_SUITE.erl   | 49 +++++++++++++++++++
 3 files changed, 78 insertions(+)

diff --git a/apps/els_lsp/src/els_code_action_provider.erl b/apps/els_lsp/src/els_code_action_provider.erl
index 2f0a4286..f48bd07b 100644
--- a/apps/els_lsp/src/els_code_action_provider.erl
+++ b/apps/els_lsp/src/els_code_action_provider.erl
@@ -62,6 +62,8 @@ make_code_actions(
             {"function (.*) undefined", fun els_code_actions:suggest_function/4},
             {"Cannot find definition for function (.*)", fun els_code_actions:suggest_function/4},
             {"Cannot find module (.*)", fun els_code_actions:suggest_module/4},
+            {"Function (.+):(.+) is not exported.",
+                fun els_code_actions:export_external_function/4},
             {"Unused file: (.*)", fun els_code_actions:remove_unused/4},
             {"Atom typo\\? Did you mean: (.*)", fun els_code_actions:fix_atom_typo/4},
             {"undefined callback function (.*) \\\(behaviour '(.*)'\\\)",
diff --git a/apps/els_lsp/src/els_code_actions.erl b/apps/els_lsp/src/els_code_actions.erl
index c4e8fb5d..9ae1e653 100644
--- a/apps/els_lsp/src/els_code_actions.erl
+++ b/apps/els_lsp/src/els_code_actions.erl
@@ -3,6 +3,7 @@
     extract_function/2,
     create_function/4,
     export_function/4,
+    export_external_function/4,
     fix_module_name/4,
     ignore_variable/4,
     remove_macro/4,
@@ -84,6 +85,32 @@ export_function(Uri, _Range, _Data, [UnusedFun]) ->
             ]
     end.
 
+-spec export_external_function(uri(), range(), binary(), [binary()]) -> [map()].
+export_external_function(_Uri, _Range, _Data, [ModBin, FABin]) ->
+    Mod = binary_to_atom(ModBin, utf8),
+    case els_utils:find_module(Mod) of
+        {ok, Uri} ->
+            {ok, Document} = els_utils:lookup_document(Uri),
+            case els_poi:sort(els_dt_document:pois(Document, [module, export])) of
+                [] ->
+                    [];
+                POIs ->
+                    #{range := #{to := {Line, _Col}}} = lists:last(POIs),
+                    Pos = {Line + 1, 1},
+                    [
+                        make_edit_action(
+                            Uri,
+                            <<"Export ", FABin/binary>>,
+                            ?CODE_ACTION_KIND_QUICKFIX,
+                            <<"-export([", FABin/binary, "]).\n">>,
+                            els_protocol:range(#{from => Pos, to => Pos})
+                        )
+                    ]
+            end;
+        {error, not_found} ->
+            []
+    end.
+
 -spec ignore_variable(uri(), range(), binary(), [binary()]) -> [map()].
 ignore_variable(Uri, Range, _Data, [UnusedVariable]) ->
     {ok, Document} = els_utils:lookup_document(Uri),
diff --git a/apps/els_lsp/test/els_code_action_SUITE.erl b/apps/els_lsp/test/els_code_action_SUITE.erl
index 1e1a51bd..68f1f2f3 100644
--- a/apps/els_lsp/test/els_code_action_SUITE.erl
+++ b/apps/els_lsp/test/els_code_action_SUITE.erl
@@ -14,6 +14,7 @@
 -export([
     add_underscore_to_unused_var/1,
     export_unused_function/1,
+    export_external_function/1,
     suggest_variable/1,
     fix_module_name/1,
     remove_unused_macro/1,
@@ -158,6 +159,54 @@ export_unused_function(Config) ->
     ?assertEqual(Expected, Result),
     ok.
 
+-spec export_external_function(config()) -> ok.
+export_external_function(Config) ->
+    Uri = ?config(code_navigation_uri, Config),
+    %% Don't care
+    Range = els_protocol:range(#{
+        from => {1, 1},
+        to => {1, 2}
+    }),
+    Diag = #{
+        message => <<"Function code_action:function_c/0 is not exported.">>,
+        range => Range,
+        severity => 2,
+        source => <<"CrossRef">>
+    },
+    #{result := Result} = els_client:document_codeaction(Uri, Range, [Diag]),
+    TargetUri = ?config(code_action_uri, Config),
+    Expected =
+        [
+            #{
+                edit => #{
+                    changes =>
+                        #{
+                            binary_to_atom(TargetUri, utf8) =>
+                                [
+                                    #{
+                                        range =>
+                                            #{
+                                                'end' => #{
+                                                    character => 0,
+                                                    line => ?COMMENTS_LINES + 3
+                                                },
+                                                start => #{
+                                                    character => 0,
+                                                    line => ?COMMENTS_LINES + 3
+                                                }
+                                            },
+                                        newText => <<"-export([function_c/0]).\n">>
+                                    }
+                                ]
+                        }
+                },
+                kind => <<"quickfix">>,
+                title => <<"Export function_c/0">>
+            }
+        ],
+    ?assertEqual(Expected, Result),
+    ok.
+
 -spec suggest_variable(config()) -> ok.
 suggest_variable(Config) ->
     Uri = ?config(code_action_uri, Config),