feat: code actions - document edits (#478)

* wip: Code actions

* fix(term): use current macro instead Context::context

* feat(lsp): set code_action capabilities

* feat(term): set SPC-a to code_action

* feat(term): wip on applying code actions

* deps: `cargo update`

* feat(term): applying code actions edits

* fix(term): cleanup of apply_edit

* fix(term): applying edits as a whole thing instead one by one

* refactor(term): move apply_edits below

* fix(term): improve unimplemented messages for further investigation

* fix(term): change code action command comment

Co-authored-by: Ivan Tham <pickfire@riseup.net>

* fix(term): add matching `}`

* fix(term): cleanup, todo!() on workspace edit

* fix(term): remove unrelated workspace_symbol_picker

* fix(term): apply cargo-clippy suggestions

* fix(term): replace todo!'s with editor.set_error

Co-authored-by: Blaž Hrastnik <blaz@mxxn.io>
Co-authored-by: Ivan Tham <pickfire@riseup.net>

1 files changed, 119 insertions, 2 deletions

diff --git a/helix-term/src/commands.rs b/helix-term/src/commands.rs
index 9b72a8e9..24c53897 100644
--- a/helix-term/src/commands.rs
+++ b/helix-term/src/commands.rs
@@ -9,8 +9,8 @@ use helix_core::{
     object, pos_at_coords,
     regex::{self, Regex},
     register::Register,
-    search, selection, surround, textobject, LineEnding, Position, Range, Rope, RopeGraphemes,
-    RopeSlice, Selection, SmallVec, Tendril, Transaction,
+    search, selection, surround, textobject, Change, LineEnding, Position, Range, Rope,
+    RopeGraphemes, RopeSlice, Selection, SmallVec, Tendril, Transaction,
 };
 
 use helix_view::{
@@ -215,6 +215,7 @@ impl Command {
         append_mode,
         command_mode,
         file_picker,
+        code_action,
         buffer_picker,
         symbol_picker,
         last_picker,
@@ -2092,6 +2093,120 @@ fn symbol_picker(cx: &mut Context) {
     )
 }
 
+pub fn code_action(cx: &mut Context) {
+    let (view, doc) = current!(cx.editor);
+
+    let language_server = match doc.language_server() {
+        Some(language_server) => language_server,
+        None => return,
+    };
+
+    let range = range_to_lsp_range(
+        doc.text(),
+        doc.selection(view.id).primary(),
+        language_server.offset_encoding(),
+    );
+
+    let future = language_server.code_actions(doc.identifier(), range);
+    let offset_encoding = language_server.offset_encoding();
+
+    cx.callback(
+        future,
+        move |_editor: &mut Editor,
+              compositor: &mut Compositor,
+              response: Option<lsp::CodeActionResponse>| {
+            if let Some(actions) = response {
+                let picker = Picker::new(
+                    actions,
+                    |action| match action {
+                        lsp::CodeActionOrCommand::CodeAction(action) => {
+                            action.title.as_str().into()
+                        }
+                        lsp::CodeActionOrCommand::Command(command) => command.title.as_str().into(),
+                    },
+                    move |editor, code_action, _action| match code_action {
+                        lsp::CodeActionOrCommand::Command(command) => {
+                            log::debug!("code action command: {:?}", command);
+                            editor.set_error(String::from("Handling code action command is not implemented yet, see https://github.com/helix-editor/helix/issues/183"));
+                        }
+                        lsp::CodeActionOrCommand::CodeAction(code_action) => {
+                            log::debug!("code action: {:?}", code_action);
+                            if let Some(ref workspace_edit) = code_action.edit {
+                                apply_workspace_edit(editor, offset_encoding, workspace_edit)
+                            }
+                        }
+                    },
+                );
+                compositor.push(Box::new(picker))
+            }
+        },
+    )
+}
+
+fn apply_workspace_edit(
+    editor: &mut Editor,
+    offset_encoding: OffsetEncoding,
+    workspace_edit: &lsp::WorkspaceEdit,
+) {
+    let edits_to_transaction = |doc: &Rope, edits: &Vec<&lsp::TextEdit>| {
+        let lsp_pos_to_pos = |lsp_pos| lsp_pos_to_pos(&doc, lsp_pos, offset_encoding).unwrap();
+        let changes = edits.iter().map(|edit| -> Change {
+            log::debug!("text edit: {:?}", edit);
+            // This clone probably could be optimized if Picker::new would give T instead of &T
+            let text_replacement = Tendril::from(edit.new_text.clone());
+            (
+                lsp_pos_to_pos(edit.range.start),
+                lsp_pos_to_pos(edit.range.end),
+                Some(text_replacement),
+            )
+        });
+        Transaction::change(doc, changes)
+    };
+
+    if let Some(ref changes) = workspace_edit.changes {
+        log::debug!("workspace changes: {:?}", changes);
+        editor.set_error(String::from("Handling workspace changesis not implemented yet, see https://github.com/helix-editor/helix/issues/183"));
+        return;
+        // Not sure if it works properly, it'll be safer to just panic here to avoid breaking some parts of code on which code actions will be used
+        // TODO: find some example that uses workspace changes, and test it
+        // for (url, edits) in changes.iter() {
+        //     let file_path = url.origin().ascii_serialization();
+        //     let file_path = std::path::PathBuf::from(file_path);
+        //     let file = std::fs::File::open(file_path).unwrap();
+        //     let mut text = Rope::from_reader(file).unwrap();
+        //     let transaction = edits_to_changes(&text, edits);
+        //     transaction.apply(&mut text);
+        // }
+    }
+
+    if let Some(ref document_changes) = workspace_edit.document_changes {
+        match document_changes {
+            lsp::DocumentChanges::Edits(document_edits) => {
+                for document_edit in document_edits {
+                    let (view, doc) = current!(editor);
+                    assert_eq!(doc.url().unwrap(), document_edit.text_document.uri);
+                    let edits = document_edit
+                        .edits
+                        .iter()
+                        .map(|edit| match edit {
+                            lsp::OneOf::Left(text_edit) => text_edit,
+                            lsp::OneOf::Right(annotated_text_edit) => {
+                                &annotated_text_edit.text_edit
+                            }
+                        })
+                        .collect();
+                    let transaction = edits_to_transaction(doc.text(), &edits);
+                    doc.apply(&transaction, view.id);
+                }
+            }
+            lsp::DocumentChanges::Operations(operations) => {
+                log::debug!("document changes - operations: {:?}", operations);
+                editor.set_error(String::from("Handling document operations is not implemented yet, see https://github.com/helix-editor/helix/issues/183"));
+            }
+        }
+    }
+}
+
 fn last_picker(cx: &mut Context) {
     // TODO: last picker does not seemed to work well with buffer_picker
     cx.callback = Some(Box::new(|compositor: &mut Compositor| {
@@ -3781,6 +3896,8 @@ mode_info! {
     "P" => paste_clipboard_before,
     /// replace selections with clipboard
     "R" => replace_selections_with_clipboard,
+    /// perform code action
+    "a" => code_action,
     /// keep primary selection
     "space" => keep_primary_selection,
 }