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>

3 files changed, 178 insertions, 14 deletions

diff --git a/Cargo.lock b/Cargo.lock
index 0d96b700..a1f0a798 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -422,9 +422,9 @@ dependencies = [
 
 [[package]]
 name = "hermit-abi"
-version = "0.1.18"
+version = "0.1.19"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "322f4de77956e22ed0e5032c359a0f1273f1f7f0d79bfa3b8ffbc730d7fbcc5c"
+checksum = "62b467343b94ba476dcb2500d242dadbb39557df889310ac77c5d99100aaac33"
 dependencies = [
  "libc",
 ]
@@ -460,9 +460,9 @@ dependencies = [
 
 [[package]]
 name = "instant"
-version = "0.1.9"
+version = "0.1.10"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "61124eeebbd69b8190558df225adf7e4caafce0d743919e5d6b19652314ec5ec"
+checksum = "bee0328b1209d157ef001c94dd85b4f8f64139adb0eac2659f4b08382b2f474d"
 dependencies = [
  "cfg-if 1.0.0",
 ]
@@ -494,9 +494,9 @@ checksum = "e2abad23fbc42b3700f2f279844dc832adb2b2eb069b2df918f455c4e18cc646"
 
 [[package]]
 name = "libc"
-version = "0.2.97"
+version = "0.2.98"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "12b8adadd720df158f4d70dfe7ccc6adb0472d7c55ca83445f6a5ab3e36f8fb6"
+checksum = "320cfe77175da3a483efed4bc0adc1968ca050b098ce4f2f1c13a56626128790"
 
 [[package]]
 name = "libloading"
@@ -662,9 +662,9 @@ checksum = "d4fd5641d01c8f18a23da7b6fe29298ff4b55afcccdf78973b24cf3175fee32e"
 
 [[package]]
 name = "pin-project-lite"
-version = "0.2.6"
+version = "0.2.7"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "dc0e1f259c92177c30a4c9d177246edd0a3568b25756a977d0632cf8fa37e905"
+checksum = "8d31d11c69a6b52a174b42bdc0c30e5e11670f90788b2c471c31c1d17d449443"
 
 [[package]]
 name = "pin-utils"
@@ -994,9 +994,9 @@ dependencies = [
 
 [[package]]
 name = "tinyvec"
-version = "1.2.0"
+version = "1.3.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "5b5220f05bb7de7f3f53c7c065e1199b3172696fe2db9f9c4d8ad9b4ee74c342"
+checksum = "4ac2e1d4bd0f75279cfd5a076e0d578bbf02c22b7c39e766c437dd49b3ec43e0"
 dependencies = [
  "tinyvec_macros",
 ]
@@ -1029,9 +1029,9 @@ dependencies = [
 
 [[package]]
 name = "tokio-macros"
-version = "1.2.0"
+version = "1.3.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "c49e3df43841dafb86046472506755d8501c5615673955f6aa17181125d13c37"
+checksum = "54473be61f4ebe4efd09cec9bd5d16fa51d70ea0192213d754d2d500457db110"
 dependencies = [
  "proc-macro2",
  "quote",
diff --git a/helix-lsp/src/client.rs b/helix-lsp/src/client.rs
index 1c2a49b5..fd34f45d 100644
--- a/helix-lsp/src/client.rs
+++ b/helix-lsp/src/client.rs
@@ -247,6 +247,26 @@ impl Client {
                         content_format: Some(vec![lsp::MarkupKind::Markdown]),
                         ..Default::default()
                     }),
+                    code_action: Some(lsp::CodeActionClientCapabilities {
+                        code_action_literal_support: Some(lsp::CodeActionLiteralSupport {
+                            code_action_kind: lsp::CodeActionKindLiteralSupport {
+                                value_set: [
+                                    lsp::CodeActionKind::EMPTY,
+                                    lsp::CodeActionKind::QUICKFIX,
+                                    lsp::CodeActionKind::REFACTOR,
+                                    lsp::CodeActionKind::REFACTOR_EXTRACT,
+                                    lsp::CodeActionKind::REFACTOR_INLINE,
+                                    lsp::CodeActionKind::REFACTOR_REWRITE,
+                                    lsp::CodeActionKind::SOURCE,
+                                    lsp::CodeActionKind::SOURCE_ORGANIZE_IMPORTS,
+                                ]
+                                .iter()
+                                .map(|kind| kind.as_str().to_string())
+                                .collect(),
+                            },
+                        }),
+                        ..Default::default()
+                    }),
                     ..Default::default()
                 }),
                 window: Some(lsp::WindowClientCapabilities {
@@ -713,4 +733,31 @@ impl Client {
 
         self.call::<lsp::request::DocumentSymbolRequest>(params)
     }
+
+    // empty string to get all symbols
+    pub fn workspace_symbols(&self, query: String) -> impl Future<Output = Result<Value>> {
+        let params = lsp::WorkspaceSymbolParams {
+            query,
+            work_done_progress_params: lsp::WorkDoneProgressParams::default(),
+            partial_result_params: lsp::PartialResultParams::default(),
+        };
+
+        self.call::<lsp::request::WorkspaceSymbol>(params)
+    }
+
+    pub fn code_actions(
+        &self,
+        text_document: lsp::TextDocumentIdentifier,
+        range: lsp::Range,
+    ) -> impl Future<Output = Result<Value>> {
+        let params = lsp::CodeActionParams {
+            text_document,
+            range,
+            context: lsp::CodeActionContext::default(),
+            work_done_progress_params: lsp::WorkDoneProgressParams::default(),
+            partial_result_params: lsp::PartialResultParams::default(),
+        };
+
+        self.call::<lsp::request::CodeActionRequest>(params)
+    }
 }
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,
 }