use std::collections::HashSet;
use std::sync::Arc;
use std::time::Duration;
use arc_swap::ArcSwap;
use futures_util::stream::FuturesUnordered;
use helix_core::chars::char_is_word;
use helix_core::syntax::LanguageServerFeature;
use helix_event::{
cancelable_future, cancelation, register_hook, send_blocking, CancelRx, CancelTx,
};
use helix_lsp::lsp;
use helix_lsp::util::pos_to_lsp_pos;
use helix_stdx::rope::RopeSliceExt;
use helix_view::document::{Mode, SavePoint};
use helix_view::handlers::lsp::CompletionEvent;
use helix_view::{DocumentId, Editor, ViewId};
use tokio::sync::mpsc::Sender;
use tokio::time::Instant;
use tokio_stream::StreamExt;
use crate::commands;
use crate::compositor::Compositor;
use crate::config::Config;
use crate::events::{OnModeSwitch, PostCommand, PostInsertChar};
use crate::job::{dispatch, dispatch_blocking};
use crate::keymap::MappableCommand;
use crate::ui::editor::InsertEvent;
use crate::ui::lsp::SignatureHelp;
use crate::ui::{self, CompletionItem, Popup};
use super::Handlers;
#[derive(Debug, PartialEq, Eq, Clone, Copy)]
enum TriggerKind {
Auto,
TriggerChar,
Manual,
}
#[derive(Debug, Clone, Copy)]
struct Trigger {
pos: usize,
view: ViewId,
doc: DocumentId,
kind: TriggerKind,
}
#[derive(Debug)]
pub(super) struct CompletionHandler {
/// currently active trigger which will cause a
/// completion request after the timeout
trigger: Option<Trigger>,
/// A handle for currently active completion request.
/// This can be used to determine whether the current
/// request is still active (and new triggers should be
/// ignored) and can also be used to abort the current
/// request (by dropping the handle)
request: Option<CancelTx>,
config: Arc<ArcSwap<Config>>,
}
impl CompletionHandler {
pub fn new(config: Arc<ArcSwap<Config>>) -> CompletionHandler {
Self {
config,
request: None,
trigger: None,
}
}
}
impl helix_event::AsyncHook for CompletionHandler {
type Event = CompletionEvent;
fn handle_event(
&mut self,
event: Self::Event,
_old_timeout: Option<Instant>,
) -> Option<Instant> {
match event {
CompletionEvent::AutoTrigger {
cursor: trigger_pos,
doc,
view,
} => {
// techically it shouldn't be possible to switch views/documents in insert mode
// but people may create weird keymaps/use the mouse so lets be extra careful
if self
.trigger
.as_ref()
.map_or(true, |trigger| trigger.doc != doc || trigger.view != view)
{
self.trigger = Some(Trigger {
pos: trigger_pos,
view,
doc,
kind: TriggerKind::Auto,
});
}
}
CompletionEvent::TriggerChar { cursor, doc, view } => {
// immediately request completions and drop all auto completion requests
self.request = None;
self.trigger = Some(Trigger {
pos: cursor,
view,
doc,
kind: TriggerKind::TriggerChar,
});
}
CompletionEvent::ManualTrigger { cursor, doc, view } => {
// immediately request completions and drop all auto completion requests
self.request = None;
self.trigger = Some(Trigger {
pos: cursor,
view,
doc,
kind: TriggerKind::Manual,
});
// stop debouncing immediately and request the completion
self.finish_debounce();
return None;
}
CompletionEvent::Cancel => {
self.trigger = None;
self.request = None;
}
CompletionEvent::DeleteText { cursor } => {
// if we deleted the original trigger, abort the completion
if matches!(self.trigger, Some(Trigger{ pos, .. }) if cursor < pos) {
self.trigger = None;
self.request = None;
}
}
}
self.trigger.map(|trigger| {
// if the current request was closed forget about it
// otherwise immediately restart the completion request
let cancel = self.request.take().map_or(false, |req| !req.is_closed());
let timeout = if trigger.kind == TriggerKind::Auto && !cancel {
self.config.load().editor.completion_timeout
} else {
// we want almost instant completions for trigger chars
// and restarting completion requests. The small timeout here mainly
// serves to better handle cases where the completion handler
// may fall behind (so multiple events in the channel) and macros
Duration::from_millis(5)
};
Instant::now() + timeout
})
}
fn finish_debounce(&mut self) {
let trigger = self.trigger.take().expect("debounce always has a trigger");
let (tx, rx) = cancelation();
self.request = Some(tx);
dispatch_blocking(move |editor, compositor| {
request_completion(trigger, rx, editor, compositor)
});
}
}
fn request_completion(
mut trigger: Trigger,
cancel: CancelRx,
editor: &mut Editor,
compositor: &mut Compositor,
) {
let (view, doc) = current!(editor);
if compositor
.find::<ui::EditorView>()
.unwrap()
.completion
.is_some()
|| editor.mode != Mode::Insert
{
return;
}
let text = doc.text();
let cursor = doc.selection(view.id).primary().cursor(text.slice(..));
if trigger.view != view.id || trigger.doc != doc.id() || cursor < trigger.pos {
return;
}
// this looks odd... Why are we not using the trigger position from
// the `trigger` here? Won't that mean that the trigger char doesn't get
// send to the LS if we type fast enougn? Yes that is true but it's
// not actually a problem. The LSP will resolve the completion to the identifier
// anyway (in fact sending the later position is necessary to get the right results
// from LSPs that provide incomplete completion list). We rely on trigger offset
// and primary cursor matching for multi-cursor completions so this is definitely
// necessary from our side too.
trigger.pos = cursor;
let trigger_text = text.slice(..cursor);
let mut seen_language_servers = HashSet::new();
let mut futures: FuturesUnordered<_> = doc
.language_servers_with_feature(LanguageServerFeature::Completion)
.filter(|ls| seen_language_servers.insert(ls.id()))
.map(|ls| {
let language_server_id = ls.id();
let offset_encoding = ls.offset_encoding();
let pos = pos_to_lsp_pos(text, cursor, offset_encoding);
let doc_id = doc.identifier();
let context = if trigger.kind == TriggerKind::Manual {
lsp::CompletionContext {
trigger_kind: lsp::CompletionTriggerKind::INVOKED,
trigger_character: None,
}
} else {
let trigger_char =
ls.capabilities()
.completion_provider
.as_ref()
.and_then(|provider| {
provider
.trigger_characters
.as_deref()?
.iter()
.find(|&trigger| trigger_text.ends_with(trigger))
});
lsp::CompletionContext {
trigger_kind: lsp::CompletionTriggerKind::TRIGGER_CHARACTER,
trigger_character: trigger_char.cloned(),
}
};
let completion_response = ls.completion(doc_id, pos, None, context).unwrap();
async move {
let json = completion_response.await?;
let response: Option<lsp::CompletionResponse> = serde_json::from_value(json)?;
let items = match response {
Some(lsp::CompletionResponse::Array(items)) => items,
// TODO: do something with is_incomplete
Some(lsp::CompletionResponse::List(lsp::CompletionList {
is_incomplete: _is_incomplete,
items,
})) => items,
None => Vec::new(),
}
.into_iter()
.map(|item| CompletionItem {
item,
language_server_id,
resolved: false,
})
.collect();
anyhow::Ok(items)
}
})
.collect();
let future = async move {
let mut items = Vec::new();
while let Some(lsp_items) = futures.next().await {
match lsp_items {
Ok(mut lsp_items) => items.append(&mut lsp_items),
Err(err) => {
log::debug!("completion request failed: {err:?}");
}
};
}
items
};
let savepoint = doc.savepoint(view);
let ui = compositor.find::<ui::EditorView>().unwrap();
ui.last_insert.1.push(InsertEvent::RequestCompletion);
tokio::spawn(async move {
let items = cancelable_future(future, cancel).await.unwrap_or_default();
if items.is_empty() {
return;
}
dispatch(move |editor, compositor| {
show_completion(editor, compositor, items, trigger, savepoint)
})
.await
});
}
fn show_completion(
editor: &mut Editor,
compositor: &mut Compositor,
items: Vec<CompletionItem>,
trigger: Trigger,
savepoint: Arc<SavePoint>,
) {
let (view, doc) = current_ref!(editor);
// check if the completion request is stale.
//
// Completions are completed asynchronously and therefore the user could
//switch document/view or leave insert mode. In all of thoise cases the
// completion should be discarded
if editor.mode != Mode::Insert || view.id != trigger.view || doc.id() != trigger.doc {
return;
}
let size = compositor.size();
let ui = compositor.find::<ui::EditorView>().unwrap();
if ui.completion.is_some() {
return;
}
let completion_area = ui.set_completion(editor, savepoint, items, trigger.pos, size);
let signature_help_area = compositor
.find_id::<Popup<SignatureHelp>>(SignatureHelp::ID)
.map(|signature_help| signature_help.area(size, editor));
// Delete the signature help popup if they intersect.
if matches!((completion_area, signature_help_area),(Some(a), Some(b)) if a.intersects(b)) {
compositor.remove(SignatureHelp::ID);
}
}
pub fn trigger_auto_completion(
tx: &Sender<CompletionEvent>,
editor: &Editor,
trigger_char_only: bool,
) {
let config = editor.config.load();
if !config.auto_completion {
return;
}
let (view, doc): (&helix_view::View, &helix_view::Document) = current_ref!(editor);
let mut text = doc.text().slice(..);
let cursor = doc.selection(view.id).primary().cursor(text);
text = doc.text().slice(..cursor);
let is_trigger_char = doc
.language_servers_with_feature(LanguageServerFeature::Completion)
.any(|ls| {
matches!(&ls.capabilities().completion_provider, Some(lsp::CompletionOptions {
trigger_characters: Some(triggers),
..
}) if triggers.iter().any(|trigger| text.ends_with(trigger)))
});
if is_trigger_char {
send_blocking(
tx,
CompletionEvent::TriggerChar {
cursor,
doc: doc.id(),
view: view.id,
},
);
return;
}
let is_auto_trigger = !trigger_char_only
&& doc
.text()
.chars_at(cursor)
.reversed()
.take(config.completion_trigger_len as usize)
.all(char_is_word);
if is_auto_trigger {
send_blocking(
tx,
CompletionEvent::AutoTrigger {
cursor,
doc: doc.id(),
view: view.id,
},
);
}
}
fn update_completions(cx: &mut commands::Context, c: Option<char>) {
cx.callback.push(Box::new(move |compositor, cx| {
let editor_view = compositor.find::<ui::EditorView>().unwrap();
if let Some(completion) = &mut editor_view.completion {
completion.update_filter(c);
if completion.is_empty() {
editor_view.clear_completion(cx.editor);
// clearing completions might mean we want to immediately rerequest them (usually
// this occurs if typing a trigger char)
if c.is_some() {
trigger_auto_completion(&cx.editor.handlers.completions, cx.editor, false);
}
}
}
}))
}
fn clear_completions(cx: &mut commands::Context) {
cx.callback.push(Box::new(|compositor, cx| {
let editor_view = compositor.find::<ui::EditorView>().unwrap();
editor_view.clear_completion(cx.editor);
}))
}
fn completion_post_command_hook(
tx: &Sender<CompletionEvent>,
PostCommand { command, cx }: &mut PostCommand<'_, '_>,
) -> anyhow::Result<()> {
if cx.editor.mode == Mode::Insert {
if cx.editor.last_completion.is_some() {
match command {
MappableCommand::Static {
name: "delete_word_forward" | "delete_char_forward" | "completion",
..
} => (),
MappableCommand::Static {
name: "delete_char_backward",
..
} => update_completions(cx, None),
_ => clear_completions(cx),
}
} else {
let event = match command {
MappableCommand::Static {
name: "delete_char_backward" | "delete_word_forward" | "delete_char_forward",
..
} => {
let (view, doc) = current!(cx.editor);
let primary_cursor = doc
.selection(view.id)
.primary()
.cursor(doc.text().slice(..));
CompletionEvent::DeleteText {
cursor: primary_cursor,
}
}
// hacks: some commands are handeled elsewhere and we don't want to
// cancel in that case
MappableCommand::Static {
name: "completion" | "insert_mode" | "append_mode",
..
} => return Ok(()),
_ => CompletionEvent::Cancel,
};
send_blocking(tx, event);
}
}
Ok(())
}
pub(super) fn register_hooks(handlers: &Handlers) {
let tx = handlers.completions.clone();
register_hook!(move |event: &mut PostCommand<'_, '_>| completion_post_command_hook(&tx, event));
let tx = handlers.completions.clone();
register_hook!(move |event: &mut OnModeSwitch<'_, '_>| {
if event.old_mode == Mode::Insert {
send_blocking(&tx, CompletionEvent::Cancel);
clear_completions(event.cx);
} else if event.new_mode == Mode::Insert {
trigger_auto_completion(&tx, event.cx.editor, false)
}
Ok(())
});
let tx = handlers.completions.clone();
register_hook!(move |event: &mut PostInsertChar<'_, '_>| {
if event.cx.editor.last_completion.is_some() {
update_completions(event.cx, Some(event.c))
} else {
trigger_auto_completion(&tx, event.cx.editor, false);
}
Ok(())
});
}