aboutsummaryrefslogtreecommitdiff
path: root/helix-term/src/ui/completion.rs
blob: 6cbb5b1095f4c579a542c4d6d3c0fbd0c87194ba (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
use crate::{
    compositor::{Component, Context, Event, EventResult},
    handlers::trigger_auto_completion,
    job,
};
use helix_event::AsyncHook;
use helix_view::{
    document::SavePoint,
    editor::CompleteAction,
    graphics::Margin,
    handlers::lsp::SignatureHelpInvoked,
    theme::{Modifier, Style},
    ViewId,
};
use tokio::time::Instant;
use tui::{buffer::Buffer as Surface, text::Span};

use std::{borrow::Cow, sync::Arc, time::Duration};

use helix_core::{chars, Change, Transaction};
use helix_view::{graphics::Rect, Document, Editor};

use crate::ui::{menu, Markdown, Menu, Popup, PromptEvent};

use helix_lsp::{lsp, util, OffsetEncoding};

impl menu::Item for CompletionItem {
    type Data = ();
    fn sort_text(&self, data: &Self::Data) -> Cow<str> {
        self.filter_text(data)
    }

    #[inline]
    fn filter_text(&self, _data: &Self::Data) -> Cow<str> {
        self.item
            .filter_text
            .as_ref()
            .unwrap_or(&self.item.label)
            .as_str()
            .into()
    }

    fn format(&self, _data: &Self::Data) -> menu::Row {
        let deprecated = self.item.deprecated.unwrap_or_default()
            || self.item.tags.as_ref().map_or(false, |tags| {
                tags.contains(&lsp::CompletionItemTag::DEPRECATED)
            });

        menu::Row::new(vec![
            menu::Cell::from(Span::styled(
                self.item.label.as_str(),
                if deprecated {
                    Style::default().add_modifier(Modifier::CROSSED_OUT)
                } else {
                    Style::default()
                },
            )),
            menu::Cell::from(match self.item.kind {
                Some(lsp::CompletionItemKind::TEXT) => "text",
                Some(lsp::CompletionItemKind::METHOD) => "method",
                Some(lsp::CompletionItemKind::FUNCTION) => "function",
                Some(lsp::CompletionItemKind::CONSTRUCTOR) => "constructor",
                Some(lsp::CompletionItemKind::FIELD) => "field",
                Some(lsp::CompletionItemKind::VARIABLE) => "variable",
                Some(lsp::CompletionItemKind::CLASS) => "class",
                Some(lsp::CompletionItemKind::INTERFACE) => "interface",
                Some(lsp::CompletionItemKind::MODULE) => "module",
                Some(lsp::CompletionItemKind::PROPERTY) => "property",
                Some(lsp::CompletionItemKind::UNIT) => "unit",
                Some(lsp::CompletionItemKind::VALUE) => "value",
                Some(lsp::CompletionItemKind::ENUM) => "enum",
                Some(lsp::CompletionItemKind::KEYWORD) => "keyword",
                Some(lsp::CompletionItemKind::SNIPPET) => "snippet",
                Some(lsp::CompletionItemKind::COLOR) => "color",
                Some(lsp::CompletionItemKind::FILE) => "file",
                Some(lsp::CompletionItemKind::REFERENCE) => "reference",
                Some(lsp::CompletionItemKind::FOLDER) => "folder",
                Some(lsp::CompletionItemKind::ENUM_MEMBER) => "enum_member",
                Some(lsp::CompletionItemKind::CONSTANT) => "constant",
                Some(lsp::CompletionItemKind::STRUCT) => "struct",
                Some(lsp::CompletionItemKind::EVENT) => "event",
                Some(lsp::CompletionItemKind::OPERATOR) => "operator",
                Some(lsp::CompletionItemKind::TYPE_PARAMETER) => "type_param",
                Some(kind) => {
                    log::error!("Received unknown completion item kind: {:?}", kind);
                    ""
                }
                None => "",
            }),
        ])
    }
}

#[derive(Debug, PartialEq, Default, Clone)]
pub struct CompletionItem {
    pub item: lsp::CompletionItem,
    pub language_server_id: usize,
    pub resolved: bool,
}

/// Wraps a Menu.
pub struct Completion {
    popup: Popup<Menu<CompletionItem>>,
    #[allow(dead_code)]
    trigger_offset: usize,
    filter: String,
    resolve_handler: tokio::sync::mpsc::Sender<CompletionItem>,
}

impl Completion {
    pub const ID: &'static str = "completion";

    pub fn new(
        editor: &Editor,
        savepoint: Arc<SavePoint>,
        mut items: Vec<CompletionItem>,
        trigger_offset: usize,
    ) -> Self {
        let preview_completion_insert = editor.config().preview_completion_insert;
        let replace_mode = editor.config().completion_replace;
        // Sort completion items according to their preselect status (given by the LSP server)
        items.sort_by_key(|item| !item.item.preselect.unwrap_or(false));

        // Then create the menu
        let menu = Menu::new(items, (), move |editor: &mut Editor, item, event| {
            fn item_to_transaction(
                doc: &Document,
                view_id: ViewId,
                item: &lsp::CompletionItem,
                offset_encoding: OffsetEncoding,
                trigger_offset: usize,
                include_placeholder: bool,
                replace_mode: bool,
            ) -> Transaction {
                use helix_lsp::snippet;
                let selection = doc.selection(view_id);
                let text = doc.text().slice(..);
                let primary_cursor = selection.primary().cursor(text);

                let (edit_offset, new_text) = if let Some(edit) = &item.text_edit {
                    let edit = match edit {
                        lsp::CompletionTextEdit::Edit(edit) => edit.clone(),
                        lsp::CompletionTextEdit::InsertAndReplace(item) => {
                            let range = if replace_mode {
                                item.replace
                            } else {
                                item.insert
                            };
                            lsp::TextEdit::new(range, item.new_text.clone())
                        }
                    };

                    let Some(range) =
                        util::lsp_range_to_range(doc.text(), edit.range, offset_encoding)
                    else {
                        return Transaction::new(doc.text());
                    };

                    let start_offset = range.anchor as i128 - primary_cursor as i128;
                    let end_offset = range.head as i128 - primary_cursor as i128;

                    (Some((start_offset, end_offset)), edit.new_text)
                } else {
                    let new_text = item
                        .insert_text
                        .clone()
                        .unwrap_or_else(|| item.label.clone());
                    // check that we are still at the correct savepoint
                    // we can still generate a transaction regardless but if the
                    // document changed (and not just the selection) then we will
                    // likely delete the wrong text (same if we applied an edit sent by the LS)
                    debug_assert!(primary_cursor == trigger_offset);
                    (None, new_text)
                };

                if matches!(item.kind, Some(lsp::CompletionItemKind::SNIPPET))
                    || matches!(
                        item.insert_text_format,
                        Some(lsp::InsertTextFormat::SNIPPET)
                    )
                {
                    match snippet::parse(&new_text) {
                        Ok(snippet) => util::generate_transaction_from_snippet(
                            doc.text(),
                            selection,
                            edit_offset,
                            replace_mode,
                            snippet,
                            doc.line_ending.as_str(),
                            include_placeholder,
                            doc.tab_width(),
                            doc.indent_width(),
                        ),
                        Err(err) => {
                            log::error!(
                                "Failed to parse snippet: {:?}, remaining output: {}",
                                &new_text,
                                err
                            );
                            Transaction::new(doc.text())
                        }
                    }
                } else {
                    util::generate_transaction_from_completion_edit(
                        doc.text(),
                        selection,
                        edit_offset,
                        replace_mode,
                        new_text,
                    )
                }
            }

            fn completion_changes(transaction: &Transaction, trigger_offset: usize) -> Vec<Change> {
                transaction
                    .changes_iter()
                    .filter(|(start, end, _)| (*start..=*end).contains(&trigger_offset))
                    .collect()
            }

            let (view, doc) = current!(editor);

            macro_rules! language_server {
                ($item:expr) => {
                    match editor
                        .language_servers
                        .get_by_id($item.language_server_id)
                    {
                        Some(ls) => ls,
                        None => {
                            editor.set_error("completions are outdated");
                            // TODO close the completion menu somehow,
                            // currently there is no trivial way to access the EditorView to close the completion menu
                            return;
                        }
                    }
                };
            }

            match event {
                PromptEvent::Abort => {}
                PromptEvent::Update if preview_completion_insert => {
                    // Update creates "ghost" transactions which are not sent to the
                    // lsp server to avoid messing up re-requesting completions. Once a
                    // completion has been selected (with tab, c-n or c-p) it's always accepted whenever anything
                    // is typed. The only way to avoid that is to explicitly abort the completion
                    // with c-c. This will remove the "ghost" transaction.
                    //
                    // The ghost transaction is modeled with a transaction that is not sent to the LS.
                    // (apply_temporary) and a savepoint. It's extremely important this savepoint is restored
                    // (also without sending the transaction to the LS) *before any further transaction is applied*.
                    // Otherwise incremental sync breaks (since the state of the LS doesn't match the state the transaction
                    // is applied to).
                    if matches!(editor.last_completion, Some(CompleteAction::Triggered)) {
                        editor.last_completion = Some(CompleteAction::Selected {
                            savepoint: doc.savepoint(view),
                        })
                    }
                    // if more text was entered, remove it
                    doc.restore(view, &savepoint, false);
                    // always present here
                    let item = item.unwrap();

                    let transaction = item_to_transaction(
                        doc,
                        view.id,
                        &item.item,
                        language_server!(item).offset_encoding(),
                        trigger_offset,
                        true,
                        replace_mode,
                    );
                    doc.apply_temporary(&transaction, view.id);
                }
                PromptEvent::Update => {}
                PromptEvent::Validate => {
                    if let Some(CompleteAction::Selected { savepoint }) =
                        editor.last_completion.take()
                    {
                        doc.restore(view, &savepoint, false);
                    }
                    // always present here
                    let mut item = item.unwrap().clone();

                    let language_server = language_server!(item);
                    let offset_encoding = language_server.offset_encoding();

                    let language_server = editor
                        .language_servers
                        .get_by_id(item.language_server_id)
                        .unwrap();

                    // resolve item if not yet resolved
                    if !item.resolved {
                        if let Some(resolved) =
                            Self::resolve_completion_item(language_server, item.item.clone())
                        {
                            item.item = resolved;
                        }
                    };
                    // if more text was entered, remove it
                    doc.restore(view, &savepoint, true);
                    // save an undo checkpoint before the completion
                    doc.append_changes_to_history(view);
                    let transaction = item_to_transaction(
                        doc,
                        view.id,
                        &item.item,
                        offset_encoding,
                        trigger_offset,
                        false,
                        replace_mode,
                    );
                    doc.apply(&transaction, view.id);

                    editor.last_completion = Some(CompleteAction::Applied {
                        trigger_offset,
                        changes: completion_changes(&transaction, trigger_offset),
                    });

                    // TODO: add additional _edits to completion_changes?
                    if let Some(additional_edits) = item.item.additional_text_edits {
                        if !additional_edits.is_empty() {
                            let transaction = util::generate_transaction_from_edits(
                                doc.text(),
                                additional_edits,
                                offset_encoding, // TODO: should probably transcode in Client
                            );
                            doc.apply(&transaction, view.id);
                        }
                    }
                    // we could have just inserted a trigger char (like a `crate::` completion for rust
                    // so we want to retrigger immediately when accepting a completion.
                    trigger_auto_completion(&editor.handlers.completions, editor, true);
                }
            };

            // In case the popup was deleted because of an intersection w/ the auto-complete menu.
            if event != PromptEvent::Update {
                editor
                    .handlers
                    .trigger_signature_help(SignatureHelpInvoked::Automatic, editor);
            }
        });

        let margin = if editor.menu_border() {
            Margin::vertical(1)
        } else {
            Margin::none()
        };

        let popup = Popup::new(Self::ID, menu)
            .with_scrollbar(false)
            .ignore_escape_key(true)
            .margin(margin);

        let (view, doc) = current_ref!(editor);
        let text = doc.text().slice(..);
        let cursor = doc.selection(view.id).primary().cursor(text);
        let offset = text
            .chars_at(cursor)
            .reversed()
            .take_while(|ch| chars::char_is_word(*ch))
            .count();
        let start_offset = cursor.saturating_sub(offset);

        let fragment = doc.text().slice(start_offset..cursor);
        let mut completion = Self {
            popup,
            trigger_offset,
            // TODO: expand nucleo api to allow moving straight to a Utf32String here
            // and avoid allocation during matching
            filter: String::from(fragment),
            resolve_handler: ResolveHandler::default().spawn(),
        };

        // need to recompute immediately in case start_offset != trigger_offset
        completion
            .popup
            .contents_mut()
            .score(&completion.filter, false);

        completion
    }

    /// Synchronously resolve the given completion item. This is used when
    /// accepting a completion.
    fn resolve_completion_item(
        language_server: &helix_lsp::Client,
        completion_item: lsp::CompletionItem,
    ) -> Option<lsp::CompletionItem> {
        let future = language_server.resolve_completion_item(completion_item)?;
        let response = helix_lsp::block_on(future);
        match response {
            Ok(item) => Some(item),
            Err(err) => {
                log::error!("Failed to resolve completion item: {}", err);
                None
            }
        }
    }

    /// Appends (`c: Some(c)`) or removes (`c: None`) a character to/from the filter
    /// this should be called whenever the user types or deletes a character in insert mode.
    pub fn update_filter(&mut self, c: Option<char>) {
        // recompute menu based on matches
        let menu = self.popup.contents_mut();
        match c {
            Some(c) => self.filter.push(c),
            None => {
                self.filter.pop();
                if self.filter.is_empty() {
                    menu.clear();
                    return;
                }
            }
        }
        menu.score(&self.filter, c.is_some());
    }

    pub fn is_empty(&self) -> bool {
        self.popup.contents().is_empty()
    }

    fn replace_item(&mut self, old_item: CompletionItem, new_item: CompletionItem) {
        self.popup.contents_mut().replace_option(old_item, new_item);
    }

    pub fn area(&mut self, viewport: Rect, editor: &Editor) -> Rect {
        self.popup.area(viewport, editor)
    }
}

impl Component for Completion {
    fn handle_event(&mut self, event: &Event, cx: &mut Context) -> EventResult {
        self.popup.handle_event(event, cx)
    }

    fn required_size(&mut self, viewport: (u16, u16)) -> Option<(u16, u16)> {
        self.popup.required_size(viewport)
    }

    fn render(&mut self, area: Rect, surface: &mut Surface, cx: &mut Context) {
        self.popup.render(area, surface, cx);

        // if we have a selection, render a markdown popup on top/below with info
        let option = match self.popup.contents().selection() {
            Some(option) => option,
            None => return,
        };
        if !option.resolved {
            helix_event::send_blocking(&self.resolve_handler, option.clone());
        }
        // need to render:
        // option.detail
        // ---
        // option.documentation

        let (view, doc) = current!(cx.editor);
        let language = doc.language_name().unwrap_or("");
        let text = doc.text().slice(..);
        let cursor_pos = doc.selection(view.id).primary().cursor(text);
        let coords = view
            .screen_coords_at_pos(doc, text, cursor_pos)
            .expect("cursor must be in view");
        let cursor_pos = coords.row as u16;

        let markdowned = |lang: &str, detail: Option<&str>, doc: Option<&str>| {
            let md = match (detail, doc) {
                (Some(detail), Some(doc)) => format!("```{lang}\n{detail}\n```\n{doc}"),
                (Some(detail), None) => format!("```{lang}\n{detail}\n```"),
                (None, Some(doc)) => doc.to_string(),
                (None, None) => String::new(),
            };
            Markdown::new(md, cx.editor.syn_loader.clone())
        };

        let mut markdown_doc = match &option.item.documentation {
            Some(lsp::Documentation::String(contents))
            | Some(lsp::Documentation::MarkupContent(lsp::MarkupContent {
                kind: lsp::MarkupKind::PlainText,
                value: contents,
            })) => {
                // TODO: convert to wrapped text
                markdowned(language, option.item.detail.as_deref(), Some(contents))
            }
            Some(lsp::Documentation::MarkupContent(lsp::MarkupContent {
                kind: lsp::MarkupKind::Markdown,
                value: contents,
            })) => {
                // TODO: set language based on doc scope
                markdowned(language, option.item.detail.as_deref(), Some(contents))
            }
            None if option.item.detail.is_some() => {
                // TODO: set language based on doc scope
                markdowned(language, option.item.detail.as_deref(), None)
            }
            None => return,
        };

        let popup_area = {
            let (popup_x, popup_y) = self.popup.get_rel_position(area, cx.editor);
            let (popup_width, popup_height) = self.popup.get_size();
            Rect::new(popup_x, popup_y, popup_width, popup_height)
        };

        let doc_width_available = area.width.saturating_sub(popup_area.right());
        let doc_area = if doc_width_available > 30 {
            let mut doc_width = doc_width_available;
            let mut doc_height = area.height.saturating_sub(popup_area.top());
            let x = popup_area.right();
            let y = popup_area.top();

            if let Some((rel_width, rel_height)) =
                markdown_doc.required_size((doc_width, doc_height))
            {
                doc_width = rel_width.min(doc_width);
                doc_height = rel_height.min(doc_height);
            }
            Rect::new(x, y, doc_width, doc_height)
        } else {
            // Documentation should not cover the cursor or the completion popup
            // Completion popup could be above or below the current line
            let avail_height_above = cursor_pos.min(popup_area.top()).saturating_sub(1);
            let avail_height_below = area
                .height
                .saturating_sub(cursor_pos.max(popup_area.bottom()) + 1 /* padding */);
            let (y, avail_height) = if avail_height_below >= avail_height_above {
                (
                    area.height.saturating_sub(avail_height_below),
                    avail_height_below,
                )
            } else {
                (0, avail_height_above)
            };
            if avail_height <= 1 {
                return;
            }

            Rect::new(0, y, area.width, avail_height.min(15))
        };

        // clear area
        let background = cx.editor.theme.get("ui.popup");
        surface.clear_with(doc_area, background);

        if cx.editor.popup_border() {
            use tui::widgets::{Block, Borders, Widget};
            Widget::render(Block::default().borders(Borders::ALL), doc_area, surface);
        }

        markdown_doc.render(doc_area, surface, cx);
    }
}

/// A hook for resolving incomplete completion items.
///
/// From the [LSP spec](https://microsoft.github.io/language-server-protocol/specifications/lsp/3.17/specification/#textDocument_completion):
///
/// > If computing full completion items is expensive, servers can additionally provide a
/// > handler for the completion item resolve request. ...
/// > A typical use case is for example: the `textDocument/completion` request doesn't fill
/// > in the `documentation` property for returned completion items since it is expensive
/// > to compute. When the item is selected in the user interface then a
/// > 'completionItem/resolve' request is sent with the selected completion item as a parameter.
/// > The returned completion item should have the documentation property filled in.
#[derive(Debug, Default)]
struct ResolveHandler {
    trigger: Option<CompletionItem>,
    request: Option<helix_event::CancelTx>,
}

impl AsyncHook for ResolveHandler {
    type Event = CompletionItem;

    fn handle_event(
        &mut self,
        item: Self::Event,
        timeout: Option<tokio::time::Instant>,
    ) -> Option<tokio::time::Instant> {
        if self
            .trigger
            .as_ref()
            .is_some_and(|trigger| trigger == &item)
        {
            timeout
        } else {
            self.trigger = Some(item);
            self.request = None;
            Some(Instant::now() + Duration::from_millis(150))
        }
    }

    fn finish_debounce(&mut self) {
        let Some(item) = self.trigger.take() else { return };
        let (tx, rx) = helix_event::cancelation();
        self.request = Some(tx);
        job::dispatch_blocking(move |editor, _| resolve_completion_item(editor, item, rx))
    }
}

fn resolve_completion_item(
    editor: &mut Editor,
    item: CompletionItem,
    cancel: helix_event::CancelRx,
) {
    let Some(language_server) = editor.language_server_by_id(item.language_server_id) else {
        return;
    };

    let Some(future) = language_server.resolve_completion_item(item.item.clone()) else {
        return;
    };

    tokio::spawn(async move {
        match helix_event::cancelable_future(future, cancel).await {
            Some(Ok(resolved_item)) => {
                job::dispatch(move |_, compositor| {
                    if let Some(completion) = &mut compositor
                        .find::<crate::ui::EditorView>()
                        .unwrap()
                        .completion
                    {
                        let resolved_item = CompletionItem {
                            item: resolved_item,
                            language_server_id: item.language_server_id,
                            resolved: true,
                        };

                        completion.replace_item(item, resolved_item);
                    };
                })
                .await
            }
            Some(Err(err)) => log::error!("completion resolve request failed: {err}"),
            None => (),
        }
    });
}