From 8c2e447b16e4d11db411b18f2fbe3ac2bc031d89 Mon Sep 17 00:00:00 2001
From: Andrii Grynenko
Date: Thu, 2 Mar 2023 21:41:06 -0800
Subject: Handle snippets for LSPs not providing offsets for completion

---
 helix-term/src/ui/completion.rs | 95 +++++++++++++++++++++++------------------
 1 file changed, 54 insertions(+), 41 deletions(-)

(limited to 'helix-term')

diff --git a/helix-term/src/ui/completion.rs b/helix-term/src/ui/completion.rs
index e7815e12..85931fe3 100644
--- a/helix-term/src/ui/completion.rs
+++ b/helix-term/src/ui/completion.rs
@@ -121,8 +121,9 @@ impl Completion {
                 include_placeholder: bool,
             ) -> Transaction {
                 use helix_lsp::snippet;
+                let selection = doc.selection(view_id);
 
-                if let Some(edit) = &item.text_edit {
+                let (start_offset, end_offset, new_text) = if let Some(edit) = &item.text_edit {
                     let edit = match edit {
                         lsp::CompletionTextEdit::Edit(edit) => edit.clone(),
                         lsp::CompletionTextEdit::InsertAndReplace(item) => {
@@ -130,46 +131,27 @@ impl Completion {
                             lsp::TextEdit::new(item.replace, item.new_text.clone())
                         }
                     };
-
-                    if matches!(item.kind, Some(lsp::CompletionItemKind::SNIPPET))
-                        || matches!(
-                            item.insert_text_format,
-                            Some(lsp::InsertTextFormat::SNIPPET)
-                        )
-                    {
-                        match snippet::parse(&edit.new_text) {
-                            Ok(snippet) => util::generate_transaction_from_snippet(
-                                doc.text(),
-                                doc.selection(view_id),
-                                &edit.range,
-                                snippet,
-                                doc.line_ending.as_str(),
-                                include_placeholder,
-                                offset_encoding,
-                            ),
-                            Err(err) => {
-                                log::error!(
-                                    "Failed to parse snippet: {:?}, remaining output: {}",
-                                    &edit.new_text,
-                                    err
-                                );
-                                Transaction::new(doc.text())
-                            }
-                        }
-                    } else {
-                        util::generate_transaction_from_completion_edit(
-                            doc.text(),
-                            doc.selection(view_id),
-                            edit,
-                            offset_encoding, // TODO: should probably transcode in Client
-                        )
-                    }
+                    let text = doc.text().slice(..);
+                    let primary_cursor = selection.primary().cursor(text);
+
+                    let start_offset =
+                        match util::lsp_pos_to_pos(doc.text(), edit.range.start, offset_encoding) {
+                            Some(start) => start as i128 - primary_cursor as i128,
+                            None => return Transaction::new(doc.text()),
+                        };
+                    let end_offset =
+                        match util::lsp_pos_to_pos(doc.text(), edit.range.end, offset_encoding) {
+                            Some(end) => end as i128 - primary_cursor as i128,
+                            None => return Transaction::new(doc.text()),
+                        };
+
+                    (start_offset, end_offset, edit.new_text)
                 } else {
-                    let text = item.insert_text.as_ref().unwrap_or(&item.label);
+                    let new_text = item.insert_text.as_ref().unwrap_or(&item.label);
                     // Some LSPs just give you an insertText with no offset ¯\_(ツ)_/¯
                     // in these cases we need to check for a common prefix and remove it
                     let prefix = Cow::from(doc.text().slice(start_offset..trigger_offset));
-                    let text = text.trim_start_matches::<&str>(&prefix);
+                    let new_text = new_text.trim_start_matches::<&str>(&prefix);
 
                     // TODO: this needs to be true for the numbers to work out correctly
                     // in the closure below. It's passed in to a callback as this same
@@ -182,11 +164,42 @@ impl Completion {
                             == trigger_offset
                     );
 
-                    Transaction::change_by_selection(doc.text(), doc.selection(view_id), |range| {
-                        let cursor = range.cursor(doc.text().slice(..));
+                    (0, 0, new_text.into())
+                };
 
-                        (cursor, cursor, Some(text.into()))
-                    })
+                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,
+                            start_offset,
+                            end_offset,
+                            snippet,
+                            doc.line_ending.as_str(),
+                            include_placeholder,
+                        ),
+                        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,
+                        start_offset,
+                        end_offset,
+                        new_text,
+                    )
                 }
             }
 
-- 
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