feat(lsp): implement show document request (#8865)

* feat(lsp): implement show document request

Implement [window.showDocument](https://microsoft.github.io/language-server-protocol/specifications/lsp/3.17/specification/#window_showDocument)
LSP server-sent request.

This PR builds on top of helix-editor#5820,
moves the external-URL opening functionality into shared crate-level
function that returns a callback that is now used by both the
`open_file` command as well as the window.showDocument handler if
the URL is marked as external.

* add return

* use vertical split

* refactor

---------

Co-authored-by: Michael Davis <mcarsondavis@gmail.com>

1 files changed, 70 insertions, 0 deletions

diff --git a/helix-term/src/application.rs b/helix-term/src/application.rs
index 01c120d0..1b0a06dd 100644
--- a/helix-term/src/application.rs
+++ b/helix-term/src/application.rs
@@ -3,6 +3,7 @@ use futures_util::Stream;
 use helix_core::{path::get_relative_path, pos_at_coords, syntax, Selection};
 use helix_lsp::{
     lsp::{self, notification::Notification},
+    util::lsp_range_to_range,
     LspProgressMap,
 };
 use helix_view::{
@@ -1100,6 +1101,13 @@ impl Application {
                         }
                         Ok(serde_json::Value::Null)
                     }
+                    Ok(MethodCall::ShowDocument(params)) => {
+                        let language_server = language_server!();
+                        let offset_encoding = language_server.offset_encoding();
+
+                        let result = self.handle_show_document(params, offset_encoding);
+                        Ok(json!(result))
+                    }
                 };
 
                 tokio::spawn(language_server!().reply(id, reply));
@@ -1108,6 +1116,68 @@ impl Application {
         }
     }
 
+    fn handle_show_document(
+        &mut self,
+        params: lsp::ShowDocumentParams,
+        offset_encoding: helix_lsp::OffsetEncoding,
+    ) -> lsp::ShowDocumentResult {
+        if let lsp::ShowDocumentParams {
+            external: Some(true),
+            uri,
+            ..
+        } = params
+        {
+            self.jobs.callback(crate::open_external_url_callback(uri));
+            return lsp::ShowDocumentResult { success: true };
+        };
+
+        let lsp::ShowDocumentParams {
+            uri,
+            selection,
+            take_focus,
+            ..
+        } = params;
+
+        let path = match uri.to_file_path() {
+            Ok(path) => path,
+            Err(err) => {
+                log::error!("unsupported file URI: {}: {:?}", uri, err);
+                return lsp::ShowDocumentResult { success: false };
+            }
+        };
+
+        let action = match take_focus {
+            Some(true) => helix_view::editor::Action::Replace,
+            _ => helix_view::editor::Action::VerticalSplit,
+        };
+
+        let doc_id = match self.editor.open(&path, action) {
+            Ok(id) => id,
+            Err(err) => {
+                log::error!("failed to open path: {:?}: {:?}", uri, err);
+                return lsp::ShowDocumentResult { success: false };
+            }
+        };
+
+        let doc = doc_mut!(self.editor, &doc_id);
+        if let Some(range) = selection {
+            // TODO: convert inside server
+            if let Some(new_range) = lsp_range_to_range(doc.text(), range, offset_encoding) {
+                let view = view_mut!(self.editor);
+
+                // we flip the range so that the cursor sits on the start of the symbol
+                // (for example start of the function).
+                doc.set_selection(view.id, Selection::single(new_range.head, new_range.anchor));
+                if action.align_view(view, doc.id()) {
+                    align_view(doc, view, Align::Center);
+                }
+            } else {
+                log::warn!("lsp position out of bounds - {:?}", range);
+            };
+        };
+        lsp::ShowDocumentResult { success: true }
+    }
+
     async fn claim_term(&mut self) -> std::io::Result<()> {
         let terminal_config = self.config.load().editor.clone().into();
         self.terminal.claim(terminal_config)