[ty] Add signature help provider to playground (#19276)

crates/ty_wasm/src/lib.rs

@@ -14,6 +14,7 @@ use ruff_notebook::Notebook;
 use ruff_python_formatter::formatted_file;
 use ruff_source_file::{LineIndex, OneIndexed, SourceLocation};
 use ruff_text_size::{Ranged, TextSize};
+use ty_ide::signature_help;
 use ty_ide::{MarkupKind, goto_type_definition, hover, inlay_hints};
 use ty_project::ProjectMetadata;
 use ty_project::metadata::options::Options;
@@ -385,6 +386,51 @@ impl Workspace {
 
         Ok(result)
     }
+
+    #[wasm_bindgen(js_name = "signatureHelp")]
+    pub fn signature_help(
+        &self,
+        file_id: &FileHandle,
+        position: Position,
+    ) -> Result<Option<SignatureHelp>, Error> {
+        let source = source_text(&self.db, file_id.file);
+        let index = line_index(&self.db, file_id.file);
+
+        let offset = position.to_text_size(&source, &index, self.position_encoding)?;
+
+        let Some(signature_help_info) = signature_help(&self.db, file_id.file, offset) else {
+            return Ok(None);
+        };
+
+        let signatures = signature_help_info
+            .signatures
+            .into_iter()
+            .map(|sig| {
+                let parameters = sig
+                    .parameters
+                    .into_iter()
+                    .map(|param| ParameterInformation {
+                        label: param.label,
+                        documentation: param.documentation,
+                    })
+                    .collect();
+
+                SignatureInformation {
+                    label: sig.label,
+                    documentation: sig.documentation,
+                    parameters,
+                    active_parameter: sig.active_parameter.and_then(|p| u32::try_from(p).ok()),
+                }
+            })
+            .collect();
+
+        Ok(Some(SignatureHelp {
+            signatures,
+            active_signature: signature_help_info
+                .active_signature
+                .and_then(|s| u32::try_from(s).ok()),
+        }))
+    }
 }
 
 pub(crate) fn into_error<E: std::fmt::Display>(err: E) -> Error {
@@ -749,6 +795,35 @@ pub struct SemanticToken {
     pub range: Range,
 }
 
+#[wasm_bindgen]
+#[derive(Clone)]
+pub struct SignatureHelp {
+    #[wasm_bindgen(getter_with_clone)]
+    pub signatures: Vec<SignatureInformation>,
+    pub active_signature: Option<u32>,
+}
+
+#[wasm_bindgen]
+#[derive(Clone)]
+pub struct SignatureInformation {
+    #[wasm_bindgen(getter_with_clone)]
+    pub label: String,
+    #[wasm_bindgen(getter_with_clone)]
+    pub documentation: Option<String>,
+    #[wasm_bindgen(getter_with_clone)]
+    pub parameters: Vec<ParameterInformation>,
+    pub active_parameter: Option<u32>,
+}
+
+#[wasm_bindgen]
+#[derive(Clone)]
+pub struct ParameterInformation {
+    #[wasm_bindgen(getter_with_clone)]
+    pub label: String,
+    #[wasm_bindgen(getter_with_clone)]
+    pub documentation: Option<String>,
+}
+
 #[wasm_bindgen]
 impl SemanticToken {
     pub fn kinds() -> Vec<String> {

playground/ty/src/Editor/Editor.tsx

@@ -152,7 +152,8 @@ class PlaygroundServer
     languages.DocumentFormattingEditProvider,
     languages.CompletionItemProvider,
     languages.DocumentSemanticTokensProvider,
-    languages.DocumentRangeSemanticTokensProvider
+    languages.DocumentRangeSemanticTokensProvider,
+    languages.SignatureHelpProvider
 {
   private typeDefinitionProviderDisposable: IDisposable;
   private editorOpenerDisposable: IDisposable;
@@ -162,6 +163,7 @@ class PlaygroundServer
   private completionDisposable: IDisposable;
   private semanticTokensDisposable: IDisposable;
   private rangeSemanticTokensDisposable: IDisposable;
+  private signatureHelpDisposable: IDisposable;
 
   constructor(
     private monaco: Monaco,
@@ -191,9 +193,13 @@ class PlaygroundServer
     this.editorOpenerDisposable = monaco.editor.registerEditorOpener(this);
     this.formatDisposable =
       monaco.languages.registerDocumentFormattingEditProvider("python", this);
+    this.signatureHelpDisposable =
+      monaco.languages.registerSignatureHelpProvider("python", this);
   }
 
   triggerCharacters: string[] = ["."];
+  signatureHelpTriggerCharacters: string[] = ["(", ","];
+  signatureHelpRetriggerCharacters: string[] = [")"];
 
   getLegend(): languages.SemanticTokensLegend {
     return {
@@ -292,6 +298,61 @@ class PlaygroundServer
 
   resolveCompletionItem: undefined;
 
+  provideSignatureHelp(
+    model: editor.ITextModel,
+    position: Position,
+    // eslint-disable-next-line @typescript-eslint/no-unused-vars
+    _token: CancellationToken,
+    // eslint-disable-next-line @typescript-eslint/no-unused-vars
+    _context: languages.SignatureHelpContext,
+  ): languages.ProviderResult<languages.SignatureHelpResult> {
+    const selectedFile = this.props.files.selected;
+
+    if (selectedFile == null) {
+      return;
+    }
+
+    const selectedHandle = this.props.files.handles[selectedFile];
+
+    if (selectedHandle == null) {
+      return;
+    }
+
+    const signatureHelp = this.props.workspace.signatureHelp(
+      selectedHandle,
+      new TyPosition(position.lineNumber, position.column),
+    );
+
+    if (signatureHelp == null) {
+      return undefined;
+    }
+
+    return {
+      dispose() {},
+      value: {
+        signatures: signatureHelp.signatures.map((sig) => ({
+          label: sig.label,
+          documentation: sig.documentation
+            ? { value: sig.documentation }
+            : undefined,
+          parameters: sig.parameters.map((param) => ({
+            label: param.label,
+            documentation: param.documentation
+              ? { value: param.documentation }
+              : undefined,
+          })),
+          activeParameter: sig.active_parameter,
+        })),
+        activeSignature: signatureHelp.active_signature ?? 0,
+        activeParameter:
+          signatureHelp.active_signature != null
+            ? (signatureHelp.signatures[signatureHelp.active_signature]
+                ?.active_parameter ?? 0)
+            : 0,
+      },
+    };
+  }
+
   provideInlayHints(
     _model: editor.ITextModel,
     range: Range,
@@ -569,6 +630,7 @@ class PlaygroundServer
     this.rangeSemanticTokensDisposable.dispose();
     this.semanticTokensDisposable.dispose();
     this.completionDisposable.dispose();
+    this.signatureHelpDisposable.dispose();
   }
 }