1 files changed, 115 insertions, 0 deletions
diff --git a/extension/src/activation/languageClient.ts b/extension/src/activation/languageClient.ts
new file mode 100644
index 00000000..5b0bd612
--- /dev/null
+++ b/extension/src/activation/languageClient.ts
@@ -0,0 +1,115 @@
+/**
+ * If we wanted to run or use another language server from our extension, this is how we would do it.
+ */
+
+import * as path from "path";
+import { workspace, ExtensionContext, extensions } from "vscode";
+
+import {
+  DefinitionParams,
+  LanguageClient,
+  LanguageClientOptions,
+  ServerOptions,
+  StateChangeEvent,
+  TransportKind,
+  State,
+} from "vscode-languageclient/node";
+import { getExtensionUri } from "../util/vscode";
+
+let client: LanguageClient;
+
+export async function startLanguageClient(context: ExtensionContext) {
+  let pythonLS = startPythonLanguageServer(context);
+  pythonLS.start();
+}
+
+export async function makeRequest(method: string, param: any): Promise<any> {
+  if (!client) {
+    return;
+  } else if (client.state === State.Starting) {
+    return new Promise((resolve, reject) => {
+      let stateListener = client.onDidChangeState((e: StateChangeEvent) => {
+        if (e.newState === State.Running) {
+          stateListener.dispose();
+          resolve(client.sendRequest(method, param));
+        } else if (e.newState === State.Stopped) {
+          stateListener.dispose();
+          reject(new Error("Language server stopped unexpectedly"));
+        }
+      });
+    });
+  } else {
+    return client.sendRequest(method, param);
+  }
+}
+
+export function deactivate(): Thenable<void> | undefined {
+  if (!client) {
+    return undefined;
+  }
+  return client.stop();
+}
+
+function startPythonLanguageServer(context: ExtensionContext): LanguageClient {
+  let extensionPath = getExtensionUri().fsPath;
+  const command = `cd ${path.join(
+    extensionPath,
+    "scripts"
+  )} && source env/bin/activate.fish && python -m pyls`;
+  const serverOptions: ServerOptions = {
+    command: command,
+    args: ["-vv"],
+  };
+  const clientOptions: LanguageClientOptions = {
+    documentSelector: ["python"],
+    synchronize: {
+      configurationSection: "pyls",
+    },
+  };
+  return new LanguageClient(command, serverOptions, clientOptions);
+}
+
+async function startPylance(context: ExtensionContext) {
+  let pylance = extensions.getExtension("ms-python.vscode-pylance");
+  await pylance?.activate();
+  if (!pylance) {
+    return;
+  }
+  let { path: lsPath } = await pylance.exports.languageServerFolder();
+
+  // The server is implemented in node
+  let serverModule = context.asAbsolutePath(lsPath);
+  // The debug options for the server
+  // --inspect=6009: runs the server in Node's Inspector mode so VS Code can attach to the server for debugging
+  let debugOptions = { execArgv: ["--nolazy", "--inspect=6009"] };
+
+  // If the extension is launched in debug mode then the debug server options are used
+  // Otherwise the run options are used
+  let serverOptions: ServerOptions = {
+    run: { module: serverModule, transport: TransportKind.ipc },
+    debug: {
+      module: serverModule,
+      transport: TransportKind.ipc,
+      options: debugOptions,
+    },
+  };
+
+  // Options to control the language client
+  let clientOptions: LanguageClientOptions = {
+    // Register the server for plain text documents
+    documentSelector: [{ scheme: "file", language: "python" }],
+    synchronize: {
+      // Notify the server about file changes to '.clientrc files contained in the workspace
+      fileEvents: workspace.createFileSystemWatcher("**/.clientrc"),
+    },
+  };
+
+  // Create the language client and start the client.
+  client = new LanguageClient(
+    "languageServerExample",
+    "Language Server Example",
+    serverOptions,
+    clientOptions
+  );
+  return client;
+}