tsconfig.json

import * as vscode from 'vscode';

let output: vscode.OutputChannel;

export function activate(context: vscode.ExtensionContext) {
    output = vscode.window.createOutputChannel("Language Server Watchdog");
    output.appendLine("🐍 Watchdog started.");

    const interval = setInterval(async () => {
        const editor = vscode.window.activeTextEditor;
        if (!editor || editor.document.languageId !== 'python') {
            output.appendLine("📄 No active Python document – skipping check.");
            return;
        }

        try {
            const ok = await checkLanguageServerHealth(editor.document.uri);
            if (!ok) {
                output.appendLine("⚠️ Health check failed – attempting passive restart...");
                await passiveRecovery(editor.document);
            } else {
                output.appendLine("✅ Language Server is responsive.");
            }
        } catch (err) {
            output.appendLine(`❌ Unexpected error: ${err}`);
        }
    }, 30000); // alle 30 Sekunden

    context.subscriptions.push({
        dispose() {
            clearInterval(interval);
            output.appendLine("🛑 Watchdog stopped.");
        }
    });
}

export function deactivate() {
    output?.appendLine("🛑 Watchdog deactivated.");
    output?.dispose();
}

async function checkLanguageServerHealth(uri: vscode.Uri): Promise<boolean> {
    try {
        const result = await withTimeout(
            vscode.commands.executeCommand<vscode.DocumentSymbol[]>('vscode.executeDocumentSymbolProvider', uri),
            3000
        );
        return !!(result && result.length >= 0);
    } catch (e) {
        output.appendLine(`⏱ Timeout or error during health check: ${e}`);
        return false;
    }
}

async function passiveRecovery(doc: vscode.TextDocument) {
    try {
        const dummyChange = new vscode.WorkspaceEdit();
        const pos = new vscode.Position(0, 0);
        dummyChange.insert(doc.uri, pos, "");
        await vscode.workspace.applyEdit(dummyChange);
        await delay(500);
        output.appendLine("🔄 Triggered passive restart via empty insert.");
    } catch (err) {
        output.appendLine(`❌ Passive restart failed: ${err}`);
    }
}

function delay(ms: number): Promise<void> {
    return new Promise(resolve => setTimeout(resolve, ms));
}

function withTimeout<T>(promise: Thenable<T>, timeoutMs: number): Promise<T> {
    return new Promise((resolve, reject) => {
        const timeout = setTimeout(() => reject(new Error("Timeout")), timeoutMs);
        promise.then(result => {
            clearTimeout(timeout);
            resolve(result);
        }, err => {
            clearTimeout(timeout);
            reject(err);
        });
    });
}