const { NewTelemetryClient, Exporters, Instrumentation } = require('@vtex/diagnostics-nodejs');

async function main() {
  // 1. Initialize the telemetry client. This MUST be done before importing Express.
  const telemetryClient = await NewTelemetryClient(
    'my-client-name', // Name of the client/app instance
    'my-service-name' // Name of the service
  );

  // 2. Create the traces client, passing the desired instrumentations.
  const tracesClient = await telemetryClient.newTracesClient({
    exporter: Exporters.CreateExporter(Exporters.CreateTracesExporterConfig({ endpoint: 'localhost:4317' }), 'otlp'),
    instrumentations: Instrumentation.CommonInstrumentations.express(), // <-- Instrumentation bundle for Express
  });

  // 3. Create clients for logs and metrics as needed
  const logsClient = await telemetryClient.newLogsClient({ /* ... */ });
  const metricsClient = await telemetryClient.newMetricsClient({ /* ... */ });
  
  // 4. Now, it's safe to import Express and other instrumented modules.
  const express = require('express');
  const app = express();
  
  app.get('/hello', (req, res) => {
    // This request is automatically traced.
    logsClient.info('Hello endpoint was called');
    res.json({ message: 'Hello World!' });
  });

  app.listen(3000, () => console.log('Server running on port 3000'));

  // Graceful shutdown
  process.on('SIGTERM', async () => {
    await tracesClient.shutdown();
  });
}

main().catch(console.error);

const { Instrumentation } = require('@vtex/diagnostics-nodejs');

// Choose ONE of the following bundles:
const myInstrumentations = Instrumentation.CommonInstrumentations.express(); // For Express.js
const myInstrumentations = Instrumentation.CommonInstrumentations.fastify(); // For Fastify
const myInstrumentations = Instrumentation.CommonInstrumentations.koa();     // For Koa
const myInstrumentations = Instrumentation.CommonInstrumentations.nestjs();  // For NestJS
const myInstrumentations = Instrumentation.CommonInstrumentations.minimal(); // Basic HTTP/Net only

// --- Then, pass it in the config ---
const tracesClient = await telemetryClient.newTracesClient({
  exporter: myExporter,
  instrumentations: myInstrumentations, // <-- Here
});

const { MongoDBInstrumentation } = require('@opentelemetry/instrumentation-mongodb');
const { RedisInstrumentation } = require('@opentelemetry/instrumentation-redis');

const tracesClient = await telemetryClient.newTracesClient({
  exporter: myExporter,
  instrumentations: [
    ...Instrumentation.CommonInstrumentations.express(), // Keep the default bundle
    new MongoDBInstrumentation(),
    new RedisInstrumentation(),
  ],
});

// Start a manual span
const span = tracesClient.startSpan('my-operation');

try {
  // Your business logic
  span.setAttributes({ 
    'my.attribute': 'value',
    'operation.type': 'data-processing'
  });
  
  // Record an event
  span.addEvent('processing-started', { 'items.count': 100 });
  
} catch (error) {
  span.recordException(error);
  span.setStatus({ code: 2, message: error.message }); // 2 = ERROR
  throw error;
} finally {
  span.end();
}

const { Metrics } = require('@vtex/diagnostics-nodejs');
const { WithDescription, WithUnit, WithBuckets } = Metrics;

// Create a counter
const requestCounter = metricsClient.createCounter('http_requests_total', [
  WithDescription('Total HTTP requests processed'),
  WithUnit('1')
]);

// Create a histogram with custom buckets
const responseTimeHistogram = metricsClient.createHistogram('response_time_seconds', [
  WithDescription('HTTP response time'),
  WithUnit('s'),
  WithBuckets([0.01, 0.05, 0.1, 0.5, 1, 5])
]);

// Usage
requestCounter.add(1, { method: 'GET', route: '/api/users' });
responseTimeHistogram.record(0.25, { method: 'POST', status: '200' });

// Log with different levels and structured attributes
logsClient.info('Application started', { 
  version: '1.0.0',
  environment: 'production',
});

logsClient.warn('Resource usage high', { 
  cpu: 0.85,
  memory: 0.72,
});

try {
  throw new Error('Database connection failed');
} catch (err) {
  logsClient.error('Operation failed', { 
    error: err.message,
    operation: 'database_connect'
  });
}

// Local Development
const config = Exporters.CreateTracesExporterConfig({
  endpoint: 'localhost:4317'
});

// Production with TLS
const config = Exporters.CreateTracesExporterConfig({
  endpoint: 'telemetry.your-domain.com:443'
});

const telemetryClient = await NewTelemetryClient('my-service', 'my-service', {
  additionalAttrs: {
    'service.instance.id': process.env.HOSTNAME,
  },
  envMappings: [
    { envVar: 'REGION', attributeName: 'cloud.region' },
  ],
  disableCloudDetect: false,
  disableK8sDetect: false,
});

const { Samplers, Providers } = require('@vtex/diagnostics-nodejs');

const accountProvider = Providers.AccountProvider.newStaticProvider({
  defaultRate: 0.1, // 10%
  accounts: {
    'my-special-account': 1.0 // 100%
  }
});

const tracesClient = await telemetryClient.newTracesClient({
  exporter: myExporter,
  instrumentations: myInstrumentations,
  sampler: Samplers.TracesSamplers.newVtexAccountSampler(accountProvider),
});