// EXAMPLE: otel_metrics
// HIDE_START
package main

import (
	"context"
	"log"
	"strconv"
	"time"

	redisotel "github.com/redis/go-redis/extra/redisotel-native/v9"
	"github.com/redis/go-redis/v9"
	"go.opentelemetry.io/otel"
	"go.opentelemetry.io/otel/exporters/otlp/otlpmetric/otlpmetricgrpc"
	"go.opentelemetry.io/otel/sdk/metric"
)

// ExampleClient_otel_metrics demonstrates how to enable OpenTelemetry metrics
// for Redis operations and export them to an OTLP collector.
func main() {
	ctx := context.Background()

	// HIDE_END

	// STEP_START otel_exporter_setup
	// Create OTLP exporter that sends metrics to the collector
	// Default endpoint is localhost:4317 (gRPC)
	exporter, err := otlpmetricgrpc.New(ctx,
		otlpmetricgrpc.WithInsecure(), // Use insecure for local development
		// For production, configure TLS and authentication:
		// otlpmetricgrpc.WithEndpoint("your-collector:4317"),
		// otlpmetricgrpc.WithTLSCredentials(...),
	)
	if err != nil {
		log.Fatalf("Failed to create OTLP exporter: %v", err)
	}
	// STEP_END

	// STEP_START otel_meter_provider
	// Create meter provider with periodic reader
	// Metrics are exported every 10 seconds
	meterProvider := metric.NewMeterProvider(
		metric.WithReader(
			metric.NewPeriodicReader(exporter,
				metric.WithInterval(10*time.Second),
			),
		),
	)
	defer func() {
		if err := meterProvider.Shutdown(ctx); err != nil {
			log.Printf("Error shutting down meter provider: %v", err)
		}
	}()

	// Set the global meter provider
	otel.SetMeterProvider(meterProvider)
	// STEP_END

	// STEP_START redis_client_setup
	// Create Redis client
	rdb := redis.NewClient(&redis.Options{
		Addr: "localhost:6379",
	})
	defer rdb.Close()

	// Initialize OTel instrumentation (uses global meter provider)
	if err := redisotel.Init(rdb); err != nil {
		log.Fatalf("Failed to initialize OTel: %v", err)
	}
	defer redisotel.Shutdown()
	// STEP_END

	// STEP_START redis_operations
	// Execute Redis operations - metrics are automatically collected
	log.Println("Executing Redis operations...")
	for i := range 100 {
		if err := rdb.Set(ctx, "key"+strconv.Itoa(i), "value", 0).Err(); err != nil {
			log.Printf("Error setting key: %v", err)
		}
		time.Sleep(time.Millisecond * 100)
	}
	log.Println("Operations complete. Waiting for metrics to be exported...")

	// Wait for metrics to be exported
	time.Sleep(15 * time.Second)
	// STEP_END
}