package trace

import (
	"context"
	"fmt"
	"go.opentelemetry.io/otel"
	"go.opentelemetry.io/otel/exporters/jaeger"
	"go.opentelemetry.io/otel/sdk/resource"
	sdktrace "go.opentelemetry.io/otel/sdk/trace"
	semconv "go.opentelemetry.io/otel/semconv/v1.4.0"

	"net/url"
	"sync"
)

const (
	kindJaeger = "jaeger"
)

var (
	lock sync.Mutex
	tp   *sdktrace.TracerProvider
)

func StartAgent(c Config) {
	lock.Lock()
	defer lock.Unlock()
	if err := startAgent(c); err != nil {
		return
	}
}
func StopAgent() {
	_ = tp.Shutdown(context.Background())
}

func createExporter(c Config) (sdktrace.SpanExporter, error) {
	//switch c.Batcher {
	//case kindJaeger:
	u, _ := url.Parse(c.Endpoint)
	if u.Scheme == "udp" {
		return jaeger.New(jaeger.WithAgentEndpoint(jaeger.WithAgentHost(u.Host), jaeger.WithAgentPort(u.Port())))
	}
	return jaeger.New(jaeger.WithCollectorEndpoint(jaeger.WithEndpoint(u.Host)))
	//}
}
func startAgent(c Config) error {
	opts := []sdktrace.TracerProviderOption{
		sdktrace.WithSampler(sdktrace.ParentBased(sdktrace.TraceIDRatioBased(c.Sampler))),
		sdktrace.WithResource(resource.NewSchemaless(semconv.ServiceNameKey.String(c.Name))),
	}
	if len(c.Endpoint) > 0 {
		exp, err := createExporter(c)
		if err != nil {
			return err
		}
		opts = append(opts, sdktrace.WithBatcher(exp))
	}
	tp = sdktrace.NewTracerProvider(opts...)
	otel.SetTracerProvider(tp)
	otel.SetErrorHandler(otel.ErrorHandlerFunc(func(err error) {
		fmt.Println("[otel]", err)
	}))
	return nil
}