package tracing

import (
	"context"
	"github.com/gin-gonic/gin"
	"go.opentelemetry.io/otel"
	"go.opentelemetry.io/otel/exporters/jaeger"
	"go.opentelemetry.io/otel/propagation"
	"go.opentelemetry.io/otel/sdk/resource"
	tracesdk "go.opentelemetry.io/otel/sdk/trace"
	semconv "go.opentelemetry.io/otel/semconv/v1.12.0"
	"go.opentelemetry.io/otel/trace"
)

// NewTracerProvider returns an OpenTelemetry TracerProvider configured to use
// the Jaeger exporter that will send spans to the provided url. The returned
// TracerProvider will also use a Resource configured with all the information
// about the application.
func NewTracerProvider(serviceName, version, serviceID, url string) (*tracesdk.TracerProvider, error) {
	// Create the Jaeger exporter
	exp, err := jaeger.New(jaeger.WithCollectorEndpoint(jaeger.WithEndpoint(url)))
	if err != nil {
		return nil, err
	}
	tp := tracesdk.NewTracerProvider(
		tracesdk.WithBatcher(exp),
		tracesdk.WithResource(resource.NewWithAttributes(
			semconv.SchemaURL,
			semconv.ServiceNameKey.String(serviceName),
			semconv.ServiceVersionKey.String(version),
			semconv.ServiceInstanceIDKey.String(serviceID),
		)),
		tracesdk.WithSampler(tracesdk.AlwaysSample()),
	)
	otel.SetTracerProvider(tp)
	otel.SetTextMapPropagator(propagation.NewCompositeTextMapPropagator(propagation.TraceContext{}, propagation.Baggage{}))
	return tp, nil
}

//	func TracingContextWrapper(next http.Handler) http.Handler {
//		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
//			propagator, md := otel.GetTextMapPropagator(), make(metadata.Metadata)
//			propagator.Inject(r.Context(), propagation.MapCarrier(md))
//			r2 := r.WithContext(metadata.NewContext(r.Context(), md))
//			next.ServeHTTP(w, r2)
//		})
//	}

func NewTracingContextWrapper() gin.HandlerFunc {
	return func(c *gin.Context) {
		propagator := otel.GetTextMapPropagator()

		// 从 Gin 上下文中提取 HTTP 请求头
		md := make(map[string]string)
		propagator.Inject(c.Request.Context(), propagation.HeaderCarrier(c.Request.Header))
		propagator.Inject(c.Request.Context(), propagation.MapCarrier(md))

		// 创建包含提取的元数据的新 Gin 上下文
		ctx := trace.ContextWithSpan(c.Request.Context(), trace.SpanFromContext(c.Request.Context()))
		ctx = context.WithValue(ctx, "metadata", md)
		c.Request = c.Request.WithContext(ctx)

		// 继续处理请求
		c.Next()
	}
}