package middleware

import (
	"fmt"
	"net/http"

	"github.com/gin-gonic/gin"
	"go.opentelemetry.io/otel"
	"go.opentelemetry.io/otel/attribute"
	"go.opentelemetry.io/otel/codes"
	"go.opentelemetry.io/otel/propagation"
	"go.opentelemetry.io/otel/trace"
)

func Tracing(tracer trace.Tracer) gin.HandlerFunc {
	return func(c *gin.Context) {
		ctx := otel.GetTextMapPropagator().Extract(c.Request.Context(), propagation.HeaderCarrier(c.Request.Header))
		spanName := fmt.Sprintf("%s %s", c.Request.Method, c.Request.URL.Path)

		ctx, span := tracer.Start(
			ctx,
			spanName,
			trace.WithSpanKind(trace.SpanKindServer),
			trace.WithAttributes(
				attribute.String("http.request.method", c.Request.Method),
			),
		)
		defer span.End()

		c.Request = c.Request.WithContext(ctx)
		c.Next()

		route := c.FullPath()
		if route == "" {
			route = "/unknown"
		}

		status := c.Writer.Status()
		span.SetName(fmt.Sprintf("%s %s", c.Request.Method, route))
		span.SetAttributes(
			attribute.String("http.route", route),
			attribute.Int("http.response.status_code", status),
		)

		if status >= http.StatusInternalServerError {
			span.SetStatus(codes.Error, http.StatusText(status))
		}
		if len(c.Errors) > 0 {
			for _, err := range c.Errors {
				span.RecordError(err)
			}
			span.SetStatus(codes.Error, c.Errors.String())
		}
	}
}