package middleware

import (
	"encoding/json"
	"strconv"

	"finclip-app-manager/infrastructure/config"
	"github.com/gin-gonic/gin"
	"github.com/openzipkin/zipkin-go"
	"github.com/openzipkin/zipkin-go/model"
	zkHttp "github.com/openzipkin/zipkin-go/reporter/http"
)

var gTracer *zipkin.Tracer

func init() {
	if config.GetConfig().ZipKinUrl != "" && config.GetConfig().ZipKinSToS {
		reporter := zkHttp.NewReporter(config.GetConfig().ZipKinUrl)
		endpoint, err := zipkin.NewEndpoint(config.GetConfig().ServerName, "")
		if err != nil {
			log.Errorf("zipkin unable to create local endpoint: %v\n", err)
			return
		}
		nativeTracer, err := zipkin.NewTracer(reporter, zipkin.WithLocalEndpoint(endpoint))
		if err != nil {
			log.Errorf("zipkin unable to create tracer: %v\n", err)
			return
		}
		gTracer = nativeTracer
	}
}

func AddZipkinTraceSpan(c *gin.Context) {
	if gTracer != nil {
		spanContextStr := c.Request.Header.Get("Zipkin-Span-Context")
		var span zipkin.Span

		if spanContextStr != "" {
			var spanContext model.SpanContext
			json.Unmarshal([]byte(spanContextStr), &spanContext)
			span = gTracer.StartSpan(c.Request.URL.Path, zipkin.Parent(spanContext))
		} else {
			kongTraceId := c.Request.Header.Get("X-B3-Traceid")
			kongSpanId := c.Request.Header.Get("X-B3-Spanid") //X-B3-Spanid X-B3-Parentspanid X-B3-Sampled
			if kongTraceId != "" && kongSpanId != "" {
				var kongParentSpanContext model.SpanContext

				spandIdInt, _ := strconv.ParseUint(kongSpanId, 16, 64)
				kongParentSpanContext.ID = model.ID(spandIdInt)
				kongTraceIdIntHigh, _ := strconv.ParseUint(kongTraceId[0:16], 16, 64)
				kongTraceIdIntLow, _ := strconv.ParseUint(kongTraceId[16:], 16, 64)
				kongParentSpanContext.TraceID.High = kongTraceIdIntHigh
				kongParentSpanContext.TraceID.Low = kongTraceIdIntLow
				span = gTracer.StartSpan(c.Request.URL.Path, zipkin.Parent(kongParentSpanContext))
			} else {
				span = gTracer.StartSpan(c.Request.URL.Path)
			}
		}

		if config.GetConfig().ZipKinSToS { //需要调用其他服务
			spanBytes, _ := json.Marshal(span.Context())
			spanId := span.Context().ID.String()
			c.Set("zipkin_span_id", spanId)
			c.Set("zipkin_trace_span_id_"+spanId, string(spanBytes))
		}
		defer span.Finish()
	}

	c.Next()
}