package tracer

import (
	"context"
	"path"
	"runtime"
	"strings"

	"github.com/spf13/viper"
	"go.opentelemetry.io/otel"
	"go.opentelemetry.io/otel/attribute"
	"go.opentelemetry.io/otel/trace"
)

type AdditionSpanLayerInfo struct {
	LayerName string
	FuncName  string
	FilePath  string
	Line      int
}

func StartSpan(ctx context.Context, libName, spanName string, additionSpanLayer ...AdditionSpanLayerInfo) (context.Context, trace.Span) {
	var (
		finalFunc  string
		finalFile  string
		finalLine  int
		finalLayer string
	)

	if len(additionSpanLayer) > 0 {
		finalFunc = additionSpanLayer[0].FuncName
		finalFile = additionSpanLayer[0].FilePath
		finalLine = additionSpanLayer[0].Line
		finalLayer = additionSpanLayer[0].LayerName
	} else {
		pc, file, line, ok := runtime.Caller(1)
		if ok {
			finalFile = file
			finalLine = line
			if fn := runtime.FuncForPC(pc); fn != nil {
				finalFunc = fn.Name()
			}
			finalLayer = "undefined"
		}
	}

	tracer := otel.Tracer(path.Join(viper.GetString("server.application"), libName))
	return tracer.Start(ctx, path.Join(libName, spanName), trace.WithAttributes(
		attribute.String("code.function", finalFunc),
		attribute.String("code.file", ShortPath(finalFile)),
		attribute.Int("code.line", finalLine),
		attribute.String("trace.layer", finalLayer),
	))
}

func ShortPath(path string) string {
	parts := strings.Split(path, "cms-server/")
	if len(parts) > 1 {
		return "cms-server/" + parts[1]
	}
	return path
}