package metrics

import (
	"context"
	"strconv"
	"time"

	"google.golang.org/grpc"
	"google.golang.org/grpc/status"
)

func UnaryServerInterceptor() grpc.UnaryServerInterceptor {
	return func(ctx context.Context, req any, info *grpc.UnaryServerInfo, handler grpc.UnaryHandler) (any, error) {
		start := time.Now()
		resp, err := handler(ctx, req)
		elapsed := time.Since(start).Seconds()

		code := "OK"
		if err != nil {
			if st, ok := status.FromError(err); ok {
				code = strconv.Itoa(int(st.Code()))
			} else {
				code = "Unknown"
			}
		}

		RPCDurationSeconds.WithLabelValues(info.FullMethod).Observe(elapsed)
		RPCRequestsTotal.WithLabelValues(info.FullMethod, code).Inc()

		return resp, err
	}
}