package main

import (
	"errors"
	"log"
	"os"
	"github.com/influxdata/kapacitor/udf/agent"
)

type createTagFromMeasurementNameHandler struct {
	agent *agent.Agent
}

func newcreateTagFromMeasurementNameHandler(agent *agent.Agent) *createTagFromMeasurementNameHandler {
	return &createTagFromMeasurementNameHandler{agent: agent}
}

// Return the InfoResponse. Describing the properties of this UDF agent.
func (*createTagFromMeasurementNameHandler) Info() (*agent.InfoResponse, error) {
	return &agent.InfoResponse{
		Wants:    agent.EdgeType_STREAM,
		Provides: agent.EdgeType_STREAM,
		Options: map[string]*agent.OptionInfo{},
	}, nil
}

// Initialze the handler based of the provided options.
func (*createTagFromMeasurementNameHandler) Init(r *agent.InitRequest) (*agent.InitResponse, error) {
	init := &agent.InitResponse{
		Success: true,
		Error:   "",
	}
	return init, nil
}

// Create a snapshot of the running state of the process.
func (*createTagFromMeasurementNameHandler) Snapshot() (*agent.SnapshotResponse, error) {
	return &agent.SnapshotResponse{}, nil
}

// Restore a previous snapshot.
func (*createTagFromMeasurementNameHandler) Restore(req *agent.RestoreRequest) (*agent.RestoreResponse, error) {
	return &agent.RestoreResponse{
		Success: true,
	}, nil
}

func (*createTagFromMeasurementNameHandler) BeginBatch(begin *agent.BeginBatch) error {
	return errors.New("batching not supported")
}

func (h *createTagFromMeasurementNameHandler) Point(point *agent.Point) error {
	point.Tags["measurementName"] = point.Name

	h.agent.Responses <- &agent.Response{
		Message: &agent.Response_Point{
			Point: point,
		},
	}
	return nil
}

func (*createTagFromMeasurementNameHandler) EndBatch(end *agent.EndBatch) error {
	return nil
}

// Stop the handler gracefully.
func (h *createTagFromMeasurementNameHandler) Stop() {
	close(h.agent.Responses)
}

func main() {
	a := agent.New(os.Stdin, os.Stdout)
	h := newcreateTagFromMeasurementNameHandler(a)
	a.Handler = h

	log.Println("Starting agent")
	a.Start()
	err := a.Wait()
	if err != nil {
		log.Fatal(err)
	}
}