package main

import (
	"fmt"
	"net/http"
	"os"
	"os/signal"
	"syscall"

	"github.com/go-kit/kit/log"
	kitprometheus "github.com/go-kit/kit/metrics/prometheus"
	adapter "github.com/mainflux/mainflux/http"
	"github.com/mainflux/mainflux/http/api"
	"github.com/mainflux/mainflux/http/nats"
	broker "github.com/nats-io/go-nats"
	stdprometheus "github.com/prometheus/client_golang/prometheus"
)

const (
	port       int    = 7070
	defNatsURL string = broker.DefaultURL
	envNatsURL string = "HTTP_ADAPTER_NATS_URL"
)

type config struct {
	Port    int
	NatsURL string
}

func main() {
	cfg := config{
		Port:    port,
		NatsURL: env(envNatsURL, defNatsURL),
	}

	logger := log.NewJSONLogger(log.NewSyncWriter(os.Stdout))
	logger = log.With(logger, "ts", log.DefaultTimestampUTC)

	nc, err := broker.Connect(cfg.NatsURL)
	if err != nil {
		status := fmt.Sprintf("Cannot connect to NATS due to %s", err.Error())
		logger.Log("status", status)
		os.Exit(1)
	}
	defer nc.Close()

	repo := nats.NewMessageRepository(nc)
	svc := adapter.NewService(repo)

	svc = api.NewLoggingService(logger, svc)

	fields := []string{"method"}
	svc = api.NewMetricService(
		kitprometheus.NewCounterFrom(stdprometheus.CounterOpts{
			Namespace: "http_adapter",
			Subsystem: "api",
			Name:      "request_count",
			Help:      "Number of requests received.",
		}, fields),
		kitprometheus.NewSummaryFrom(stdprometheus.SummaryOpts{
			Namespace: "http_adapter",
			Subsystem: "api",
			Name:      "request_latency_microseconds",
			Help:      "Total duration of requests in microseconds.",
		}, fields),
		svc,
	)

	errs := make(chan error, 2)

	go func() {
		p := fmt.Sprintf(":%d", cfg.Port)
		logger.Log("status", "HTTP adapter started.")
		errs <- http.ListenAndServe(p, api.MakeHandler(svc))
	}()

	go func() {
		c := make(chan os.Signal)
		signal.Notify(c, syscall.SIGINT)
		errs <- fmt.Errorf("%s", <-c)
	}()

	status := fmt.Sprintf("HTTP adapter stopped due to %s", <-errs)
	logger.Log("status", status)
}

func env(key, fallback string) string {
	value := os.Getenv(key)
	if value == "" {
		return fallback
	}

	return value
}