package main

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

	"github.com/prometheus/client_golang/prometheus/promhttp"
)

func main() {
	cfgFile := flag.String("config", "config.yaml", "path to config file")
	flag.Parse()

	cfg, err := LoadConfig(*cfgFile)
	if err != nil {
		log.Fatalf("error loading config: %v", err)
	}

	// HTTP server für Prometheus
	http.Handle("/metrics", promhttp.Handler())
	go func() {
		log.Printf("listening on %s", cfg.ListenAddr)
		if err := http.ListenAndServe(cfg.ListenAddr, nil); err != nil {
			log.Fatalf("http server error: %v", err)
		}
	}()

	// Targets starten
	stop := make(chan struct{})
	for _, t := range cfg.Targets {
		settings := mergeSettings(cfg.Defaults, t)
		r := NewTargetRunner(t.Name, t.Host, settings)
		go r.Run(stop)
	}

	// sauber beenden
	sig := make(chan os.Signal, 1)
	signal.Notify(sig, os.Interrupt, syscall.SIGTERM)
	<-sig
	close(stop)
	fmt.Println("shutting down...")
}

func mergeSettings(def TargetSettings, t TargetConfig) TargetSettings {
	out := def

	if t.Interval != nil {
		out.Interval = *t.Interval
	}
	if t.Timeout != nil {
		out.Timeout = *t.Timeout
	}
	if t.Size != nil {
		out.Size = *t.Size
	}
	if t.HistorySize != nil {
		out.HistorySize = *t.HistorySize
	}
	if t.DNSServer != nil {
		out.DNSServer = *t.DNSServer
	}
	if t.DisableIPv6 != nil {
		out.DisableIPv6 = *t.DisableIPv6
	}

	return out
}