package main

import (
	"context"
	"log"
	"net"
	"os/signal"
	"syscall"
	"time"

	"github.com/mkelcik/cloudflare-ddns-update/internal"
	"github.com/mkelcik/cloudflare-ddns-update/internal/dns_providers"
	"github.com/mkelcik/cloudflare-ddns-update/internal/dns_resolver"
	"github.com/mkelcik/cloudflare-ddns-update/notifications"
	"github.com/mkelcik/cloudflare-ddns-update/public_resolvers"
)

type PublicIpResolver interface {
	ResolvePublicIp(ctx context.Context) (net.IP, error)
}

func getResolver(resolverName string) (PublicIpResolver, string) {
	switch resolverName {
	// HERE add another resolver if needed
	case public_resolvers.CloudflareTraceTag:
		return public_resolvers.NewDefaultCloudflareTrace(), public_resolvers.CloudflareTraceTag
	case public_resolvers.V4IdentMeTag:
		return public_resolvers.NewV4IdentMeDefault(), public_resolvers.V4IdentMeTag
	case public_resolvers.IcanhazipTag:
		return public_resolvers.NewIcanhazipDefault(), public_resolvers.IcanhazipTag
	case public_resolvers.IfConfigMeTag:
		fallthrough
	default:
		return public_resolvers.NewDefaultIfConfigMe(), public_resolvers.IfConfigMeTag
	}
}

func getProvider(ctx context.Context, config internal.Config) (dns_providers.DNSProvider, string) {
	switch config.DNSProviderTag {
	case dns_providers.DirectadminTag:
		return dns_providers.NewDirectAdminProvider(ctx, config), dns_providers.DirectadminTag
	case dns_providers.CloudflareTag:
		fallthrough
	default:
		return dns_providers.NewCloudflareProvider(ctx, config), dns_providers.CloudflareTag
	}
}

func main() {
	ctx, stop := signal.NotifyContext(context.Background(), syscall.SIGINT, syscall.SIGTERM)
	defer stop()

	config := internal.NewConfig()
	if err := config.Validate(); err != nil {
		log.Fatalln(err)
	}

	notifiers := notifications.GetNotifiers(config.Notifiers)

	// public ip resolver
	publicIpResolver, resolverTag := getResolver(config.PublicIpResolverTag)
	dnsProvider, providerTag := getProvider(ctx, config)
	log.Printf("Using DNS Provider %s", providerTag)

	checkFunc := func() {
		currentPublicIP, err := publicIpResolver.ResolvePublicIp(ctx)
		if err != nil {
			log.Fatal(err)
		}

		log.Printf("Current public ip `%s` (resolver: %s)", currentPublicIP, resolverTag)

		if err != nil {
			log.Fatal(err)
		}

		for _, dnsRecord := range config.DnsRecordsToCheck {
			current_dns_record := dns_resolver.ResolveHostname(dnsRecord, "1.1.1.1")

			log.Printf("Checking record `%s` with current value `%s` ...", dnsRecord, current_dns_record.String())
			if currentPublicIP.String() == current_dns_record.String() {
				log.Println("OK")
				continue // no update needed
			}

			if err := dnsProvider.UpdateRecord(dnsRecord, currentPublicIP.String(), current_dns_record.String()); err != nil {
				log.Printf("error updating dns record: %s", err)
				continue
			}

			if err := notifiers.NotifyWithLog(ctx, notifications.Notification{
				OldIp:        net.ParseIP(string(current_dns_record)),
				NewIp:        currentPublicIP,
				CheckedAt:    time.Now(),
				ResolverTag:  resolverTag,
				Domain:       dnsRecord,
				WebhookToken: config.WebhookToken,
			}); err != nil {
				log.Printf("errors in notifications: %s", err)
			}
			log.Printf("Updated to `%s`", currentPublicIP)
		}
	}

	log.Printf("checking ...")
	checkFunc()

	log.Println("waiting for check tick ...")
	ticker := time.NewTicker(config.CheckInterval)
	defer ticker.Stop()
	for {
		select {
		case <-ticker.C:
			log.Println("tick received checking ...")
			checkFunc()
		case <-ctx.Done():
			break
		}
	}
}