feat: notification provider (#8)

Co-authored-by: Timo Behrendt <t.behrendt@t00n.de>
Co-committed-by: Timo Behrendt <t.behrendt@t00n.de>

pkg/changeDetector/changeDetector.go

@@ -1,26 +1,31 @@
 package changeDetector
 
 import (
+	"fmt"
 	"realdnydns/pkg/config"
 	"realdnydns/pkg/dnsProvider"
 	"realdnydns/pkg/externalIpProvider"
+	"realdnydns/pkg/notificationProvider"
 )
 
 type ChangeDetector struct {
-	externalIpProvider externalIpProvider.ExternalIpProvider
-	dnsProvider        dnsProvider.DNSProvider
-	domains            []config.DomainConfig
+	externalIpProvider   externalIpProvider.ExternalIpProvider
+	dnsProvider          dnsProvider.DNSProvider
+	notificationProvider notificationProvider.NotificationProvider
+	domains              []config.DomainConfig
 }
 
 func New(
 	externalIpProvider externalIpProvider.ExternalIpProvider,
 	dnsProvider dnsProvider.DNSProvider,
+	notificationProvider notificationProvider.NotificationProvider,
 	domains []config.DomainConfig,
 ) ChangeDetector {
 	return ChangeDetector{
-		externalIpProvider: externalIpProvider,
-		dnsProvider:        dnsProvider,
-		domains:            domains,
+		externalIpProvider:   externalIpProvider,
+		dnsProvider:          dnsProvider,
+		notificationProvider: notificationProvider,
+		domains:              domains,
 	}
 }
 
@@ -40,6 +45,14 @@ func (c *ChangeDetector) DetectAndApplyChanges() (int, error) {
 			}
 
 			if currentRecord.IP != externalIp.String() {
+				err = c.notificationProvider.SendNotification(
+					fmt.Sprintf("Update %s.%s", subdomain, domain.TLD),
+					fmt.Sprintf("The IP of %s has changed from %s to %s", domain.TLD, currentRecord.IP, externalIp.String()),
+				)
+				if err != nil {
+					return numberUpdated, err
+				}
+
 				_, err = c.dnsProvider.UpdateRecord(domain.TLD, subdomain, externalIp, currentRecord.TTL, currentRecord.Prio, currentRecord.Disabled)
 				numberUpdated++
 				if err != nil {