Womp

.gitignore

@@ -0,0 +1 @@
+.gocache

jobs/clan_monitor_job.go

@@ -35,6 +35,7 @@ type ClanMonitorJob struct {
 	recipientID   string
 	clashClient   *clash.Client
 	discordClient *discord.Client
+	notified      map[string]time.Time
 }
 
 func newClanMonitorJobFromEnv() (*ClanMonitorJob, error) {
@@ -63,6 +64,7 @@ func newClanMonitorJobFromEnv() (*ClanMonitorJob, error) {
 		recipientID:   recipientID,
 		clashClient:   clash.NewClient(clashToken),
 		discordClient: discord.NewClient(discordToken),
+		notified:      make(map[string]time.Time),
 	}, nil
 }
 
@@ -107,7 +109,24 @@ func (j *ClanMonitorJob) Run(ctx context.Context) error {
 		return inactive[i].InactiveFor > inactive[j].InactiveFor
 	})
 
-	messages := buildMessages(inactive)
+	j.purgeResolved(inactive)
+
+	var newlyInactive []inactiveMember
+	for _, member := range inactive {
+		if _, alreadyNotified := j.notified[member.Tag]; alreadyNotified {
+			continue
+		}
+
+		newlyInactive = append(newlyInactive, member)
+		j.notified[member.Tag] = time.Now()
+		log.Printf("clan monitor: notifying inactivity for %s (%s); offline %s", member.Name, member.Tag, formatDuration(member.InactiveFor))
+	}
+
+	if len(newlyInactive) == 0 {
+		return nil
+	}
+
+	messages := buildMessages(newlyInactive)
 
 	for _, message := range messages {
 		if err := j.discordClient.SendDM(ctx, j.recipientID, message); err != nil {
@@ -123,6 +142,19 @@ type inactiveMember struct {
 	InactiveFor time.Duration
 }
 
+func (j *ClanMonitorJob) purgeResolved(inactive []inactiveMember) {
+	active := make(map[string]struct{}, len(inactive))
+	for _, member := range inactive {
+		active[member.Tag] = struct{}{}
+	}
+
+	for tag := range j.notified {
+		if _, stillInactive := active[tag]; !stillInactive {
+			delete(j.notified, tag)
+		}
+	}
+}
+
 func buildMessages(members []inactiveMember) []string {
 	header := fmt.Sprintf("Clan members inactive ≥ %s\n", formatDuration(offlineThreshold))
 	var chunks []string