internal/delivery/telegramsink/intake.go

@@ -14,6 +14,7 @@ package telegramsink
 import (
 	"context"
 	"errors"
+	"fmt"
 	"log"
 	"net/http"
 	"strings"
@@ -58,6 +59,13 @@ func NewPoller(s *Sink, turn Turn, correct Correct) (*Poller, error) {
 	if turn == nil {
 		return nil, errors.New("telegramsink: intake needs a turn handler")
 	}
+	// The push half accepts @channelusername as a destination. The intake half
+	// cannot: an inbound update names its chat by numeric id, so an @-name would
+	// match nothing and the poller would read the chat and answer none of it.
+	// Refusing here is the difference between a boot error and a dead reach.
+	if strings.HasPrefix(strings.TrimSpace(s.cfg.ChatID), "@") {
+		return nil, fmt.Errorf("telegramsink: intake needs the numeric chat id, not %s", s.cfg.ChatID)
+	}
 	// The sink's transport already carries the relay. Only the timeout differs,
 	// and it has to clear the long poll.
 	hc := &http.Client{
@@ -101,15 +109,26 @@ func (p *Poller) Run(ctx context.Context) {
 // stopped mattering, and a reminder set from it would land at the wrong time.
 // Missing it is the safe direction.
 func (p *Poller) discardBacklog(ctx context.Context) {
-	updates, err := p.getUpdates(ctx, 0)
-	if err != nil {
-		// Not fatal. The offset stays 0, so the first real poll sees the backlog
-		// and the messages below get answered late. Say so rather than hide it.
-		log.Printf("telegram intake: could not skip the backlog, old messages may be answered: %v", err)
-		return
+	// getUpdates returns at most 100 per call, so one call is not the queue. The
+	// loop is bounded rather than "until empty": the timeout is 0, so an instance
+	// that keeps handing back a full batch would spin, and a thousand skipped
+	// messages is already a box that was down for a long time.
+	skipped := 0
+	for range 10 {
+		updates, err := p.getUpdates(ctx, 0)
+		if err != nil {
+			// Not fatal. The offset stays where it was, so the first real poll sees
+			// what is left and answers it late. Say so rather than hide it.
+			log.Printf("telegram intake: could not skip the backlog, old messages may be answered: %v", err)
+			return
+		}
+		skipped += len(updates)
+		if len(updates) == 0 {
+			break
+		}
 	}
-	if len(updates) > 0 {
-		log.Printf("telegram intake: skipped %d message(s) queued while the daemon was down", len(updates))
+	if skipped > 0 {
+		log.Printf("telegram intake: skipped %d message(s) queued while the daemon was down", skipped)
 	}
 }