GODT-1815: Combined/Split mode

internal/user/flusher.go

@@ -0,0 +1,76 @@
+package user
+
+import (
+	"sync"
+	"time"
+
+	"github.com/ProtonMail/gluon/imap"
+	"github.com/ProtonMail/gluon/queue"
+	"github.com/ProtonMail/proton-bridge/v2/internal/events"
+)
+
+type flusher struct {
+	userID   string
+	updateCh *queue.QueuedChannel[imap.Update]
+	eventCh  *queue.QueuedChannel[events.Event]
+
+	updates      []*imap.MessageCreated
+	maxChunkSize int
+	curChunkSize int
+
+	count int
+	total int
+	start time.Time
+
+	pushLock sync.Mutex
+}
+
+func newFlusher(
+	userID string,
+	updateCh *queue.QueuedChannel[imap.Update],
+	eventCh *queue.QueuedChannel[events.Event],
+	total, maxChunkSize int,
+) *flusher {
+	return &flusher{
+		userID:   userID,
+		updateCh: updateCh,
+		eventCh:  eventCh,
+
+		maxChunkSize: maxChunkSize,
+
+		total: total,
+		start: time.Now(),
+	}
+}
+
+func (f *flusher) push(update *imap.MessageCreated) {
+	f.pushLock.Lock()
+	defer f.pushLock.Unlock()
+
+	f.updates = append(f.updates, update)
+
+	if f.curChunkSize += len(update.Literal); f.curChunkSize >= f.maxChunkSize {
+		f.flush()
+	}
+}
+
+func (f *flusher) flush() {
+	if len(f.updates) == 0 {
+		return
+	}
+
+	f.count += len(f.updates)
+	f.updateCh.Enqueue(imap.NewMessagesCreated(f.updates...))
+	f.eventCh.Enqueue(newSyncProgress(f.userID, f.count, f.total, f.start))
+	f.updates = nil
+	f.curChunkSize = 0
+}
+
+func newSyncProgress(userID string, count, total int, start time.Time) events.SyncProgress {
+	return events.SyncProgress{
+		UserID:    userID,
+		Progress:  float64(count) / float64(total),
+		Elapsed:   time.Since(start),
+		Remaining: time.Since(start) * time.Duration(total-count) / time.Duration(count),
+	}
+}