初始化仓库

core/dedup.go

@@ -0,0 +1,51 @@
+package core
+
+import (
+	"sync"
+	"time"
+)
+
+const dedupTTL = 60 * time.Second
+
+// StartTime is set once at process startup.
+// Platforms use it to discard messages created before the current process started,
+// preventing replayed/unacknowledged messages from being re-processed after a restart.
+var StartTime = time.Now()
+
+// MessageDedup tracks recently seen message IDs to prevent duplicate processing.
+// Safe for concurrent use.
+type MessageDedup struct {
+	mu   sync.Mutex
+	seen map[string]time.Time
+}
+
+// IsDuplicate returns true if msgID was already seen within the TTL window.
+// Empty msgID is never considered a duplicate.
+func (d *MessageDedup) IsDuplicate(msgID string) bool {
+	if msgID == "" {
+		return false
+	}
+	d.mu.Lock()
+	defer d.mu.Unlock()
+	if d.seen == nil {
+		d.seen = make(map[string]time.Time)
+	}
+	now := time.Now()
+	for k, t := range d.seen {
+		if now.Sub(t) > dedupTTL {
+			delete(d.seen, k)
+		}
+	}
+	if _, ok := d.seen[msgID]; ok {
+		return true
+	}
+	d.seen[msgID] = now
+	return false
+}
+
+// IsOldMessage returns true if msgTime is before the process StartTime.
+// A small grace period (2 seconds) is applied to avoid race conditions
+// with messages sent right at startup.
+func IsOldMessage(msgTime time.Time) bool {
+	return msgTime.Before(StartTime.Add(-2 * time.Second))
+}