Stage 11: account linking & merge (email + Telegram Login Widget) (#12)

backend/internal/session/cache.go

@@ -4,6 +4,8 @@ import (
 	"context"
 	"sync"
 	"sync/atomic"
+
+	"github.com/google/uuid"
 )
 
 // Cache is the in-memory write-through projection of the active rows in
@@ -93,3 +95,19 @@ func (c *Cache) Remove(tokenHash string) {
 	defer c.mu.Unlock()
 	delete(c.byHash, tokenHash)
 }
+
+// RemoveByAccount evicts every cached session belonging to accountID. The
+// account-merge flow uses it to drop a retired secondary account's sessions
+// (Stage 11); a linear scan is adequate at the cache's size.
+func (c *Cache) RemoveByAccount(accountID uuid.UUID) {
+	if c == nil {
+		return
+	}
+	c.mu.Lock()
+	defer c.mu.Unlock()
+	for hash, s := range c.byHash {
+		if s.AccountID == accountID {
+			delete(c.byHash, hash)
+		}
+	}
+}