fix db funcs

internal/db/delegation.go

@@ -35,6 +35,23 @@ func (db *Database) SaveNewBTCDelegation(
 func (db *Database) UpdateBTCDelegationState(
 	ctx context.Context, stakingTxHash string, newState types.DelegationState,
 ) error {
+	filter := map[string]interface{}{"_id": stakingTxHash}
+	update := map[string]interface{}{"$set": map[string]string{"state": newState.String()}}
+
+	res := db.client.Database(db.dbName).
+		Collection(model.BTCDelegationDetailsCollection).
+		FindOneAndUpdate(ctx, filter, update)
+
+	if res.Err() != nil {
+		if errors.Is(res.Err(), mongo.ErrNoDocuments) {
+			return &NotFoundError{
+				Key:     stakingTxHash,
+				Message: "BTC delegation not found when updating state",
+			}
+		}
+		return res.Err()
+	}
+
 	return nil
 }
 
@@ -52,7 +69,7 @@ func (db *Database) GetBTCDelegationByStakingTxHash(
 		if errors.Is(err, mongo.ErrNoDocuments) {
 			return nil, &NotFoundError{
 				Key:     stakingTxHash,
-				Message: "BTC delegation not found",
+				Message: "BTC delegation not found when getting by staking tx hash",
 			}
 		}
 		return nil, err

internal/types/state.go

@@ -11,3 +11,7 @@ const (
 	StateSlashed   DelegationState = "SLASHED"
 	StateUnbonded  DelegationState = "UNBONDED"
 )
+
+func (s DelegationState) String() string {
+	return string(s)
+}