[MultiSig] Clean federation wallet from CCTS (#515)

* Clean fed wallet from CCTS

* Review

* Add log

Author: fassadlr

src/Stratis.Features.FederatedPeg/Interfaces/IFederationWalletManager.cs

@@ -28,6 +28,19 @@ public interface IFederationWalletManager : ILockProtected
         /// <summary> The last processed block's height.</summary>
         int WalletTipHeight { get; set; }
 
+        /// <summary>
+        /// Because the CCTS syncs from the federation wallet, it needs to be
+        /// responsible for cleaning transactions past max reorg.
+        /// <para>
+        /// Doing this from the federation wallet manager could mean transactions
+        /// are cleaned before they are processed by the CCTS (which means they will
+        /// be wrongly added back.
+        /// </para>
+        /// </summary>
+        /// <param name="crossChainTransferTip">The tip of the <see cref="ICrossChainTransferStore"/>.</param>
+        /// <returns><c>true</c> if transactions were cleaned and the wallet should be saved.</returns>
+        bool CleanTransactionsPastMaxReorg(int crossChainTransferTip);
+
         /// <summary>
         /// Lists all spendable transactions from all accounts in the wallet.
         /// </summary>

src/Stratis.Features.FederatedPeg/TargetChain/CrossChainTransferStore.cs

@@ -1000,6 +1000,14 @@ private bool Synchronize()
                                 dbreezeTransaction.Commit();
                             }
 
+                            // As the CCTS syncs from the federation wallet, it needs to be
+                            // responsible for cleaning transaciton past max reorg.
+                            // Doing this from the federatrion wallet manager could mean transactions
+                            // are cleaned before they are processed by the CCTS (which means they will
+                            // be wrongly added back.
+                            if (this.federationWalletManager.CleanTransactionsPastMaxReorg(this.TipHashAndHeight.Height))
+                                this.federationWalletManager.SaveWallet();
+
                             return true;
                         }
                     }

src/Stratis.Features.FederatedPeg/Wallet/FederationWalletManager.cs

@@ -425,8 +425,6 @@ public void ProcessBlock(Block block, ChainedHeader chainedHeader)
                         walletUpdated = true;
                 }
 
-                walletUpdated |= this.CleanTransactionsPastMaxReorg(chainedHeader.Height);
-
                 // Update the wallets with the last processed block height.
                 // It's important that updating the height happens after the block processing is complete,
                 // as if the node is stopped, on re-opening it will start updating from the previous height.
@@ -539,26 +537,27 @@ public bool ProcessTransaction(Transaction transaction, int? blockHeight = null,
             }
         }
 
-        private bool CleanTransactionsPastMaxReorg(int height)
+        /// <inheritdoc />
+        public bool CleanTransactionsPastMaxReorg(int crossChainTransferStoreTip)
         {
             bool walletUpdated = false;
 
             if (this.network.Consensus.MaxReorgLength == 0 || this.Wallet.MultiSigAddress.Transactions.Count <= MinimumRetainedTransactions)
                 return walletUpdated;
 
-            int finalisedHeight = height - (int)this.network.Consensus.MaxReorgLength;
-            var pastMaxReorg = new List<TransactionData>();
+            int heightToCleanFrom = crossChainTransferStoreTip - (int)this.network.Consensus.MaxReorgLength;
+            var transactionsPastMaxReorg = new List<TransactionData>();
 
-            foreach ((_, List<TransactionData> txList) in this.Wallet.MultiSigAddress.Transactions.SpentTransactionsBeforeHeight(finalisedHeight))
+            // Only want to remove transactions that are spent, and the spend must have passed max reorg too
+            foreach ((_, List<TransactionData> txList) in this.Wallet.MultiSigAddress.Transactions.SpentTransactionsBeforeHeight(heightToCleanFrom))
             {
                 foreach (TransactionData transactionData in txList)
                 {
-                    // Only want to remove transactions that are spent, and the spend must have passed max reorg too
-                    pastMaxReorg.Add(transactionData);
+                    transactionsPastMaxReorg.Add(transactionData);
                 }
             }
 
-            foreach (TransactionData transactionData in pastMaxReorg)
+            foreach (TransactionData transactionData in transactionsPastMaxReorg)
             {
                 this.Wallet.MultiSigAddress.Transactions.Remove(transactionData);
                 walletUpdated = true;
@@ -567,6 +566,8 @@ private bool CleanTransactionsPastMaxReorg(int height)
                     break;
             }
 
+            this.logger.Debug("Cleaned {0} transactions older than the CCTS tip less max reorg of {1}.", transactionsPastMaxReorg.Count, crossChainTransferStoreTip);
+
             return walletUpdated;
         }