lib: fix multiple bugs in balance recovery

lib/android/src/main/cpp/wallet.cc

@@ -139,21 +139,38 @@ cryptonote::account_base& Wallet::require_account() {
 
 const payment_details* find_matching_payment(
     const std::list<std::pair<crypto::hash, payment_details>> pds,
-    uint64_t amount,
-    const crypto::hash& txid,
-    const cryptonote::subaddress_index& subaddr_index) {
-  if (txid == crypto::null_hash) {
+    const transfer_details& td) {
+  if (td.m_txid == crypto::null_hash) {
     return nullptr;
   }
   for (const auto& p: pds) {
     const auto& pd = p.second;
-    if (pd.m_amount == amount && pd.m_tx_hash == txid && pd.m_subaddr_index == subaddr_index) {
+    if (td.m_amount == pd.m_amount
+        && td.m_subaddr_index == pd.m_subaddr_index
+        && td.m_txid == pd.m_tx_hash) {
       return &pd;
     }
   }
   return nullptr;
 };
 
+const confirmed_transfer_details* find_matching_transfer_for_change(
+    const std::list<std::pair<crypto::hash, confirmed_transfer_details>> txs,
+    const transfer_details& td) {
+  if (td.m_txid == crypto::null_hash || td.m_subaddr_index.minor != 0) {
+    return nullptr;
+  }
+  for (const auto& p: txs) {
+    const auto& tx = p.second;
+    if (td.m_amount == tx.m_change
+        && td.m_subaddr_index.major == tx.m_subaddr_account
+        && td.m_txid == p.first) {
+      return &tx;
+    }
+  }
+  return nullptr;
+};
+
 // Only call this function from the callback thread or during initialization,
 // as there is no locking mechanism to safeguard reading transaction history
 // from wallet2.
@@ -174,7 +191,7 @@ void Wallet::captureTxHistorySnapshot(std::vector<TxInfo>& snapshot) {
   m_wallet.get_payments_out(txs, min_height);
   m_wallet.get_unconfirmed_payments_out(utxs);
 
-  // Iterate through the known owned outputs (incoming transactions).
+  // Iterate through the known owned outputs.
   for (const auto& td: tds) {
     snapshot.emplace_back(td.m_txid, TxInfo::INCOMING);
     TxInfo& recv = snapshot.back();
@@ -188,14 +205,18 @@ void Wallet::captureTxHistorySnapshot(std::vector<TxInfo>& snapshot) {
     recv.m_amount = td.m_amount;
     recv.m_unlock_time = td.m_tx.unlock_time;
 
-    // Check if the payment exists and update metadata if found.
-    const auto* pd = find_matching_payment(pds, td.m_amount, td.m_txid, td.m_subaddr_index);
-    if (pd) {
+    // Check if the payment or change exists and update metadata if found.
+    if (const auto* pd = find_matching_payment(pds, td)) {
       recv.m_height = pd->m_block_height;
       recv.m_timestamp = pd->m_timestamp;
       recv.m_fee = pd->m_fee;
       recv.m_coinbase = pd->m_coinbase;
       recv.m_state = TxInfo::ON_CHAIN;
+    } else if (const auto tx = find_matching_transfer_for_change(txs, td)) {
+      recv.m_height = tx->m_block_height;
+      recv.m_timestamp = tx->m_timestamp;
+      recv.m_fee = tx->m_amount_in - tx->m_amount_out;
+      recv.m_state = TxInfo::ON_CHAIN;
     } else {
       recv.m_state = TxInfo::OFF_CHAIN;
     }
@@ -219,18 +240,16 @@ void Wallet::captureTxHistorySnapshot(std::vector<TxInfo>& snapshot) {
       spent.m_state = TxInfo::ON_CHAIN;
     }
 
-    for (const auto& in: tx.m_tx.vin) {
-      if (in.type() != typeid(cryptonote::txin_to_key)) continue;
-      const auto& txin = boost::get<cryptonote::txin_to_key>(in);
+    for (const auto& ring : tx.m_rings) {
       snapshot.emplace_back(pair.first, TxInfo::OUTGOING);
       TxInfo& spent = snapshot.back();
-      spent.m_key_image = txin.k_image;
+      spent.m_key_image = ring.first;
       spent.m_key_image_known = true;
-      spent.m_amount = txin.amount;
       spent.m_height = tx.m_block_height;
       spent.m_unlock_time = tx.m_unlock_time;
       spent.m_timestamp = tx.m_timestamp;
       spent.m_fee = fee;
+      spent.m_change = tx.m_change;
       spent.m_state = TxInfo::ON_CHAIN;
     }
   }
@@ -269,7 +288,7 @@ void Wallet::captureTxHistorySnapshot(std::vector<TxInfo>& snapshot) {
       }
     }
 
-    // Change is ours too.
+    // Change is ours too, but the output is not yet in transfer_details
     if (utx.m_change > 0) {
       snapshot.emplace_back(pair.first, TxInfo::INCOMING);
       TxInfo& change = snapshot.back();
@@ -283,16 +302,14 @@ void Wallet::captureTxHistorySnapshot(std::vector<TxInfo>& snapshot) {
       change.m_state = state;
     }
 
-    for (const auto& in: utx.m_tx.vin) {
-      if (in.type() != typeid(cryptonote::txin_to_key)) continue;
-      const auto& txin = boost::get<cryptonote::txin_to_key>(in);
+    for (const auto& ring : utx.m_rings) {
       snapshot.emplace_back(pair.first, TxInfo::OUTGOING);
       TxInfo& spent = snapshot.back();
-      spent.m_key_image = txin.k_image;
+      spent.m_key_image = ring.first;
       spent.m_key_image_known = true;
-      spent.m_amount = txin.amount;
       spent.m_timestamp = utx.m_timestamp;
       spent.m_fee = fee;
+      spent.m_change = utx.m_change;
       spent.m_state = state;
     }
   }

lib/android/src/main/kotlin/im/molly/monero/Balance.kt

@@ -1,5 +1,7 @@
 package im.molly.monero
 
+import java.time.Instant
+
 data class Balance(
     val pendingAmount: MoneroAmount,
     val timeLockedAmounts: List<TimeLocked<MoneroAmount>>,
@@ -7,18 +9,26 @@ data class Balance(
     val confirmedAmount: MoneroAmount = timeLockedAmounts.sumOf { it.value }
     val totalAmount: MoneroAmount = confirmedAmount + pendingAmount
 
-    fun unlockedAmountAt(targetTime: BlockchainTime): MoneroAmount =
-        timeLockedAmounts
-            .filter { it.isUnlocked(targetTime) }
-            .sumOf { it.value }
+    fun unlockedAmountAt(
+        blockHeight: Int,
+        currentInstant: Instant = Instant.now(),
+    ): MoneroAmount {
+        val targetTime = BlockchainTime(blockHeight, currentInstant)
+        return timeLockedAmounts.filter { it.isUnlocked(targetTime) }.sumOf { it.value }
+    }
 
-    fun lockedAmountsAt(targetTime: BlockchainTime): Map<BlockchainTimeSpan, MoneroAmount> =
-        timeLockedAmounts
+    fun lockedAmountsAt(
+        blockHeight: Int,
+        currentInstant: Instant = Instant.now(),
+    ): Map<BlockchainTimeSpan, MoneroAmount> {
+        val targetTime = BlockchainTime(blockHeight, currentInstant)
+        return timeLockedAmounts
             .filter { it.isLocked(targetTime) }
             .groupBy({ it.timeUntilUnlock(targetTime) }, { it.value })
             .mapValues { (_, amounts) ->
                 amounts.sum()
             }
+    }
 }
 
 fun Iterable<TimeLocked<Enote>>.calculateBalance(): Balance {
@@ -26,7 +36,7 @@ fun Iterable<TimeLocked<Enote>>.calculateBalance(): Balance {
 
     val lockedAmounts = mutableListOf<TimeLocked<MoneroAmount>>()
 
-    for (timeLocked in filter { it.value.spent }) {
+    for (timeLocked in filter { !it.value.spent }) {
         if (timeLocked.value.age == 0) {
             pendingAmount += timeLocked.value.amount
         } else {

lib/android/src/main/kotlin/im/molly/monero/BlockchainTime.kt

@@ -96,19 +96,24 @@ fun max(a: BlockchainTime, b: BlockchainTime) = if (a >= b) a else b
 fun min(a: BlockchainTime, b: BlockchainTime) = if (a <= b) a else b
 
 data class BlockchainTimeSpan(val duration: Duration, val blocks: Int) {
+    val timeRemaining: Duration
+        get() = maxOf(Duration.ZERO, duration)
+
     companion object {
         val ZERO = BlockchainTimeSpan(duration = Duration.ZERO, blocks = 0)
     }
 }
 
-class TimeLocked<T>(val value: T, val unlockTime: BlockchainTime) {
-    fun isLocked(currentTime: BlockchainTime): Boolean = currentTime < unlockTime
+class TimeLocked<T>(val value: T, val unlockTime: BlockchainTime?) {
+    fun isLocked(currentTime: BlockchainTime): Boolean {
+        return currentTime < (unlockTime ?: return false)
+    }
 
     fun isUnlocked(currentTime: BlockchainTime) = !isLocked(currentTime)
 
     fun timeUntilUnlock(currentTime: BlockchainTime): BlockchainTimeSpan {
         return if (isLocked(currentTime)) {
-            unlockTime.minus(currentTime)
+            unlockTime!!.minus(currentTime)
         } else {
             BlockchainTimeSpan.ZERO
         }

lib/android/src/main/kotlin/im/molly/monero/HashDigest.kt

@@ -3,6 +3,8 @@ package im.molly.monero
 @JvmInline
 value class HashDigest(private val hashDigest: String) {
     init {
-        require(hashDigest.length == 32) { "Hash length must be 32 bytes" }
+        require(hashDigest.length == 64) { "Hash length must be 64 hex chars" }
     }
+
+    override fun toString(): String = hashDigest
 }

lib/android/src/main/kotlin/im/molly/monero/PublicAddress.kt

@@ -25,7 +25,7 @@ interface PublicAddress {
                 return StandardAddress(network)
             }
             SubAddress.prefixes[prefix]?.let { network ->
-                TODO()
+                return SubAddress(network)
             }
             IntegratedAddress.prefixes[prefix]?.let { network ->
                 TODO()
@@ -60,7 +60,7 @@ data class SubAddress(
     companion object {
         val prefixes = mapOf(
             42L to MoneroNetwork.Mainnet,
-            64L to MoneroNetwork.Testnet,
+            63L to MoneroNetwork.Testnet,
             36L to MoneroNetwork.Stagenet,
         )
     }

lib/android/src/main/kotlin/im/molly/monero/internal/TxInfo.kt

@@ -81,13 +81,16 @@ internal fun List<TxInfo>.consolidateTransactions(
 
         // If transaction isn't failed, calculate unlock time and save enotes
         if (tx.state !is TxState.Failed) {
-            val defaultUnlockTime = BlockchainTime.Block(
-                height = tx.blockHeight!! + CRYPTONOTE_DEFAULT_TX_SPENDABLE_AGE,
-                referencePoint = blockchainContext,
-            )
-            val maxUnlockTime = max(defaultUnlockTime, tx.timeLock ?: BlockchainTime.Genesis)
-
-            val lockedEnotesToAdd = tx.received.map { enote -> TimeLocked(enote, maxUnlockTime) }
+            val maxUnlockTime = tx.blockHeight?.let { height ->
+                val defaultUnlockTime = BlockchainTime.Block(
+                    height = height + CRYPTONOTE_DEFAULT_TX_SPENDABLE_AGE,
+                    referencePoint = blockchainContext,
+                )
+                max(defaultUnlockTime, tx.timeLock ?: BlockchainTime.Genesis)
+            }
+            val lockedEnotesToAdd = tx.received.map { enote ->
+                TimeLocked(enote, maxUnlockTime)
+            }
             validEnotes.addAll(lockedEnotesToAdd)
         }
 
@@ -114,14 +117,14 @@ private fun List<TxInfo>.createTransaction(
         if (unlockTime == 0L) null else blockchainContext.resolveUnlockTime(unlockTime)
     }
 
-    val receivedEnotes = enoteByTxId.getValue(txHash).toSet()
+    val receivedEnotes = enoteByTxId.getOrDefault(txHash, emptyList()).toSet()
 
     val outTxs = filter { !it.incoming }
 
     val spentKeyImages = outTxs.mapNotNull { it.keyImage }
     val sentEnotes = enoteByKeyImage.filterKeys { ki -> ki in spentKeyImages }.values.toSet()
 
-    val payments = outTxs.map { it.toPaymentDetail() }
+    val payments = outTxs.mapNotNull { it.toPaymentDetail() }
 
     return Transaction(
         hash = HashDigest(txHash),
@@ -166,7 +169,10 @@ private fun TxInfo.toEnote(blockchainHeight: Int): Enote {
     )
 }
 
-private fun TxInfo.toPaymentDetail() = PaymentDetail(
-    amount = MoneroAmount(atomicUnits = amount),
-    recipient = PublicAddress.parse(recipient!!),
-)
+private fun TxInfo.toPaymentDetail(): PaymentDetail? {
+    val recipient = PublicAddress.parse(recipient ?: return null)
+    return PaymentDetail(
+        amount = MoneroAmount(atomicUnits = amount),
+        recipient = recipient,
+    )
+}