Add read-only Tron (TRC20) chain family support (#9)

* Add read-only Tron (TRC20) chain family support

Adds Tron as a third chain family alongside Substrate and EVM:
address derivation (BIP44 coin type 195, secp256k1 reused from the
existing Ethereum path, Base58Check encoding), TronGrid-backed TRX
and TRC20 USDT balance display, and a Room migration for the new
per-account Tron key/address columns. Read-only only — no send,
signing, or broadcast support yet.

* fix: exhaustive when branches for Trc20/TronNative asset types

ChainExt.kt's onChainAssetId and Common.kt's existentialDepositError
both switch exhaustively over Chain.Asset.Type and didn't have cases
for the new Trc20/TronNative variants, breaking compilation. Trc20
mirrors EvmErc20 (contract address as the on-chain id, dust burns
rather than transfers on removal); TronNative mirrors EvmNative.

feature-account-impl/src/main/java/io/novafoundation/nova/feature_account_impl/data/mappers/AccountMappers.kt

@@ -63,6 +63,8 @@ class AccountMappers(
                     substrateAccountId = substrateAccountId,
                     ethereumAddress = ethereumAddress,
                     ethereumPublicKey = ethereumPublicKey,
+                    tronAddress = tronAddress,
+                    tronPublicKey = tronPublicKey,
                     isSelected = isSelected,
                     name = name,
                     status = mapMetaAccountStateFromLocal(status),
@@ -78,6 +80,8 @@ class AccountMappers(
                     substrateAccountId = substrateAccountId,
                     ethereumAddress = ethereumAddress,
                     ethereumPublicKey = ethereumPublicKey,
+                    tronAddress = tronAddress,
+                    tronPublicKey = tronPublicKey,
                     isSelected = isSelected,
                     name = name,
                     type = type,
@@ -95,6 +99,8 @@ class AccountMappers(
                     substrateAccountId = substrateAccountId,
                     ethereumAddress = ethereumAddress,
                     ethereumPublicKey = ethereumPublicKey,
+                    tronAddress = tronAddress,
+                    tronPublicKey = tronPublicKey,
                     isSelected = isSelected,
                     name = name,
                     type = type,
@@ -111,6 +117,8 @@ class AccountMappers(
                     substrateAccountId = substrateAccountId,
                     ethereumAddress = ethereumAddress,
                     ethereumPublicKey = ethereumPublicKey,
+                    tronAddress = tronAddress,
+                    tronPublicKey = tronPublicKey,
                     isSelected = isSelected,
                     name = name,
                     type = type,
@@ -128,6 +136,8 @@ class AccountMappers(
                     substrateAccountId = substrateAccountId,
                     ethereumAddress = ethereumAddress,
                     ethereumPublicKey = ethereumPublicKey,
+                    tronAddress = tronAddress,
+                    tronPublicKey = tronPublicKey,
                     isSelected = isSelected,
                     name = name,
                     type = type,
@@ -153,6 +163,8 @@ class AccountMappers(
                         substrateAccountId = substrateAccountId,
                         ethereumAddress = ethereumAddress,
                         ethereumPublicKey = ethereumPublicKey,
+                        tronAddress = tronAddress,
+                        tronPublicKey = tronPublicKey,
                         isSelected = isSelected,
                         name = name,
                         status = mapMetaAccountStateFromLocal(status),
@@ -169,6 +181,8 @@ class AccountMappers(
                         substrateAccountId = substrateAccountId,
                         ethereumAddress = ethereumAddress,
                         ethereumPublicKey = ethereumPublicKey,
+                        tronAddress = tronAddress,
+                        tronPublicKey = tronPublicKey,
                         chainAccounts = chainAccounts,
                         isSelected = isSelected,
                         name = name,

feature-account-impl/src/main/java/io/novafoundation/nova/feature_account_impl/data/repository/datasource/SecretsMetaAccountLocalFactory.kt

@@ -3,6 +3,7 @@ package io.novafoundation.nova.feature_account_impl.data.repository.datasource
 import io.novafoundation.nova.common.data.secrets.v2.KeyPairSchema
 import io.novafoundation.nova.common.data.secrets.v2.MetaAccountSecrets
 import io.novafoundation.nova.common.utils.substrateAccountId
+import io.novafoundation.nova.common.utils.tronPublicKeyToAccountId
 import io.novafoundation.nova.core.model.CryptoType
 import io.novafoundation.nova.core_db.model.chain.account.MetaAccountLocal
 import io.novasama.substrate_sdk_android.extensions.asEthereumPublicKey
@@ -29,6 +30,7 @@ class RealSecretsMetaAccountLocalFactory : SecretsMetaAccountLocalFactory {
     ): MetaAccountLocal {
         val substratePublicKey = secrets[MetaAccountSecrets.SubstrateKeypair][KeyPairSchema.PublicKey]
         val ethereumPublicKey = secrets[MetaAccountSecrets.EthereumKeypair]?.get(KeyPairSchema.PublicKey)
+        val tronPublicKey = secrets[MetaAccountSecrets.TronKeypair]?.get(KeyPairSchema.PublicKey)
 
         return MetaAccountLocal(
             substratePublicKey = substratePublicKey,
@@ -43,7 +45,9 @@ class RealSecretsMetaAccountLocalFactory : SecretsMetaAccountLocalFactory {
             type = MetaAccountLocal.Type.SECRETS,
             status = MetaAccountLocal.Status.ACTIVE,
             globallyUniqueId = MetaAccountLocal.generateGloballyUniqueId(),
-            typeExtras = null
+            typeExtras = null,
+            tronPublicKey = tronPublicKey,
+            tronAddress = tronPublicKey?.tronPublicKeyToAccountId()
         )
     }
 }

feature-account-impl/src/main/java/io/novafoundation/nova/feature_account_impl/data/secrets/AccountSecretsFactory.kt

@@ -28,6 +28,12 @@ import io.novasama.substrate_sdk_android.scale.Schema
 import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.withContext
 
+/**
+ * SLIP-44 coin type 195 is Tron's registered BIP44 coin type (Ethereum's is 60).
+ * Not user-configurable via the "Advanced Encryption" UI yet (Phase 1 read-only Tron support) - always derived at this fixed path.
+ */
+const val TRON_DEFAULT_DERIVATION_PATH = "//44//195//0/0/0"
+
 class AccountSecretsFactory(
     private val JsonDecoder: JsonDecoder
 ) {
@@ -124,6 +130,7 @@ class AccountSecretsFactory(
         substrateDerivationPath: String?,
         ethereumDerivationPath: String?,
         accountSource: AccountSource,
+        tronDerivationPath: String? = TRON_DEFAULT_DERIVATION_PATH,
     ): Result<MetaAccountSecrets> = withContext(Dispatchers.Default) {
         val (substrateSecrets, substrateCryptoType) = chainAccountSecrets(
             derivationPath = substrateDerivationPath,
@@ -139,13 +146,26 @@ class AccountSecretsFactory(
             Bip32EcdsaKeypairFactory.generate(seed = seed, junctions = decodedEthereumDerivationPath?.junctions.orEmpty())
         }
 
+        // Tron uses the same secp256k1/BIP32 keypair generation as Ethereum, just under its own SLIP-44 coin-type (195)
+        // derivation path, so it always yields a different keypair from the Ethereum one above, even though the math is identical.
+        val tronKeypair = accountSource.castOrNull<AccountSource.Mnemonic>()?.let {
+            // "Ethereum" here just means "BIP32/ECDSA junction decoding", which is exactly what Tron's path also needs.
+            val decodedTronDerivationPath = decodeDerivationPath(tronDerivationPath, ethereum = true)
+
+            val seed = deriveSeed(it.mnemonic, password = decodedTronDerivationPath?.password, ethereum = true).seed
+
+            Bip32EcdsaKeypairFactory.generate(seed = seed, junctions = decodedTronDerivationPath?.junctions.orEmpty())
+        }
+
         val secrets = MetaAccountSecrets(
             entropy = substrateSecrets[ChainAccountSecrets.Entropy],
             substrateSeed = substrateSecrets[ChainAccountSecrets.Seed],
             substrateKeyPair = mapKeypairStructToKeypair(substrateSecrets[ChainAccountSecrets.Keypair]),
             substrateDerivationPath = substrateDerivationPath,
             ethereumKeypair = ethereumKeypair,
-            ethereumDerivationPath = ethereumDerivationPath
+            ethereumDerivationPath = ethereumDerivationPath,
+            tronKeypair = tronKeypair,
+            tronDerivationPath = tronDerivationPath
         )
 
         Result(secrets = secrets, cryptoType = substrateCryptoType)

feature-account-impl/src/main/java/io/novafoundation/nova/feature_account_impl/domain/account/model/DefaultMetaAccount.kt

@@ -21,7 +21,9 @@ open class DefaultMetaAccount(
     override val type: LightMetaAccount.Type,
     override val status: LightMetaAccount.Status,
     override val chainAccounts: Map<ChainId, MetaAccount.ChainAccount>,
-    override val parentMetaId: Long?
+    override val parentMetaId: Long?,
+    override val tronAddress: ByteArray? = null,
+    override val tronPublicKey: ByteArray? = null,
 ) : MetaAccount {
 
     override suspend fun supportsAddingChainAccount(chain: Chain): Boolean {
@@ -31,6 +33,7 @@ open class DefaultMetaAccount(
     override fun hasAccountIn(chain: Chain): Boolean {
         return when {
             hasChainAccountIn(chain.id) -> true
+            chain.isTronBased -> tronAddress != null
             chain.isEthereumBased -> ethereumAddress != null
             else -> substrateAccountId != null
         }
@@ -39,6 +42,7 @@ open class DefaultMetaAccount(
     override fun accountIdIn(chain: Chain): AccountId? {
         return when {
             hasChainAccountIn(chain.id) -> chainAccounts.getValue(chain.id).accountId
+            chain.isTronBased -> tronAddress
             chain.isEthereumBased -> ethereumAddress
             else -> substrateAccountId
         }
@@ -47,6 +51,7 @@ open class DefaultMetaAccount(
     override fun publicKeyIn(chain: Chain): ByteArray? {
         return when {
             hasChainAccountIn(chain.id) -> chainAccounts.getValue(chain.id).publicKey
+            chain.isTronBased -> tronPublicKey
             chain.isEthereumBased -> ethereumPublicKey
             else -> substratePublicKey
         }

feature-account-impl/src/main/java/io/novafoundation/nova/feature_account_impl/domain/account/model/GenericLedgerMetaAccount.kt

@@ -21,7 +21,9 @@ class GenericLedgerMetaAccount(
     status: LightMetaAccount.Status,
     chainAccounts: Map<ChainId, MetaAccount.ChainAccount>,
     parentMetaId: Long?,
-    private val supportedGenericLedgerChains: Set<ChainId>
+    private val supportedGenericLedgerChains: Set<ChainId>,
+    tronAddress: ByteArray? = null,
+    tronPublicKey: ByteArray? = null,
 ) : DefaultMetaAccount(
     id = id,
     globallyUniqueId = globallyUniqueId,
@@ -35,7 +37,9 @@ class GenericLedgerMetaAccount(
     type = type,
     status = status,
     chainAccounts = chainAccounts,
-    parentMetaId = parentMetaId
+    parentMetaId = parentMetaId,
+    tronAddress = tronAddress,
+    tronPublicKey = tronPublicKey
 ) {
 
     override suspend fun supportsAddingChainAccount(chain: Chain): Boolean {

feature-account-impl/src/main/java/io/novafoundation/nova/feature_account_impl/domain/account/model/LegacyLedgerMetaAccount.kt

@@ -21,7 +21,9 @@ class LegacyLedgerMetaAccount(
     type: LightMetaAccount.Type,
     status: LightMetaAccount.Status,
     chainAccounts: Map<ChainId, MetaAccount.ChainAccount>,
-    parentMetaId: Long?
+    parentMetaId: Long?,
+    tronAddress: ByteArray? = null,
+    tronPublicKey: ByteArray? = null,
 ) : DefaultMetaAccount(
     id = id,
     globallyUniqueId = globallyUniqueId,
@@ -35,7 +37,9 @@ class LegacyLedgerMetaAccount(
     type = type,
     status = status,
     chainAccounts = chainAccounts,
-    parentMetaId = parentMetaId
+    parentMetaId = parentMetaId,
+    tronAddress = tronAddress,
+    tronPublicKey = tronPublicKey
 ) {
 
     override suspend fun supportsAddingChainAccount(chain: Chain): Boolean {

feature-account-impl/src/main/java/io/novafoundation/nova/feature_account_impl/domain/account/model/MultisigMetaAccount.kt

@@ -27,7 +27,9 @@ class RealMultisigMetaAccount(
     private val otherSignatoriesUnsorted: List<AccountIdKey>,
     override val threshold: Int,
     private val multisigRepository: MultisigRepository,
-    parentMetaId: Long?
+    parentMetaId: Long?,
+    tronAddress: ByteArray? = null,
+    tronPublicKey: ByteArray? = null,
 ) : DefaultMetaAccount(
     id = id,
     globallyUniqueId = globallyUniqueId,
@@ -41,7 +43,9 @@ class RealMultisigMetaAccount(
     type = LightMetaAccount.Type.MULTISIG,
     status = status,
     chainAccounts = chainAccounts,
-    parentMetaId = parentMetaId
+    parentMetaId = parentMetaId,
+    tronAddress = tronAddress,
+    tronPublicKey = tronPublicKey
 ),
     MultisigMetaAccount {
 

feature-account-impl/src/main/java/io/novafoundation/nova/feature_account_impl/domain/account/model/PolkadotVaultMetaAccount.kt

@@ -19,7 +19,9 @@ class PolkadotVaultMetaAccount(
     type: LightMetaAccount.Type,
     status: LightMetaAccount.Status,
     chainAccounts: Map<ChainId, MetaAccount.ChainAccount>,
-    parentMetaId: Long?
+    parentMetaId: Long?,
+    tronAddress: ByteArray? = null,
+    tronPublicKey: ByteArray? = null,
 ) : DefaultMetaAccount(
     id = id,
     globallyUniqueId = globallyUniqueId,
@@ -33,10 +35,12 @@ class PolkadotVaultMetaAccount(
     type = type,
     status = status,
     chainAccounts = chainAccounts,
-    parentMetaId = parentMetaId
+    parentMetaId = parentMetaId,
+    tronAddress = tronAddress,
+    tronPublicKey = tronPublicKey
 ) {
 
     override suspend fun supportsAddingChainAccount(chain: Chain): Boolean {
-        return !chain.isEthereumBased
+        return !chain.isEthereumBased && !chain.isTronBased
     }
 }

feature-account-impl/src/main/java/io/novafoundation/nova/feature_account_impl/domain/account/model/RealProxiedMetaAccount.kt

@@ -21,7 +21,9 @@ internal class RealProxiedMetaAccount(
     status: LightMetaAccount.Status,
     override val proxy: ProxyAccount,
     chainAccounts: Map<ChainId, MetaAccount.ChainAccount>,
-    parentMetaId: Long?
+    parentMetaId: Long?,
+    tronAddress: ByteArray? = null,
+    tronPublicKey: ByteArray? = null,
 ) : DefaultMetaAccount(
     id = id,
     globallyUniqueId = globallyUniqueId,
@@ -35,7 +37,9 @@ internal class RealProxiedMetaAccount(
     type = LightMetaAccount.Type.PROXIED,
     status = status,
     chainAccounts = chainAccounts,
-    parentMetaId = parentMetaId
+    parentMetaId = parentMetaId,
+    tronAddress = tronAddress,
+    tronPublicKey = tronPublicKey
 ),
     ProxiedMetaAccount {
 

feature-account-impl/src/main/java/io/novafoundation/nova/feature_account_impl/domain/account/model/RealSecretsMetaAccount.kt

@@ -22,7 +22,9 @@ class RealSecretsMetaAccount(
     name: String,
     status: LightMetaAccount.Status,
     chainAccounts: Map<ChainId, MetaAccount.ChainAccount>,
-    parentMetaId: Long?
+    parentMetaId: Long?,
+    tronAddress: ByteArray? = null,
+    tronPublicKey: ByteArray? = null,
 ) : DefaultMetaAccount(
     id = id,
     globallyUniqueId = globallyUniqueId,
@@ -36,7 +38,9 @@ class RealSecretsMetaAccount(
     type = LightMetaAccount.Type.SECRETS,
     status = status,
     chainAccounts = chainAccounts,
-    parentMetaId = parentMetaId
+    parentMetaId = parentMetaId,
+    tronAddress = tronAddress,
+    tronPublicKey = tronPublicKey
 ),
     SecretsMetaAccount {