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.

runtime/src/main/java/io/novafoundation/nova/runtime/ext/ChainExt.kt

@@ -14,7 +14,11 @@ import io.novafoundation.nova.common.utils.emptySubstrateAccountId
 import io.novafoundation.nova.common.utils.findIsInstanceOrNull
 import io.novafoundation.nova.common.utils.formatNamed
 import io.novafoundation.nova.common.utils.removeHexPrefix
+import io.novafoundation.nova.common.utils.emptyTronAccountId
 import io.novafoundation.nova.common.utils.substrateAccountId
+import io.novafoundation.nova.common.utils.toTronAddress
+import io.novafoundation.nova.common.utils.tronAddressToAccountId
+import io.novafoundation.nova.common.utils.tronPublicKeyToAccountId
 import io.novafoundation.nova.core_db.model.AssetAndChainId
 import io.novafoundation.nova.runtime.multiNetwork.chain.model.Chain
 import io.novafoundation.nova.runtime.multiNetwork.chain.model.Chain.Asset.StakingType.ALEPH_ZERO
@@ -266,10 +270,10 @@ fun Chain.supportsLegacyAddressFormat() = legacyAddressPrefix != null
 fun Chain.requireGenesisHash() = requireNotNull(genesisHash)
 
 fun Chain.addressOf(accountId: ByteArray): String {
-    return if (isEthereumBased) {
-        accountId.toEthereumAddress()
-    } else {
-        accountId.toAddress(addressPrefix.toShort())
+    return when {
+        isTronBased -> accountId.toTronAddress()
+        isEthereumBased -> accountId.toEthereumAddress()
+        else -> accountId.toAddress(addressPrefix.toShort())
     }
 }
 
@@ -278,7 +282,7 @@ fun Chain.addressOf(accountId: AccountIdKey): String {
 }
 
 fun Chain.legacyAddressOfOrNull(accountId: ByteArray): String? {
-    return if (isEthereumBased) {
+    return if (isEthereumBased || isTronBased) {
         null
     } else {
         legacyAddressPrefix?.let { accountId.toAddress(it.toShort()) }
@@ -290,10 +294,10 @@ fun ByteArray.toEthereumAddress(): String {
 }
 
 fun Chain.accountIdOf(address: String): ByteArray {
-    return if (isEthereumBased) {
-        address.asEthereumAddress().toAccountId().value
-    } else {
-        address.toAccountId()
+    return when {
+        isTronBased -> address.tronAddressToAccountId()
+        isEthereumBased -> address.asEthereumAddress().toAccountId().value
+        else -> address.toAccountId()
     }
 }
 
@@ -323,10 +327,10 @@ fun Chain.accountIdOrNull(address: String): ByteArray? {
     return runCatching { accountIdOf(address) }.getOrNull()
 }
 
-fun Chain.emptyAccountId() = if (isEthereumBased) {
-    emptyEthereumAccountId()
-} else {
-    emptySubstrateAccountId()
+fun Chain.emptyAccountId() = when {
+    isTronBased -> emptyTronAccountId()
+    isEthereumBased -> emptyEthereumAccountId()
+    else -> emptySubstrateAccountId()
 }
 
 fun Chain.emptyAccountIdKey() = emptyAccountId().intoKey()
@@ -336,10 +340,10 @@ fun Chain.accountIdOrDefault(maybeAddress: String): ByteArray {
 }
 
 fun Chain.accountIdOf(publicKey: ByteArray): ByteArray {
-    return if (isEthereumBased) {
-        publicKey.asEthereumPublicKey().toAccountId().value
-    } else {
-        publicKey.substrateAccountId()
+    return when {
+        isTronBased -> publicKey.tronPublicKeyToAccountId()
+        isEthereumBased -> publicKey.asEthereumPublicKey().toAccountId().value
+        else -> publicKey.substrateAccountId()
     }
 }
 
@@ -525,6 +529,26 @@ fun Chain.Asset.requireErc20(): Type.EvmErc20 {
     return type
 }
 
+fun Chain.Asset.requireTrc20(): Type.Trc20 {
+    require(type is Type.Trc20)
+
+    return type
+}
+
+/**
+ * The TronGrid-style REST API base url for a Tron-based chain.
+ * Unlike EVM chains (where balance/rpc calls go through the chain's `nodes` JSON-RPC/WS endpoints and only tx-history
+ * REST APIs are sourced from a separate `externalApis` entry), Tron has no JSON-RPC/WS node concept at all - the
+ * configured `nodes` entry directly *is* the TronGrid REST API base url used for both balance and history.
+ */
+fun Chain.requireTronGridBaseUrl(): String {
+    require(isTronBased) { "Chain $id is not Tron-based" }
+
+    return requireNotNull(nodes.nodes.minByOrNull { it.orderId }?.unformattedUrl) {
+        "No TronGrid node configured for chain $id"
+    }
+}
+
 fun Chain.Asset.requireEquilibrium(): Type.Equilibrium {
     require(type is Type.Equilibrium)
 
@@ -588,6 +612,8 @@ val Chain.Asset.onChainAssetId: String?
         is Type.EvmErc20 -> this.type.contractAddress
         is Type.Native -> null
         is Type.EvmNative -> null
+        is Type.Trc20 -> this.type.contractAddress
+        Type.TronNative -> null
         Type.Unsupported -> error("Unsupported assetId type: ${this.type::class.simpleName}")
     }
 

runtime/src/main/java/io/novafoundation/nova/runtime/multiNetwork/chain/mappers/ChainMappersConstants.kt

@@ -9,6 +9,9 @@ const val ASSET_UNSUPPORTED = "unsupported"
 const val ASSET_EVM_ERC20 = "evm"
 const val ASSET_EVM_NATIVE = "evmNative"
 
+const val ASSET_TRON_NATIVE = "tronNative"
+const val ASSET_TRC20 = "trc20"
+
 const val ASSET_EQUILIBRIUM = "equilibrium"
 const val ASSET_EQUILIBRIUM_ON_CHAIN_ID = "assetId"
 

runtime/src/main/java/io/novafoundation/nova/runtime/multiNetwork/chain/mappers/DomainToLocalChainMapper.kt

@@ -59,6 +59,12 @@ fun mapChainAssetTypeToRaw(type: Chain.Asset.Type): Pair<String, Map<String, Any
 
     is Chain.Asset.Type.EvmNative -> ASSET_EVM_NATIVE to null
 
+    is Chain.Asset.Type.TronNative -> ASSET_TRON_NATIVE to null
+
+    is Chain.Asset.Type.Trc20 -> ASSET_TRC20 to mapOf(
+        EVM_EXTRAS_CONTRACT_ADDRESS to type.contractAddress
+    )
+
     is Chain.Asset.Type.Equilibrium -> ASSET_EQUILIBRIUM to mapOf(
         ASSET_EQUILIBRIUM_ON_CHAIN_ID to type.id.toString()
     )
@@ -121,6 +127,7 @@ fun mapChainToLocal(chain: Chain, gson: Gson): ChainLocal {
         prefix = chain.addressPrefix,
         legacyPrefix = chain.legacyAddressPrefix,
         isEthereumBased = chain.isEthereumBased,
+        isTronBased = chain.isTronBased,
         isTestNet = chain.isTestNet,
         hasSubstrateRuntime = chain.hasSubstrateRuntime,
         pushSupport = chain.pushSupport,

runtime/src/main/java/io/novafoundation/nova/runtime/multiNetwork/chain/mappers/LocalToDomainChainMapper.kt

@@ -85,6 +85,14 @@ private fun mapChainAssetTypeFromRaw(type: String?, typeExtras: Map<String, Any?
 
         ASSET_EVM_NATIVE -> Chain.Asset.Type.EvmNative
 
+        ASSET_TRON_NATIVE -> Chain.Asset.Type.TronNative
+
+        ASSET_TRC20 -> {
+            Chain.Asset.Type.Trc20(
+                contractAddress = typeExtras!![EVM_EXTRAS_CONTRACT_ADDRESS] as String
+            )
+        }
+
         ASSET_EQUILIBRIUM -> Chain.Asset.Type.Equilibrium((typeExtras!![ASSET_EQUILIBRIUM_ON_CHAIN_ID] as String).toBigInteger())
 
         else -> Chain.Asset.Type.Unsupported
@@ -267,6 +275,7 @@ fun mapChainLocalToChain(
             addressPrefix = prefix,
             legacyAddressPrefix = legacyPrefix,
             isEthereumBased = isEthereumBased,
+            isTronBased = isTronBased,
             isTestNet = isTestNet,
             hasCrowdloans = hasCrowdloans,
             pushSupport = pushSupport,

runtime/src/main/java/io/novafoundation/nova/runtime/multiNetwork/chain/mappers/RemoteToLocalChainMappers.kt

@@ -20,6 +20,7 @@ import io.novafoundation.nova.runtime.multiNetwork.chain.remote.model.ChainAsset
 import io.novafoundation.nova.runtime.multiNetwork.chain.remote.model.ChainRemote
 
 private const val ETHEREUM_OPTION = "ethereumBased"
+private const val TRON_OPTION = "tronBased"
 private const val CROWDLOAN_OPTION = "crowdloans"
 private const val TESTNET_OPTION = "testnet"
 private const val PROXY_OPTION = "proxy"
@@ -90,6 +91,7 @@ fun mapRemoteChainToLocal(
             prefix = addressPrefix,
             legacyPrefix = legacyAddressPrefix,
             isEthereumBased = ETHEREUM_OPTION in optionsOrEmpty,
+            isTronBased = TRON_OPTION in optionsOrEmpty,
             isTestNet = TESTNET_OPTION in optionsOrEmpty,
             hasCrowdloans = CROWDLOAN_OPTION in optionsOrEmpty,
             supportProxy = PROXY_OPTION in optionsOrEmpty,

runtime/src/main/java/io/novafoundation/nova/runtime/multiNetwork/chain/model/Chain.kt

@@ -32,6 +32,7 @@ data class Chain(
     val legacyAddressPrefix: Int?,
     val types: Types?,
     val isEthereumBased: Boolean,
+    val isTronBased: Boolean,
     val isTestNet: Boolean,
     val source: Source,
     val hasSubstrateRuntime: Boolean,
@@ -124,6 +125,19 @@ data class Chain(
                 val id: BigInteger
             ) : Type()
 
+            /**
+             * Native TRX balance on a Tron-based chain.
+             * Balance is fetched from a TronGrid-style REST API rather than JSON-RPC.
+             */
+            object TronNative : Type()
+
+            /**
+             * TRC-20 token on a Tron-based chain (EVM-compatible token standard, different REST API shape from Ethereum's ERC-20).
+             */
+            data class Trc20(
+                val contractAddress: String
+            ) : Type()
+
             object Unsupported : Type()
         }