feat: add support for testnet 4

Author: thunderbiscuit

app/src/main/java/org/bitcoindevkit/devkitwallet/domain/BlockchainClientsConfig.kt

@@ -40,17 +40,11 @@ class BlockchainClientsConfig {
         fun createDefaultConfig(network: Network): BlockchainClientsConfig {
             val config = BlockchainClientsConfig()
             when (network) {
-                Network.REGTEST -> {
-                    config.addClient(EsploraClient("http://10.0.2.2:3002"), true)
-                }
-                Network.TESTNET -> {
-                    config.addClient(EsploraClient("https://blockstream.info/testnet/api/"), true)
-                }
-                Network.TESTNET4 -> throw IllegalArgumentException("This app does not support testnet 4 yet")
-                Network.SIGNET -> {
-                    config.addClient(EsploraClient("http://signet.bitcoindevkit.net"), true)
-                }
-                Network.BITCOIN -> throw IllegalArgumentException("This app does not support mainnet")
+                Network.REGTEST  -> config.addClient(EsploraClient("http://10.0.2.2:3002"), true)
+                Network.SIGNET   -> config.addClient(EsploraClient("http://signet.bitcoindevkit.net"), true)
+                Network.TESTNET  -> config.addClient(EsploraClient("https://blockstream.info/testnet/api/"), true)
+                Network.TESTNET4 -> config.addClient(EsploraClient("https://mempool.space/testnet4/api/"), true)
+                Network.BITCOIN  -> throw IllegalArgumentException("This app does not support mainnet")
             }
             return config
         }

app/src/main/java/org/bitcoindevkit/devkitwallet/domain/Constants.kt

@@ -1,10 +1,16 @@
+/*
+ * Copyright 2021-2025 thunderbiscuit and contributors.
+ * Use of this source code is governed by the Apache 2.0 license that can be found in the ./LICENSE file.
+ */
+
 package org.bitcoindevkit.devkitwallet.domain
 
 import org.bitcoindevkit.Network
 
 val supportedNetworks: List<Network> = listOf(
     Network.SIGNET,
     Network.TESTNET,
+    Network.TESTNET4,
     Network.REGTEST,
 )
 

app/src/main/java/org/bitcoindevkit/devkitwallet/domain/utils/ProtobufExtensions.kt

@@ -11,18 +11,19 @@ import org.bitcoindevkit.devkitwallet.data.ActiveWalletNetwork
 fun Network.intoProto(): ActiveWalletNetwork {
     return when (this) {
         Network.REGTEST -> ActiveWalletNetwork.REGTEST
-        Network.TESTNET -> ActiveWalletNetwork.TESTNET
-        Network.TESTNET4 -> throw IllegalArgumentException("Bitcoin testnet 4 network is not supported")
+        Network.TESTNET -> ActiveWalletNetwork.TESTNET3
+        Network.TESTNET4 -> ActiveWalletNetwork.TESTNET4
         Network.SIGNET -> ActiveWalletNetwork.SIGNET
         Network.BITCOIN -> throw IllegalArgumentException("Bitcoin mainnet network is not supported")
     }
 }
 
 fun ActiveWalletNetwork.intoDomain(): Network {
     return when (this) {
-        ActiveWalletNetwork.TESTNET -> Network.TESTNET
-        ActiveWalletNetwork.SIGNET -> Network.SIGNET
-        ActiveWalletNetwork.REGTEST -> Network.REGTEST
+        ActiveWalletNetwork.REGTEST      -> Network.REGTEST
+        ActiveWalletNetwork.SIGNET       -> Network.SIGNET
+        ActiveWalletNetwork.TESTNET3     -> Network.TESTNET
+        ActiveWalletNetwork.TESTNET4     -> Network.TESTNET4
         ActiveWalletNetwork.UNRECOGNIZED -> throw IllegalArgumentException("Unrecognized network")
     }
 }

app/src/main/java/org/bitcoindevkit/devkitwallet/presentation/ui/components/WalletOptionsCard.kt

@@ -60,7 +60,7 @@ fun WalletOptionsCard(
                 isSelected = selectedNetwork.value == it,
                 onSelect = { selectedNetwork.value = it }
             )
-            if (index == 2) Spacer(modifier = Modifier.padding(bottom = 8.dp))
+            if (index == 3) Spacer(modifier = Modifier.padding(bottom = 8.dp))
         }
 
         Text(

app/src/main/proto/wallets.proto

@@ -20,9 +20,10 @@ message SingleWallet {
 }
 
 enum ActiveWalletNetwork {
-  TESTNET = 0;
+  REGTEST = 0;
   SIGNET = 1;
-  REGTEST = 2;
+  TESTNET3 = 2;
+  TESTNET4 = 3;
 }
 
 enum ActiveWalletScriptType {