chore(solana): remove sol4k, use Rpc20Driver for latest blockhash

sol4k was used in only two places: RpcUrl.MAINNNET.value for the mainnet
endpoint and a single Connection.getLatestBlockhash() call. Replace both
with the existing Rpc20Driver — a new getLatestBlockhash() extension mirroring
the other RPC calls, plus a named MAINNET_RPC_URL constant — and drop the
org.sol4k:sol4k dependency.

This also removes the library's only kotlin-stdlib 2.4.0 requirement,
unblocking it from the pending Kotlin 2.4 upgrade. Behavior is unchanged:
same mainnet endpoint and finalized blockhash commitment.

Signed-off-by: Brandon McAnsh <git@bmcreations.dev>

Author: bmc08gt

apps/flipcash/shared/onramp/deeplinks/src/main/kotlin/com/flipcash/app/onramp/PhantomWalletController.kt

@@ -22,9 +22,9 @@ import com.getcode.solana.keys.Signature
 import com.getcode.solana.keys.base58
 import com.getcode.solana.rpc.RpcConfig
 import com.getcode.solana.rpc.RpcException
-import com.getcode.solana.rpc.SolanaConnection
 import com.getcode.solana.rpc.getBalance
 import com.getcode.solana.rpc.getAccountData
+import com.getcode.solana.rpc.getLatestBlockhash
 import com.getcode.solana.rpc.getTokenAccountBalance
 import com.getcode.solana.rpc.sendTransaction
 import com.getcode.solana.rpc.simulateTransaction
@@ -57,7 +57,6 @@ class PhantomWalletController @Inject constructor(
     private val phantomSdk: PhantomSdk,
     private val phantomConnector: PhantomWalletConnector,
 ) {
-    private val connection by lazy { SolanaConnection(rpcConfig.rpcUrl) }
     private val driver by lazy { Rpc20Driver(rpcConfig.rpcUrl, rpcConfig.networkDriver) }
 
     suspend fun connectWallet(
@@ -226,7 +225,7 @@ class PhantomWalletController @Inject constructor(
                 val owner = requireNotNull(userManager.accountCluster) { "Owner is null" }
 
                 val swapId = SwapId.generate()
-                val recentBlockhash = connection.getLatestBlockhash()
+                val recentBlockhash = driver.getLatestBlockhash().getOrThrow()
 
                 val liquidityPool = userFlags.resolvedFlags.value.usdcOnRampLiquidityPool.effectiveValue
                 val swapPool = when (liquidityPool) {
@@ -279,7 +278,7 @@ class PhantomWalletController @Inject constructor(
     ): Result<SolanaTransaction> {
         return withContext(Dispatchers.IO) {
             try {
-                val recentBlockhash = connection.getLatestBlockhash()
+                val recentBlockhash = driver.getLatestBlockhash().getOrThrow()
 
                 val poolAddress = FundSwapPool.CoinbaseStableSwapper.poolAddress
                 val poolData = driver.getAccountData(poolAddress).getOrThrow()

libs/crypto/solana/build.gradle.kts

@@ -23,7 +23,6 @@ dependencies {
     implementation(libs.okhttp)
     implementation(libs.okhttp.logging.interceptor)
 
-    implementation("org.sol4k:sol4k:0.5.17")
     api("com.solanamobile:web3-solana:0.2.5")
     api("com.solanamobile:rpc-core:0.2.9")
     implementation("com.solanamobile:rpc-okiodriver:0.2.9")

libs/crypto/solana/src/main/kotlin/com/getcode/solana/inject/SolanaModule.kt

@@ -8,14 +8,15 @@ import dagger.Provides
 import dagger.hilt.InstallIn
 import dagger.hilt.components.SingletonComponent
 import okhttp3.OkHttpClient
-import org.sol4k.RpcUrl
 import javax.inject.Named
 import javax.inject.Singleton
 
 @Module
 @InstallIn(SingletonComponent::class)
 object SolanaModule {
 
+    private const val MAINNET_RPC_URL = "https://api.mainnet-beta.solana.com"
+
     @Singleton
     @Provides
     fun providesOkRpcDriver(
@@ -24,7 +25,7 @@ object SolanaModule {
 
     @Provides
     @Named("solana-rpc-url")
-    fun providesSolanaRpcUrl(): String = RpcUrl.MAINNNET.value
+    fun providesSolanaRpcUrl(): String = MAINNET_RPC_URL
 
     @Provides
     @Singleton

libs/crypto/solana/src/main/kotlin/com/getcode/solana/rpc/Calls.kt

@@ -8,12 +8,27 @@ import kotlinx.serialization.json.jsonArray
 import kotlinx.serialization.json.jsonObject
 import kotlinx.serialization.json.jsonPrimitive
 import kotlinx.serialization.json.long
-import org.sol4k.Connection
 import android.util.Base64
 
-class SolanaConnection(rpcUrl: String,) {
-    private val connection = Connection(rpcUrl)
-    fun getLatestBlockhash(): String = connection.getLatestBlockhash()
+/**
+ * Returns the most recent blockhash as a base58 string.
+ */
+suspend fun Rpc20Driver.getLatestBlockhash(): Result<String> {
+    val response = runCatching {
+        makeRequest(
+            request = GetLatestBlockhash(),
+            resultSerializer = JsonElement.serializer()
+        )
+    }.getOrElse { return Result.failure(it) }
+    response.error?.let { return Result.failure(RpcException(it.code, it.message)) }
+
+    val blockhash = response.result
+        ?.jsonObject?.get("value")
+        ?.jsonObject?.get("blockhash")
+        ?.jsonPrimitive?.content
+        ?: return Result.failure(Throwable("Missing blockhash"))
+
+    return Result.success(blockhash)
 }
 
 /**

libs/crypto/solana/src/main/kotlin/com/getcode/solana/rpc/Requests.kt

@@ -64,6 +64,19 @@ internal class GetTokenAccountBalance(
     id = requestId
 )
 
+internal class GetLatestBlockhash(
+    commitment: String = "finalized",
+    requestId: String = "1",
+): JsonRpc20Request(
+    method = "getLatestBlockhash",
+    params = buildJsonArray {
+        addJsonObject {
+            put("commitment", commitment)
+        }
+    },
+    id = requestId
+)
+
 internal class SimulateTransaction(
     encodedTransaction: String,
     commitment: String = "finalized",