ContractClient

// Load spec from network - enables automatic type conversion and result parsing
val client = ContractClient.forContract(contractId, rpcUrl, network)

// Invoke with native types - automatic argument conversion and execution
val balance = client.invoke(
    functionName = "balance",
    arguments = mapOf("account" to "GABC..."),
    source = sourceAccount,
    signer = null,
    parseResultXdrFn = { xdr ->
        (xdr as SCValXdr.I128).value.lo.value.toLong()
    }
)

// Or use manual result parsing with funcResToNative
val resultXdr = client.invoke(
    functionName = "balance",
    arguments = mapOf("account" to "GABC..."),
    source = sourceAccount,
    signer = null
)
val balance = client.funcResToNative("balance", resultXdr) as BigInteger

// Build transaction for manual control before signing
val tx = client.buildInvoke(
    functionName = "transfer",
    arguments = mapOf(
        "from" to fromAccount,
        "to" to toAccount,
        "amount" to 1000
    ),
    source = account.accountId,
    signer = keypair
)

// Customize transaction
tx.raw?.addMemo(Memo.text("Payment"))

// Sign and submit
tx.signAndSubmit(keypair)