feat(kotlin-sdk): expose the drain strategy and the amount it delivers

Cargo.toml

@@ -52,14 +52,14 @@ members = [
 ]
 
 [workspace.dependencies]
-dashcore = { git = "https://github.com/dashpay/rust-dashcore", rev = "173ffac0fdc0c73dda0626cf385bbcfcf2437aeb" }
-dash-network-seeds = { git = "https://github.com/dashpay/rust-dashcore", rev = "173ffac0fdc0c73dda0626cf385bbcfcf2437aeb" }
-dash-spv = { git = "https://github.com/dashpay/rust-dashcore", rev = "173ffac0fdc0c73dda0626cf385bbcfcf2437aeb" }
-key-wallet = { git = "https://github.com/dashpay/rust-dashcore", rev = "173ffac0fdc0c73dda0626cf385bbcfcf2437aeb" }
-key-wallet-ffi = { git = "https://github.com/dashpay/rust-dashcore", rev = "173ffac0fdc0c73dda0626cf385bbcfcf2437aeb" }
-key-wallet-manager = { git = "https://github.com/dashpay/rust-dashcore", rev = "173ffac0fdc0c73dda0626cf385bbcfcf2437aeb" }
-dash-network = { git = "https://github.com/dashpay/rust-dashcore", rev = "173ffac0fdc0c73dda0626cf385bbcfcf2437aeb" }
-dashcore-rpc = { git = "https://github.com/dashpay/rust-dashcore", rev = "173ffac0fdc0c73dda0626cf385bbcfcf2437aeb" }
+dashcore = { git = "https://github.com/dashpay/rust-dashcore", rev = "0f9485909142e2cab165ef96c7f8ad245d9bec3c" }
+dash-network-seeds = { git = "https://github.com/dashpay/rust-dashcore", rev = "0f9485909142e2cab165ef96c7f8ad245d9bec3c" }
+dash-spv = { git = "https://github.com/dashpay/rust-dashcore", rev = "0f9485909142e2cab165ef96c7f8ad245d9bec3c" }
+key-wallet = { git = "https://github.com/dashpay/rust-dashcore", rev = "0f9485909142e2cab165ef96c7f8ad245d9bec3c" }
+key-wallet-ffi = { git = "https://github.com/dashpay/rust-dashcore", rev = "0f9485909142e2cab165ef96c7f8ad245d9bec3c" }
+key-wallet-manager = { git = "https://github.com/dashpay/rust-dashcore", rev = "0f9485909142e2cab165ef96c7f8ad245d9bec3c" }
+dash-network = { git = "https://github.com/dashpay/rust-dashcore", rev = "0f9485909142e2cab165ef96c7f8ad245d9bec3c" }
+dashcore-rpc = { git = "https://github.com/dashpay/rust-dashcore", rev = "0f9485909142e2cab165ef96c7f8ad245d9bec3c" }
 
 tokio-metrics = "0.5"
 

packages/kotlin-sdk/sdk/src/main/kotlin/org/dashfoundation/dashsdk/ffi/WalletManagerNative.kt

@@ -285,16 +285,22 @@ internal object WalletManagerNative {
     external fun coreWalletDestroy(coreHandle: Long)
 
     /**
-     * `core_wallet_signed_payment_finalize` — atomically fund, reserve, sign,
-     * AND register a builder for deferred (BIP70/BIP270) submission in one
-     * native call. Selection and reservation commit as a single unit under the
+     * `core_wallet_signed_payment_finalize_with_deliverable` — atomically fund,
+     * reserve, sign, AND register a builder for deferred (BIP70/BIP270)
+     * submission in one native call. Selection and reservation commit as a single unit under the
      * wallet-manager lock, closing the double-selection window. CONSUMES
      * [builder]. [accountType]/[accountIndex] identify the funding account
      * (0 BIP44, 1 BIP32, 2 CoinJoin); [coreSignerHandle] is a
      * `MnemonicResolverHandle`.
      *
      * Returns a big-endian BLOB decoded into a `SignedCoreTransaction`:
-     * `u64 token, u64 feeDuffs, u32 txidLen, txid utf8, u32 txBytesLen, txBytes`.
+     * `u64 token, u64 feeDuffs, u64 deliverableDuffs, u32 txidLen, txid utf8,
+     * u32 txBytesLen, txBytes`.
+     *
+     * `deliverableDuffs` sits between `feeDuffs` and `txidLen`, so every field
+     * after it shifts by eight bytes against the pre-drain layout. It is the
+     * value of the transaction's sole non-OP_RETURN output, or 0 when there is
+     * no single such output.
      */
     external fun coreWalletFinalizeSignedPayment(
         builder: Long,

packages/kotlin-sdk/sdk/src/main/kotlin/org/dashfoundation/dashsdk/wallet/CoreTransactionBuilder.kt

@@ -48,7 +48,31 @@ class CoreTransactionBuilder internal constructor(network: Network) : AutoClosea
 
     /**
      * Coin-selection strategy — mirror of key-wallet's `SelectionStrategy`
-     * (`CoreSelectionStrategyFFI`). [ALL] drains the account.
+     * (`CoreSelectionStrategyFFI`).
+     *
+     * [ALL] drains — it selects every spendable UTXO the chosen funding
+     * source offers, sets the single destination output to
+     * `total inputs − fee`, and leaves no change. **Its scope is whatever
+     * [AccountType] names, not "the wallet's main account":**
+     *
+     * - [AccountType.BIP44] / [AccountType.BIP32] / [AccountType.COIN_JOIN]
+     *   drain that one account family;
+     * - [AccountType.ALL_SPENDABLE] — **the default** — drains BIP44 **and**
+     *   BIP32 **and** every DashPay contact-receiving account, in one
+     *   transaction.
+     *
+     * So `selectionStrategy = ALL` on a call that does not name an
+     * [AccountType] sweeps the wallet's whole spendable balance, contact
+     * receiving accounts included. That is the intended shape of a drain: a
+     * host asking to send everything means everything it can sign for, and
+     * before the pooled selector existed a host had to sweep accounts
+     * together on-chain first to achieve it. Name a single [AccountType] only
+     * when the drain is genuinely scoped to one family — a CoinJoin sweep,
+     * say, which must stay in its own privacy domain.
+     *
+     * Read what a drain actually pays from
+     * [SignedCoreTransaction.deliverableAmountDuffs]; the engine computes it,
+     * and the caller's requested amount is discarded.
      */
     enum class SelectionStrategy(val ffiValue: Int) {
         SMALLEST_FIRST(0),