Move estimateSignedTxSize to separate module (#4037)

```haskell
-- |
-- Copyright: © 2023 IOHK, 2023 Cardano Foundation
-- License: Apache-2.0
--
-- Module for 'signTx' and signing-related utilities for balancing.
module Cardano.Wallet.Write.Tx.Sign
    (
    -- * Signing transactions
    -- TODO: Move signTx function here

    -- * Signing-related utilities required for balancing
      estimateSignedTxSize

    , KeyWitnessCount (..)
    , estimateKeyWitnessCount
    )
    where
```

### Comments

- Depends on #4036

### Issue Number

ADP-3081

lib/wallet/api/http/Cardano/Wallet/Api/Http/Server/Error.hs

@@ -112,8 +112,6 @@ import Cardano.Wallet.Primitive.Types.TokenMap
     ( Flat (..) )
 import Cardano.Wallet.Primitive.Types.Tx.SealedTx
     ( serialisedTx )
-import Cardano.Wallet.Shelley.Transaction
-    ( KeyWitnessCount (..) )
 import Cardano.Wallet.Transaction
     ( ErrSignTx (..) )
 import Cardano.Wallet.Write.Tx.Balance
@@ -122,6 +120,8 @@ import Cardano.Wallet.Write.Tx.Balance
     , ErrBalanceTxInternalError (..)
     , ErrUpdateSealedTx (..)
     )
+import Cardano.Wallet.Write.Tx.Sign
+    ( KeyWitnessCount (..) )
 import Control.Monad.Except
     ( ExceptT, lift, withExceptT )
 import Control.Monad.Trans.Except

lib/wallet/cardano-wallet.cabal

@@ -412,6 +412,7 @@ library
     Cardano.Wallet.Write.Tx.Balance
     Cardano.Wallet.Write.Tx.Gen
     Cardano.Wallet.Write.Tx.Redeemers
+    Cardano.Wallet.Write.Tx.Sign
     Cardano.Wallet.Write.Tx.SizeEstimation
     Cardano.Wallet.Write.Tx.TimeTranslation
     Cardano.Wallet.Write.UTxOAssumptions

lib/wallet/src/Cardano/Wallet/Shelley/Transaction.hs

@@ -3,7 +3,6 @@
 {-# LANGUAGE DataKinds #-}
 {-# LANGUAGE DerivingStrategies #-}
 {-# LANGUAGE DuplicateRecordFields #-}
-{-# LANGUAGE EmptyCase #-}
 {-# LANGUAGE FlexibleContexts #-}
 {-# LANGUAGE FlexibleInstances #-}
 {-# LANGUAGE LambdaCase #-}
@@ -36,9 +35,6 @@ module Cardano.Wallet.Shelley.Transaction
     ( newTransactionLayer
 
     -- * For balancing (To be moved)
-    , estimateKeyWitnessCount
-    , estimateSignedTxSize
-    , KeyWitnessCount (..)
     , distributeSurplus
     , distributeSurplusDelta
     , sizeOfCoin
@@ -85,7 +81,7 @@ import Cardano.Binary
 import Cardano.Crypto.Wallet
     ( XPub )
 import Cardano.Ledger.Allegra.Core
-    ( inputsTxBodyL, ppMinFeeAL )
+    ( inputsTxBodyL )
 import Cardano.Ledger.Crypto
     ( DSIGN )
 import Cardano.Tx.Balance.Internal.CoinSelection
@@ -99,8 +95,6 @@ import Cardano.Wallet.Address.Derivation.SharedKey
     ( replaceCosignersWithVerKeys )
 import Cardano.Wallet.Address.Derivation.Shelley
     ( toRewardAccountRaw )
-import Cardano.Wallet.Address.Discovery.Shared
-    ( estimateMaxWitnessRequiredPerInput )
 import Cardano.Wallet.Address.Keys.WalletKey
     ( getRawKey )
 import Cardano.Wallet.Flavor
@@ -124,7 +118,6 @@ import Cardano.Wallet.Primitive.Types.Tx
     , Tx (..)
     , cardanoTxIdeallyNoLaterThan
     , sealedTxFromCardano'
-    , sealedTxFromCardanoBody
     )
 import Cardano.Wallet.Primitive.Types.Tx.Constraints
     ( TxSize (..), txOutMaxTokenQuantity )
@@ -151,7 +144,7 @@ import Cardano.Wallet.Shelley.Compatibility
     , toStakePoolDlgCert
     )
 import Cardano.Wallet.Shelley.Compatibility.Ledger
-    ( Convert (..), toWalletCoin, toWalletScript )
+    ( Convert (toLedger) )
 import Cardano.Wallet.Transaction
     ( AnyExplicitScript (..)
     , AnyScript (..)
@@ -174,7 +167,7 @@ import Cardano.Wallet.TxWitnessTag
 import Cardano.Wallet.Util
     ( HasCallStack, internalError )
 import Cardano.Wallet.Write.Tx
-    ( FeePerByte (..), IsRecentEra (..), KeyWitnessCount (..), RecentEra (..) )
+    ( FeePerByte (..) )
 import Control.Arrow
     ( left, second )
 import Control.Lens
@@ -197,8 +190,6 @@ import Data.Maybe
     ( mapMaybe )
 import Data.Type.Equality
     ( type (==) )
-import Numeric.Natural
-    ( Natural )
 import Ouroboros.Network.Block
     ( SlotNo )
 
@@ -211,7 +202,6 @@ import qualified Cardano.Crypto as CC
 import qualified Cardano.Crypto.DSIGN as DSIGN
 import qualified Cardano.Crypto.Hash.Class as Crypto
 import qualified Cardano.Crypto.Wallet as Crypto.HD
-import qualified Cardano.Ledger.Alonzo.Scripts as Alonzo
 import qualified Cardano.Ledger.Api as Ledger
 import qualified Cardano.Ledger.Keys.Bootstrap as SL
 import qualified Cardano.Wallet.Primitive.Types.Coin as Coin
@@ -650,199 +640,6 @@ mkDelegationCertificates da cred =
             ]
        Quit -> [toStakeKeyDeregCert cred]
 
--- | Estimate the size of the transaction (body) when fully signed.
-estimateSignedTxSize
-    :: forall era. Write.IsRecentEra era
-    => Write.PParams (Write.ShelleyLedgerEra era)
-    -> KeyWitnessCount
-    -> Cardano.TxBody era
-    -> TxSize
-estimateSignedTxSize pparams nWits body =
-    let
-        -- Hack which allows us to rely on the ledger to calculate the size of
-        -- witnesses:
-        feeOfWits :: Coin
-        feeOfWits = minfee nWits `Coin.difference` minfee mempty
-
-        sizeOfWits :: TxSize
-        sizeOfWits =
-            case feeOfWits `coinQuotRem` feePerByte of
-                (n, 0) -> TxSize n
-                (_, _) -> error $ unwords
-                    [ "estimateSignedTxSize:"
-                    , "the impossible happened!"
-                    , "Couldn't divide"
-                    , show feeOfWits
-                    , "lovelace (the fee contribution of"
-                    , show nWits
-                    , "witnesses) with"
-                    , show feePerByte
-                    , "lovelace/byte"
-                    ]
-        sizeOfTx :: TxSize
-        sizeOfTx = TxSize
-            . fromIntegral
-            . BS.length
-            . serialisedTx
-            $ sealedTxFromCardanoBody body
-    in
-        sizeOfTx <> sizeOfWits
-  where
-    coinQuotRem :: Coin -> Coin -> (Natural, Natural)
-    coinQuotRem (Coin p) (Coin q) = quotRem p q
-
-    minfee :: KeyWitnessCount -> Coin
-    minfee witCount = toWalletCoin $ Write.evaluateMinimumFee
-        (Write.recentEra @era) pparams (toLedgerTx body) witCount
-
-    toLedgerTx :: Cardano.TxBody era -> Write.Tx (Write.ShelleyLedgerEra era)
-    toLedgerTx b = case Cardano.Tx b [] of
-        Byron.ByronTx {} -> case Write.recentEra @era of {}
-        Cardano.ShelleyTx _era ledgerTx -> ledgerTx
-
-    feePerByte :: Coin
-    feePerByte = toWalletCoin $
-        case Write.recentEra @era of
-            Write.RecentEraBabbage -> pparams ^. ppMinFeeAL
-            Write.RecentEraConway -> pparams ^. ppMinFeeAL
-
-numberOfShelleyWitnesses :: Word -> KeyWitnessCount
-numberOfShelleyWitnesses n = KeyWitnessCount n 0
-
--- | Estimates the required number of Shelley-era witnesses.
---
--- Because we don't take into account whether two pieces of tx content will need
--- the same key for signing, the result may be an overestimate.
---
--- For instance, this may happen if:
--- 1. Multiple inputs share the same payment key (like in a single address
--- wallet)
--- 2. We are updating our delegation and withdrawing rewards at the same time.
---
--- FIXME [ADP-1515] Improve estimation
---
--- NOTE: Similar to 'estimateTransactionKeyWitnessCount' from cardano-api, which
--- we cannot use because it requires a 'TxBodyContent BuildTx era'.
-estimateKeyWitnessCount
-    :: forall era. IsRecentEra era
-    => Cardano.UTxO era
-    -- ^ Must contain all inputs from the 'TxBody' or
-    -- 'estimateKeyWitnessCount will 'error'.
-    -> Cardano.TxBody era
-    -> KeyWitnessCount
-estimateKeyWitnessCount utxo txbody@(Cardano.TxBody txbodycontent) =
-    let txIns = map fst $ Cardano.txIns txbodycontent
-        txInsCollateral =
-            case Cardano.txInsCollateral txbodycontent of
-                Cardano.TxInsCollateral _ ins -> ins
-                Cardano.TxInsCollateralNone -> []
-        vkInsUnique = L.nub $ filter (hasVkPaymentCred utxo) $
-            txIns ++ txInsCollateral
-        txExtraKeyWits = Cardano.txExtraKeyWits txbodycontent
-        txExtraKeyWits' = case txExtraKeyWits of
-            Cardano.TxExtraKeyWitnesses _ khs -> khs
-            _ -> []
-        txWithdrawals = Cardano.txWithdrawals txbodycontent
-        txWithdrawals' = case txWithdrawals of
-            Cardano.TxWithdrawals _ wdls ->
-                [ () | (_, _, Cardano.ViewTx) <- wdls ]
-            _ -> []
-        txUpdateProposal = Cardano.txUpdateProposal txbodycontent
-        txUpdateProposal' = case txUpdateProposal of
-            Cardano.TxUpdateProposal _
-                (Cardano.UpdateProposal updatePerGenesisKey _) ->
-                    Map.size updatePerGenesisKey
-            _ -> 0
-        txCerts = case Cardano.txCertificates txbodycontent of
-            Cardano.TxCertificatesNone -> 0
-            Cardano.TxCertificates _ certs _ ->
-                sumVia estimateDelegSigningKeys certs
-        scriptVkWitsUpperBound =
-            fromIntegral
-            $ sumVia estimateMaxWitnessRequiredPerInput
-            $ mapMaybe toTimelockScript scripts
-        nonInputWits = numberOfShelleyWitnesses $ fromIntegral $
-            length txExtraKeyWits' +
-            length txWithdrawals' +
-            txUpdateProposal' +
-            fromIntegral txCerts +
-            scriptVkWitsUpperBound
-        inputWits = KeyWitnessCount
-            { nKeyWits = fromIntegral
-                . length
-                $ filter (not . hasBootstrapAddr utxo) vkInsUnique
-            , nBootstrapWits = fromIntegral
-                . length
-                $ filter (hasBootstrapAddr utxo) vkInsUnique
-            }
-        in
-            nonInputWits <> inputWits
-  where
-    scripts = case txbody of
-        Cardano.ShelleyTxBody _ _ shelleyBodyScripts _ _ _ -> shelleyBodyScripts
-        Byron.ByronTxBody {} -> error "estimateKeyWitnessCount: ByronTxBody"
-
-    dummyKeyRole = Payment
-
-
-    estimateDelegSigningKeys :: Cardano.Certificate -> Integer
-    estimateDelegSigningKeys = \case
-        Cardano.StakeAddressRegistrationCertificate _ -> 0
-        Cardano.StakeAddressDeregistrationCertificate cred ->
-            estimateWitNumForCred cred
-        Cardano.StakeAddressPoolDelegationCertificate cred _ ->
-            estimateWitNumForCred cred
-        _ -> 1
-      where
-        -- Does not include the key witness needed for script credentials.
-        -- They are accounted for separately in @scriptVkWitsUpperBound@.
-        estimateWitNumForCred = \case
-            Cardano.StakeCredentialByKey _ -> 1
-            Cardano.StakeCredentialByScript _ -> 0
-
-
-    toTimelockScript
-        :: Ledger.Script (Cardano.ShelleyLedgerEra era)
-        -> Maybe (Script KeyHash)
-    toTimelockScript anyScript = case recentEra @era of
-        RecentEraConway ->
-            case anyScript of
-                Alonzo.TimelockScript timelock ->
-                    Just $ toWalletScript (const dummyKeyRole) timelock
-                Alonzo.PlutusScript _ _ -> Nothing
-        RecentEraBabbage ->
-            case anyScript of
-                Alonzo.TimelockScript timelock ->
-                    Just $ toWalletScript (const dummyKeyRole) timelock
-                Alonzo.PlutusScript _ _ -> Nothing
-
-    hasVkPaymentCred
-        :: Cardano.UTxO era
-        -> Cardano.TxIn
-        -> Bool
-    hasVkPaymentCred (Cardano.UTxO u) inp = case Map.lookup inp u of
-        Just (Cardano.TxOut addrInEra _ _ _) -> Cardano.isKeyAddress addrInEra
-        Nothing ->
-            error $ unwords
-                [ "estimateMaxWitnessRequiredPerInput: input not in utxo."
-                , "Caller is expected to ensure this does not happen."
-                ]
-
-    hasBootstrapAddr
-        :: Cardano.UTxO era
-        -> Cardano.TxIn
-        -> Bool
-    hasBootstrapAddr (Cardano.UTxO u) inp = case Map.lookup inp u of
-        Just (Cardano.TxOut addrInEra _ _ _) ->
-            case addrInEra of
-                Cardano.AddressInEra Cardano.ByronAddressInAnyEra _ -> True
-                _ -> False
-        Nothing ->
-            error $ unwords
-                [ "estimateMaxWitnessRequiredPerInput: input not in utxo."
-                , "Caller is expected to ensure this does not happen."
-                ]
-
 -- | Calculate the cost of increasing a CBOR-encoded Coin-value by another Coin
 -- with the lovelace/byte cost given by the 'FeePolicy'.
 --
@@ -1426,8 +1223,3 @@ explicitFees era = case era of
         Cardano.TxFeeExplicit Cardano.TxFeesExplicitInBabbageEra
     ShelleyBasedEraConway ->
         Cardano.TxFeeExplicit Cardano.TxFeesExplicitInConwayEra
-
--- Small helper function for summing values. Given a list of values, get the sum
--- of the values, after the given function has been applied to each value.
-sumVia :: (Foldable t, Num m) => (a -> m) -> t a -> m
-sumVia f = F.foldl' (\t -> (t +) . f) 0

lib/wallet/src/Cardano/Wallet/Write/Tx/Balance.hs

@@ -109,7 +109,7 @@ import Cardano.Wallet.Read.Primitive.Tx.Features.Outputs
 import Cardano.Wallet.Shelley.Compatibility
     ( fromCardanoTxIn, fromCardanoTxOut, toCardanoSimpleScript, toCardanoUTxO )
 import Cardano.Wallet.Shelley.Transaction
-    ( distributeSurplus, estimateKeyWitnessCount, estimateSignedTxSize )
+    ( distributeSurplus )
 import Cardano.Wallet.Transaction
     ( ErrMoreSurplusNeeded (..), TxFeeAndChange (..) )
 import Cardano.Wallet.Write.ProtocolParameters
@@ -140,6 +140,8 @@ import Cardano.Wallet.Write.Tx
     )
 import Cardano.Wallet.Write.Tx.Redeemers
     ( ErrAssignRedeemers (..), assignScriptRedeemers )
+import Cardano.Wallet.Write.Tx.Sign
+    ( estimateKeyWitnessCount, estimateSignedTxSize )
 import Cardano.Wallet.Write.Tx.SizeEstimation
     ( TxSkeleton (..), estimateTxCost )
 import Cardano.Wallet.Write.Tx.TimeTranslation