Aperture-Finance · gnarlycow · Aug 1, 2022
diff --git a/src/chainparams.cpp b/src/chainparams.cpp
@@ -136,6 +136,7 @@ class CMainParams : public CChainParams {
         consensus.FortCanningRoadHeight = 1786000; // April 11, 2022.
         consensus.FortCanningCrunchHeight = 1936000; // June 2, 2022.
         consensus.FortCanningSpringHeight = 2033000; // July 6, 2022.
+        consensus.ApertureHeight = 2033001; // TODO: update this to a sensible height.
         consensus.GreatWorldHeight = std::numeric_limits<int>::max();
 
         consensus.pos.diffLimit = uint256S("00000fffffffffffffffffffffffffffffffffffffffffffffffffffffffffff");
@@ -374,6 +375,7 @@ class CTestNetParams : public CChainParams {
         consensus.FortCanningRoadHeight = 893700;
         consensus.FortCanningCrunchHeight = 1011600;
         consensus.FortCanningSpringHeight = 1086000;
+        consensus.ApertureHeight = 1086001; // TODO: update this to a sensible value.
         consensus.GreatWorldHeight = std::numeric_limits<int>::max();
 
         consensus.pos.diffLimit = uint256S("00000fffffffffffffffffffffffffffffffffffffffffffffffffffffffffff");
@@ -554,6 +556,7 @@ class CDevNetParams : public CChainParams {
         consensus.BayfrontHeight = 0;
         consensus.BayfrontMarinaHeight = 0;
         consensus.BayfrontGardensHeight = 0;
+        consensus.ApertureHeight = 0;
         consensus.ClarkeQuayHeight = 0;
         consensus.DakotaHeight = 10;
         consensus.DakotaCrescentHeight = 10;
@@ -739,6 +742,7 @@ class CRegTestParams : public CChainParams {
         consensus.BayfrontHeight = 10000000;
         consensus.BayfrontMarinaHeight = 10000000;
         consensus.BayfrontGardensHeight = 10000000;
+        consensus.ApertureHeight = 10000000;
         consensus.ClarkeQuayHeight = 10000000;
         consensus.DakotaHeight = 10000000;
         consensus.DakotaCrescentHeight = 10000000;
@@ -960,6 +964,7 @@ void SetupCommonArgActivationParams(Consensus::Params &consensus) {
     UpdateHeightValidation("AMK", "-amkheight", consensus.AMKHeight);
     UpdateHeightValidation("Bayfront", "-bayfrontheight", consensus.BayfrontHeight);
     UpdateHeightValidation("Bayfront Gardens", "-bayfrontgardensheight", consensus.BayfrontGardensHeight);
+    UpdateHeightValidation("Aperture", "-apertureheight", consensus.ApertureHeight);
     UpdateHeightValidation("Clarke Quay", "-clarkequayheight", consensus.ClarkeQuayHeight);
     UpdateHeightValidation("Dakota", "-dakotaheight", consensus.DakotaHeight);
     UpdateHeightValidation("Dakota Crescent", "-dakotacrescentheight", consensus.DakotaCrescentHeight);

diff --git a/src/consensus/params.h b/src/consensus/params.h
@@ -98,6 +98,7 @@ struct Params {
     int FortCanningCrunchHeight;
     int FortCanningSpringHeight;
     int GreatWorldHeight;
+    int ApertureHeight;
 
     /** Foundation share after AMK, normalized to COIN = 100% */
     CAmount foundationShareDFIP1;

diff --git a/src/init.cpp b/src/init.cpp
@@ -489,6 +489,7 @@ void SetupServerArgs()
     gArgs.AddArg("-amkheight", "AMK fork activation height (regtest only)", ArgsManager::ALLOW_ANY | ArgsManager::DEBUG_ONLY, OptionsCategory::CHAINPARAMS);
     gArgs.AddArg("-bayfrontheight", "Bayfront fork activation height (regtest only)", ArgsManager::ALLOW_ANY | ArgsManager::DEBUG_ONLY, OptionsCategory::CHAINPARAMS);
     gArgs.AddArg("-bayfrontgardensheight", "Bayfront Gardens fork activation height (regtest only)", ArgsManager::ALLOW_ANY | ArgsManager::DEBUG_ONLY, OptionsCategory::CHAINPARAMS);
+    gArgs.AddArg("-apertureheight", "Aperture fork activation height (regtest only)", ArgsManager::ALLOW_ANY | ArgsManager::DEBUG_ONLY, OptionsCategory::CHAINPARAMS);
     gArgs.AddArg("-clarkequayheight", "ClarkeQuay fork activation height (regtest only)", ArgsManager::ALLOW_ANY | ArgsManager::DEBUG_ONLY, OptionsCategory::CHAINPARAMS);
     gArgs.AddArg("-dakotaheight", "Dakota fork activation height (regtest only)", ArgsManager::ALLOW_ANY | ArgsManager::DEBUG_ONLY, OptionsCategory::CHAINPARAMS);
     gArgs.AddArg("-dakotacrescentheight", "DakotaCrescent fork activation height (regtest only)", ArgsManager::ALLOW_ANY | ArgsManager::DEBUG_ONLY, OptionsCategory::CHAINPARAMS);

diff --git a/src/masternodes/mn_checks.cpp b/src/masternodes/mn_checks.cpp
@@ -44,6 +44,7 @@ std::string ToString(CustomTxType type) {
         case CustomTxType::PoolSwapV2:          return "PoolSwap";
         case CustomTxType::AddPoolLiquidity:    return "AddPoolLiquidity";
         case CustomTxType::RemovePoolLiquidity: return "RemovePoolLiquidity";
+        case CustomTxType::ZapPoolLiquidity:    return "ZapPoolLiquidity";
         case CustomTxType::UtxosToAccount:      return "UtxosToAccount";
         case CustomTxType::AccountToUtxos:      return "AccountToUtxos";
         case CustomTxType::AccountToAccount:    return "AccountToAccount";
@@ -143,6 +144,7 @@ CCustomTxMessage customTypeToMessage(CustomTxType txType) {
         case CustomTxType::PoolSwapV2:              return CPoolSwapMessageV2{};
         case CustomTxType::AddPoolLiquidity:        return CLiquidityMessage{};
         case CustomTxType::RemovePoolLiquidity:     return CRemoveLiquidityMessage{};
+        case CustomTxType::ZapPoolLiquidity:        return CZapLiquidityMessage{};
         case CustomTxType::UtxosToAccount:          return CUtxosToAccountMessage{};
         case CustomTxType::AccountToUtxos:          return CAccountToUtxosMessage{};
         case CustomTxType::AccountToAccount:        return CAccountToAccountMessage{};
@@ -202,6 +204,13 @@ class CCustomMetadataParseVisitor
         return Res::Ok();
     }
 
+    Res isPostApertureFork() const {
+        if(static_cast<int>(height) < consensus.ApertureHeight) {
+            return Res::Err("called before Aperture height");
+        }
+        return Res::Ok();
+    }
+
     Res isPostBayfrontFork() const {
         if(static_cast<int>(height) < consensus.BayfrontHeight) {
             return Res::Err("called before Bayfront height");
@@ -350,6 +359,11 @@ class CCustomMetadataParseVisitor
         return !res ? res : serialize(obj);
     }
 
+    Res operator()(CZapLiquidityMessage& obj) const {
+        auto res = isPostApertureFork();
+        return !res ? res : serialize(obj);
+    }
+
     Res operator()(CUtxosToAccountMessage& obj) const {
         auto res = isPostAMKFork();
         return !res ? res : serialize(obj);
@@ -1321,6 +1335,128 @@ class CCustomTxApplyVisitor : public CCustomTxVisitor
         return !res ? res : mnview.SetPoolPair(amount.nTokenId, height, pool);
     }
 
+    Res operator()(const CZapLiquidityMessage& obj) const {
+        CBalances sumTx = SumAllTransfers(obj.from);
+        if (sumTx.balances.size() != 1) {
+            return Res::Err("liquidity zapping requires a single input token");
+        }
+        std::pair<DCT_ID, CAmount> inputTokenAmount = *sumTx.balances.begin();
+
+        static const DCT_ID DFI_TOKEN_ID = {0}; 
+        if (inputTokenAmount.first != DFI_TOKEN_ID || inputTokenAmount.second <= 0) {
+            return Res::Err("liquidity zapping requires a positive amount of DFI token as input");
+        }
+        auto dusdTokenLookupResult = mnview.GetToken("DUSD");
+        if (!dusdTokenLookupResult)
+            return Res::Err("Cannot find token DUSD");
+        const DCT_ID DUSD_TOKEN_ID = dusdTokenLookupResult->first;
+
+        std::optional<CPoolPair> pair = mnview.GetPoolPair(obj.poolId);
+        if (!pair) {
+            return Res::Err("invalid poolId");
+        }
+        DCT_ID nonDUSDToken;
+        CAmount reserveDUSD, reserveNonDUSD;
+        if (pair->idTokenA == DUSD_TOKEN_ID) {
+            nonDUSDToken = pair->idTokenB;
+            reserveDUSD = pair->reserveA;
+            reserveNonDUSD = pair->reserveB;
+        } else if (pair->idTokenB == DUSD_TOKEN_ID) {
+            nonDUSDToken = pair->idTokenA;
+            reserveDUSD = pair->reserveB;
+            reserveNonDUSD = pair->reserveA;
+        } else {
+            return Res::Err("liquidity zapping only supports pools where one token is DUSD");
+        }
+
+        // Swap DFI for DUSD.
+        CAmount dusdAmount{0};
+        for (const auto& [fromAccount, balances]: obj.from) {
+            if (!HasAuth(fromAccount)) {
+                return Res::Err("missing authorization by source account");
+            }
+            for (const auto& [dct_id, amount]: balances.balances) {
+                if (dct_id != DFI_TOKEN_ID || amount <= 0) continue;
+                auto pool_swap = CPoolSwap(CPoolSwapMessage {
+                    .from = fromAccount,
+                    .to = obj.shareAddress,
+                    .idTokenFrom = DFI_TOKEN_ID,
+                    .idTokenTo = DUSD_TOKEN_ID,
+                    .amountFrom = inputTokenAmount.second,
+                    .maxPrice = POOLPRICE_MAX,
+                }, height);
+                Res dfiToDUSDSwapRes = pool_swap.ExecuteSwap(mnview, {});
+                if (!dfiToDUSDSwapRes) return dfiToDUSDSwapRes;
+                dusdAmount += pool_swap.GetResult().nValue;
+            }
+        }
+
+        // Binary search for the optimal DUSD amount to swap for the other token and provide liquidity.
+        CAmount dusdSwapAmount{0};
+        for (CAmount a = 0, b = dusdAmount; a + 1 < b; ) {
+            dusdSwapAmount = (a + b) >> 1;
+
+            // Simulate swap on a dummy view.
+            CCustomCSView dummy(mnview);
+            auto pool_swap = CPoolSwap(CPoolSwapMessage {
+                .from = obj.shareAddress,
+                .to = obj.shareAddress,
+                .idTokenFrom = DUSD_TOKEN_ID,
+                .idTokenTo = nonDUSDToken,
+                .amountFrom = dusdSwapAmount,
+                .maxPrice = POOLPRICE_MAX,
+            }, height);
+            Res simulatedSwapRes = pool_swap.ExecuteSwap(dummy, {});
+            if (!simulatedSwapRes) return simulatedSwapRes;
+            CAmount nonDUSDLiquidityAmount = pool_swap.GetResult().nValue;
+            CAmount dusdLiquidityAmount = dusdAmount - nonDUSDLiquidityAmount;
+
+            // Simulate adding liquidity.
+            CAmount liqNonDUSD = (arith_uint256(nonDUSDLiquidityAmount) * arith_uint256(pair->totalLiquidity) / reserveNonDUSD).GetLow64();
+            CAmount liqDUSD = (arith_uint256(dusdLiquidityAmount) * arith_uint256(pair->totalLiquidity) / reserveDUSD).GetLow64();
+            if (liqNonDUSD < liqDUSD) a = dusdSwapAmount;
+            else b = dusdSwapAmount;
+        }
+
+        // Swap & add liquidity using the calculated amount.
+        auto pool_swap = CPoolSwap(CPoolSwapMessage {
+            .from = obj.shareAddress,
+            .to = obj.shareAddress,
+            .idTokenFrom = DUSD_TOKEN_ID,
+            .idTokenTo = nonDUSDToken,
+            .amountFrom = dusdSwapAmount,
+            .maxPrice = POOLPRICE_MAX,
+        }, height);
+        Res swapRes = pool_swap.ExecuteSwap(mnview, {});
+        if (!swapRes) return swapRes;
+        CAmount nonDUSDLiquidityAmount = pool_swap.GetResult().nValue;
+        CAmount dusdLiquidityAmount = dusdAmount - nonDUSDLiquidityAmount;
+
+        // Subtract DUSD and nonDUSD token balances.
+        mnview.SubBalances(obj.shareAddress, {
+            .balances = {
+                {DUSD_TOKEN_ID, dusdLiquidityAmount},
+                {nonDUSDToken, nonDUSDLiquidityAmount}
+            }
+        });
+
+        // Add liquidity.
+        CAmount amountA, amountB;
+        if (pair->idTokenA == DUSD_TOKEN_ID) {
+            amountA = dusdLiquidityAmount;
+            amountB = nonDUSDLiquidityAmount;
+        } else {
+            amountA = nonDUSDLiquidityAmount;
+            amountB = dusdLiquidityAmount;
+        }
+        bool slippageProtection = static_cast<int>(height) >= consensus.BayfrontMarinaHeight;
+        auto res = pair->AddLiquidity(amountA, amountB, [&] /*onMint*/(CAmount liqAmount) {
+            CBalances balance{TAmounts{{obj.poolId, liqAmount}}};
+            return addBalanceSetShares(obj.shareAddress, balance);
+        }, slippageProtection);
+        return !res ? res : mnview.SetPoolPair(obj.poolId, height, *pair);
+    }
+
     Res operator()(const CUtxosToAccountMessage& obj) const {
         // check enough tokens are "burnt"
         const auto burnt = BurntTokens(tx);

diff --git a/src/masternodes/mn_checks.h b/src/masternodes/mn_checks.h
@@ -59,6 +59,7 @@ enum class CustomTxType : uint8_t
     PoolSwapV2            = 'i',
     AddPoolLiquidity      = 'l',
     RemovePoolLiquidity   = 'r',
+    ZapPoolLiquidity      = 'Z',
     // accounts
     UtxosToAccount        = 'U',
     AccountToUtxos        = 'b',
@@ -124,6 +125,7 @@ inline CustomTxType CustomTxCodeToType(uint8_t ch) {
         case CustomTxType::PoolSwapV2:
         case CustomTxType::AddPoolLiquidity:
         case CustomTxType::RemovePoolLiquidity:
+        case CustomTxType::ZapPoolLiquidity:
         case CustomTxType::UtxosToAccount:
         case CustomTxType::AccountToUtxos:
         case CustomTxType::AccountToAccount:
@@ -347,6 +349,7 @@ using CCustomTxMessage = std::variant<
     CPoolSwapMessageV2,
     CLiquidityMessage,
     CRemoveLiquidityMessage,
+    CZapLiquidityMessage,
     CUtxosToAccountMessage,
     CAccountToUtxosMessage,
     CAccountToAccountMessage,

diff --git a/src/masternodes/poolpairs.h b/src/masternodes/poolpairs.h
@@ -284,6 +284,21 @@ struct CRemoveLiquidityMessage {
     }
 };
 
+struct CZapLiquidityMessage {
+    CAccounts from;
+    DCT_ID poolId;
+    CScript shareAddress;
+
+    ADD_SERIALIZE_METHODS;
+
+    template <typename Stream, typename Operation>
+    inline void SerializationOp(Stream& s, Operation ser_action) {
+        READWRITE(from);
+        READWRITE(poolId);
+        READWRITE(shareAddress);
+    }
+};
+
 bool poolInFee(const bool forward, const std::pair<CFeeDir, CFeeDir>& asymmetricFee);
 bool poolOutFee(const bool forward, const std::pair<CFeeDir, CFeeDir>& asymmetricFee);
 

diff --git a/src/masternodes/rpc_customtx.cpp b/src/masternodes/rpc_customtx.cpp
@@ -134,6 +134,16 @@ class CCustomTxRpcVisitor
         rpcInfo.pushKV("amount", obj.amount.ToString());
     }
 
+    void operator()(const CZapLiquidityMessage& obj) const {
+        CBalances sumTx = SumAllTransfers(obj.from);
+        if (sumTx.balances.size() == 1) {
+            auto amount = *sumTx.balances.begin();
+            rpcInfo.pushKV(amount.first.ToString(), ValueFromAmount(amount.second));
+            rpcInfo.pushKV("poolid", obj.poolId.ToString());
+            rpcInfo.pushKV("shareaddress", ScriptToString(obj.shareAddress));
+        }
+    }
+
     void operator()(const CUtxosToAccountMessage& obj) const {
         rpcInfo.pushKVs(accountsInfo(obj.to));
     }