Payback of DUSD loan with DFI

src/masternodes/masternodes.cpp

@@ -920,13 +920,25 @@ CAmount CCollateralLoans::precisionRatio() const
     return ratio > maxRatio / precision ? -COIN : CAmount(ratio * precision);
 }
 
-ResVal<CAmount> CCustomCSView::GetAmountInCurrency(CAmount amount, CTokenCurrencyPair priceFeedId, bool useNextPrice, bool requireLivePrice)
+ResVal<CAmount> CCustomCSView::GetAmountInCurrency(CAmount amount, CTokenCurrencyPair priceFeedId, bool useNextPrice, bool requireLivePrice, bool reverseDirection)
 {
         auto priceResult = GetValidatedIntervalPrice(priceFeedId, useNextPrice, requireLivePrice);
         if (!priceResult)
             return std::move(priceResult);
 
         auto price = priceResult.val.get();
+
+        if (reverseDirection)
+        {
+            if (price == 0)
+                return Res::Err("Price is zero (%s - %s/%s)", GetDecimaleString(price), priceFeedId.first, priceFeedId.second);
+            auto amountInCurrency = DivideAmounts(amount, price);
+            if (MultiplyAmounts(amountInCurrency, price) != amount)
+                amountInCurrency += 1;
+
+            return ResVal<CAmount>(amountInCurrency, Res::Ok());
+        }
+
         auto amountInCurrency = MultiplyAmounts(price, amount);
         if (price > COIN && amountInCurrency < amount)
             return Res::Err("Value/price too high (%s/%s)", GetDecimaleString(amount), GetDecimaleString(price));
@@ -950,7 +962,7 @@ ResVal<CCollateralLoans> CCustomCSView::GetLoanCollaterals(CVaultId const& vault
     if (!res)
         return std::move(res);
 
-    LogPrint(BCLog::LOAN, "\t\t%s(): totalCollaterals - %lld, totalLoans - %lld, ratio - %d\n",  
+    LogPrint(BCLog::LOAN, "\t\t%s(): totalCollaterals - %lld, totalLoans - %lld, ratio - %d\n",
         __func__, result.totalCollaterals, result.totalLoans, result.ratio());
 
     return ResVal<CCollateralLoans>(result, Res::Ok());

src/masternodes/masternodes.h

@@ -427,7 +427,7 @@ class CCustomCSView
 
     bool CalculateOwnerRewards(CScript const & owner, uint32_t height);
 
-    ResVal<CAmount> GetAmountInCurrency(CAmount amount, CTokenCurrencyPair priceFeedId, bool useNextPrice = false, bool requireLivePrice = true);
+    ResVal<CAmount> GetAmountInCurrency(CAmount amount, CTokenCurrencyPair priceFeedId, bool useNextPrice = false, bool requireLivePrice = true, bool reverseDirection = false);
 
     ResVal<CCollateralLoans> GetLoanCollaterals(CVaultId const & vaultId, CBalances const & collaterals, uint32_t height, int64_t blockTime, bool useNextPrice = false, bool requireLivePrice = true);
 

src/masternodes/mn_checks.cpp

@@ -2645,6 +2645,14 @@ class CCustomTxApplyVisitor : public CCustomTxVisitor
         for (const auto& kv : obj.amounts.balances)
         {
             DCT_ID tokenId = kv.first;
+            auto paybackAmount = kv.second;
+
+            if (height >= Params().GetConsensus().FortCanningHillHeight && kv.first == DCT_ID{0})
+            {
+                tokenId = mnview.GetToken("DUSD")->first;
+                paybackAmount = mnview.GetAmountInCurrency(paybackAmount, {"DFI","USD"});
+            }
+
             auto loanToken = mnview.GetLoanTokenByID(tokenId);
             if (!loanToken)
                 return Res::Err("Loan token with id (%s) does not exist!", tokenId.ToString());
@@ -2663,17 +2671,17 @@ class CCustomTxApplyVisitor : public CCustomTxVisitor
 
             LogPrint(BCLog::LOAN,"CLoanPaybackMessage()->%s->", loanToken->symbol); /* Continued */
             auto subInterest = TotalInterest(*rate, height);
-            auto subLoan = kv.second - subInterest;
+            auto subLoan = paybackAmount - subInterest;
 
-            if (kv.second < subInterest)
+            if (paybackAmount < subInterest)
             {
-                subInterest = kv.second;
+                subInterest = paybackAmount;
                 subLoan = 0;
             }
             else if (it->second - subLoan < 0)
                 subLoan = it->second;
 
-            res = mnview.SubLoanToken(obj.vaultId, CTokenAmount{kv.first, subLoan});
+            res = mnview.SubLoanToken(obj.vaultId, CTokenAmount{tokenId, subLoan});
             if (!res)
                 return res;
 
@@ -2692,21 +2700,40 @@ class CCustomTxApplyVisitor : public CCustomTxVisitor
                         return Res::Err("Cannot payback this amount of loan for %s, either payback full amount or less than this amount!", loanToken->symbol);
             }
 
-            res = mnview.SubMintedTokens(loanToken->creationTx, subLoan);
-            if (!res)
-                return res;
+            if (height < Params().GetConsensus().FortCanningHillHeight || kv.first != DCT_ID{0})
+            {
+                res = mnview.SubMintedTokens(loanToken->creationTx, subLoan);
+                if (!res)
+                    return res;
+            }
 
             CalculateOwnerRewards(obj.from);
-            // subtract loan amount first, interest is burning below
-            res = mnview.SubBalance(obj.from, CTokenAmount{kv.first, subLoan});
-            if (!res)
-                return res;
 
-            // burn interest Token->USD->DFI->burnAddress
+            // sub amount from balance and burn interest Token->USD->DFI->burnAddress
             if (subInterest)
             {
-                LogPrint(BCLog::LOAN, "CLoanTakeLoanMessage(): Swapping %s interest to DFI - %lld, height - %d\n", loanToken->symbol, subInterest, height);
-                res = SwapToDFIOverUSD(mnview, kv.first, subInterest, obj.from, consensus.burnAddress, height);
+                if (height < Params().GetConsensus().FortCanningHillHeight || kv.first != DCT_ID{0})
+                {
+                    // subtract loan amount first, interest is burning below
+                    res = mnview.SubBalance(obj.from, CTokenAmount{tokenId, subLoan});
+                    if (!res)
+                        return res;
+
+                    LogPrint(BCLog::LOAN, "CLoanTakeLoanMessage(): Swapping %s interest to DFI - %lld, height - %d\n", loanToken->symbol, subInterest, height);
+                    res = SwapToDFIOverUSD(mnview, tokenId, subInterest, obj.from, consensus.burnAddress, height);
+                }
+                else
+                {
+                    CAmount subLoanInDFI = mnview.GetAmountInCurrency(subLoan, {"DFI","USD"}, false, true, true);
+                    res = TransferTokenBalance(DCT_ID{0}, subLoanInDFI, obj.from, consensus.burnAddress);
+                    if (!res)
+                        return res;
+
+                    LogPrint(BCLog::LOAN, "CLoanTakeLoanMessage(): Burning interest in DFI directly - %lld, height - %d\n", subInterest, height);
+                    CAmount subInterestInDFI = mnview.GetAmountInCurrency(subInterest, {"DFI","USD"}, false, true, true);
+                    res = TransferTokenBalance(DCT_ID{0}, subInterestInDFI, obj.from, consensus.burnAddress);
+                }
+
                 if (!res)
                     return res;
             }
@@ -3150,7 +3177,7 @@ void PopulateVaultHistoryData(CHistoryWriters* writers, CAccountsHistoryWriter&
 bool IsDisabledTx(uint32_t height, CustomTxType type, const Consensus::Params& consensus) {
     if (height < consensus.FortCanningParkHeight)
         return false;
-    
+
     // ICXCreateOrder      = '1',
     // ICXMakeOffer        = '2',
     // ICXSubmitDFCHTLC    = '3',
@@ -3182,7 +3209,7 @@ Res ApplyCustomTx(CCustomCSView& mnview, const CCoinsViewCache& coins, const CTr
 
 
     const auto metadataValidation = height >= consensus.FortCanningHeight;
-    
+
     auto txType = GuessCustomTxType(tx, metadata, metadataValidation);
     if (txType == CustomTxType::None) {
         return res;
@@ -3191,7 +3218,7 @@ Res ApplyCustomTx(CCustomCSView& mnview, const CCoinsViewCache& coins, const CTr
     if (IsDisabledTx(height, txType, consensus)) {
         return Res::ErrCode(CustomTxErrCodes::Fatal, "Disabled custom transaction");
     }
-    
+
     if (metadataValidation && txType == CustomTxType::Reject) {
         return Res::ErrCode(CustomTxErrCodes::Fatal, "Invalid custom transaction");
     }
@@ -3507,7 +3534,7 @@ std::vector<std::vector<DCT_ID>> CPoolSwap::CalculatePoolPaths(CCustomCSView& vi
 
 // Note: `testOnly` doesn't update views, and as such can result in a previous price calculations
 // for a pool, if used multiple times (or duplicated pool IDs) with the same view.
-// testOnly is only meant for one-off tests per well defined view.  
+// testOnly is only meant for one-off tests per well defined view.
 Res CPoolSwap::ExecuteSwap(CCustomCSView& view, std::vector<DCT_ID> poolIDs, bool testOnly) {
 
     CTokenAmount swapAmountResult{{},0};
@@ -3577,7 +3604,7 @@ Res CPoolSwap::ExecuteSwap(CCustomCSView& view, std::vector<DCT_ID> poolIDs, boo
 
             // If we're just testing, don't do any balance transfers.
             // Just go over pools and return result. The only way this can
-            // cause inaccurate result is if we go over the same path twice, 
+            // cause inaccurate result is if we go over the same path twice,
             // which shouldn't happen in the first place.
             if (testOnly)
                 return Res::Ok();

test/functional/feature_loan_payback_dfi.py

@@ -0,0 +1,180 @@
+#!/usr/bin/env python3
+# Copyright (c) 2014-2019 The Bitcoin Core developers
+# Copyright (c) DeFi Blockchain Developers
+# Distributed under the MIT software license, see the accompanying
+# file LICENSE or http://www.opensource.org/licenses/mit-license.php.
+"""Test Loan - payback loan."""
+
+from test_framework.test_framework import DefiTestFramework
+from test_framework.util import assert_equal, assert_raises_rpc_error
+
+import calendar
+import time
+from decimal import Decimal
+
+
+class PaybackLoanTest (DefiTestFramework):
+    def set_test_params(self):
+        self.num_nodes = 1
+        self.setup_clean_chain = True
+        self.extra_args = [
+            ['-txnotokens=0', '-amkheight=50', '-bayfrontheight=50', '-bayfrontgardensheight=1',
+                '-fortcanningheight=50', '-fortcanninghillheight=50', '-eunosheight=50', '-txindex=1']
+        ]
+
+    def run_test(self):
+        self.nodes[0].generate(150)
+
+        account0 = self.nodes[0].get_genesis_keys().ownerAuthAddress
+
+        symbolDFI = "DFI"
+        symbolBTC = "BTC"
+        symboldUSD = "DUSD"
+        symbolTSLA = "TSLA"
+
+        self.nodes[0].createtoken({
+            "symbol": symbolBTC,
+            "name": "BTC token",
+            "isDAT": True,
+            "collateralAddress": account0
+        })
+
+        self.nodes[0].generate(1)
+
+        idDFI = list(self.nodes[0].gettoken(symbolDFI).keys())[0]
+        idBTC = list(self.nodes[0].gettoken(symbolBTC).keys())[0]
+
+        self.nodes[0].utxostoaccount({account0: "1000@" + symbolDFI})
+
+        oracle_address1 = self.nodes[0].getnewaddress("", "legacy")
+        price_feeds1 = [
+            {"currency": "USD", "token": "DFI"},
+            {"currency": "USD", "token": "BTC"},
+            {"currency": "USD", "token": "TSLA"}
+        ]
+        oracle_id1 = self.nodes[0].appointoracle(
+            oracle_address1, price_feeds1, 10)
+        self.nodes[0].generate(1)
+
+        # feed oracle
+        oracle1_prices = [
+            {"currency": "USD", "tokenAmount": "10@TSLA"},
+            {"currency": "USD", "tokenAmount": "10@DFI"},
+            {"currency": "USD", "tokenAmount": "10@BTC"}
+        ]
+        timestamp = calendar.timegm(time.gmtime())
+        self.nodes[0].setoracledata(oracle_id1, timestamp, oracle1_prices)
+        self.nodes[0].generate(1)
+
+        self.nodes[0].setcollateraltoken({
+            'token': idDFI,
+            'factor': 1,
+            'fixedIntervalPriceId': "DFI/USD"
+        })
+
+        self.nodes[0].setcollateraltoken({
+            'token': idBTC,
+            'factor': 1,
+            'fixedIntervalPriceId': "BTC/USD"})
+
+        self.nodes[0].generate(1)
+
+        self.nodes[0].setloantoken({
+            'symbol': symbolTSLA,
+            'name': "Tesla stock token",
+            'fixedIntervalPriceId': "TSLA/USD",
+            'mintable': True,
+            'interest': 1
+        })
+
+        self.nodes[0].setloantoken({
+            'symbol': symboldUSD,
+            'name': "DUSD stable token",
+            'fixedIntervalPriceId': "DUSD/USD",
+                                    'mintable': True,
+                                    'interest': 1
+        })
+        self.nodes[0].generate(1)
+
+        self.nodes[0].createloanscheme(150, 5, 'LOAN150')
+
+        self.nodes[0].generate(5)
+
+        iddUSD = list(self.nodes[0].gettoken(symboldUSD).keys())[0]
+
+        vaultId = self.nodes[0].createvault(account0, 'LOAN150')
+        self.nodes[0].generate(1)
+
+        self.nodes[0].deposittovault(vaultId, account0, "400@DFI")
+        self.nodes[0].generate(1)
+
+        self.nodes[0].takeloan({
+            'vaultId': vaultId,
+            'amounts': "2000@" + symboldUSD
+        })
+        self.nodes[0].generate(1)
+
+        poolOwner = self.nodes[0].getnewaddress("", "legacy")
+        # create pool DUSD-DFI
+        self.nodes[0].createpoolpair({
+            "tokenA": iddUSD,
+            "tokenB": idDFI,
+            "commission": Decimal('0.002'),
+            "status": True,
+            "ownerAddress": poolOwner,
+            "pairSymbol": "DUSD-DFI",
+        })
+        self.nodes[0].generate(1)
+
+        self.nodes[0].addpoolliquidity(
+            {account0: ["30@" + symbolDFI, "300@" + symboldUSD]}, account0)
+        self.nodes[0].generate(1)
+
+        # Should not be able to payback loan with BTC
+        assert_raises_rpc_error(-32600, "Loan token with id (1) does not exist!", self.nodes[0].paybackloan, {
+            'vaultId': vaultId,
+            'from': account0,
+            'amounts': "1@BTC"
+        })
+
+        vaultBefore = self.nodes[0].getvault(vaultId)
+        [amountBefore, _] = vaultBefore['loanAmounts'][0].split('@')
+
+        # Partial loan payback in DFI
+        self.nodes[0].paybackloan({
+            'vaultId': vaultId,
+            'from': account0,
+            'amounts': "1@DFI"
+        })
+        self.nodes[0].generate(1)
+
+        vaultAfter = self.nodes[0].getvault(vaultId)
+        [amountAfter, _] = vaultAfter['loanAmounts'][0].split('@')
+        [interestAfter, _] = vaultAfter['interestAmounts'][0].split('@')
+
+        assert_equal(float(amountAfter) -
+                     float(interestAfter), float(amountBefore) - 10)
+
+        # Payback of loan token other than DUSD
+        vaultId2 = self.nodes[0].createvault(account0, 'LOAN150')
+        self.nodes[0].generate(1)
+
+        self.nodes[0].deposittovault(vaultId2, account0, "100@DFI")
+        self.nodes[0].generate(1)
+
+        self.nodes[0].takeloan({
+            'vaultId': vaultId2,
+            'amounts': "10@" + symbolTSLA
+        })
+        self.nodes[0].generate(1)
+
+        # Should not be able to payback loan token other than DUSD with DFI
+        assert_raises_rpc_error(-32600, "There is no loan on token (DUSD) in this vault!", self.nodes[0].paybackloan, {
+            'vaultId': vaultId2,
+            'from': account0,
+            'amounts': "10@DFI"
+        })
+
+
+if __name__ == '__main__':
+    PaybackLoanTest().main()

test/functional/test_runner.py

@@ -161,6 +161,7 @@
     'feature_loan_setcollateraltoken.py',
     'feature_loan_setloantoken.py',
     'feature_loan_basics.py',
+    'feature_loan_payback_dfi.py',
     'feature_loan_listauctions.py',
     'feature_loan_auctions.py',
     'feature_any_accounts_to_accounts.py',