Add origination fees (#65)

* Add origination fees

* Extract ILoanFees struct

This is necessary because we ran out of call stack

contracts/Loan.sol

@@ -38,7 +38,8 @@ contract Loan is ILoan {
     uint256 public immutable payment;
     uint256 public paymentsRemaining;
     uint256 public paymentDueDate;
-    uint256 public latePaymentFee;
+    uint256 public originationFee;
+    ILoanFees fees;
 
     /**
      * @dev Modifier that requires the Loan be in the given `state_`
@@ -98,7 +99,7 @@ contract Loan is ILoan {
         address liquidityAsset_,
         uint256 principal_,
         uint256 dropDeadTimestamp,
-        uint256 latePaymentFee_
+        ILoanFees memory fees_
     ) {
         _serviceConfiguration = serviceConfiguration;
         _factory = factory;
@@ -113,7 +114,7 @@ contract Loan is ILoan {
         apr = apr_;
         liquidityAsset = liquidityAsset_;
         principal = principal_;
-        latePaymentFee = latePaymentFee_;
+        fees = fees_;
 
         LoanLib.validateLoan(
             serviceConfiguration,
@@ -131,6 +132,14 @@ contract Loan is ILoan {
             .div(RAY)
             .div(10000);
         payment = paymentsTotal.mul(RAY).div(paymentsRemaining).div(RAY);
+
+        // Persist origination fee per payment period
+        originationFee = principal
+            .mul(fees.originationBps)
+            .mul(duration.mul(RAY).div(360))
+            .div(paymentsRemaining)
+            .div(RAY)
+            .div(10000);
     }
 
     /**
@@ -312,7 +321,7 @@ contract Loan is ILoan {
                 payment,
                 _serviceConfiguration.firstLossFeeBps(),
                 IPool(_pool).poolFeePercentOfInterest(),
-                latePaymentFee,
+                fees.latePayment,
                 paymentDueDate
             );
 
@@ -321,7 +330,8 @@ contract Loan is ILoan {
             IPool(_pool).firstLossVault(),
             firstLossFee,
             IPool(_pool).feeVault(),
-            poolFee
+            poolFee,
+            originationFee
         );
         LoanLib.completePayment(liquidityAsset, _pool, poolPayment);
         paymentsRemaining -= 1;
@@ -342,7 +352,7 @@ contract Loan is ILoan {
                 amount,
                 _serviceConfiguration.firstLossFeeBps(),
                 IPool(_pool).poolFeePercentOfInterest(),
-                latePaymentFee,
+                fees.latePayment,
                 paymentDueDate
             );
 
@@ -351,7 +361,8 @@ contract Loan is ILoan {
             IPool(_pool).firstLossVault(),
             firstLossFee,
             IPool(_pool).manager(),
-            poolFee
+            poolFee,
+            originationFee
         );
 
         LoanLib.completePayment(

contracts/LoanFactory.sol

@@ -41,7 +41,7 @@ contract LoanFactory {
         address liquidityAsset,
         uint256 principal,
         uint256 dropDeadDate,
-        uint256 latePaymentFee
+        ILoanFees memory fees
     ) public virtual returns (address LoanAddress) {
         require(
             _serviceConfiguration.paused() == false,
@@ -59,7 +59,7 @@ contract LoanFactory {
             liquidityAsset,
             principal,
             dropDeadDate,
-            latePaymentFee
+            fees
         );
         address addr = address(loan);
         emit LoanCreated(addr);

contracts/interfaces/ILoan.sol

@@ -26,6 +26,11 @@ struct ILoanNonFungibleCollateral {
     uint256 tokenId;
 }
 
+struct ILoanFees {
+    uint256 latePayment;
+    uint256 originationBps;
+}
+
 interface ILoan {
     /**
      * @dev Emitted when loan is funded.

contracts/libraries/LoanLib.sol

@@ -271,7 +271,8 @@ library LoanLib {
         address firstLossVault,
         uint256 firstLoss,
         address poolAdmin,
-        uint256 poolFeePercentOfInterest
+        uint256 poolFeePercentOfInterest,
+        uint256 originationFee
     ) public {
         if (firstLoss > 0) {
             IERC20(asset).safeTransferFrom(
@@ -287,5 +288,12 @@ library LoanLib {
                 poolFeePercentOfInterest
             );
         }
+        if (originationFee > 0) {
+            IERC20(asset).safeTransferFrom(
+                msg.sender,
+                poolAdmin,
+                originationFee
+            );
+        }
     }
 }

test/Loan.test.ts

@@ -5,6 +5,7 @@ import { DEFAULT_POOL_SETTINGS } from "./support/pool";
 import {
   collateralizeLoan,
   collateralizeLoanNFT,
+  DEFAULT_LOAN_SETTINGS,
   fundLoan,
   matureLoan
 } from "./support/loan";
@@ -14,7 +15,10 @@ describe("Loan", () => {
   const SEVEN_DAYS = 6 * 60 * 60 * 24;
   const THIRTY_DAYS = 30 * 60 * 60 * 24;
 
-  async function deployFixture(poolSettings = DEFAULT_POOL_SETTINGS) {
+  async function deployFixture(
+    poolSettings = DEFAULT_POOL_SETTINGS,
+    loanSettings = DEFAULT_LOAN_SETTINGS
+  ) {
     // Contracts are deployed using the first signer/account by default
     const [operator, poolManager, borrower, lender, other] =
       await ethers.getSigners();
@@ -100,7 +104,10 @@ describe("Loan", () => {
       liquidityAsset.address,
       500_000,
       Math.floor(Date.now() / 1000) + SEVEN_DAYS,
-      1_000
+      {
+        latePayment: 1_000,
+        originationBps: loanSettings.originationFee
+      }
     );
     const tx2Receipt = await tx2.wait();
 
@@ -149,6 +156,15 @@ describe("Loan", () => {
     return deployFixture(poolSettings);
   }
 
+  async function deployFixtureOriginationFees() {
+    return deployFixture(
+      DEFAULT_POOL_SETTINGS,
+      Object.assign({}, DEFAULT_LOAN_SETTINGS, {
+        originationFee: 100
+      })
+    );
+  }
+
   describe("after initialization", () => {
     it("is initialized!", async () => {
       const { loan, pool, borrower, loanFactory } = await loadFixture(
@@ -1099,6 +1115,47 @@ describe("Loan", () => {
       const newDueDate = await loan.paymentDueDate();
       expect(newDueDate).to.equal(dueDate.add(THIRTY_DAYS));
     });
+
+    it("can collect origination fees from the next payment", async () => {
+      const fixture = await loadFixture(deployFixtureOriginationFees);
+      const {
+        borrower,
+        collateralAsset,
+        liquidityAsset,
+        loan,
+        pool,
+        poolManager
+      } = fixture;
+
+      // Setup
+      await collateralAsset.connect(borrower).approve(loan.address, 100);
+      await loan
+        .connect(borrower)
+        .postFungibleCollateral(collateralAsset.address, 100);
+      await pool.connect(poolManager).fundLoan(loan.address);
+      await loan.connect(borrower).drawdown();
+      expect(await loan.originationFee()).to.equal(416);
+
+      // Make payment
+      const firstLoss = await pool.firstLossVault();
+      const feeVault = await pool.feeVault();
+      const dueDate = await loan.paymentDueDate();
+      expect(await loan.paymentsRemaining()).to.equal(6);
+      await liquidityAsset.connect(borrower).approve(loan.address, 2083 + 416);
+      const tx = loan.connect(borrower).completeNextPayment();
+      await expect(tx).to.not.be.reverted;
+      await expect(tx).to.changeTokenBalance(
+        liquidityAsset,
+        borrower,
+        -2083 - 416
+      );
+      await expect(tx).to.changeTokenBalance(liquidityAsset, pool, 1979);
+      await expect(tx).to.changeTokenBalance(liquidityAsset, feeVault, 416);
+      await expect(tx).to.changeTokenBalance(liquidityAsset, firstLoss, 104);
+      expect(await loan.paymentsRemaining()).to.equal(5);
+      const newDueDate = await loan.paymentDueDate();
+      expect(newDueDate).to.equal(dueDate.add(THIRTY_DAYS));
+    });
   });
 
   const findEventByName = (receipt, name) => {

test/support/loan.ts

@@ -3,6 +3,11 @@ import { deployServiceConfiguration } from "./serviceconfiguration";
 
 const SEVEN_DAYS = 6 * 60 * 60 * 24;
 
+export const DEFAULT_LOAN_SETTINGS = {
+  latePayment: 0,
+  originationFee: 0
+};
+
 /**
  * Deploy a loan
  */
@@ -43,7 +48,10 @@ export async function deployLoan(
     liquidityAsset,
     1_000_000,
     Math.floor(Date.now() / 1000) + SEVEN_DAYS,
-    0
+    {
+      latePayment: 1_000,
+      originationBps: 0
+    }
   );
 
   const txnReceipt = await txn.wait();