marketplace: transfer repair reward in vault

contracts/Marketplace.sol

@@ -147,10 +147,14 @@ contract Marketplace is SlotReservations, Proofs, StateRetrieval, Endian {
 
     _addToMyRequests(request.client, id);
 
+    TokensPerSecond pricePerSecond = request.ask.pricePerSecond();
+    uint128 price = pricePerSecond.accumulate(request.ask.duration);
+
     FundId fund = id.asFundId();
     AccountId account = _vault.clientAccount(request.client);
     _vault.lock(fund, expiresAt, endsAt);
-    _transferToVault(request.client, fund, account, request.maxPrice());
+    _transferToVault(request.client, fund, account, price);
+    _vault.flow(fund, account, account, pricePerSecond);
 
     emit StorageRequested(id, request.ask, expiresAt);
   }
@@ -195,25 +199,23 @@ contract Marketplace is SlotReservations, Proofs, StateRetrieval, Endian {
 
     context.slotsFilled += 1;
 
-    // Collect collateral
-    uint128 collateralAmount = request.collateralPerSlot();
-    uint128 designatedAmount = _config.collateral.designatedCollateral(
-      collateralAmount
-    );
-    if (slotState(slotId) == SlotState.Repair) {
-      // Host is repairing a slot and is entitled for repair reward, so he gets "discounted collateral"
-      // in this way he gets "physically" the reward at the end of the request when the full amount of collateral
-      // is returned to him.
-      collateralAmount -= _config.collateral.repairReward(collateralAmount);
-    }
-
     FundId fund = requestId.asFundId();
     AccountId clientAccount = _vault.clientAccount(request.client);
     AccountId hostAccount = _vault.hostAccount(slot.host, slotIndex);
     TokensPerSecond rate = request.ask.pricePerSlotPerSecond();
 
-    _transferToVault(slot.host, fund, hostAccount, collateralAmount);
-    _vault.designate(fund, hostAccount, designatedAmount);
+    uint128 collateral = request.collateralPerSlot();
+    uint128 designated = _config.collateral.designatedCollateral(collateral);
+
+    if (slotState(slotId) == SlotState.Repair) {
+      // host gets a discount on its collateral, paid for by the repair reward
+      uint128 repairReward = _config.collateral.repairReward(collateral);
+      _vault.transfer(fund, clientAccount, hostAccount, repairReward);
+      collateral -= repairReward;
+    }
+
+    _transferToVault(slot.host, fund, hostAccount, collateral);
+    _vault.designate(fund, hostAccount, designated);
     _vault.flow(fund, clientAccount, hostAccount, rate);
 
     _addToMySlots(slot.host, slotId);
@@ -334,12 +336,15 @@ contract Marketplace is SlotReservations, Proofs, StateRetrieval, Endian {
 
     Request storage request = _requests[requestId];
 
+    TokensPerSecond rate = request.ask.pricePerSlotPerSecond();
+    uint128 collateral = request.collateralPerSlot();
+    uint128 repairReward = _config.collateral.repairReward(collateral);
+
     FundId fund = requestId.asFundId();
     AccountId hostAccount = _vault.hostAccount(slot.host, slot.slotIndex);
     AccountId clientAccount = _vault.clientAccount(request.client);
-    TokensPerSecond rate = request.ask.pricePerSlotPerSecond();
-
     _vault.flow(fund, hostAccount, clientAccount, rate);
+    _vault.transfer(fund, hostAccount, clientAccount, repairReward);
     _vault.burnAccount(fund, hostAccount);
 
     _removeFromMySlots(slot.host, slotId);

contracts/Requests.sol

@@ -49,12 +49,19 @@ enum SlotState {
 }
 
 library AskHelpers {
+  using AskHelpers for Ask;
+
   function pricePerSlotPerSecond(
     Ask memory ask
   ) internal pure returns (TokensPerSecond) {
     uint96 perByte = TokensPerSecond.unwrap(ask.pricePerBytePerSecond);
     return TokensPerSecond.wrap(perByte * ask.slotSize);
   }
+
+  function pricePerSecond(Ask memory ask) internal pure returns (TokensPerSecond) {
+    uint96 perSlot = TokensPerSecond.unwrap(ask.pricePerSlotPerSecond());
+    return TokensPerSecond.wrap(perSlot * ask.slots);
+  }
 }
 
 library Requests {
@@ -89,11 +96,4 @@ library Requests {
       result := ids
     }
   }
-
-  function maxPrice(Request memory request) internal pure returns (uint128) {
-    uint64 slots = request.ask.slots;
-    TokensPerSecond rate = request.ask.pricePerSlotPerSecond();
-    Duration duration = request.ask.duration;
-    return slots * rate.accumulate(duration);
-  }
 }

test/Marketplace.test.js

@@ -28,7 +28,7 @@ const {
   pricePerSlotPerSecond,
   payoutForDuration,
 } = require("./price")
-const { collateralPerSlot } = require("./collateral")
+const { collateralPerSlot, repairReward } = require("./collateral")
 const {
   snapshot,
   revert,
@@ -296,33 +296,39 @@ describe("Marketplace", function () {
       expect(await marketplace.getHost(slotId(slot))).to.equal(host.address)
     })
 
-    it("gives discount on the collateral for repaired slot", async function () {
-      await marketplace.reserveSlot(slot.request, slot.index)
-      await marketplace.fillSlot(slot.request, slot.index, proof)
-      await marketplace.freeSlot(slotId(slot))
-      expect(await marketplace.slotState(slotId(slot))).to.equal(
-        SlotState.Repair
-      )
+    describe("when repairing a slot", function () {
+      beforeEach(async function () {
+        await marketplace.reserveSlot(slot.request, slot.index)
+        await marketplace.fillSlot(slot.request, slot.index, proof)
+        await advanceTime(config.proofs.period + 1)
+        await marketplace.freeSlot(slotId(slot))
+      })
 
-      // We need to advance the time to next period, because filling slot
-      // must not be done in the same period as for that period there was already proof
-      // submitted with the previous `fillSlot` and the transaction would revert with "Proof already submitted".
-      await advanceTime(config.proofs.period + 1)
+      it("gives the host a discount on the collateral", async function () {
+        const collateral = collateralPerSlot(request)
+        const reward = repairReward(config, collateral)
+        const discountedCollateral = collateral - reward
+        await token.approve(marketplace.address, discountedCollateral)
 
-      const startBalance = await token.balanceOf(host.address)
-      const collateral = collateralPerSlot(request)
-      const discountedCollateral =
-        collateral -
-        Math.round(
-          (collateral * config.collateral.repairRewardPercentage) / 100
-        )
-      await token.approve(marketplace.address, discountedCollateral)
-      await marketplace.fillSlot(slot.request, slot.index, proof)
-      const endBalance = await token.balanceOf(host.address)
-      expect(startBalance - endBalance).to.equal(discountedCollateral)
-      expect(await marketplace.slotState(slotId(slot))).to.equal(
-        SlotState.Filled
-      )
+        const startBalance = await token.balanceOf(host.address)
+        await marketplace.fillSlot(slot.request, slot.index, proof)
+        const endBalance = await token.balanceOf(host.address)
+
+        expect(startBalance - endBalance).to.equal(discountedCollateral)
+      })
+
+      it("tops up the host collateral with the repair reward", async function () {
+        const collateral = collateralPerSlot(request)
+        const reward = repairReward(config, collateral)
+        const discountedCollateral = collateral - reward
+        await token.approve(marketplace.address, discountedCollateral)
+
+        const startBalance = await marketplace.getSlotBalance(slotId(slot))
+        await marketplace.fillSlot(slot.request, slot.index, proof)
+        const endBalance = await marketplace.getSlotBalance(slotId(slot))
+
+        expect(endBalance - startBalance).to.equal(collateral)
+      })
     })
 
     it("fails to retrieve a request of an empty slot", async function () {
@@ -850,8 +856,9 @@ describe("Marketplace", function () {
 
       const hostPayouts = payouts.reduce((a, b) => a + b, 0)
       const refund = payoutForDuration(request, freedAt, requestEnd)
+      const reward = repairReward(config, collateralPerSlot(request))
       expect(endBalance - startBalance).to.equal(
-        maxPrice(request) - hostPayouts + refund
+        maxPrice(request) - hostPayouts + refund + reward
       )
     })
   })

test/collateral.js

@@ -2,4 +2,9 @@ function collateralPerSlot(request) {
   return request.ask.collateralPerByte * request.ask.slotSize
 }
 
-module.exports = { collateralPerSlot }
+function repairReward(configuration, collateral) {
+  const percentage = configuration.collateral.repairRewardPercentage
+  return Math.round((collateral * percentage) / 100)
+}
+
+module.exports = { collateralPerSlot, repairReward }