feat(billboard): use ERC-20 token instead of native token

.gas-snapshot

@@ -11,16 +11,16 @@ ACLManagerTest:testRoles() (gas: 15393)
 ACLManagerTest:testTransferRole() (gas: 21528)
 BillboardTest:testAddToWhitelist() (gas: 35114)
 BillboardTest:testApproveAndTransfer() (gas: 162512)
-BillboardTest:testCalculateTax() (gas: 21782)
-BillboardTest:testCannnotWithdrawTaxIfSmallAmount(uint8) (runs: 256, μ: 418269, ~: 424925)
-BillboardTest:testCannnotWithdrawTaxIfZero() (gas: 379035)
+BillboardTest:testCalculateTax() (gas: 21760)
+BillboardTest:testCannnotWithdrawTaxIfSmallAmount(uint8) (runs: 256, μ: 519606, ~: 524472)
+BillboardTest:testCannnotWithdrawTaxIfZero() (gas: 490270)
 BillboardTest:testCannotAddToWhitelistByAttacker() (gas: 9037)
-BillboardTest:testCannotApproveByAttacker() (gas: 130271)
-BillboardTest:testCannotClearAuctionIfAuctionNotEnded() (gas: 579292)
+BillboardTest:testCannotApproveByAttacker() (gas: 130304)
+BillboardTest:testCannotClearAuctionIfAuctionNotEnded() (gas: 699798)
 BillboardTest:testCannotClearAuctionOnNewBoard() (gas: 136253)
 BillboardTest:testCannotMintBoardByAttacker() (gas: 13321)
-BillboardTest:testCannotPlaceBidByAttacker() (gas: 138273)
-BillboardTest:testCannotPlaceBidTwice(uint96) (runs: 256, μ: 623750, ~: 630370)
+BillboardTest:testCannotPlaceBidByAttacker() (gas: 246276)
+BillboardTest:testCannotPlaceBidTwice(uint96) (runs: 256, μ: 749693, ~: 754800)
 BillboardTest:testCannotRemoveToWhitelistByAttacker() (gas: 9104)
 BillboardTest:testCannotSafeTransferByAttacker() (gas: 127438)
 BillboardTest:testCannotSetBoardProprtiesByAttacker() (gas: 157292)
@@ -29,35 +29,35 @@ BillboardTest:testCannotSetTaxRateByAttacker() (gas: 9006)
 BillboardTest:testCannotTransferByOperator() (gas: 132771)
 BillboardTest:testCannotTransferToZeroAddress() (gas: 128258)
 BillboardTest:testCannotUpgradeRegistryByAttacker() (gas: 9128)
-BillboardTest:testCannotWithBidTwice(uint96) (runs: 256, μ: 901993, ~: 901993)
-BillboardTest:testCannotWithdrawBidIfAuctionNotCleared(uint96) (runs: 256, μ: 742413, ~: 742413)
-BillboardTest:testCannotWithdrawBidIfAuctionNotEnded(uint96) (runs: 256, μ: 618541, ~: 618541)
-BillboardTest:testCannotWithdrawBidIfNotFound() (gas: 414332)
-BillboardTest:testCannotWithdrawBidIfWon(uint96) (runs: 256, μ: 710358, ~: 710358)
+BillboardTest:testCannotWithBidTwice(uint96) (runs: 256, μ: 1079596, ~: 1079596)
+BillboardTest:testCannotWithdrawBidIfAuctionNotCleared(uint96) (runs: 256, μ: 910976, ~: 910976)
+BillboardTest:testCannotWithdrawBidIfAuctionNotEnded(uint96) (runs: 256, μ: 725647, ~: 725647)
+BillboardTest:testCannotWithdrawBidIfNotFound() (gas: 428057)
+BillboardTest:testCannotWithdrawBidIfWon(uint96) (runs: 256, μ: 833971, ~: 833971)
 BillboardTest:testCannotWithdrawTaxByAttacker() (gas: 16677)
-BillboardTest:testClearAuctionIfAuctionEnded() (gas: 623626)
-BillboardTest:testClearAuctionsIfAuctionEnded() (gas: 1156359)
-BillboardTest:testGetBids(uint8,uint8,uint8) (runs: 256, μ: 2878685, ~: 1412103)
-BillboardTest:testGetTokenURI() (gas: 154980)
+BillboardTest:testClearAuctionIfAuctionEnded() (gas: 743933)
+BillboardTest:testClearAuctionsIfAuctionEnded() (gas: 1376419)
+BillboardTest:testGetBids(uint8,uint8,uint8) (runs: 256, μ: 4716997, ~: 2077258)
+BillboardTest:testGetTokenURI() (gas: 154936)
 BillboardTest:testMintBoard() (gas: 225541)
 BillboardTest:testMintBoardByWhitelist() (gas: 154942)
 BillboardTest:testMintBoardIfOpened() (gas: 145715)
-BillboardTest:testPlaceBidByWhitelist() (gas: 461646)
-BillboardTest:testPlaceBidIfAuctionEnded() (gas: 905458)
-BillboardTest:testPlaceBidOnNewBoard(uint96) (runs: 256, μ: 510257, ~: 521365)
-BillboardTest:testPlaceBidWithHigherPrice(uint96) (runs: 256, μ: 736177, ~: 744573)
-BillboardTest:testPlaceBidWithSamePrices(uint96) (runs: 256, μ: 735897, ~: 748506)
-BillboardTest:testPlaceBidZeroPrice() (gas: 355447)
+BillboardTest:testPlaceBidByWhitelist() (gas: 579075)
+BillboardTest:testPlaceBidIfAuctionEnded() (gas: 1090505)
+BillboardTest:testPlaceBidOnNewBoard(uint96) (runs: 256, μ: 619050, ~: 635095)
+BillboardTest:testPlaceBidWithHigherPrice(uint96) (runs: 256, μ: 904667, ~: 913141)
+BillboardTest:testPlaceBidWithSamePrices(uint96) (runs: 256, μ: 907776, ~: 917960)
+BillboardTest:testPlaceBidZeroPrice() (gas: 376910)
 BillboardTest:testRemoveToWhitelist() (gas: 23207)
 BillboardTest:testSafeTransferByOperator() (gas: 141237)
-BillboardTest:testSetBoardProperties() (gas: 305883)
-BillboardTest:testSetBoardPropertiesAfterTransfer() (gas: 335509)
+BillboardTest:testSetBoardProperties() (gas: 305950)
+BillboardTest:testSetBoardPropertiesAfterTransfer() (gas: 335477)
 BillboardTest:testSetIsOpened() (gas: 22661)
-BillboardTest:testSetTaxRate() (gas: 22909)
-BillboardTest:testSomethin() (gas: 1624285)
-BillboardTest:testUpgradeRegistry() (gas: 2935587)
-BillboardTest:testWithdrawBid(uint96) (runs: 256, μ: 903495, ~: 903495)
-BillboardTest:testWithdrawTax(uint96) (runs: 256, μ: 500488, ~: 500488)
+BillboardTest:testSetTaxRate() (gas: 22887)
+BillboardTest:testSomethin() (gas: 1672218)
+BillboardTest:testUpgradeRegistry() (gas: 3038450)
+BillboardTest:testWithdrawBid(uint96) (runs: 256, μ: 1081104, ~: 1081104)
+BillboardTest:testWithdrawTax(uint96) (runs: 256, μ: 597534, ~: 597534)
 CurationTest:testCannotCurateERC20CurateZeroAmount() (gas: 12194)
 CurationTest:testCannotCurateERC20EmptyURI() (gas: 15797)
 CurationTest:testCannotCurateERC20IfNotApproval() (gas: 21624)
@@ -71,8 +71,8 @@ CurationTest:testCannotCurateNativeTokenZeroAddress() (gas: 16488)
 CurationTest:testERC20Curation() (gas: 59908)
 CurationTest:testNativeTokenCuration() (gas: 60085)
 CurationTest:testNativeTokenCurationToContractAcceptor() (gas: 37466)
-DistributionTest:testCannotDropIfInsufficientAllowance(uint256) (runs: 256, μ: 158669, ~: 158683)
-DistributionTest:testCannotDropIfInsufficientBalance(uint256) (runs: 256, μ: 160867, ~: 161105)
+DistributionTest:testCannotDropIfInsufficientAllowance(uint256) (runs: 256, μ: 158670, ~: 158683)
+DistributionTest:testCannotDropIfInsufficientBalance(uint256) (runs: 256, μ: 160868, ~: 161107)
 DistributionTest:testCannotSetAdminByAdmin() (gas: 17364)
 DistributionTest:testCannotSetAdminByAttacker() (gas: 11111)
 DistributionTest:testClaim() (gas: 402817)

src/Billboard/Billboard.sol

@@ -1,6 +1,8 @@
 //SPDX-License-Identifier: Apache-2.0
 pragma solidity ^0.8.20;
 
+import "@openzeppelin/contracts/token/ERC20/utils/SafeERC20.sol";
+
 import "./BillboardRegistry.sol";
 import "./IBillboard.sol";
 import "./IBillboardRegistry.sol";
@@ -13,6 +15,7 @@ contract Billboard is IBillboard {
     bool public isOpened = false;
 
     constructor(
+        address token_,
         address payable registry_,
         uint256 taxRate_,
         uint64 leaseTerm_,
@@ -28,7 +31,7 @@ contract Billboard is IBillboard {
         }
         // deploy operator and registry
         else {
-            registry = new BillboardRegistry(address(this), taxRate_, leaseTerm_, name_, symbol_);
+            registry = new BillboardRegistry(token_, address(this), taxRate_, leaseTerm_, name_, symbol_);
         }
     }
 
@@ -260,15 +263,7 @@ contract Billboard is IBillboard {
 
     function _lockBidPriceAndTax(uint256 amount_) private {
         // transfer bid price and tax to the registry
-        (bool _success, ) = address(registry).call{value: amount_}("");
-        require(_success, "Transfer failed");
-
-        // refund if overpaid
-        uint256 _overpaid = msg.value - amount_;
-        if (_overpaid > 0) {
-            (bool _refundSuccess, ) = msg.sender.call{value: _overpaid}("");
-            require(_refundSuccess, "Transfer failed");
-        }
+        SafeERC20.safeTransferFrom(registry.token(), msg.sender, address(registry), amount_);
     }
 
     /// @inheritdoc IBillboard

src/Billboard/BillboardRegistry.sol

@@ -1,6 +1,7 @@
 //SPDX-License-Identifier: Apache-2.0
 pragma solidity ^0.8.20;
 
+import "@openzeppelin/contracts/token/ERC20/IERC20.sol";
 import "@openzeppelin/contracts/token/ERC721/ERC721.sol";
 import "@openzeppelin/contracts/utils/Counters.sol";
 
@@ -14,6 +15,7 @@ contract BillboardRegistry is IBillboardRegistry, ERC721 {
 
     Counters.Counter public lastTokenId;
 
+    IERC20 public immutable token;
     uint256 public taxRate;
     uint64 public leaseTerm;
 
@@ -36,13 +38,17 @@ contract BillboardRegistry is IBillboardRegistry, ERC721 {
     mapping(address => TaxTreasury) public taxTreasury;
 
     constructor(
+        address token_,
         address operator_,
         uint256 taxRate_,
         uint64 leaseTerm_,
         string memory name_,
         string memory symbol_
     ) ERC721(name_, symbol_) {
         require(operator_ != address(0), "Zero address");
+        require(token_ != address(0), "Zero address");
+
+        token = IERC20(token_);
         operator = operator_;
         taxRate = taxRate_;
         leaseTerm = leaseTerm_;
@@ -229,8 +235,8 @@ contract BillboardRegistry is IBillboardRegistry, ERC721 {
     /// @inheritdoc IBillboardRegistry
     function transferAmount(address to_, uint256 amount_) external isFromOperator {
         require(to_ != address(0), "Zero address");
-        (bool _success, ) = to_.call{value: amount_}("");
-        require(_success, "transfer failed");
+
+        require(token.transfer(to_, amount_), "Failed token transfer");
     }
 
     //////////////////////////////

src/Billboard/Distribution.sol

@@ -99,6 +99,8 @@ contract Distribution is IDistribution, Ownable {
     function sweep(uint256 treeId_, address target_) external isFromAdmin {
         uint256 _balance = balances[treeId_];
 
+        require(_balance > 0, "zero balance");
+
         // Transfer
         require(IERC20(token).transfer(target_, _balance), "failed token transfer");