refactor: update creditclock to facet

packages/contracts/scripts/deploy/dollar/solidityScripting/01_Diamond.s.sol

@@ -15,6 +15,7 @@ import {CollectableDustFacet} from "../../../../src/dollar/facets/CollectableDus
 import {ChefFacet} from "../../../../src/dollar/facets/ChefFacet.sol";
 import {StakingFacet} from "../../../../src/dollar/facets/StakingFacet.sol";
 import {StakingFormulasFacet} from "../../../../src/dollar/facets/StakingFormulasFacet.sol";
+import {CreditClockFacet} from "../../../../src/dollar/facets/CreditClockFacet.sol";
 import {CreditNftManagerFacet} from "../../../../src/dollar/facets/CreditNftManagerFacet.sol";
 import {CreditNftRedemptionCalculatorFacet} from "../../../../src/dollar/facets/CreditNftRedemptionCalculatorFacet.sol";
 import {CreditRedemptionCalculatorFacet} from "../../../../src/dollar/facets/CreditRedemptionCalculatorFacet.sol";
@@ -48,6 +49,7 @@ contract DiamondScript is Constants {
 
     bytes4[] selectorsOfDollarMintCalculatorFacet;
     bytes4[] selectorsOfDollarMintExcessFacet;
+    bytes4[] selectorsOfCreditClockFacet;
     // contract types of facets to be deployed
     Diamond diamond;
     DiamondCutFacet dCutFacet;
@@ -72,6 +74,7 @@ contract DiamondScript is Constants {
 
     DollarMintCalculatorFacet dollarMintCalculatorFacet;
     DollarMintExcessFacet dollarMintExcessFacet;
+    CreditClockFacet creditClockFacet;
 
     string[] facetNames;
 
@@ -96,6 +99,7 @@ contract DiamondScript is Constants {
 
         dollarMintCalculatorFacet = new DollarMintCalculatorFacet();
         dollarMintExcessFacet = new DollarMintExcessFacet();
+        creditClockFacet = new CreditClockFacet();
 
         dInit = new DiamondInit();
         facetNames = [
@@ -113,7 +117,8 @@ contract DiamondScript is Constants {
             "CreditNftRedemptionCalculatorFacet",
             "CreditRedemptionCalculatorFacet",
             "DollarMintCalculatorFacet",
-            "DollarMintExcessFacet"
+            "DollarMintExcessFacet",
+            "CreditClockFacet"
         ];
 
         DiamondInit.Args memory initArgs = DiamondInit.Args({
@@ -133,7 +138,7 @@ contract DiamondScript is Constants {
                 initArgs
             )
         });
-        IDiamondCut.FacetCut[] memory cuts = new IDiamondCut.FacetCut[](15);
+        IDiamondCut.FacetCut[] memory cuts = new IDiamondCut.FacetCut[](16);
         setFacet(cuts);
         // deploy diamond
 
@@ -256,6 +261,13 @@ contract DiamondScript is Constants {
                 functionSelectors: selectorsOfDollarMintExcessFacet
             })
         );
+        cuts[15] = (
+            IDiamondCut.FacetCut({
+                facetAddress: address(creditClockFacet),
+                action: IDiamondCut.FacetCutAction.Add,
+                functionSelectors: selectorsOfCreditClockFacet
+            })
+        );
     }
 
     function getSelectors() internal {
@@ -521,5 +533,17 @@ contract DiamondScript is Constants {
         selectorsOfDollarMintExcessFacet.push(
             (dollarMintExcessFacet.distributeDollars.selector)
         );
+
+        // Credit Clock Facet
+        selectorsOfCreditClockFacet.push((creditClockFacet.getRate.selector));
+        selectorsOfCreditClockFacet.push(
+            creditClockFacet.setRatePerBlock.selector
+        );
+        selectorsOfCreditClockFacet.push(
+            (creditClockFacet.setManager.selector)
+        );
+        selectorsOfCreditClockFacet.push(
+            (creditClockFacet.getManager.selector)
+        );
     }
 }

packages/contracts/src/dollar/facets/CreditClockFacet.sol

@@ -0,0 +1,43 @@
+// SPDX-License-Identifier: MIT
+pragma solidity 0.8.19;
+
+import "abdk/ABDKMathQuad.sol";
+import "../libraries/Constants.sol";
+import {Modifiers} from "../libraries/LibAppStorage.sol";
+import {LibCreditClock} from "../libraries/LibCreditClock.sol";
+
+/**
+ * @notice CreditClock Facet
+ */
+contract CreditClockFacet is Modifiers {
+    /**
+     * @notice Updates the manager address
+     * @param _manager New manager address
+     */
+    function setManager(address _manager) external onlyAdmin {
+        LibCreditClock.setManager(_manager);
+    }
+
+    /**
+     * @notice Returns the manager address
+     * @return Manager address
+     */
+    function getManager() external view returns (address) {
+        return LibCreditClock.getManager();
+    }
+
+    /**
+     * @notice Sets rate to apply from this block onward
+     * @param _ratePerBlock ABDKMathQuad new rate per block to apply from this block onward
+     */
+    function setRatePerBlock(bytes16 _ratePerBlock) external onlyAdmin {
+        LibCreditClock.setRatePerBlock(_ratePerBlock);
+    }
+
+    /**
+     * @param blockNumber Block number to get the rate for. 0 for current block.
+     */
+    function getRate(uint256 blockNumber) external view {
+        LibCreditClock.getRate(blockNumber);
+    }
+}

packages/contracts/src/dollar/libraries/LibCreditClock.sol

@@ -0,0 +1,109 @@
+// SPDX-License-Identifier: MIT
+pragma solidity 0.8.19;
+
+import "abdk/ABDKMathQuad.sol";
+import {LibAccessControl} from "./LibAccessControl.sol";
+import {IAccessControl} from "../interfaces/IAccessControl.sol";
+import "../libraries/Constants.sol";
+
+/// @notice Library for Credit Clock Facet
+library LibCreditClock {
+    using ABDKMathQuad for uint256;
+    using ABDKMathQuad for bytes16;
+
+    /// @notice Emitted when depreciation rate per block is updated
+    event SetRatePerBlock(
+        uint256 rateStartBlock,
+        bytes16 rateStartValue,
+        bytes16 ratePerBlock
+    );
+
+    /// @notice Storage slot used to store data for this library
+    bytes32 constant CREDIT_CLOCK_STORAGE_POSITION =
+        bytes32(
+            uint256(keccak256("ubiquity.contracts.credit.clock.storage")) - 1
+        );
+
+    /// @notice Struct used as a storage for the current library
+    struct CreditClockData {
+        IAccessControl accessControl;
+        uint256 rateStartBlock;
+        bytes16 rateStartValue;
+        bytes16 ratePerBlock;
+        bytes16 one;
+    }
+
+    /**
+     * @notice Returns struct used as a storage for this library
+     * @return data Struct used as a storage
+     */
+    function creditClockStorage()
+        internal
+        pure
+        returns (CreditClockData storage data)
+    {
+        bytes32 position = CREDIT_CLOCK_STORAGE_POSITION;
+        assembly {
+            data.slot := position
+        }
+    }
+
+    /**
+     * @notice Updates the manager address
+     * @param _manager New manager address
+     */
+    function setManager(address _manager) internal {
+        creditClockStorage().accessControl = IAccessControl(_manager);
+    }
+
+    /**
+     * @notice Returns the manager address
+     * @return Manager address
+     */
+    function getManager() internal view returns (address) {
+        return address(creditClockStorage().accessControl);
+    }
+
+    /**
+     * @notice Sets rate to apply from this block onward
+     * @param _ratePerBlock ABDKMathQuad new rate per block to apply from this block onward
+     */
+    function setRatePerBlock(bytes16 _ratePerBlock) internal {
+        CreditClockData storage data = creditClockStorage();
+        data.rateStartValue = getRate(block.number);
+        data.rateStartBlock = block.number;
+        data.ratePerBlock = _ratePerBlock;
+
+        emit SetRatePerBlock(
+            data.rateStartBlock,
+            data.rateStartValue,
+            data.ratePerBlock
+        );
+    }
+
+    /**
+     * @notice Calculates `rateStartValue * (1 / ((1 + ratePerBlock)^blockNumber - rateStartBlock)))`
+     * @param blockNumber Block number to get the rate for. 0 for current block.
+     * @return rate ABDKMathQuad rate calculated for the block number
+     */
+    function getRate(uint256 blockNumber) internal view returns (bytes16 rate) {
+        CreditClockData storage data = creditClockStorage();
+        if (blockNumber == 0) {
+            blockNumber = block.number;
+        } else {
+            if (blockNumber < block.number) {
+                revert("CreditClock: block number must not be in the past.");
+            }
+        }
+        // slither-disable-next-line divide-before-multiply
+        rate = data.rateStartValue.mul(
+            data.one.div(
+                // b ^ n == 2^(n*log²(b))
+                (blockNumber - data.rateStartBlock)
+                    .fromUInt()
+                    .mul(data.one.add(data.ratePerBlock).log_2())
+                    .pow_2()
+            )
+        );
+    }
+}

packages/contracts/test/diamond/DiamondTest.t.sol

@@ -12,7 +12,7 @@ contract TestDiamond is DiamondTestSetup {
     }
 
     function testHasMultipleFacets() public {
-        assertEq(facetAddressList.length, 18);
+        assertEq(facetAddressList.length, 19);
     }
 
     function testFacetsHaveCorrectSelectors() public {