chore: introduce IStakeManager interface

This introduces a first version of `IStakeManager`, highly inspired by
the changes done in
#39.

However, in this commit, it only adds the methods that are currently
supported by both, `StakeManager` and `RewardStreamerMP`.

Future commits will add APIs for locking and leaving.

.gas-report

@@ -17,29 +17,29 @@
 | Deployment Cost                                      | Deployment Size |       |        |       |         |
 | 1010922                                              | 4521            |       |        |       |         |
 | Function Name                                        | min             | avg   | median | max   | # calls |
-| MAX_LOCKING_PERIOD                                   | 273             | 273   | 273    | 273   | 22      |
-| MAX_MULTIPLIER                                       | 252             | 252   | 252    | 252   | 28      |
-| MIN_LOCKING_PERIOD                                   | 273             | 273   | 273    | 273   | 11      |
+| MAX_LOCKUP_PERIOD                                    | 273             | 273   | 273    | 273   | 22      |
+| MAX_MULTIPLIER                                       | 274             | 274   | 274    | 274   | 28      |
+| MIN_LOCKUP_PERIOD                                    | 253             | 253   | 253    | 253   | 11      |
 | MP_RATE_PER_YEAR                                     | 231             | 231   | 231    | 231   | 3       |
 | SCALE_FACTOR                                         | 229             | 229   | 229    | 229   | 39      |
-| STAKING_TOKEN                                        | 273             | 273   | 273    | 273   | 128     |
-| accountedRewards                                     | 351             | 909   | 351    | 2351  | 68      |
+| STAKE_TOKEN                                          | 250             | 250   | 250    | 250   | 128     |
+| accountedRewards                                     | 373             | 931   | 373    | 2373  | 68      |
 | getAccount                                           | 1574            | 1574  | 1574   | 1574  | 65      |
 | rewardIndex                                          | 351             | 380   | 351    | 2351  | 68      |
-| totalMP                                              | 374             | 374   | 374    | 374   | 71      |
-| totalMaxMP                                           | 351             | 351   | 351    | 351   | 71      |
-| totalStaked                                          | 330             | 330   | 330    | 330   | 71      |
-| updateAccountMP                                      | 34610           | 36848 | 37112  | 37112 | 19      |
+| totalMP                                              | 330             | 330   | 330    | 330   | 71      |
+| totalMaxMP                                           | 373             | 373   | 373    | 373   | 71      |
+| totalStaked                                          | 352             | 352   | 352    | 352   | 71      |
+| updateAccountMP                                      | 34632           | 36870 | 37134  | 37134 | 19      |
 | updateGlobalState                                    | 29986           | 55567 | 47365  | 80313 | 25      |
 
 
 | src/StakeVault.sol:StakeVault contract |                 |        |        |        |         |
 |----------------------------------------|-----------------|--------|--------|--------|---------|
 | Deployment Cost                        | Deployment Size |        |        |        |         |
-| 857122                                 | 4070            |        |        |        |         |
+| 857099                                 | 4070            |        |        |        |         |
 | Function Name                          | min             | avg    | median | max    | # calls |
-| stake                                  | 194703          | 231763 | 238396 | 258880 | 46      |
-| unstake                                | 81435           | 109751 | 98993  | 141658 | 13      |
+| stake                                  | 194660          | 231720 | 238353 | 258837 | 46      |
+| unstake                                | 81452           | 109772 | 99015  | 141680 | 13      |
 
 
 | src/XPNFTToken.sol:XPNFTToken contract          |                 |       |        |       |         |

.gas-snapshot

@@ -1,42 +1,42 @@
-IntegrationTest:testStakeFoo() (gas: 1459038)
+IntegrationTest:testStakeFoo() (gas: 1459151)
 NFTMetadataGeneratorSVGTest:testGenerateMetadata() (gas: 92874)
 NFTMetadataGeneratorSVGTest:testSetImageStrings() (gas: 60081)
 NFTMetadataGeneratorSVGTest:testSetImageStringsRevert() (gas: 35818)
 NFTMetadataGeneratorURLTest:testGenerateMetadata() (gas: 109345)
 NFTMetadataGeneratorURLTest:testSetBaseURL() (gas: 50653)
 NFTMetadataGeneratorURLTest:testSetBaseURLRevert() (gas: 35993)
 RewardsStreamerTest:testStake() (gas: 869874)
-StakeTest:test_StakeMultipleAccounts() (gas: 484237)
-StakeTest:test_StakeMultipleAccountsAndRewards() (gas: 629617)
-StakeTest:test_StakeMultipleAccountsMPIncreasesMaxMPDoesNotChange() (gas: 796183)
-StakeTest:test_StakeMultipleAccountsWithMinLockUp() (gas: 490118)
-StakeTest:test_StakeMultipleAccountsWithRandomLockUp() (gas: 511520)
-StakeTest:test_StakeOneAccount() (gas: 279766)
-StakeTest:test_StakeOneAccountAndRewards() (gas: 425142)
-StakeTest:test_StakeOneAccountMPIncreasesMaxMPDoesNotChange() (gas: 485820)
-StakeTest:test_StakeOneAccountReachingMPLimit() (gas: 480886)
-StakeTest:test_StakeOneAccountWithMaxLockUp() (gas: 293512)
-StakeTest:test_StakeOneAccountWithMinLockUp() (gas: 293543)
-StakeTest:test_StakeOneAccountWithRandomLockUp() (gas: 293654)
-UnstakeTest:test_StakeMultipleAccounts() (gas: 484259)
-UnstakeTest:test_StakeMultipleAccountsAndRewards() (gas: 629594)
-UnstakeTest:test_StakeMultipleAccountsMPIncreasesMaxMPDoesNotChange() (gas: 796205)
-UnstakeTest:test_StakeMultipleAccountsWithMinLockUp() (gas: 490095)
-UnstakeTest:test_StakeMultipleAccountsWithRandomLockUp() (gas: 511542)
-UnstakeTest:test_StakeOneAccount() (gas: 279789)
-UnstakeTest:test_StakeOneAccountAndRewards() (gas: 425164)
-UnstakeTest:test_StakeOneAccountMPIncreasesMaxMPDoesNotChange() (gas: 485842)
-UnstakeTest:test_StakeOneAccountReachingMPLimit() (gas: 480866)
-UnstakeTest:test_StakeOneAccountWithMaxLockUp() (gas: 293557)
-UnstakeTest:test_StakeOneAccountWithMinLockUp() (gas: 293543)
-UnstakeTest:test_StakeOneAccountWithRandomLockUp() (gas: 293632)
-UnstakeTest:test_UnstakeBonusMPAndAccuredMP() (gas: 495149)
-UnstakeTest:test_UnstakeMultipleAccounts() (gas: 672560)
-UnstakeTest:test_UnstakeMultipleAccountsAndRewards() (gas: 991506)
-UnstakeTest:test_UnstakeOneAccount() (gas: 468535)
-UnstakeTest:test_UnstakeOneAccountAndAccruedMP() (gas: 483413)
-UnstakeTest:test_UnstakeOneAccountAndRewards() (gas: 574857)
-UnstakeTest:test_UnstakeOneAccountWithLockUpAndAccruedMP() (gas: 504995)
+StakeTest:test_StakeMultipleAccounts() (gas: 484173)
+StakeTest:test_StakeMultipleAccountsAndRewards() (gas: 629575)
+StakeTest:test_StakeMultipleAccountsMPIncreasesMaxMPDoesNotChange() (gas: 796295)
+StakeTest:test_StakeMultipleAccountsWithMinLockUp() (gas: 490078)
+StakeTest:test_StakeMultipleAccountsWithRandomLockUp() (gas: 511480)
+StakeTest:test_StakeOneAccount() (gas: 279745)
+StakeTest:test_StakeOneAccountAndRewards() (gas: 425143)
+StakeTest:test_StakeOneAccountMPIncreasesMaxMPDoesNotChange() (gas: 485909)
+StakeTest:test_StakeOneAccountReachingMPLimit() (gas: 480997)
+StakeTest:test_StakeOneAccountWithMaxLockUp() (gas: 293513)
+StakeTest:test_StakeOneAccountWithMinLockUp() (gas: 293524)
+StakeTest:test_StakeOneAccountWithRandomLockUp() (gas: 293635)
+UnstakeTest:test_StakeMultipleAccounts() (gas: 484195)
+UnstakeTest:test_StakeMultipleAccountsAndRewards() (gas: 629552)
+UnstakeTest:test_StakeMultipleAccountsMPIncreasesMaxMPDoesNotChange() (gas: 796317)
+UnstakeTest:test_StakeMultipleAccountsWithMinLockUp() (gas: 490055)
+UnstakeTest:test_StakeMultipleAccountsWithRandomLockUp() (gas: 511502)
+UnstakeTest:test_StakeOneAccount() (gas: 279768)
+UnstakeTest:test_StakeOneAccountAndRewards() (gas: 425165)
+UnstakeTest:test_StakeOneAccountMPIncreasesMaxMPDoesNotChange() (gas: 485931)
+UnstakeTest:test_StakeOneAccountReachingMPLimit() (gas: 480977)
+UnstakeTest:test_StakeOneAccountWithMaxLockUp() (gas: 293558)
+UnstakeTest:test_StakeOneAccountWithMinLockUp() (gas: 293524)
+UnstakeTest:test_StakeOneAccountWithRandomLockUp() (gas: 293613)
+UnstakeTest:test_UnstakeBonusMPAndAccuredMP() (gas: 495152)
+UnstakeTest:test_UnstakeMultipleAccounts() (gas: 672552)
+UnstakeTest:test_UnstakeMultipleAccountsAndRewards() (gas: 991588)
+UnstakeTest:test_UnstakeOneAccount() (gas: 468592)
+UnstakeTest:test_UnstakeOneAccountAndAccruedMP() (gas: 483480)
+UnstakeTest:test_UnstakeOneAccountAndRewards() (gas: 574902)
+UnstakeTest:test_UnstakeOneAccountWithLockUpAndAccruedMP() (gas: 505088)
 XPNFTTokenTest:testApproveNotAllowed() (gas: 10507)
 XPNFTTokenTest:testGetApproved() (gas: 10531)
 XPNFTTokenTest:testIsApprovedForAll() (gas: 10705)

certora/confs/RewardsStreamerMP.conf

@@ -4,7 +4,7 @@
     "certora/helpers/ERC20A.sol"
   ],
   "link" : [
-    "RewardsStreamerMP:STAKING_TOKEN=ERC20A",
+    "RewardsStreamerMP:STAKE_TOKEN=ERC20A",
     "RewardsStreamerMP:REWARD_TOKEN=ERC20A"
   ],
   "msg": "Verifying RewardsStreamerMP.sol",

src/RewardsStreamerMP.sol

@@ -3,24 +3,25 @@ pragma solidity ^0.8.26;
 
 import { IERC20 } from "@openzeppelin/contracts/token/ERC20/IERC20.sol";
 import { ReentrancyGuard } from "@openzeppelin/contracts/utils/ReentrancyGuard.sol";
+import { IStakeManager } from "./interfaces/IStakeManager.sol";
 
 // Rewards Streamer with Multiplier Points
-contract RewardsStreamerMP is ReentrancyGuard {
+contract RewardsStreamerMP is ReentrancyGuard, IStakeManager {
     error StakingManager__AmountCannotBeZero();
     error StakingManager__TransferFailed();
     error StakingManager__InsufficientBalance();
     error StakingManager__InvalidLockingPeriod();
     error StakingManager__CannotRestakeWithLockedFunds();
     error StakingManager__TokensAreLocked();
 
-    IERC20 public immutable STAKING_TOKEN;
+    IERC20 public immutable STAKE_TOKEN;
     IERC20 public immutable REWARD_TOKEN;
 
     uint256 public constant SCALE_FACTOR = 1e18;
     uint256 public constant MP_RATE_PER_YEAR = 1e18;
 
-    uint256 public constant MIN_LOCKING_PERIOD = 90 days;
-    uint256 public constant MAX_LOCKING_PERIOD = 4 * 365 days;
+    uint256 public constant MIN_LOCKUP_PERIOD = 90 days;
+    uint256 public constant MAX_LOCKUP_PERIOD = 4 * 365 days;
     uint256 public constant MAX_MULTIPLIER = 4;
 
     uint256 public totalStaked;
@@ -42,7 +43,7 @@ contract RewardsStreamerMP is ReentrancyGuard {
     mapping(address account => Account data) public accounts;
 
     constructor(address _stakingToken, address _rewardToken) {
-        STAKING_TOKEN = IERC20(_stakingToken);
+        STAKE_TOKEN = IERC20(_stakingToken);
         REWARD_TOKEN = IERC20(_rewardToken);
         lastMPUpdatedTime = block.timestamp;
     }
@@ -52,7 +53,7 @@ contract RewardsStreamerMP is ReentrancyGuard {
             revert StakingManager__AmountCannotBeZero();
         }
 
-        if (lockPeriod != 0 && (lockPeriod < MIN_LOCKING_PERIOD || lockPeriod > MAX_LOCKING_PERIOD)) {
+        if (lockPeriod != 0 && (lockPeriod < MIN_LOCKUP_PERIOD || lockPeriod > MAX_LOCKUP_PERIOD)) {
             revert StakingManager__InvalidLockingPeriod();
         }
 
@@ -77,7 +78,7 @@ contract RewardsStreamerMP is ReentrancyGuard {
         uint256 bonusMP = 0;
 
         if (lockPeriod != 0) {
-            uint256 lockMultiplier = (lockPeriod * MAX_MULTIPLIER * SCALE_FACTOR) / MAX_LOCKING_PERIOD;
+            uint256 lockMultiplier = (lockPeriod * MAX_MULTIPLIER * SCALE_FACTOR) / MAX_LOCKUP_PERIOD;
             bonusMP = amount * lockMultiplier / SCALE_FACTOR;
             account.lockUntil = block.timestamp + lockPeriod;
         } else {

src/StakeVault.sol

@@ -4,7 +4,7 @@ pragma solidity ^0.8.26;
 
 import { Ownable } from "@openzeppelin/contracts/access/Ownable.sol";
 import { IERC20 } from "@openzeppelin/contracts/token/ERC20/IERC20.sol";
-import { RewardsStreamerMP } from "./RewardsStreamerMP.sol";
+import { IStakeManager } from "./interfaces/IStakeManager.sol";
 
 /**
  * @title StakeVault
@@ -23,7 +23,7 @@ contract StakeVault is Ownable {
     //if is needed that STAKE_TOKEN to be a variable, RewardStreamerMP should be changed to check codehash and
     //StakeVault(msg.sender).STAKE_TOKEN()
     IERC20 public immutable STAKE_TOKEN;
-    RewardsStreamerMP private stakeManager;
+    IStakeManager private stakeManager;
 
     /**
      * @dev Emitted when tokens are staked.
@@ -46,8 +46,8 @@ contract StakeVault is Ownable {
      * @param _owner The address of the owner.
      * @param _stakeManager The address of the RewardStreamerMP contract.
      */
-    constructor(address _owner, RewardsStreamerMP _stakeManager) Ownable(_owner) {
-        STAKE_TOKEN = _stakeManager.STAKING_TOKEN();
+    constructor(address _owner, IStakeManager _stakeManager) Ownable(_owner) {
+        STAKE_TOKEN = _stakeManager.STAKE_TOKEN();
         stakeManager = _stakeManager;
     }
 

src/interfaces/IStakeManager.sol

@@ -0,0 +1,26 @@
+// SPDX-License-Identifier: MIT
+pragma solidity ^0.8.26;
+
+import { IERC20 } from "@openzeppelin/contracts/token/ERC20/IERC20.sol";
+
+interface IStakeManager {
+    error StakeManager__FundsLocked();
+    error StakeManager__InvalidLockTime();
+    error StakeManager__InsufficientFunds();
+    error StakeManager__StakeIsTooLow();
+
+    function stake(uint256 _amount, uint256 _seconds) external;
+    function unstake(uint256 _amount) external;
+
+    function totalStaked() external view returns (uint256);
+    function totalMP() external view returns (uint256);
+    function totalMaxMP() external view returns (uint256);
+    function getStakedBalance(address _vault) external view returns (uint256 _balance);
+
+    function STAKE_TOKEN() external view returns (IERC20);
+    function REWARD_TOKEN() external view returns (IERC20);
+    function MIN_LOCKUP_PERIOD() external view returns (uint256);
+    function MAX_LOCKUP_PERIOD() external view returns (uint256);
+    function MP_RATE_PER_YEAR() external view returns (uint256);
+    function MAX_MULTIPLIER() external view returns (uint256);
+}

test/RewardsStreamerMP.t.sol

@@ -107,7 +107,7 @@ contract RewardsStreamerMPTest is Test {
 
     function _calculateBonusMP(uint256 amount, uint256 lockupTime) public view returns (uint256) {
         return amount
-            * (lockupTime * streamer.MAX_MULTIPLIER() * streamer.SCALE_FACTOR() / streamer.MAX_LOCKING_PERIOD())
+            * (lockupTime * streamer.MAX_MULTIPLIER() * streamer.SCALE_FACTOR() / streamer.MAX_LOCKUP_PERIOD())
             / streamer.SCALE_FACTOR();
     }
 
@@ -535,15 +535,15 @@ contract StakeTest is RewardsStreamerMPTest {
 
     function test_StakeOneAccountWithMinLockUp() public {
         uint256 stakeAmount = 10e18;
-        uint256 lockUpPeriod = streamer.MIN_LOCKING_PERIOD();
+        uint256 lockUpPeriod = streamer.MIN_LOCKUP_PERIOD();
         uint256 expectedBonusMP = _calculateBonusMP(stakeAmount, lockUpPeriod);
 
         _stake(alice, stakeAmount, lockUpPeriod);
 
         checkStreamer(
             CheckStreamerParams({
                 totalStaked: stakeAmount,
-                // 10e18 + (amount * (lockPeriod * MAX_MULTIPLIER * SCALE_FACTOR / MAX_LOCKING_PERIOD) / SCALE_FACTOR)
+                // 10e18 + (amount * (lockPeriod * MAX_MULTIPLIER * SCALE_FACTOR / MAX_LOCKUP_PERIOD) / SCALE_FACTOR)
                 totalMP: stakeAmount + expectedBonusMP,
                 totalMaxMP: 52_465_753_424_657_534_240,
                 stakingBalance: stakeAmount,
@@ -556,15 +556,15 @@ contract StakeTest is RewardsStreamerMPTest {
 
     function test_StakeOneAccountWithMaxLockUp() public {
         uint256 stakeAmount = 10e18;
-        uint256 lockUpPeriod = streamer.MAX_LOCKING_PERIOD();
+        uint256 lockUpPeriod = streamer.MAX_LOCKUP_PERIOD();
         uint256 expectedBonusMP = _calculateBonusMP(stakeAmount, lockUpPeriod);
 
         _stake(alice, stakeAmount, lockUpPeriod);
 
         checkStreamer(
             CheckStreamerParams({
                 totalStaked: stakeAmount,
-                // 10 + (amount * (lockPeriod * MAX_MULTIPLIER * SCALE_FACTOR / MAX_LOCKING_PERIOD) / SCALE_FACTOR)
+                // 10 + (amount * (lockPeriod * MAX_MULTIPLIER * SCALE_FACTOR / MAX_LOCKUP_PERIOD) / SCALE_FACTOR)
                 totalMP: stakeAmount + expectedBonusMP,
                 totalMaxMP: 90e18,
                 stakingBalance: stakeAmount,
@@ -577,15 +577,15 @@ contract StakeTest is RewardsStreamerMPTest {
 
     function test_StakeOneAccountWithRandomLockUp() public {
         uint256 stakeAmount = 10e18;
-        uint256 lockUpPeriod = streamer.MIN_LOCKING_PERIOD() + 13 days;
+        uint256 lockUpPeriod = streamer.MIN_LOCKUP_PERIOD() + 13 days;
         uint256 expectedBonusMP = _calculateBonusMP(stakeAmount, lockUpPeriod);
 
         _stake(alice, stakeAmount, lockUpPeriod);
 
         checkStreamer(
             CheckStreamerParams({
                 totalStaked: stakeAmount,
-                // 10 + (amount * (lockPeriod * MAX_MULTIPLIER * SCALE_FACTOR / MAX_LOCKING_PERIOD) / SCALE_FACTOR)
+                // 10 + (amount * (lockPeriod * MAX_MULTIPLIER * SCALE_FACTOR / MAX_LOCKUP_PERIOD) / SCALE_FACTOR)
                 totalMP: stakeAmount + expectedBonusMP,
                 totalMaxMP: 52_821_917_808_219_178_080,
                 stakingBalance: stakeAmount,
@@ -860,7 +860,7 @@ contract StakeTest is RewardsStreamerMPTest {
 
     function test_StakeMultipleAccountsWithMinLockUp() public {
         uint256 aliceStakeAmount = 10e18;
-        uint256 aliceLockUpPeriod = streamer.MIN_LOCKING_PERIOD();
+        uint256 aliceLockUpPeriod = streamer.MIN_LOCKUP_PERIOD();
         uint256 aliceExpectedBonusMP = _calculateBonusMP(aliceStakeAmount, aliceLockUpPeriod);
 
         uint256 bobStakeAmount = 30e18;
@@ -891,11 +891,11 @@ contract StakeTest is RewardsStreamerMPTest {
 
     function test_StakeMultipleAccountsWithRandomLockUp() public {
         uint256 aliceStakeAmount = 10e18;
-        uint256 aliceLockUpPeriod = streamer.MAX_LOCKING_PERIOD() - 21 days;
+        uint256 aliceLockUpPeriod = streamer.MAX_LOCKUP_PERIOD() - 21 days;
         uint256 aliceExpectedBonusMP = _calculateBonusMP(aliceStakeAmount, aliceLockUpPeriod);
 
         uint256 bobStakeAmount = 30e18;
-        uint256 bobLockUpPeriod = streamer.MIN_LOCKING_PERIOD() + 43 days;
+        uint256 bobLockUpPeriod = streamer.MIN_LOCKUP_PERIOD() + 43 days;
         uint256 bobExpectedBonusMP = _calculateBonusMP(bobStakeAmount, bobLockUpPeriod);
 
         // alice stakes with lockup period
@@ -1157,7 +1157,7 @@ contract UnstakeTest is StakeTest {
         test_StakeOneAccountWithMinLockUp();
 
         uint256 stakeAmount = 10e18;
-        uint256 lockUpPeriod = streamer.MIN_LOCKING_PERIOD();
+        uint256 lockUpPeriod = streamer.MIN_LOCKUP_PERIOD();
         // 10e18 is what's used in `test_StakeOneAccountWithMinLockUp`
         uint256 expectedBonusMP = _calculateBonusMP(stakeAmount, lockUpPeriod);
 
@@ -1230,7 +1230,7 @@ contract UnstakeTest is StakeTest {
     function test_UnstakeBonusMPAndAccuredMP() public {
         // setup variables
         uint256 amountStaked = 10e18;
-        uint256 secondsLocked = streamer.MIN_LOCKING_PERIOD();
+        uint256 secondsLocked = streamer.MIN_LOCKUP_PERIOD();
         uint256 reducedStake = 5e18;
         uint256 increasedTime = 365 days;