feat: spend from stake

src/WanderStaking.sol

@@ -13,6 +13,7 @@ contract WanderStaking is Initializable, PausableUpgradeable, OwnableUpgradeable
 
     event Stake(address indexed user, uint256 amount);
     event Unstake(address indexed user, uint256 amount);
+    event SpendFromStake(address indexed user, address indexed to, uint256 amount);
 
     error ZeroAmount();
     error InsufficientBalance();
@@ -74,6 +75,24 @@ contract WanderStaking is Initializable, PausableUpgradeable, OwnableUpgradeable
         token.safeTransfer(msg.sender, amount);
     }
 
+    function spendFromStake(address to, uint256 amount) external whenNotPaused {
+        if (amount == 0) {
+            revert ZeroAmount();
+        }
+
+        if (userStake[msg.sender] < amount) {
+            revert InsufficientBalance();
+        }
+
+        userStake[msg.sender] -= amount;
+        totalStaked -= amount;
+
+        emit Unstake(msg.sender, amount);
+        emit SpendFromStake(msg.sender, to, amount);
+
+        token.safeTransfer(to, amount);
+    }
+
     function getTotalStaked() external view returns (uint256) {
         return totalStaked;
     }

test/WanderStaking.t.sol

@@ -89,4 +89,41 @@ contract WanderStakingTest is Test {
         vm.expectRevert();
         staking.unstake(unstakeAmount);
     }
+
+    function test_spend(uint64 _amount, uint64 _spendAmount) public {
+        // hello nick
+        address to = 0x6F4E4664E9B519DEAB043676D9Aafe6c9621C088;
+
+        vm.assume(_amount > 0);
+        vm.assume(_spendAmount > 0);
+        vm.assume(_amount >= _spendAmount);
+        uint256 amount = uint256(_amount) * (10 ** 18);
+        uint256 spendAmount = uint256(_spendAmount) * (10 ** 18);
+
+        token.mint(address(this), amount);
+        staking.stake(amount);
+
+        staking.spendFromStake(to, spendAmount);
+
+        assert(token.balanceOf(to) == spendAmount);
+        assert(staking.getAmountStaked(address(this)) == amount - spendAmount);
+        assert(token.balanceOf(address(staking)) == amount - spendAmount);
+    }
+
+    function test_spend_over(uint64 _amount, uint64 _spendAmount) public {
+        // hello nick
+        address to = 0x6F4E4664E9B519DEAB043676D9Aafe6c9621C088;
+
+        vm.assume(_amount > 0);
+        vm.assume(_spendAmount > 0);
+        vm.assume(_amount < _spendAmount);
+        uint256 amount = uint256(_amount) * (10 ** 18);
+        uint256 spendAmount = uint256(_spendAmount) * (10 ** 18);
+
+        token.mint(address(this), amount);
+        staking.stake(amount);
+
+        vm.expectRevert(WanderStaking.InsufficientBalance.selector);
+        staking.spendFromStake(to, spendAmount);
+    }
 }