Feat/transfer stake

contracts/dao/DXDInfluence.sol

@@ -166,6 +166,43 @@ contract DXDInfluence is OwnableUpgradeable, AccountSnapshot {
         votingPower.callback();
     }
 
+    /**
+     * @dev Mints influence tokens according to the amount staked and takes a snapshot. The influence value
+     * is not stored, only the linear and exponential terms of the formula are updated, which are then used
+     * to compute the influence on the fly in the balance getter.
+     * @param _account Account that has staked the tokens.
+     * @param _to Account that has staked the tokens.
+     * @param _amount Amount of tokens to have been staked.
+     * @param _timeCommitment Time that the user commits to lock the tokens.
+     */
+    function transfer(
+        address _account,
+        address _to,
+        uint256 _amount,
+        uint256 _timeCommitment
+    ) external onlyOwner {
+        CumulativeStake storage lastCumulativeStake = cumulativeStakesSnapshots[_account][_lastSnapshotId(_account)];
+        CumulativeStake storage lastToCumulativeStake = cumulativeStakesSnapshots[_to][_lastSnapshotId(_account)];
+        uint256 currentSnapshotId = _snapshot(_account);
+
+        (uint256 linearTerm, uint256 exponentialTerm) = getFormulaTerms(_amount, _timeCommitment);
+
+        // Update account's stake data
+        CumulativeStake storage cumulativeStake = cumulativeStakesSnapshots[_account][currentSnapshotId];
+        cumulativeStake.linearTerm = lastCumulativeStake.linearTerm - linearTerm;
+        cumulativeStake.exponentialTerm = lastCumulativeStake.exponentialTerm - exponentialTerm;
+        // Update recipients stake data
+        CumulativeStake storage toCumulativeStake = cumulativeStakesSnapshots[_to][currentSnapshotId];
+        toCumulativeStake.linearTerm = lastToCumulativeStake.linearTerm + linearTerm;
+        toCumulativeStake.exponentialTerm = lastToCumulativeStake.exponentialTerm + exponentialTerm;
+
+        // Update global stake data
+        _totalInfluenceSnapshots[currentSnapshotId] = _totalInfluenceSnapshots[currentSnapshotId - 1];
+
+        // Notify Voting Power contract.
+        votingPower.callback();
+    }
+
     /**
      * @dev Updates the time a given amount of DXD was staked for and takes a snapshot. The influence value
      * is not stored, only the linear and exponential terms of the formula are updated, which are then used

contracts/dao/DXDStake.sol

@@ -153,6 +153,41 @@ contract DXDStake is OwnableUpgradeable, OptimizedERC20SnapshotUpgradeable {
         stakeCommitment.commitmentEnd = uint40(block.timestamp) + _newTimeCommitment;
     }
 
+    /**
+     * @dev Transfers a commitment. The recipient gets the voting power rights that come from DXDInfluence
+     * and can claim the locked DXD once the stakes completes.
+     * @param _commitmentId Id of the commitment. The Id is an incremental variable for each account.
+     * @param _amount How much of the stake to transfer.
+     * @param _to Address that the stake commitment will be transferred to.
+     */
+    function transferCommitment(uint256 _commitmentId, uint176 _amount, address _to) external {
+        StakeCommitment storage stakeCommitment = stakeCommitments[msg.sender][_commitmentId];
+        require(stakeCommitment.commitmentEnd != 0, "DXDStake: commitment inactive");
+
+        // Set new commitment
+        StakeCommitment storage newStakeCommitment = stakeCommitments[_to].push();
+        newStakeCommitment.stake = _amount;
+        newStakeCommitment.timeCommitment = stakeCommitment.timeCommitment;
+        newStakeCommitment.commitmentEnd = stakeCommitment.commitmentEnd;
+
+        // Transfer influence.
+        dxdInfluence.transfer(msg.sender, _to, _amount, stakeCommitment.timeCommitment);
+
+        // Transfer staked DXD tokens.
+        _burn(msg.sender, _amount);
+        _mint(_to, _amount);
+        _snapshot();
+
+        stakeCommitment.stake -= _amount;
+        if (stakeCommitment.stake == 0) {
+            // Clean old commitment.
+            stakeCommitment.timeCommitment = 0;
+            stakeCommitment.commitmentEnd = 0;
+            userWithdrawals[msg.sender] += 1;
+            totalWithdrawals += 1;
+        }
+    }
+
     /**
      * @dev Withdraws the tokens to the user.
      * @param _account Account that has staked.