Merge pull request #6 from RSSNext/feat/addPurchase

feat: add purchase method

deployments/PowerToken.abi

@@ -459,6 +459,34 @@
     ],
     "stateMutability": "view"
   },
+  {
+    "type": "function",
+    "name": "purchase",
+    "inputs": [
+      {
+        "name": "amount",
+        "type": "uint256",
+        "internalType": "uint256"
+      },
+      {
+        "name": "to",
+        "type": "address",
+        "internalType": "address"
+      },
+      {
+        "name": "feedId",
+        "type": "bytes32",
+        "internalType": "bytes32"
+      },
+      {
+        "name": "taxBasisPoints",
+        "type": "uint256",
+        "internalType": "uint256"
+      }
+    ],
+    "outputs": [],
+    "stateMutability": "nonpayable"
+  },
   {
     "type": "function",
     "name": "removeUser",
@@ -754,6 +782,37 @@
     ],
     "anonymous": false
   },
+  {
+    "type": "event",
+    "name": "Purchase",
+    "inputs": [
+      {
+        "name": "from",
+        "type": "address",
+        "indexed": true,
+        "internalType": "address"
+      },
+      {
+        "name": "to",
+        "type": "address",
+        "indexed": true,
+        "internalType": "address"
+      },
+      {
+        "name": "feedId",
+        "type": "bytes32",
+        "indexed": true,
+        "internalType": "bytes32"
+      },
+      {
+        "name": "amount",
+        "type": "uint256",
+        "indexed": false,
+        "internalType": "uint256"
+      }
+    ],
+    "anonymous": false
+  },
   {
     "type": "event",
     "name": "RoleAdminChanged",
@@ -997,6 +1056,11 @@
       }
     ]
   },
+  {
+    "type": "error",
+    "name": "AmountIsZero",
+    "inputs": []
+  },
   {
     "type": "error",
     "name": "ERC20InsufficientAllowance",
@@ -1131,12 +1195,7 @@
   },
   {
     "type": "error",
-    "name": "TipAmountIsZero",
-    "inputs": []
-  },
-  {
-    "type": "error",
-    "name": "TipReceiverIsEmpty",
+    "name": "ReceiverIsEmpty",
     "inputs": []
   }
 ]

src/PowerToken.sol

@@ -130,34 +130,21 @@ contract PowerToken is
     }
 
     /// @inheritdoc IPowerToken
-    function tip(uint256 amount, address to, bytes32 feedId, uint256 taxBasisPoints)
+    function purchase(uint256 amount, address to, bytes32 feedId, uint256 taxBasisPoints)
         external
         override
     {
-        if (amount == 0) revert TipAmountIsZero();
-        if (feedId == bytes32(0) && to == address(0)) revert TipReceiverIsEmpty();
-        if (balanceOf(msg.sender) < amount) revert InsufficientBalanceAndPoints();
-
-        if (_pointsBalancesV2[msg.sender] >= amount) {
-            _pointsBalancesV2[msg.sender] -= amount;
-        } else {
-            _pointsBalancesV2[msg.sender] = 0;
-        }
-        uint256 tax = _getTaxAmount(taxBasisPoints, amount);
-
-        uint256 tipAmount = amount - tax;
-
-        address receiver = to != address(0) ? to : address(this);
-        if (receiver == address(this)) {
-            _feedBalances[feedId] += tipAmount;
-        }
+        uint256 purchaseAmount = _payWithTax(msg.sender, to, feedId, amount, taxBasisPoints);
 
-        if (tax > 0) {
-            _transfer(msg.sender, ADMIN, tax);
-            emit TaxCollected(ADMIN, tax);
-        }
+        emit Purchase(msg.sender, to, feedId, purchaseAmount);
+    }
 
-        _transfer(msg.sender, receiver, tipAmount);
+    /// @inheritdoc IPowerToken
+    function tip(uint256 amount, address to, bytes32 feedId, uint256 taxBasisPoints)
+        external
+        override
+    {
+        uint256 tipAmount = _payWithTax(msg.sender, to, feedId, amount, taxBasisPoints);
 
         emit Tip(msg.sender, to, feedId, tipAmount);
     }
@@ -231,6 +218,43 @@ contract PowerToken is
         return super.transferFrom(from, to, value);
     }
 
+    function _payWithTax(
+        address from,
+        address to,
+        bytes32 feedId,
+        uint256 amount,
+        uint256 taxBasisPoints
+    ) internal returns (uint256) {
+        if (amount == 0) revert AmountIsZero();
+
+        if (balanceOf(from) < amount) revert InsufficientBalanceAndPoints();
+
+        if (feedId == bytes32(0) && to == address(0)) revert ReceiverIsEmpty();
+
+        if (_pointsBalancesV2[from] >= amount) {
+            _pointsBalancesV2[from] -= amount;
+        } else {
+            _pointsBalancesV2[from] = 0;
+        }
+        uint256 tax = _getTaxAmount(taxBasisPoints, amount);
+
+        if (tax > 0) {
+            _transfer(msg.sender, ADMIN, tax);
+            emit TaxCollected(ADMIN, tax);
+        }
+
+        uint256 tipAmount = amount - tax;
+
+        address receiver = to != address(0) ? to : address(this);
+        if (receiver == address(this)) {
+            _feedBalances[feedId] += tipAmount;
+        }
+
+        _transfer(msg.sender, receiver, tipAmount);
+
+        return tipAmount;
+    }
+
     /**
      * @dev Issues points to a specified address by transferring tokens from the token contract.
      */

src/interfaces/IErrors.sol

@@ -2,14 +2,14 @@
 pragma solidity 0.8.22;
 
 interface IErrors {
-    /// @dev Tip parameter is empty.
-    error TipReceiverIsEmpty();
+    /// @dev receiver is empty.
+    error ReceiverIsEmpty();
 
     /// @dev Points receiver is invalid.
     error PointsInvalidReceiver(bytes32);
 
-    /// @dev Tip amount is zero.
-    error TipAmountIsZero();
+    /// @dev Amount is zero.
+    error AmountIsZero();
 
     /// @dev Insufficient balance and points.
     error InsufficientBalanceAndPoints();

src/interfaces/IEvents.sol

@@ -10,6 +10,13 @@ interface IEvents {
      * @dev Emitted when points are tipped from one address to another.
      */
     event Tip(address indexed from, address indexed to, bytes32 indexed feedId, uint256 amount);
+    /**
+     * @dev Emitted when points are paid from one address to another for some purchase.
+     */
+    event Purchase(
+        address indexed from, address indexed to, bytes32 indexed feedId, uint256 amount
+    );
+
     /**
      * @dev Emitted when points are airdropped to an address.
      */

src/interfaces/IPowerToken.sol

@@ -57,9 +57,21 @@ interface IPowerToken {
      */
     function airdrop(address to, uint256 amount, uint256 taxBasisPoints) external;
 
+    /**
+     * @notice Purchases with token points. If token points are not enough, it will try the balance.
+     * @param amount The amount of token points to send.
+     * @param to The address to send the token points. It can be empty.
+     * @param feedId The feed id. It can be empty.
+     * @param taxBasisPoints The tax basis points.
+     * @dev The to and feedId are optional, but at least one of them must be provided.
+     * If both are provided, the `to` will be used.
+     */
+    function purchase(uint256 amount, address to, bytes32 feedId, uint256 taxBasisPoints)
+        external;
+
     /**
      * @notice Tips with token points. If token points are not enough, it will try the balance.
-     * @param amount The amount of token points to send. It can be empty.
+     * @param amount The amount of token points to send.
      * @param to The address to send the token points. It can be empty.
      * @param feedId The feed id. It can be empty.
      * @param taxBasisPoints The tax basis points.

test/PowerToken.t.sol

@@ -479,17 +479,20 @@ contract PowerTokenTest is Utils, IErrors, IEvents, ERC20Upgradeable {
     }
 
     function testTipFail() public {
-        // case 1:  TipAmountIsZero
-        vm.expectRevert(abi.encodeWithSelector(TipAmountIsZero.selector));
+        _mintPoints(alice, 100);
+        vm.startPrank(alice);
+        // case 1:  AmountIsZero
+        vm.expectRevert(abi.encodeWithSelector(AmountIsZero.selector));
         _token.tip(0, bob, "", 0);
 
-        // case 2: TipReceiverIsEmpty
-        vm.expectRevert(abi.encodeWithSelector(TipReceiverIsEmpty.selector));
+        // case 2: ReceiverIsEmpty
+        vm.expectRevert(abi.encodeWithSelector(ReceiverIsEmpty.selector));
         _token.tip(1, address(0x0), "", 0);
 
         // case 3: InsufficientBalanceAndPoints
         vm.expectRevert(abi.encodeWithSelector(InsufficientBalanceAndPoints.selector));
-        _token.tip(1, bob, "", 0);
+        _token.tip(101, bob, "", 0);
+        vm.stopPrank();
 
         // case 4: InsufficientBalanceToTransfer
         _mintPoints(charlie, 100);
@@ -503,6 +506,20 @@ contract PowerTokenTest is Utils, IErrors, IEvents, ERC20Upgradeable {
         _token.tip(200, david, "", 0);
     }
 
+    function testPurchase() public {
+        _mintPoints(alice, 100 ether);
+
+        vm.prank(alice);
+        expectEmit();
+        emit Purchase(alice, address(0), "0x1234", 10 ether);
+        _token.purchase(10 ether, address(0), "0x1234", 0);
+
+        vm.prank(alice);
+        expectEmit();
+        emit Purchase(alice, address(0), "0x1234", 9 ether);
+        _token.purchase(10 ether, address(0), "0x1234", 1000);
+    }
+
     function testWithdrawByFeedId(uint256 amount) public {
         amount = bound(amount, 1, 100 ether);
         uint256 initialPoints = 10 * amount;