# IFeeCalculator

Interface for a contract that calculates fees for a vault and protocol

## Functions

### registerVault

Register a new vault with the fee calculator

```solidity
function registerVault() external;
```

### claimFees

Process a fee claim for a specific vault

*Expected to be called by the vault only when claiming fees Only accrues fees and updates stored values; does not transfer tokens Caller must perform the actual transfers to avoid permanent fee loss*

```solidity
function claimFees(uint256 feeTokenBalance) external returns (uint256, uint256, address);
```

**Parameters**

| Name              | Type      | Description                               |
| ----------------- | --------- | ----------------------------------------- |
| `feeTokenBalance` | `uint256` | Available fee token balance to distribute |

**Returns**

| Name     | Type      | Description                                                                  |
| -------- | --------- | ---------------------------------------------------------------------------- |
| `<none>` | `uint256` | earnedFees The amount of fees to be claimed by the fee recipient             |
| `<none>` | `uint256` | protocolEarnedFees The amount of protocol fees to be claimed by the protocol |
| `<none>` | `address` | protocolFeeRecipient The address of the protocol fee recipient               |

### claimProtocolFees

Process a protocol fee claim for a vault

*Expected to be called by the vault only when claiming protocol fees Only accrues protocol fees and updates stored values; does not transfer tokens Caller must perform the actual transfers to avoid permanent protocol fee loss*

```solidity
function claimProtocolFees(uint256 feeTokenBalance) external returns (uint256, address);
```

**Parameters**

| Name              | Type      | Description                               |
| ----------------- | --------- | ----------------------------------------- |
| `feeTokenBalance` | `uint256` | Available fee token balance to distribute |

**Returns**

| Name     | Type      | Description                                                    |
| -------- | --------- | -------------------------------------------------------------- |
| `<none>` | `uint256` | accruedFees The amount of protocol fees claimed                |
| `<none>` | `address` | protocolFeeRecipient The address of the protocol fee recipient |

### previewFees

Returns the current claimable fees for the given vault, as if a claim was made now

```solidity
function previewFees(address vault, uint256 feeTokenBalance)
    external
    view
    returns (uint256 vaultFees, uint256 protocolFees);
```

**Parameters**

| Name              | Type      | Description                                                                                                                                                                               |
| ----------------- | --------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| `vault`           | `address` | The address of the vault to preview fees for                                                                                                                                              |
| `feeTokenBalance` | `uint256` | Available fee token balance to distribute If set to `type(uint256).max`, the function returns all accrued fees If set to an actual balance, the result is capped to that claimable amount |

**Returns**

| Name           | Type      | Description                                |
| -------------- | --------- | ------------------------------------------ |
| `vaultFees`    | `uint256` | The amount of claimable fees for the vault |
| `protocolFees` | `uint256` | The amount of claimable protocol fees      |

### protocolFeeRecipient

Returns the address that receives protocol fees

```solidity
function protocolFeeRecipient() external view returns (address);
```

**Returns**

| Name     | Type      | Description                                 |
| -------- | --------- | ------------------------------------------- |
| `<none>` | `address` | The address that receives the protocol fees |

## Events

### VaultRegistered

Emitted when a new vault is registered

```solidity
event VaultRegistered(address indexed vault);
```

**Parameters**

| Name    | Type      | Description                         |
| ------- | --------- | ----------------------------------- |
| `vault` | `address` | The address of the registered vault |

## Errors

### Aera\_\_VaultAlreadyRegistered

Thrown when attempting to register an already registered vault

```solidity
error Aera__VaultAlreadyRegistered();
```