# BaseFeeCalculator

**Inherits:** IBaseFeeCalculator, IFeeCalculator, Auth2Step, VaultAuth

Module used with FeeVault to allow an off-chain accountant to submit necessary inputs that help compute TVL and performance fees owed to the vault. Serves as a central registry for all vaults and their associated fees

## State Variables

### protocolFees

The protocol's fee configuration

```solidity
Fee public protocolFees;
```

### protocolFeeRecipient

The address that receives the protocol's fees

```solidity
address public protocolFeeRecipient;
```

### \_vaultAccruals

A mapping of vault addresses to their associated state

```solidity
mapping(address vault => VaultAccruals vaultAccruals) internal _vaultAccruals;
```

### vaultAccountant

A mapping of vault addresses to their assigned accountant

```solidity
mapping(address vault => address accountant) public vaultAccountant;
```

## Functions

### onlyVaultAccountant

Modifier that checks the caller is the accountant assigned to the specified vault

```solidity
modifier onlyVaultAccountant(address vault);
```

**Parameters**

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

### constructor

```solidity
constructor(address initialOwner, Authority initialAuthority) Auth2Step(initialOwner, initialAuthority);
```

### setProtocolFeeRecipient

Set the protocol fee recipient

```solidity
function setProtocolFeeRecipient(address feeRecipient) external requiresAuth;
```

**Parameters**

| Name           | Type      | Description                               |
| -------------- | --------- | ----------------------------------------- |
| `feeRecipient` | `address` | The address of the protocol fee recipient |

### setProtocolFees

Set the protocol fee rates

```solidity
function setProtocolFees(uint16 tvl, uint16 performance) external requiresAuth;
```

**Parameters**

| Name          | Type     | Description                              |
| ------------- | -------- | ---------------------------------------- |
| `tvl`         | `uint16` | The TVL fee rate in basis points         |
| `performance` | `uint16` | The performance fee rate in basis points |

### setVaultAccountant

Set the accountant for a vault

```solidity
function setVaultAccountant(address vault, address accountant) external requiresVaultAuth(vault);
```

**Parameters**

| Name         | Type      | Description                       |
| ------------ | --------- | --------------------------------- |
| `vault`      | `address` | The address of the vault          |
| `accountant` | `address` | The address of the new accountant |

### registerVault

Register a new vault with the fee calculator

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

### setVaultFees

Set the vault-specific fee rates

```solidity
function setVaultFees(address vault, uint16 tvl, uint16 performance) external requiresVaultAuth(vault);
```

**Parameters**

| Name          | Type      | Description                              |
| ------------- | --------- | ---------------------------------------- |
| `vault`       | `address` | The address of the vault                 |
| `tvl`         | `uint16`  | The TVL fee rate in basis points         |
| `performance` | `uint16`  | The performance fee rate in basis points |

### 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 virtual 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 virtual 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 virtual returns (uint256, uint256);
```

**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                                          |
| -------- | --------- | ---------------------------------------------------- |
| `<none>` | `uint256` | vaultFees The amount of claimable fees for the vault |
| `<none>` | `uint256` | protocolFees The amount of claimable protocol fees   |

### \_beforeClaimFees

Hook called before claiming fees

*Can be overridden by child contracts to add custom logic*

```solidity
function _beforeClaimFees() internal virtual;
```

### \_beforeClaimProtocolFees

Hook called before claiming protocol fees

*Can be overridden by child contracts to add custom logic*

```solidity
function _beforeClaimProtocolFees() internal virtual;
```

### \_calculateTvlFee

Calculates the TVL fee for a given period

*Fee is annualized and prorated for the time period*

```solidity
function _calculateTvlFee(uint256 averageValue, uint256 tvlFee, uint256 timeDelta) internal pure returns (uint256);
```

**Parameters**

| Name           | Type      | Description                               |
| -------------- | --------- | ----------------------------------------- |
| `averageValue` | `uint256` | The average value during the period       |
| `tvlFee`       | `uint256` | The TVL fee rate in basis points          |
| `timeDelta`    | `uint256` | The duration of the fee period in seconds |

**Returns**

| Name     | Type      | Description        |
| -------- | --------- | ------------------ |
| `<none>` | `uint256` | The earned TVL fee |

### \_calculatePerformanceFee

Calculates the performance fee for a given period

```solidity
function _calculatePerformanceFee(uint256 profit, uint256 feeRate) internal pure returns (uint256);
```

**Parameters**

| Name      | Type      | Description                              |
| --------- | --------- | ---------------------------------------- |
| `profit`  | `uint256` | The profit during the period             |
| `feeRate` | `uint256` | The performance fee rate in basis points |

**Returns**

| Name     | Type      | Description                |
| -------- | --------- | -------------------------- |
| `<none>` | `uint256` | The earned performance fee |