# FeeController

[Git Source](https://github.com/EntreDevelopers-Lab-Inc/Mezz-Companies/blob/f7a3e84e3dd5bb33c4bd7f77283983f9e8ba20b2/src/FeeController.sol)

**Inherits:** Initializable, ERC165Upgradeable, HubOwnableUUPSUpgradeable, IFeeController

**Author:** Daniel Yamagata & Naveen Ailawadi

A contract to set and manage fees for the Mezzanine Protocol

*All fees are denominated in 100\_000 as 100%. For example, a fee of 1\_000 is equivalent to 1% All fees in Mezzanine are transferred to the fee controller, which then can be collected by the owner of the Mezz Hub. All implementations that charge a fee are responsible for transferring the fees to the fee controller.*

## State Variables

### MAX\_IMPLEMENTATION\_FEE

```solidity
uint256 public constant MAX_IMPLEMENTATION_FEE = Constants.MAX_IMPLEMENTATION_FEE;
```

### FeeControllerStorageLocation

```solidity
bytes32 private constant FeeControllerStorageLocation =
    0x9980cbcd1eea9936b8d3caaf89dd2ea96db52917f1123c39e72b02e9cb513100;
```

## Functions

### \_getFeeControllerStorage

```solidity
function _getFeeControllerStorage() internal pure returns (FeeControllerStorage storage $);
```

### constructor

```solidity
constructor(address _mezzHub) HubOwnableUUPSUpgradeable(_mezzHub);
```

### setImplementationFee

Sets the fee of the 'implementation' to 'newFee'. Only callable by the 'owner' of the MezzHub

```solidity
function setImplementationFee(address implementation, uint256 newFee) external virtual onlyHubOwner;
```

### collectFees

Transfers 'amount' of 'asset' to the owner of the Mezz Hub

```solidity
function collectFees(address asset, uint256 amount) external virtual onlyHubOwner;
```

### calculateFee

Returns the fee for 'amount' based on the 'asset' and 'implementation' Returns zero if 'asset' is not a denomination asset or the implementation does not have a fee

```solidity
function calculateFee(address asset, uint256 amount, address implementation) public view virtual returns (uint256);
```

### getFeeByImplementation

Returns the fee for 'implementation'. Returns zero if there is no fee

```solidity
function getFeeByImplementation(address implementation) public view returns (uint256);
```

### supportsInterface

*ERC165 support*

```solidity
function supportsInterface(bytes4 interfaceId)
    public
    view
    virtual
    override(ERC165Upgradeable, IERC165)
    returns (bool);
```

## Structs

### FeeControllerStorage

```solidity
struct FeeControllerStorage {
    mapping(address => uint256) _feeByImplementation;
}
```


---

# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://docs.mezzanine.xyz/smart-contracts/source-code/feecontroller.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.