# GNSFeeTiers

*Facet #3: Fee tiers*

## constructor

```solidity
constructor() public
```

## initializeFeeTiers

```solidity
function initializeFeeTiers(uint256[] _groupIndices, uint256[] _groupVolumeMultipliers, uint256[] _feeTiersIndices, struct IFeeTiers.FeeTier[] _feeTiers) external
```

### Parameters

| Name                     | Type                                                                                                    | Description                                                     |
| ------------------------ | ------------------------------------------------------------------------------------------------------- | --------------------------------------------------------------- |
| \_groupIndices           | uint256\[]                                                                                              | group indices (pairs storage fee index) to initialize           |
| \_groupVolumeMultipliers | uint256\[]                                                                                              | corresponding group volume multipliers (1e3)                    |
| \_feeTiersIndices        | uint256\[]                                                                                              | fee tiers indices to initialize                                 |
| \_feeTiers               | [IFeeTiers.FeeTier\[\]](/developer/technical-reference/contracts/interfaces/types/ifeetiers.md#feetier) | fee tiers values to initialize (feeMultiplier, pointsThreshold) |

## setGroupVolumeMultipliers

```solidity
function setGroupVolumeMultipliers(uint256[] _groupIndices, uint256[] _groupVolumeMultipliers) external
```

*Updates groups volume multipliers*

### Parameters

| Name                     | Type       | Description                                |
| ------------------------ | ---------- | ------------------------------------------ |
| \_groupIndices           | uint256\[] | indices of groups to update                |
| \_groupVolumeMultipliers | uint256\[] | corresponding new volume multipliers (1e3) |

## setFeeTiers

```solidity
function setFeeTiers(uint256[] _feeTiersIndices, struct IFeeTiers.FeeTier[] _feeTiers) external
```

*Updates fee tiers*

### Parameters

| Name              | Type                                                                                                    | Description                                           |
| ----------------- | ------------------------------------------------------------------------------------------------------- | ----------------------------------------------------- |
| \_feeTiersIndices | uint256\[]                                                                                              | indices of fee tiers to update                        |
| \_feeTiers        | [IFeeTiers.FeeTier\[\]](/developer/technical-reference/contracts/interfaces/types/ifeetiers.md#feetier) | new fee tiers values (feeMultiplier, pointsThreshold) |

## setTradersFeeTiersEnrollment

```solidity
function setTradersFeeTiersEnrollment(address[] _traders, struct IFeeTiers.TraderEnrollment[] _values) external
```

*Updates traders enrollment status in fee tiers*

### Parameters

| Name      | Type                                                                                                                      | Description                     |
| --------- | ------------------------------------------------------------------------------------------------------------------------- | ------------------------------- |
| \_traders | address\[]                                                                                                                | group of traders                |
| \_values  | [IFeeTiers.TraderEnrollment\[\]](/developer/technical-reference/contracts/interfaces/types/ifeetiers.md#traderenrollment) | corresponding enrollment values |

## addTradersUnclaimedPoints

```solidity
function addTradersUnclaimedPoints(address[] _traders, enum IFeeTiers.CreditType[] _creditTypes, uint224[] _points) external
```

*Credits points to traders*

### Parameters

| Name          | Type                         | Description                            |
| ------------- | ---------------------------- | -------------------------------------- |
| \_traders     | address\[]                   | traders addresses                      |
| \_creditTypes | enum IFeeTiers.CreditType\[] | types of credit (IMMEDIATE, CLAIMABLE) |
| \_points      | uint224\[]                   | points to credit (1e18)                |

## updateTraderPoints

```solidity
function updateTraderPoints(address _trader, uint256 _volumeUsd, uint256 _pairIndex) external virtual
```

*Increases daily points from a new trade, re-calculate trailing points, and cache daily fee tier for a trader.*

### Parameters

| Name        | Type    | Description                  |
| ----------- | ------- | ---------------------------- |
| \_trader    | address | trader address               |
| \_volumeUsd | uint256 | trading volume in USD (1e18) |
| \_pairIndex | uint256 | pair index                   |

## calculateFeeAmount

```solidity
function calculateFeeAmount(address _trader, uint256 _normalFeeAmountCollateral) external view returns (uint256)
```

*Returns fee amount after applying the trader's active fee tier multiplier*

### Parameters

| Name                        | Type    | Description                            |
| --------------------------- | ------- | -------------------------------------- |
| \_trader                    | address | address of trader                      |
| \_normalFeeAmountCollateral | uint256 | base fee amount (collateral precision) |

## getFeeTiersCount

```solidity
function getFeeTiersCount() external view returns (uint256)
```

Returns the current number of active fee tiers

## getFeeTier

```solidity
function getFeeTier(uint256 _feeTierIndex) external view returns (struct IFeeTiers.FeeTier)
```

*Returns a fee tier's details (feeMultiplier, pointsThreshold)*

### Parameters

| Name           | Type    | Description    |
| -------------- | ------- | -------------- |
| \_feeTierIndex | uint256 | fee tier index |

## getGroupVolumeMultiplier

```solidity
function getGroupVolumeMultiplier(uint256 _groupIndex) external view returns (uint256)
```

*Returns a group's volume multiplier*

### Parameters

| Name         | Type    | Description                           |
| ------------ | ------- | ------------------------------------- |
| \_groupIndex | uint256 | group index (pairs storage fee index) |

## getFeeTiersTraderInfo

```solidity
function getFeeTiersTraderInfo(address _trader) external view returns (struct IFeeTiers.TraderInfo)
```

*Returns a trader's info (lastDayUpdated, trailingPoints)*

### Parameters

| Name     | Type    | Description    |
| -------- | ------- | -------------- |
| \_trader | address | trader address |

## getFeeTiersTraderDailyInfo

```solidity
function getFeeTiersTraderDailyInfo(address _trader, uint32 _day) external view returns (struct IFeeTiers.TraderDailyInfo)
```

*Returns a trader's daily fee tier info (feeMultiplierCache, points)*

### Parameters

| Name     | Type    | Description    |
| -------- | ------- | -------------- |
| \_trader | address | trader address |
| \_day    | uint32  | day            |

## getTraderFeeTiersEnrollment

```solidity
function getTraderFeeTiersEnrollment(address _trader) external view returns (struct IFeeTiers.TraderEnrollment)
```

*Returns a trader's fee tiers enrollment status*

### Parameters

| Name     | Type    | Description    |
| -------- | ------- | -------------- |
| \_trader | address | trader address |

## getTraderUnclaimedPoints

```solidity
function getTraderUnclaimedPoints(address _trader) external view returns (uint224)
```

*Returns a trader's unclaimed points, credited by Governance*

### Parameters

| Name     | Type    | Description    |
| -------- | ------- | -------------- |
| \_trader | address | trader address |


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