# WstEthHandler

[Git Source](https://github.com/Ion-Protocol/ion-protocol/blob/88cc595825f1dc2eb738fb93e172a3e8ab7a5c43/src/flash/lst/WstEthHandler.sol)

**Inherits:** UniswapFlashswapHandler, BalancerFlashloanDirectMintHandler

Handler for the wstETH collateral.

### [State Variables](https://docs.ionprotocol.io/devs/smart-contract-architecture/flash/lst/broken-reference) <a href="#state-variables" id="state-variables"></a>

#### [STETH](https://docs.ionprotocol.io/devs/smart-contract-architecture/flash/lst/broken-reference) <a href="#steth" id="steth"></a>

```
IERC20 constant STETH = IERC20(0xae7ab96520DE3A18E5e111B5EaAb095312D7fE84);
```

### [Functions](https://docs.ionprotocol.io/devs/smart-contract-architecture/flash/lst/broken-reference) <a href="#functions" id="functions"></a>

#### [constructor](https://docs.ionprotocol.io/devs/smart-contract-architecture/flash/lst/broken-reference) <a href="#constructor" id="constructor"></a>

Creates a new `WstEthHandler` instance.

```
constructor(
    uint8 _ilkIndex,
    IonPool _ionPool,
    GemJoin _gemJoin,
    Whitelist _whitelist,
    IUniswapV3Pool _wstEthUniswapPool
)
    IonHandlerBase(_ilkIndex, _ionPool, _gemJoin, _whitelist)
    UniswapFlashswapHandler(_wstEthUniswapPool, false);
```

**Parameters**

| Name                 | Type             | Description                                        |
| -------------------- | ---------------- | -------------------------------------------------- |
| `_ilkIndex`          | `uint8`          | of wstETH.                                         |
| `_ionPool`           | `IonPool`        | `IonPool` contract address.                        |
| `_gemJoin`           | `GemJoin`        | `GemJoin` contract address associated with wstETH. |
| `_whitelist`         | `Whitelist`      | Address of the `Whitelist` contract.               |
| `_wstEthUniswapPool` | `IUniswapV3Pool` | Address of the wstETH/ETH Uniswap V3 pool.         |

#### [\_depositWethForLst](https://docs.ionprotocol.io/devs/smart-contract-architecture/flash/lst/broken-reference) <a href="#depositwethforlst" id="depositwethforlst"></a>

Unwraps weth into eth and deposits into lst contract.

*Unwraps weth into eth and deposits into lst contract.*

```
function _depositWethForLst(uint256 amountWeth) internal override returns (uint256);
```

**Parameters**

| Name         | Type      | Description                        |
| ------------ | --------- | ---------------------------------- |
| `amountWeth` | `uint256` | The WETH amount to deposit. \[WAD] |

**Returns**

| Name     | Type      | Description                    |
| -------- | --------- | ------------------------------ |
| `<none>` | `uint256` | Amount of lst received. \[WAD] |

#### [\_getEthAmountInForLstAmountOut](https://docs.ionprotocol.io/devs/smart-contract-architecture/flash/lst/broken-reference) <a href="#getethamountinforlstamountout" id="getethamountinforlstamountout"></a>

Calculates the amount of eth required to receive `amountLst`.

*Calculates the amount of eth required to receive `amountLst`.*

```
function _getEthAmountInForLstAmountOut(uint256 amountLst) internal view override returns (uint256);
```

**Parameters**

| Name        | Type      | Description                   |
| ----------- | --------- | ----------------------------- |
| `amountLst` | `uint256` | Desired output amount. \[WAD] |

**Returns**

| Name     | Type      | Description                                 |
| -------- | --------- | ------------------------------------------- |
| `<none>` | `uint256` | Eth required for desired lst output. \[WAD] |

#### [zapDepositAndBorrow](https://docs.ionprotocol.io/devs/smart-contract-architecture/flash/lst/broken-reference) <a href="#zapdepositandborrow" id="zapdepositandborrow"></a>

```
function zapDepositAndBorrow(
    uint256 stEthAmount,
    uint256 amountToBorrow,
    bytes32[] calldata proof
)
    external
    onlyWhitelistedBorrowers(proof);
```

#### [zapFlashLeverageCollateral](https://docs.ionprotocol.io/devs/smart-contract-architecture/flash/lst/broken-reference) <a href="#zapflashleveragecollateral" id="zapflashleveragecollateral"></a>

```
function zapFlashLeverageCollateral(
    uint256 initialDeposit,
    uint256 resultingAdditionalStEthCollateral,
    uint256 maxResultingAdditionalDebt,
    bytes32[] calldata proof
)
    external
    onlyWhitelistedBorrowers(proof);
```

#### [zapFlashLeverageWeth](https://docs.ionprotocol.io/devs/smart-contract-architecture/flash/lst/broken-reference) <a href="#zapflashleverageweth" id="zapflashleverageweth"></a>

```
function zapFlashLeverageWeth(
    uint256 initialDeposit,
    uint256 resultingAdditionalStEthCollateral,
    uint256 maxResultingAdditionalDebt,
    bytes32[] calldata proof
)
    external
    onlyWhitelistedBorrowers(proof);
```

#### [zapFlashswapLeverage](https://docs.ionprotocol.io/devs/smart-contract-architecture/flash/lst/broken-reference) <a href="#zapflashswapleverage" id="zapflashswapleverage"></a>

```
function zapFlashswapLeverage(
    uint256 initialDeposit,
    uint256 resultingAdditionalStEthCollateral,
    uint256 maxResultingAdditionalDebt,
    uint160 sqrtPriceLimitX96,
    uint256 deadline,
    bytes32[] calldata proof
)
    external
    checkDeadline(deadline)
    onlyWhitelistedBorrowers(proof);
```