# EtherFiLibrary

[Git Source](https://github.com/Ion-Protocol/ion-protocol/blob/88cc595825f1dc2eb738fb93e172a3e8ab7a5c43/src/libraries/lrt/EtherFiLibrary.sol)

A helper library for EtherFi-related conversions.

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

#### [getEthAmountInForLstAmountOut](https://docs.ionprotocol.io/devs/smart-contract-architecture/libraries/lrt/broken-reference) <a href="#getethamountinforlstamountout" id="getethamountinforlstamountout"></a>

Returns the amount of ETH required to obtain a given amount of weETH.

*Performing the calculations seems to potentially yield a rounding error of 1-2 wei. In order to ensure that the correct value is returned, both versions are tested and the correct one is returned. Should a correct version ever not be found, any contracts using the library should halt execution.*

```
function getEthAmountInForLstAmountOut(IWeEth weEth, uint256 lrtAmount) internal view returns (uint256);
```

**Parameters**

| Name        | Type      | Description                     |
| ----------- | --------- | ------------------------------- |
| `weEth`     | `IWeEth`  | contract.                       |
| `lrtAmount` | `uint256` | Desired amount of weETH. \[WAD] |

**Returns**

| Name     | Type      | Description                                                        |
| -------- | --------- | ------------------------------------------------------------------ |
| `<none>` | `uint256` | Amount of ETH required to obtain the given amount of weETH. \[WAD] |

#### [getLstAmountOutForEthAmountIn](https://docs.ionprotocol.io/devs/smart-contract-architecture/libraries/lrt/broken-reference) <a href="#getlstamountoutforethamountin" id="getlstamountoutforethamountin"></a>

Returns the amount of weETH that will be obtained from a given amount of ETH.

```
function getLstAmountOutForEthAmountIn(IWeEth weEth, uint256 ethAmount) internal view returns (uint256);
```

**Parameters**

| Name        | Type      | Description                      |
| ----------- | --------- | -------------------------------- |
| `weEth`     | `IWeEth`  | contract.                        |
| `ethAmount` | `uint256` | Amount of ETH to deposit. \[WAD] |

**Returns**

| Name     | Type      | Description                                   |
| -------- | --------- | --------------------------------------------- |
| `<none>` | `uint256` | Amount of weETH that will be obtained. \[WAD] |

#### [\_getLstAmountOutForEthAmountIn](https://docs.ionprotocol.io/devs/smart-contract-architecture/libraries/lrt/broken-reference) <a href="#getlstamountoutforethamountin" id="getlstamountoutforethamountin"></a>

An internal helper function to calculate the amount of weETH that will be obtained from a given amount of ETH.

*This is useful if the function arguments are already known so that additional external calls can be avoided.*

```
function _getLstAmountOutForEthAmountIn(
    uint256 totalPooledEther,
    uint256 totalShares,
    uint256 ethAmount
)
    internal
    pure
    returns (uint256);
```

**Parameters**

| Name               | Type      | Description                                     |
| ------------------ | --------- | ----------------------------------------------- |
| `totalPooledEther` | `uint256` | Total pooled ether in the Ether Fi pool. \[WAD] |
| `totalShares`      | `uint256` | Total amount of minted shares. \[WAD]           |
| `ethAmount`        | `uint256` | Amount of ETH to deposit. \[WAD]                |

**Returns**

| Name     | Type      | Description                                   |
| -------- | --------- | --------------------------------------------- |
| `<none>` | `uint256` | Amount of weETH that will be obtained. \[WAD] |

#### [depositForLrt](https://docs.ionprotocol.io/devs/smart-contract-architecture/libraries/lrt/broken-reference) <a href="#depositforlrt" id="depositforlrt"></a>

Deposits a given amount of ETH into the Ether Fi pool and then uses the received eETH to mint weETH.

```
function depositForLrt(IWeEth weEth, uint256 ethAmount) internal returns (uint256);
```

**Parameters**

| Name        | Type      | Description                      |
| ----------- | --------- | -------------------------------- |
| `weEth`     | `IWeEth`  | contract.                        |
| `ethAmount` | `uint256` | Amount of ETH to deposit. \[WAD] |

**Returns**

| Name     | Type      | Description                               |
| -------- | --------- | ----------------------------------------- |
| `<none>` | `uint256` | Amount of weETH that was obtained. \[WAD] |

#### [\_sharesForAmount](https://docs.ionprotocol.io/devs/smart-contract-architecture/libraries/lrt/broken-reference) <a href="#sharesforamount" id="sharesforamount"></a>

An internal helper function to calculate the amount of shares from amount.

*Useful for avoiding external calls when the function arguments are already known.*

```
function _sharesForAmount(
    uint256 totalPooledEther,
    uint256 totalShares,
    uint256 _depositAmount
)
    internal
    pure
    returns (uint256);
```

**Parameters**

| Name               | Type      | Description                                     |
| ------------------ | --------- | ----------------------------------------------- |
| `totalPooledEther` | `uint256` | Total pooled ether in the Ether Fi pool. \[WAD] |
| `totalShares`      | `uint256` | Total amount of minted shares. \[WAD]           |
| `_depositAmount`   | `uint256` | Amount of ETH. \[WAD]                           |

#### [\_amountForShares](https://docs.ionprotocol.io/devs/smart-contract-architecture/libraries/lrt/broken-reference) <a href="#amountforshares" id="amountforshares"></a>

An internal helper function to calculate the amount from given amount of shares.

*Useful for avoiding external calls when the function arguments are already known.*

```
function _amountForShares(
    uint256 totalPooledEther,
    uint256 totalShares,
    uint256 _shares
)
    internal
    pure
    returns (uint256);
```

**Parameters**

| Name               | Type      | Description                                     |
| ------------------ | --------- | ----------------------------------------------- |
| `totalPooledEther` | `uint256` | Total pooled ether in the Ether Fi pool. \[WAD] |
| `totalShares`      | `uint256` | Total amount of minted shares. \[WAD]           |
| `_shares`          | `uint256` | Amount of shares. \[WAD]                        |

### [Errors](https://docs.ionprotocol.io/devs/smart-contract-architecture/libraries/lrt/broken-reference) <a href="#errors" id="errors"></a>

#### [NoAmountInFound](https://docs.ionprotocol.io/devs/smart-contract-architecture/libraries/lrt/broken-reference) <a href="#noamountinfound" id="noamountinfound"></a>

```
error NoAmountInFound();
```