# LoanManager Contracts

The `LoanManager` contract holds all the main borrower-oriented actions of the Teller protocol. 

There are 2 types of loans. Loans with Ether as collateral and loans with an ERC20 token as collateral. The main difference is how the loans are created and collateral paid out. 

Below are the key methods that reside in the contract. For the complete source code, check out [LoanManager.sol on GitHub](https://github.com/teller-protocol/teller-protocol-v1/blob/develop/contracts/base/loans/LoanManager.sol).

## {1} createLoanWithTerms()

`function createLoanWithTerms(`\
  `TellerCommon.LoanRequest calldata request,`\
  `TellerCommon.LoanResponse[] calldata responses,` \
  `uint256 collateral`\
`)`

Creates an instance of a loan with terms on the protocol that has been accepted by a consensus of nodes. There are two special parameters in this method, that are structs specific to the Teller protocol.

`TellerCommon.LoanRequest` is a request struct/object that is sent to the Teller Nodes and subsequently on-chain, with all the required entries such as:

| Variable           | Type              | Description                                                                           |
| ------------------ | ----------------- | ------------------------------------------------------------------------------------- |
| `borrower`         | `address payable` | The wallet address of the borrower                                                    |
| `recipient`        | `address`         | The address where funds will be sent, only applicable in over collateralized loans    |
| `consensusAddress` | `address`         | The address of the Teller loan consensus contract to which the request should be sent |
| `requestNonce`     | `uint256`         | The nonce of the borrower wallet address required for authentication                  |
| `amount`           | `uint256`         | The number of tokens requested by the borrower for the loan                           |
| `duration`         | `uint256`         | The length of time in seconds that the loan has been requested for                    |
| `requestTime`      | `uint256`         | The timestamp at which the loan was requested                                         |

`TellerCommon.LoanResponse[]` is an array of signed response structs/objects that are returned from registered Teller nodes that need to be passed on-chain in order to register the loan terms on-chain.

| Variable           | Type        | Description                                                                                          |
| ------------------ | ----------- | ---------------------------------------------------------------------------------------------------- |
| `signer`           | `address`   | The wallet address of the signer validating the interest request of the lender                       |
| `consensusAddress` | `address`   | The address of the Teller loan consensus contract to which the request should be sent                |
| `responseTime`     | `uint256`   | The timestamp at which the response was sent                                                         |
| `interestRate`     | `uint256`   | The signed interest rate generated by the signer's Credit Risk Algorithm (CRA)                       |
| `collateralRatio`  | `uint256`   | The ratio of collateral to loan amount that is generated by the signer's Credit Risk Algorithm (CRA) |
| `maxLoanAmount`    | `uint256`   | The largest amount of tokens that can be taken out in the loan by the borrower                       |
| `signature`        | `Signature` | The signature generated by the signer in the format of the below Signature struct                    |

The last param `collateral` is the amount of collateral that needs to be deposited into the protocol in order to be able to take out the funds of the loan.

## {2} depositCollateral() 

`function(`\
  `address borrower,`\
  `uint256 loanID,`\
  `uint256 amount`\
`)`

In situations where a borrower's collateral drops in value (e.g. price drops 90% in value), the borrower would need to deposit more collateral to keep the loan `Active` and out of `liquidation.` This can be done with the `depositCollateral()` method called by the borrower or developer dApp.

| Param      | Type      | Description                              |
| ---------- | --------- | ---------------------------------------- |
| `borrower` | `address` | The address of the loan borrower         |
| `loanID`   | `uint256` | The ID of the loan the collateral is for |
| `amount`   | `uint256` | The amount to deposit as collateral      |

## {3} takeOutLoan()

`function(`\
  `uint256 loanID,`\
  `uint256 amountBorrow`\
`)`

Once a loan with terms has been created on-chain with `createLoanWithTerms()` and collateral deposited, a borrower can now take out the loan.

| Param          | Type      | Description                                 |
| -------------- | --------- | ------------------------------------------- |
| `loanID`       | `uint256` | The ID of the loan being taken out          |
| `amountBorrow` | `uint256` | The number of funds to take out in the loan |

## {4} repay()

`function(`\
  `uint256 amount,`\
  `uint256 loanID`\
`)`

Once the borrower has used the loan he will also need to pay back the loan. This can be done with the `repay()` method on the respective loan contract.

| Param    | Type      | Description                                   |
| -------- | --------- | --------------------------------------------- |
| `amount` | `uint256` | The number of funds to pay back into the loan |
| `loanID` | `uint256` | The ID of the loan the payment is for         |

One thing to note: if a loan is repaid in full with the `repay()` method, the borrower's collateral is automatically sent to their wallet, no additional calls are needed!

## {5} withdrawCollateral()

`function(`\
  `uint256 amount,`\
  `uint256 loanID`\
`)`

In situations where the value of the borrower's collateral has risen (hello there new ATH!), a borrower can withdraw a portion of their collateral and still keep the loan active by calling the `withdrawCollateral()` method on-chain. 

| Param    | Type      | Description                                                              |
| -------- | --------- | ------------------------------------------------------------------------ |
| `amount` | `uint256` | The amount of collateral token or ether the caller is hoping to withdraw |
| `loanID` | `uint256` | The ID of the loan the collateral is for                                 |