> For the complete documentation index, see [llms.txt](https://midaswap.gitbook.io/docs/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://midaswap.gitbook.io/docs/contracts/midaspair721.md).

# MidasPair721

### MidasPair721

Contract used to trade through the Liquidity Book and also acts as the manager of liquidity positions.

#### constructor

```Solidity
constructor(address _factory) {}
```

**Parameters**

| **Name**  | **Type** | **Description**                                   |
| --------- | -------- | ------------------------------------------------- |
| \_factory | address  | The address of the factory which creates the pair |

#### SellNFT

```Solidity
```

BuyNFT

<pre class="language-Solidity"><code class="lang-Solidity"><strong>event BuyNFT(uint256 indexed nftTokenId, address indexed from, uint24 tradeBin, uint128 indexed lpTokenId);
</strong></code></pre>

#### ERC721PositionMinted

```Solidity
event ERC721PositionMinted(uint256 lpTokenId, uint24 binLower, uint24 binStep, uint256 binAmount, uint256[] nftTokenIds);
```

#### ERC20PositionMinted

```Solidity
event ERC20PositionMinted(uint256 lpTokenId, uint24 binLower, uint24 binStep, uint256 binAmount);
```

#### PositionBurned

```Solidity
event PositionBurned(uint256 lpTokenId, address owner, uint256 nftAmount, uint256 ftAmount, uint256 feeCollected);
```

#### ClaimFee

```Solidity
event ClaimFee(uint128 indexed lpTokenId, address indexed owner, uint256 indexed feeCollected);
```

#### FlashLoan

```Solidity
    event FlashLoan(address indexed caller, IMidasFlashLoanCallback receiver, uint256[] NFTIDs)
```

#### NewRoyaltyFee

```Solidity
    event NewRoyaltyFee(uint128 indexed newFee)
```

#### initialize

```Solidity
function initialize() external;
```

Function to initialize the pair which is strict to MidasFactory.

#### getTokenX

```Solidity
function getTokenX() external pure override returns (IERC721)
```

Pure function to get the NFT address of this pair.

#### getTokenY

```Solidity
function getTokenY() external pure override returns (IERC20)
```

Pure function to get the FT address of this pair.

#### getLPToken

```Solidity
function getLPToken() external pure override returns (LPToken)
```

Pure function to get the LP Token address of this pair.

#### factory

```Solidity
function factory() external view override returns (IMidasFactory721)
```

View function to get the factory address of this pair.

#### getReserves

```Solidity
function getReserves() external view override returns (uint128 reserveX, uint128 reserveY)
```

View function to get the NFT and FT reserves of this pair.

**Return Values**

| **Name** | **Type** | **Description**     |
| -------- | -------- | ------------------- |
| reserveX | uint128  | The reserves of NFT |
| reserveY | uint128  | The reserves of FT  |

#### getIDs

```Solidity
function getIDs() external view override returns (uint24 bestOfferID, uint24 floorPriceID, uint128 currentPositionID)
```

View function to get current index price info of this pair.

**Return Values**

| **Name**          | **Type** | **Description**                 |
| ----------------- | -------- | ------------------------------- |
| bestOfferID       | uint24   | The best offer id of this pair  |
| floorPriceID      | uint24   | The floor price id of this pair |
| currentPositionID | uint128  | The latest position ID          |

#### getGlobalFees

```Solidity
function getGlobalFees() external view override returns (uint128 feesTotal, uint128 feesProtocol)
```

View function to get the global fees information, the total fees and those for protocol

**Return Values**

| **Name**     | **Type** | **Description**             |
| ------------ | -------- | --------------------------- |
| feesTotal    | uint128  | The unclaimed total fees    |
| feesProtocol | uint128  | The unclaimed protocol fees |

#### feeParameters

```Solidity
function feeParameters() external view override returns (uint128 rate, uint128 protocolRate, uint128 royaltyRate)
```

View function to get the fee parameters of this pair.

**Return Values**

| **Name**     | **Type** | **Description**                                          |
| ------------ | -------- | -------------------------------------------------------- |
| rate         | uint128  | The fee rate of the LP could collected from trades       |
| protocolRate | uint128  | The protocol fee rate which is collected through the fee |
| royaltyRate  | uint128  | The royalty rate of this pair                            |

#### getBin

```Solidity
function getBin(uint24 _id) external view override returns (uint128 reserveX, uint128 reserveY)
```

View function to get the reserves of bin at `id`.

**Parameters**

| **Name** | **Type** | **Description** |
| -------- | -------- | --------------- |
| \_id     | uint24   | The bin id      |

**Return Values**

| **Name** | **Type** | **Description**                |
| -------- | -------- | ------------------------------ |
| reserveX | uint128  | The reserves of NFT in the bin |
| reserveY | uint128  | The reserves of FT in the bin  |

#### getLpInfos

```Solidity
function getLpInfos(uint128 _LPtokenID) external view override returns (uint24, uint24, uint128)
```

View function to get the LP info via LP tokenId.

**Parameters**

| **Name**    | **Type** | **Description**    |
| ----------- | -------- | ------------------ |
| \_LPtokenID | uint128  | The ID of LP Token |

**Return Values**

| **Name**  | **Type** | **Description**                     |
| --------- | -------- | ----------------------------------- |
| originBin | uint24   | The start bin of this position      |
| binStep   | uint24   | The bin step of this position       |
| fee       | uint128  | The unclaimed fee for this position |

#### getPriceFromBin

```Solidity
function getPriceFromBin(uint24 _id) external view override returns (uint128)
```

View function to get the price mapping to the specific bin id.

**Parameters**

| **Name** | **Type** | **Description** |
| -------- | -------- | --------------- |
| \_id     | uint24   | The id of bin   |

**Return Values**

| **Name** | **Type** | **Description**                          |
| -------- | -------- | ---------------------------------------- |
| price    | uint128  | The price mapping to the specific bin id |

#### getLPFromNFT

```Solidity
function getLPFromNFT(uint24 _id) external view override returns (uint128)
```

View function to get the LP tokenId of the specific NFT.

**Parameters**

| **Name** | **Type** | **Description**         |
| -------- | -------- | ----------------------- |
| \_id     | uint24   | The token id of the NFT |

**Return Values**

| **Name**  | **Type** | **Description**        |
| --------- | -------- | ---------------------- |
| \_LPtoken | uint128  | The ID of the LP token |

#### getBinParamFromLP

```Solidity
function getBinParamFromLP(uint128 _LPtokenID, uint256 _amount) external view override returns (uint128 _totalPrice)
```

View function to get the quote price of the specific position.

**Parameters**

| **Name**    | **Type** | **Description**                   |
| ----------- | -------- | --------------------------------- |
| \_lpTokenID | uint128  | The ID of the LP token            |
| \_amount    | uint256  | The amount of NFT is going to buy |

**Return Values**

| **Name**     | **Type** | **Description**         |
| ------------ | -------- | ----------------------- |
| \_totalPrice | uint128  | The quote price of NFTs |

#### getLpReserve

```Solidity
function getLpReserve(uint128 _lpTokenID) external view override returns (uint128, uint128)
```

View function to get the reserves of the specific position.

**Parameters**

| **Name**    | **Type** | **Description**    |
| ----------- | -------- | ------------------ |
| \_lpTokenID | uint128  | The id of LP Token |

**Return Values**

| **Name** | **Type** | **Description**                     |
| -------- | -------- | ----------------------------------- |
| amountX  | uint128  | The amount of NFTs in this position |
| amountY  | uint128  | The amount of FT in this position   |

#### sellNFT

```Solidity
function sellNFT(uint256 NFTID, address _to) external override nonReentrant returns (uint128 _amountOut)
```

Function to buy the NFT asset at the spot price.

**Parameters**

| **Name** | **Type** | **Description**                    |
| -------- | -------- | ---------------------------------- |
| NFTID    | uint256  | The token id of the NFT to be sold |
| \_to     | address  | The address of the recipient       |

**Return Values**

| **Name**    | **Type** | **Description**                       |
| ----------- | -------- | ------------------------------------- |
| \_amountOut | uint128  | The amount of FT the receiver can get |

#### buyNFT

```Solidity
function buyNFT(uint256 NFTID, address _to) external override nonReentrant
```

Function to buy the NFT asset at the spot price.

**Parameters**

| **Name** | **Type** | **Description**                      |
| -------- | -------- | ------------------------------------ |
| NFTID    | uint256  | The token id of the NFT to be bought |
| \_to     | address  | The address of the recipient         |

#### mintNFT

```Solidity
function mintNFT(uint24[] calldata _ids, uint256[] calldata _NFTIDs, address _to, bool isLimited) external override nonReentrant
```

Performs a low level add liquidity of NFT. This needs to be called from a contract which performs important safety checks.

**Parameters**

| **Name**  | **Type**            | **Description**                                           |
| --------- | ------------------- | --------------------------------------------------------- |
| \_ids     | uint24\[] calldata  | The list of ids to add liquidity                          |
| \_NFTIDs  | uint256\[] calldata | The token id of the NFT                                   |
| \_to      | address             | The address of the recipient                              |
| isLimited | bool                | Determine whether the liquidity position is a limit order |

**Return Values**

| **Name**     | **Type** | **Description**          |
| ------------ | -------- | ------------------------ |
| \_ids.length | uint256  | The amount of NFT to add |
| \_LPtokenID  | uint128  | The ID of the LP token   |

#### mintFT

```Solidity
function mintFT(uint24[] calldata _ids, address _to) external override nonReentrant
```

Performs a low level add liquidity of FT. This needs to be called from a contract which performs important safety checks.

**Parameters**

| **Name** | **Type**           | **Description**                  |
| -------- | ------------------ | -------------------------------- |
| \_ids    | uint24\[] calldata | The list of ids to add liquidity |
| \_to     | address            | The address of the recipient     |

**Return Values**

| **Name**             | **Type** | **Description**         |
| -------------------- | -------- | ----------------------- |
| \_amountYAddedToPair | uint128  | The amount of FT to add |
| \_LPtokenID          | uint128  | The ID of the LP token  |

#### burn

```Solidity
function burn(uint128 _LPtokenID, address _nftReceiver, address _to) external override nonReentrant
```

Performs a low level remove liquidity. This needs to be called from a contract which performs important safety checks

**Parameters**

| **Name**      | **Type** | **Description**                         |
| ------------- | -------- | --------------------------------------- |
| \_LPtokenID   | uint128  | The ID of the LP token                  |
| \_nftReceiver | address  | The address of the NFT assets recipient |
| \_to          | address  | The address of the FT assets recipient  |

**Return Values**

| **Name** | **Type** | **Description**                |
| -------- | -------- | ------------------------------ |
| amountY  | uint128  | The amount of FT sent to `_to` |

#### collectProtocolFees

```Solidity
function collectProtocolFees() external override nonReentrant
```

Collect the protocol fees and send them to the fee recipient.

**Return Values**

| **Name** | **Type** | **Description**                             |
| -------- | -------- | ------------------------------------------- |
| amountY  | uint128  | The amount of FT sent to the fee recipient. |

#### collectLPFees

```Solidity
function collectLPFees(uint128 _LPtokenID , address _to) external override nonReentrant
```

Collect the LP fees and send them to the fee recipient.

**Return Values**

| **Name**  | **Type** | **Description**                             |
| --------- | -------- | ------------------------------------------- |
| amountFee | uint128  | The amount of FT sent to the fee recipient. |

#### collectRoyaltyFees

```Solidity
function collectRoyaltyFees() external override nonReentrant
```

Collect the royalty fees and send them to the royalty fee recipient.

**Return Values**

| **Name**      | **Type** | **Description**                             |
| ------------- | -------- | ------------------------------------------- |
| \_royaltyFees | uint128  | The amount of FT sent to the fee recipient. |

#### updateRoyalty

```Solidity
function updateRoyalty(uint128 _newRate, address payable[] calldata newrecipients, uint256[] calldata newshares) external override nonReentrant
```

Update the royalty info of the NFT according to EIP2981.

**Parameters**

| **Name**      | **Type**                    | **Description**                |
| ------------- | --------------------------- | ------------------------------ |
| \_newRate     | uint256                     | The ID of the LP token         |
| newrecipients | address payable\[] calldata | The addresses of the recipient |
| newshares     | uint256\[] calldata         | The shares of these recipients |

#### updateSafetyLock

```Solidity
function updateSafetyLock(bool newLock) external override nonReentrant
```

Update the safety locker status which is strict to factory.

**Parameters**

| **Name** | **Type** | **Description**                         |
| -------- | -------- | --------------------------------------- |
| newLock  | bool     | The status of this pair's safety locker |

#### flashLoan

```Solidity
function flashLoan(IMidasFlashLoanCallback receiver, uint256[] calldata _tokenIds, bytes calldata data) external override nonReentrant
```

**Parameters**

| **Name**   | **Type**                | **Description**                                         |
| ---------- | ----------------------- | ------------------------------------------------------- |
| receiver   | IMidasFlashLoanCallback | The implementation of receiver                          |
| \_tokenIds | uint256\[] calldata     | The list of NFT tokenIds to be borrowed                 |
| data       | bytes calldata          | The data to be transferred along with function revoking |