# MarketPool

## `MarketPool.sol`

The `MarketPool` contract is a **core component of Scall.io**, responsible for managing **perpetual options**, **liquidity deposits**, and **strike price pools** for a specific market (e.g., BTC/USDC or ETH/USDC).

Each deployed `MarketPool` instance handles one market and uses a **Chainlink price feed** to determine valid strike prices and market conditions.

***

### 🧩 What It Does

* Accepts deposits from **Liquidity Providers (LPs)** who want to earn yield at specific strike prices.
* Allows **traders** to open and close **Call or Put perpetual options**.
* Tracks individual **LP positions** and **open option contracts** through NFTs.

***

### 📤 Public Functions

Here are the key functions users and external contracts can call:

#### `deposit(bool isCall, uint256 strikeIndex, uint256 amount)`

* Called by LPs to **provide liquidity** at a specific strike price.
* Mints an LP NFT representing their position.
* Emits: `Deposit` event

```solidity
/// @notice Allows a user to deposit assets and open an LP position
/// @dev Mints an NFT for the LP position and updates liquidity information
/// @param _isCall Specifies if the option is a call or a put
/// @param _strikeIndex The strike Index from getIntervals()
/// @param _amount The amount of assets to deposit (token decimal)
/// @return id The unique ID assigned to the newly created LP position.
function deposit(bool _isCall, uint256 _amount) external returns(uint256)
```

#### `withdraw(uint256 lpId)`

* Allows LPs to **withdraw their deposited liquidity** (if not in use).
* Burns the associated LP NFT.
* Emits: `Withdraw` event

```solidity
/// @notice Allows a user to withdraw assets from an LP position
/// @dev Claims rewards for the LP position before withdrawal and burns the NFT if fully withdrawn
/// @param _id The ID of the LP position to withdraw from
/// @return tokenAtoTransfer The amount of token A withdrawn by the LP (token decimals).
/// @return tokenBtoTransfer The amount of token B withdrawn by the LP (token decimals).
/// @return claimedRewards The additional reward amount received by the LP (token decimals).
function withdraw(uint256 _id) external returns(uint256, uint256, uint256)
```

#### `openContract(bool isCall, uint256 strikeIndex, uint256 amount)`

* Called by traders to **open a new perpetual option**.
* Requires sufficient collateral in the CollateralPool.
* Mints a contract NFT.
* Emits: `ContractOpened` event

```solidity
/// @notice Opens a new option contract using liquidity provided in the pool
/// @dev Mints an NFT for the option contract and updates liquidity information
/// @param _isCall Specifies if the option is a call or a put
/// @param _strikeIndex The strike Index from getIntervals()
/// @param _amount The amount of assets for the option contract
function openContract(bool _isCall, uint256 _strikeIndex, uint256 _amount) external
```

#### `closeContract(uint256 contractId)`

* Allows traders to **manually close** their perpetual options at any time.
* Burns the contract NFT.
* Emits: `ContractClosed` event

```solidity
/// @notice Closes an open contract position, settles based on the current price, and burns the contract NFT.
/// @dev Checks if the caller is the contract owner. Determines if the position is a call or put and settles the contract based on the current price relative to the strike price.
/// @param _id The unique ID of the contract to close.
function closeContract(uint256 _id) external
```

***

### 👀 View Functions

Here are helpful read-only functions to query data:

<table><thead><tr><th width="374">Function</th><th>	Description</th></tr></thead><tbody><tr><td>getMain()</td><td>Returns the address of the <code>Main</code> contract.</td></tr><tr><td>getERC721_Contract()</td><td>Returns the address of the ERC721 contract representing trader positions.</td></tr><tr><td>getERC721_LP()</td><td>Returns the address of the ERC721 contract representing LP positions.</td></tr><tr><td>getTokenA()</td><td>Returns the address of the asset token (e.g., BTC).</td></tr><tr><td>getTokenB()</td><td>Returns the address of the collateral token (e.g., USDC).</td></tr><tr><td>getPriceFeed()</td><td>Returns the address of the Chainlink price feed used for indexing.</td></tr><tr><td>getIntervalLength()</td><td>Returns the strike price interval setting.</td></tr><tr><td>getRange()</td><td>Returns the range of strike prices around the market price.</td></tr><tr><td>getYield()</td><td>Returns the current yield (APR) configured for the market.</td></tr><tr><td>getContractInfos(uint256 _id)</td><td>Returns all stored data for a given trader contract ID.</td></tr><tr><td>getLpInfos(uint256 _id)</td><td>Returns all stored data for a given LP position ID.</td></tr><tr><td>getStrikeInfos(uint256 _strike)</td><td>Returns aggregated info about liquidity at a specific strike.</td></tr><tr><td>getStrikeHistory(uint256 _strike, uint256 _index)</td><td>Returns historical data for a strike (useful for rewards calculations or snapshots).</td></tr><tr><td>getPrice()</td><td>Fetches the current price from the Chainlink oracle.</td></tr><tr><td>getIntervals()</td><td>Returns the list of active strike price intervals.</td></tr><tr><td>getRewards(uint256 _id)</td><td>Returns the claimable rewards for a given LP NFT ID.</td></tr></tbody></table>

***

### 🔐 Roles & Interactions

This contract interacts with:

* `CollateralPool.sol` for rent collection and liquidation triggers
* `Main.sol` to access governance parameters
* Chainlink price feeds for accurate strike pricing
* Custom ERC721 contracts for on-chain position tracking


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