# MarketFacet

Inherits: Modifiers, ReentrancyGuard

Trade entity tokens

This should only be called through an entity, never directly by an EOA

# Functions

# cancelOffer

Cancel offer #_offerId. This will cancel the offer so that it's no longer active.

This function can be frontrun: In the scenario where a user wants to cancel an unfavorable market offer, an attacker can potentially monitor and identify that the user has called this method, determine that filling this market offer is profitable, and as a result call executeLimitOffer with a higher gas price to have their transaction filled before the user can have cancelOffer filled. The most ideal situation for the user is to not have placed the unfavorable market offer in the first place since an attacker can always monitor our marketplace and potentially identify profitable market offers. Our UI will aide users in not placing market offers that are obviously unfavorable to the user and/or seem like mistake orders. In the event that a user needs to cancel an offer, it is recommended to use Flashbots in order to privately send your transaction so an attack cannot be triggered from monitoring the mempool for calls to cancelOffer. A user is recommended to change their RPC endpoint to point to https://rpc.flashbots.net when calling cancelOffer. We will add additional documentation to aide our users in this process. More information on using Flashbots: https://docs.flashbots.net/flashbots-protect/rpc/quick-start/

function cancelOffer(uint256 _offerId)
    external
    notLocked(msg.sig)
    nonReentrant
    assertPrivilege(LibObject._getParentFromAddress(msg.sender), LC.GROUP_CANCEL_OFFER);

Parameters

Name	Type	Description
`_offerId`	`uint256`	offer ID

# executeLimitOffer

Execute a limit offer.

function executeLimitOffer(bytes32 _sellToken, uint256 _sellAmount, bytes32 _buyToken, uint256 _buyAmount)
    external
    notLocked(msg.sig)
    nonReentrant
    assertPrivilege(LibObject._getParentFromAddress(msg.sender), LC.GROUP_EXECUTE_LIMIT_OFFER)
    returns (uint256 offerId_, uint256 buyTokenCommissionsPaid_, uint256 sellTokenCommissionsPaid_);

Parameters

Name	Type	Description
`_sellToken`	`bytes32`	Token to sell.
`_sellAmount`	`uint256`	Amount to sell.
`_buyToken`	`bytes32`	Token to buy.
`_buyAmount`	`uint256`	Amount to buy.

Returns

Name	Type	Description
`offerId_`	`uint256`	returns >0 if a limit offer was created on the market because the offer couldn't be totally fulfilled immediately. In this case the return value is the created offer's id.
`buyTokenCommissionsPaid_`	`uint256`	The amount of the buy token paid as commissions on this particular order.
`sellTokenCommissionsPaid_`	`uint256`	The amount of the sell token paid as commissions on this particular order.

# getLastOfferId

Get last created offer.

function getLastOfferId() external view returns (uint256);

Returns

Name	Type	Description
`<none>`	`uint256`	offer id.

# getBestOfferId

Get current best offer for given token pair.

This means finding the highest sellToken-per-buyToken price, i.e. price = sellToken / buyToken

function getBestOfferId(bytes32 _sellToken, bytes32 _buyToken) external view returns (uint256);

Parameters

Name	Type	Description
`_sellToken`	`bytes32`	ID of the token being sold
`_buyToken`	`bytes32`	ID of the token being bought

Returns

Name	Type	Description
`<none>`	`uint256`	offerId, or 0 if no offer exists for given pair

# getOffer

Get the details of the offer #_offerId

function getOffer(uint256 _offerId) external view returns (MarketInfo memory _offerState);

Parameters

Name	Type	Description
`_offerId`	`uint256`	ID of a particular offer

Returns

Name	Type	Description
`_offerState`	`MarketInfo`	details of the offer

# isActiveOffer

Check if the offer #_offerId is active or not.

function isActiveOffer(uint256 _offerId) external view returns (bool);

Parameters

Name	Type	Description
`_offerId`	`uint256`	ID of a particular offer

Returns

Name	Type	Description
`<none>`	`bool`	active or not

# calculateTradingFees

Calculate the trading fees based on a buy amount.

function calculateTradingFees(bytes32 _buyerId, bytes32 _sellToken, bytes32 _buyToken, uint256 _buyAmount)
    external
    view
    returns (uint256 totalFees_, uint256 totalBP_);

Parameters

Name	Type	Description
`_buyerId`	`bytes32`	The account buying the asset.
`_sellToken`	`bytes32`	The asset being sold.
`_buyToken`	`bytes32`	The asset being bought.
`_buyAmount`	`uint256`	The amount that the fees payments are calculated from.

Returns

Name	Type	Description
`totalFees_`	`uint256`	total fee to be paid
`totalBP_`	`uint256`	total basis points

# getMakerBP

Get the maker commission basis points.

function getMakerBP() external view returns (uint16);

Returns

Name	Type	Description
`<none>`	`uint16`	maker fee BP

# objectMinimumSell

Get the minimum amount of tokens that can be sold on the market.

function objectMinimumSell(bytes32 _objectId) external view returns (uint256);

Parameters

Name	Type	Description
`_objectId`	`bytes32`	ID of the object (Par token or external token)

# setMinimumSell

Set the minimum amount of tokens that can be sold on the market.

function setMinimumSell(bytes32 _objectId, uint256 _minimumSell)
    external
    assertPrivilege(LibAdmin._getSystemId(), LC.GROUP_SYSTEM_MANAGERS);

Parameters

Name	Type	Description
`_objectId`	`bytes32`	ID of the object (Par token or external token)
`_minimumSell`	`uint256`	The minimum amount of tokens that can be sold on the market.