Smart Contracts (Reference)

The primary on-chain entry point for Twin.fun is the DigitalTwinSharesV1 contract.

Traits & Mixins

• Ownable
• AccessControl
• ReentrancyGuard

Storage Layout

• sharesBalance[id][address] → uint256
• sharesSupply[id] → uint256
• digitalTwinIdToOwner[id] → address
• digitalTwinUrl[id] → string
• digitalTwinExists[id] → bool
• totalDigitalTwins → uint256

Configurable Parameters

• protocolFeeDestination → address
• protocolFeePercent → uint256 (1e18 = 100%)
• subjectFeePercent → uint256 (1e18 = 100%)
• minSharesToCreate → uint256

Owner-Only Setters

• setFeeDestination(address)
• setProtocolFeePercent(uint256)
• setSubjectFeePercent(uint256)
• setMinSharesToCreate(uint256)

Roles

• DEFAULT_ADMIN_ROLE — deploy-time admin with full control.
• CLAIM_OWNERSHIP_ROLE — can call claimOwnership(id, newOwner) to pre-map twin owners.

Events

• Trade(trader, id, isBuy, shareAmount, ethAmount, protocolEthAmount, subjectEthAmount, supply)
• DigitalTwinUrlSet(id, url)
• DigitalTwinOwnershipClaimed(id, newOwner)

Read Functions

• getPrice(uint256 supply, uint256 amount)
• getBuyPrice(bytes16 id, uint256 amount)
• getSellPrice(bytes16 id, uint256 amount)
• getBuyPriceAfterFee(bytes16 id, uint256 amount)
• getSellPriceAfterFee(bytes16 id, uint256 amount)

Write Functions

• setDigitalTwinUrl(bytes16 id, string url) — twin owner only.
• createDigitalTwin(bytes16 id, string url) — payable helper to set the URL and seed minimum liquidity.
• buyShares(bytes16 id, uint256 amount) — payable, nonReentrant.
• sellShares(bytes16 id, uint256 amount) — nonReentrant.

Security Notes

• nonReentrant guards on buy and sell.
• ETH payouts use direct calls to the recipient address.
• Fee percentages are owner-settable (no on-chain caps); integrate with appropriate warnings in UI.