`NFTXV4Hook`

Contracts/src/contracts/NFTXV4Hook.sol
Public interface: Contracts/src/interfaces/INFTXV4Hook.sol

The single Uniswap V4 hook implementation registered against the Locker. Owns:

Per-collection V4 pool config (PoolParams).
Pool-fee queue / donate lifecycle (replaces the legacy receive/distribute/swap pipeline).
AMM fee + beneficiary; per-beneficiary flat-fee overrides.
AMM-fee escrow (inherited from TokenEscrow).

⚠️

As of May 2026 this contract is the renamed UniswapV4Implementation and INFTXV4Hook is the renamed IBaseImplementation. All errors, events, and structs have moved into the interface so external integrators have a single source of truth.

State views

Function	Returns
`nativeToken()`	The ETH-equivalent ERC-20 paired against every `CollectionToken` (typically flETH)
`getCollectionPoolKey(_collection)`	Encoded V4 `PoolKey` bytes
`poolParams(_poolId)`	`(collection, poolFee, initialized, currencyFlipped)`
`getFee(_poolId, _origin)`	Resolved swap fee (override → poolFee → defaultFee)
`feeOverrides(_beneficiary)`	Encoded override (`(flatFee \<\< 24) \| 0xFFFFFF` when active, 0 otherwise)
`defaultFee()`	Global LP fee
`ammFee()`	AMM cut taken from the unspecified swap leg
`ammBeneficiary()`	AMM cut recipient (or `address(0)` to burn)

Public surface

Locker-only

Function	Description
`registerCollection(_collection, _collectionToken)`	Called by `Locker.createCollection`
`initializeCollection(_collection, _eth, _tokens, _amount1Slippage, _sqrtPriceX96, _recipient)`	Called by `Locker.initializeCollection`; mints the LP NFT to `_recipient`

Both revert with CallerIsNotLocker if any other address calls them.

Listings + admin

Function	Caller	Description
`depositFees(_collection, _amount0, _amount1)`	`Listings` (or admin)	Queues fees in the pool’s V4-sorted currency order; emits `PoolFeesQueued`

Admin

Function	Description
`setDefaultFee(_defaultFee)`	Update the global LP fee
`setFee(_poolId, _fee)`	Per-pool LP override (`0` = use default)
`setAmmFee(_ammFee)`	Update AMM cut
`setAmmBeneficiary(_ammBeneficiary)`	Update AMM beneficiary (`address(0)` = burn)
`setFeeExemption(_beneficiary, _flatFee)`	Per-beneficiary flat fee override
`removeFeeExemption(_beneficiary)`	Clear override

Structs

struct PoolParams {
  address collection;
  uint24 poolFee;
  bool initialized;
  bool currencyFlipped;  // nativeToken > collectionToken (collection sits on currency0)
}
 
struct PendingDonation {
  uint128 amount0;
  uint128 amount1;
}

Errors

Error	Cause
`NotImplemented`	A V4 hook callback that the protocol explicitly disables was invoked
`ZeroAddress`	Invariant violation in admin setter
`LPRecipientIsZeroAddress`	`initializeCollection` recipient is zero
`UnknownCollection`	Hook lookup against an unregistered collection
`CannotBeInitializedDirectly`	V4 `PoolManager.initialize` was called outside `initializeCollection`
`PoolNotInitialized`	Hook callback before pool initialization completes
`CallerIsNotLocker`	Privileged entry-point invoked by anyone other than the registered Locker
`FeeExemptionInvalid(_invalidFee, _maxFee)`	`setFeeExemption` over the V4 max LP fee
`NoBeneficiaryExemption(_beneficiary)`	`removeFeeExemption` for a beneficiary with no override

Events

Pool fee lifecycle

Event	Notes
`PoolFeesQueued(_collection, _amount0, _amount1)`	Fees enqueued via `depositFees`; awaiting next swap
`PoolFeesDonated(_collection, _amount0, _amount1)`	Fees donated to LPs in the next swap callback

Pool state

Event	Notes
`PoolStateUpdated(_collection, _sqrtPriceX96, _tick, _protocolFee, _swapFee, _liquidity)`	Emitted after every transaction that reads the slot

Fee config

Event	Notes
`DefaultFeeSet(_fee)`	Global LP fee updated
`PoolFeeSet(_collection, _fee)`	Per-pool override
`AMMFeeSet(_ammFee)`	AMM cut updated
`AMMBeneficiarySet(_ammBeneficiary)`	AMM beneficiary updated
`AMMFeesTaken(_recipient, _token, _amount)`	AMM cut realised on a swap; `_recipient` may be `address(0)` (burn)
`FeeOverrideSet(_beneficiary, _flatFee)`	Per-beneficiary flat fee set/updated
`FeeOverrideRemoved(_beneficiary)`	Per-beneficiary flat fee cleared

Inherited from `TokenEscrow`

Event	Notes
`Deposit(_payee, _token, _amount)`	Funds escrowed (e.g. AMM cut)
`Withdrawal(_payee, _token, _amount)`	`withdraw` claim

Inherited surface

BaseHook — full V4 hook callback set; the public ones used here are beforeInitialize, afterInitialize, beforeSwap, afterSwap, beforeAddLiquidity. Outside of these the hook reverts with NotImplemented.
BaseOracle — TWAP oracle used by getFee and read paths. Public views: observe(_poolId, _secondsAgos) returning the standard V4 oracle cumulative arrays.
TokenEscrow — withdraw(_recipient, _token, _amount) and balances(_recipient, _token). Both AMM beneficiary claims and any refunded escrow live here.
Ownable, ReentrancyGuard.

Listings CollectionToken

NFTXV4Hook