EulerSwap

// SPDX-License-Identifier: BUSL-1.1
function getHookPermissions() public pure override returns (Hooks.Permissions memory) {
    return Hooks.Permissions({
        beforeInitialize: true,
        afterInitialize: false,
        beforeAddLiquidity: true,
        afterAddLiquidity: false,
        beforeRemoveLiquidity: false,
        afterRemoveLiquidity: false,
        beforeSwap: true,
        afterSwap: false,
        beforeDonate: true,
        afterDonate: false,
        beforeSwapReturnDelta: true,
        afterSwapReturnDelta: false,
        afterAddLiquidityReturnDelta: false,
        afterRemoveLiquidityReturnDelta: false
    });
}

// take input to Euler vaults, pay output, offset the CLAMM swap
function _beforeSwap(address sender, PoolKey calldata key, IPoolManager.SwapParams calldata params, bytes calldata)
    internal
    override
    nonReentrant
    returns (bytes4, BeforeSwapDelta, uint24)
{
    // QuoteLib.computeQuote → poolManager.take(input) → vaults → poolManager.settle(output)
    BeforeSwapDelta returnDelta = isExactInput
        ? toBeforeSwapDelta(amountIn.toInt128(), -(amountOut.toInt128()))
        : toBeforeSwapDelta(-(amountOut.toInt128()), amountIn.toInt128());
    return (BaseHook.beforeSwap.selector, returnDelta, 0);
}