Twap oracle

.gitmodules

@@ -6,4 +6,7 @@
     url = https://github.com/OpenZeppelin/openzeppelin-contracts
 [submodule "lib/solady"]
     path = lib/solady
-    url = https://github.com/vectorized/solady
+    url = https://github.com/vectorized/solady
+[submodule "lib/v3-core"]
+	path = lib/v3-core
+	url = https://github.com/uniswap/v3-core

contracts/interfaces/IEtherexPair.sol

@@ -0,0 +1,135 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+pragma solidity ^0.8.0;
+
+interface IEtherexPair {
+    struct Observation {
+        uint256 timestamp;
+        uint256 reserve0Cumulative;
+        uint256 reserve1Cumulative;
+    }
+
+    event Mint(address indexed sender, uint256 amount0, uint256 amount1);
+    event Burn(address indexed sender, uint256 amount0, uint256 amount1, address indexed to);
+    event Swap(
+        address indexed sender,
+        uint256 amount0In,
+        uint256 amount1In,
+        uint256 amount0Out,
+        uint256 amount1Out,
+        address indexed to
+    );
+    event Sync(uint112 reserve0, uint112 reserve1);
+
+    function quote(address tokenIn, uint256 amountIn, uint256 granularity)
+        external
+        view
+        returns (uint256 amountOut);
+    function sample(address tokenIn, uint256 amountIn, uint256 points, uint256 window)
+        external
+        view
+        returns (uint256[] memory);
+    function current(address tokenIn, uint256 amountIn) external view returns (uint256 amountOut);
+
+    function currentCumulativePrices()
+        external
+        view
+        returns (uint256 reserve0Cumulative, uint256 reserve1Cumulative, uint256 blockTimestamp);
+
+    function observationLength() external view returns (uint256);
+
+    function lastObservation() external view returns (Observation memory);
+
+    function observations(uint256 index) external view returns (Observation memory);
+
+    /// @notice initialize the pool, called only once programatically
+    function initialize(address _token0, address _token1, bool _stable) external;
+
+    /// @notice calculate the current reserves of the pool and their last 'seen' timestamp
+    /// @return _reserve0 amount of token0 in reserves
+    /// @return _reserve1 amount of token1 in reserves
+    /// @return _blockTimestampLast the timestamp when the pool was last updated
+    function getReserves()
+        external
+        view
+        returns (uint112 _reserve0, uint112 _reserve1, uint32 _blockTimestampLast);
+
+    /// @notice mint the pair tokens (LPs)
+    /// @param to where to mint the LP tokens to
+    /// @return liquidity amount of LP tokens to mint
+    function mint(address to) external returns (uint256 liquidity);
+
+    /// @notice burn the pair tokens (LPs)
+    /// @param to where to send the underlying
+    /// @return amount0 amount of amount0
+    /// @return amount1 amount of amount1
+    function burn(address to) external returns (uint256 amount0, uint256 amount1);
+
+    /// @notice direct swap through the pool
+    function swap(uint256 amount0Out, uint256 amount1Out, address to, bytes calldata data)
+        external;
+
+    /// @notice force balances to match reserves, can be used to harvest rebases from rebasing tokens or other external factors
+    /// @param to where to send the excess tokens to
+    function skim(address to) external;
+
+    /// @notice force reserves to match balances, prevents skim excess if skim is enabled
+    function sync() external;
+
+    /// @notice set the pair fees contract address
+    function setFeeRecipient(address _pairFees) external;
+
+    /// @notice set the feesplit variable
+    function setFeeSplit(uint256 _feeSplit) external;
+
+    /// @notice sets the swap fee of the pair
+    /// @dev scaled to a max of 50% (500_000/1_000_000)
+    /// @param _fee the fee
+    function setFee(uint256 _fee) external;
+
+    /// @notice 'mint' the fees as LP tokens
+    /// @dev this is used for protocol/voter fees
+    function mintFee() external;
+
+    /// @notice calculates the amount of tokens to receive post swap
+    /// @param amountIn the token amount
+    /// @param tokenIn the address of the token
+    function getAmountOut(uint256 amountIn, address tokenIn)
+        external
+        view
+        returns (uint256 amountOut);
+
+    /// @notice returns various metadata about the pair
+    function metadata()
+        external
+        view
+        returns (
+            uint256 _decimals0,
+            uint256 _decimals1,
+            uint256 _reserve0,
+            uint256 _reserve1,
+            bool _stable,
+            address _token0,
+            address _token1
+        );
+
+    /// @notice returns the feeSplit of the pair
+    function feeSplit() external view returns (uint256);
+
+    /// @notice returns the fee of the pair
+    function fee() external view returns (uint256);
+
+    /// @notice returns the feeRecipient of the pair
+    function feeRecipient() external view returns (address);
+
+    /// @notice returns the token0 of the pair
+    function token0() external view returns (address);
+
+    /// @notice returns the token1 of the pair
+    function token1() external view returns (address);
+
+    /// @notice returns if pair is stable
+    function stable() external view returns (bool);
+
+    /// @notice returns kLast
+    function kLast() external view returns (uint256);
+}