TwapGetter.sol

import "@uniswap/v3-core/contracts/interfaces/IUniswapV3Pool.sol";
import "@uniswap/v3-core/contracts/libraries/TickMath.sol";
import "@uniswap/v3-core/contracts/libraries/FixedPoint96.sol";
import "@uniswap/v3-core/contracts/libraries/FullMath.sol";

contract TwapGetter {
    function getSqrtTwapX96(address uniswapV3Pool, uint32 twapInterval) public view returns (uint160 sqrtPriceX96) {
        if (twapInterval == 0) {
            // return the current price if twapInterval == 0
            (sqrtPriceX96, , , , , , ) = IUniswapV3Pool(uniswapV3Pool).slot0();
        } else {
            uint32[] memory secondsAgos = new uint32[](2);
            secondsAgos[0] = twapInterval; // from (before)
            secondsAgos[1] = 0; // to (now)

            (int56[] memory tickCumulatives, ) = IUniswapV3Pool(uniswapV3Pool).observe(secondsAgos);

            // tick(imprecise as it's an integer) to price
            sqrtPriceX96 = TickMath.getSqrtRatioAtTick(
                int24((tickCumulatives[1] - tickCumulatives[0]) / twapInterval)
            );
        }
    }

    function getPriceX96FromSqrtPriceX96(uint160 sqrtPriceX96) public pure returns(uint256 priceX96) {
        return FullMath.mulDiv(sqrtPriceX96, sqrtPriceX96, FixedPoint96.Q96);
    }
}