Lottery.sol

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.13;

contract Lottery {
    event Receive(address indexed from, address to, uint amount);

    address owner;
    address public winner;
    uint public totalBets;

    address payable [] players;

    constructor() {
        owner = msg.sender;
    }

    receive() external payable {
        require(msg.value >= 0.1 ether, "min value is 0.1 ether"); //
        emit Receive(msg.sender, address(this), msg.value);
        players.push(payable(msg.sender));
        totalBets++;
    }

    modifier onlyOwner() {
        require(owner == msg.sender, "not owner");
        _;
    }

    function getAllPlayers() external view returns(address payable [] memory) {
        return players;
    }

    function random() private view returns(uint) {
        return uint(keccak256(abi.encodePacked(block.difficulty, block.timestamp, msg.sender, players.length))) % totalBets;
    }

    function pickRandomWinner() external onlyOwner returns(address) {
        require(players.length >= 3, "Needs 3 or more players");
        require(winner == address(0), "There is a winner");
        winner = payable(players[random()]);
        return winner;
    }
}