// SPDX-License-Identifier: MIT
pragma solidity ^0.8.20;

import "@openzeppelin/contracts/token/ERC20/IERC20.sol";
import "@openzeppelin/contracts/access/Ownable.sol";
import "@openzeppelin/contracts/security/ReentrancyGuard.sol";
import "@openzeppelin/contracts/utils/math/SafeMath.sol";

contract SellTixICO is Ownable, ReentrancyGuard {
    using SafeMath for uint256;
    
    IERC20 public token;
    
    uint256 public constant TEAM_ALLOCATION = 15_000_000 * 10**18;      // 15%
    uint256 public constant PUBLIC_SALE = 30_000_000 * 10**18;          // 30%
    uint256 public constant PLATFORM_DEV = 20_000_000 * 10**18;         // 20%
    uint256 public constant MARKETING = 15_000_000 * 10**18;            // 15%
    uint256 public constant COMMUNITY_REWARDS = 10_000_000 * 10**18;    // 10%
    uint256 public constant LIQUIDITY = 10_000_000 * 10**18;            // 10%

    uint256 public icoStartTime;
    uint256 public icoEndTime;
    uint256 public tokenPrice; // in wei

    mapping(address => uint256) public teamVesting;
    mapping(address => uint256) public publicSaleVesting;
    mapping(address => uint256) public platformVesting;
    mapping(address => uint256) public marketingVesting;

    event TokensPurchased(address buyer, uint256 amount);
    event TokensVested(address beneficiary, uint256 amount);

    constructor(address _token, uint256 _tokenPrice) {
        token = IERC20(_token);
        tokenPrice = _tokenPrice;
    }

    function startICO(uint256 _duration) external onlyOwner {
        icoStartTime = block.timestamp;
        icoEndTime = block.timestamp.add(_duration);
    }

    function buyTokens() external payable nonReentrant {
        require(block.timestamp >= icoStartTime && block.timestamp <= icoEndTime, "ICO not active");
        require(msg.value > 0, "Invalid amount");

        uint256 tokens = msg.value.mul(10**18).div(tokenPrice);
        require(tokens <= PUBLIC_SALE, "Exceeds available tokens");

        // 40% unlocked immediately
        uint256 unlockedTokens = tokens.mul(40).div(100);
        uint256 vestedTokens = tokens.sub(unlockedTokens);

        token.transfer(msg.sender, unlockedTokens);
        publicSaleVesting[msg.sender] = publicSaleVesting[msg.sender].add(vestedTokens);

        emit TokensPurchased(msg.sender, tokens);
    }

    function claimVestedTokens() external nonReentrant {
        uint256 claimableAmount = getClaimableTokens(msg.sender);
        require(claimableAmount > 0, "No tokens to claim");

        if (publicSaleVesting[msg.sender] > 0) {
            publicSaleVesting[msg.sender] = 0;
        }

        token.transfer(msg.sender, claimableAmount);
        emit TokensVested(msg.sender, claimableAmount);
    }

    function getClaimableTokens(address _beneficiary) public view returns (uint256) {
        if (block.timestamp < icoEndTime.add(180 days)) {
            return 0;
        }
        return publicSaleVesting[_beneficiary];
    }
}