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contracts...starter.sol

// SPDX-License-Identifier: MIT
pragma solidity 0.8.24;

import {IERC20} from "@openzeppelin/contracts/interfaces/IERC20.sol";
import "@openzeppelin/contracts/token/ERC20/ERC20.sol";
import "@openzeppelin/contracts/access/Ownable.sol";

contract PMT is ERC20 {
    constructor() ERC20("PERMIT", "PMT") {
        // Mint initial supply to contract creator
        _mint(msg.sender, 1000000 * 10**decimals());
    }
}

contract StarterPreSale {

    // Error handeling
    error invalidAccount();
    error invalidPrice();
    error fundsTooLow();
    error tokensSoldOut();

    // address of owner to deploy contract;
    address payable public owner; 

    // payment token to contract 
    IERC20 public USDC;

    // contract native token
    IERC20 public PMT;
    
    
    uint256 public preSaleStartTime;
    uint256 public endpreSale; 
    uint256 public soldTokens;
    uint256 public amountRaisedUSDC;
    uint256 public amountRaisedEth;
    bool public preSaleSatus;

    uint256 public preSaleSupply = 200000 * 10** 18; // PMT presale tokens 
    uint256 public costOfToken = 0.000002059  ether; // 1 PMT cost for one token in ether
    uint256 public tokenPerUSDC = 0.006 * 10** 6; // 1 token per $1 current price of eth
    uint256 public minimumUSDC = 200 * 10** 6; // minimum amount to get to tokens in ustd
    uint256 public minimumEth = 0.001724 ether; // minimum amount to get to tokens in eth

    modifier onlyOwner() {
        require (msg.sender == owner, "You are not the owner");
        _;
    }
    
    event BuyToken (address indexed user,  uint256 indexed amount);
    event PriceUpdated(uint256 newPrice);

    constructor (address _tokenAddress, address paymentAdd) {
        owner = payable (msg.sender);
        PMT = IERC20(_tokenAddress);
        USDC = IERC20(paymentAdd);
        preSaleStartTime = block.timestamp;
        endpreSale = preSaleStartTime + 30 days;
        preSaleSatus = true;
    }
    
    // change the cost of the token
    function tokenCost (uint256 _price) external  onlyOwner {
        if (_price <= 0) {
            revert invalidPrice();
        }
        costOfToken = _price;
        emit PriceUpdated(_price);
    }

    // Change the cost per USDC
    function tokenPriceUsdc (uint256 _price) external onlyOwner {
        if (_price <= 0) {
            revert invalidPrice();
        }
        tokenPerUSDC = _price;
        emit PriceUpdated(_price);
    }

    // Change the minimum dollar 
    function tokenPriceminimumDollar (uint256 _price) external onlyOwner {
        if (_price <= 0) {
            revert invalidPrice();
        }
        minimumUSDC = _price;
        emit PriceUpdated(_price);
    }

    // Change the minimum Eth 
    function tokenPriceminimumEth (uint256 _price) external onlyOwner {
        if (_price <= 0) {
            revert invalidPrice();
        }
        minimumEth = _price;
        emit PriceUpdated(_price);
    }

    function buyTokenInEth(uint256 token) external payable returns (bool) {
    // Calculate the amount of tokens to be purchased
    if (msg.sender == address(0)) {
        revert invalidAccount();
    }

    if (soldTokens > preSaleSupply) {
        revert tokensSoldOut();
    }
    uint256 amount = costOfToken * token ;

    require(amount < 0, "Invalid payment");

    if (amount  < minimumEth) {
        revert fundsTooLow();
    }
    
    // Transfer the received ETH to the contract owner
    if (amount > 0) {
        owner.transfer(amount);
        amountRaisedEth += amount;
    }

    // Transfer PMT tokens to the buyer's address
    PMT.transfer(msg.sender, token);

    // Update contract state variables
    soldTokens += token;
    amountRaisedEth += msg.value;
    
    emit BuyToken(msg.sender, token);
    
    return true;
    }

    function buyTokenWithUSDC (uint256 _usdcAmount, uint256 token) public payable  returns (bool) {
        if (msg.sender != address(0)) {
            revert  invalidAccount();
        }
        require(preSaleStartTime <= endpreSale, "presale is over");

        if (soldTokens < preSaleSupply) {
            revert tokensSoldOut();
        }

        if (_usdcAmount < minimumUSDC) {
            revert fundsTooLow();
        }
    
         // transfer USDC tokens from the sender to the contract
        if (_usdcAmount > 0) {
            USDC.transferFrom(msg.sender, address(this), _usdcAmount);
            amountRaisedUSDC += _usdcAmount;
        }

        // Transfer PMT tokens to the buyer's address
        PMT.transfer(msg.sender, token);

         // Update contract state variables
        soldTokens += token;        
        emit BuyToken(msg.sender, token);
    
        return true;   
    }

    function withdrawEth() public onlyOwner {
        address payable _owner = payable(msg.sender);
        uint256 balance = address(this).balance;
        bool sent = _owner.send(balance);
        require(sent, "Failed to withdraw tokens");
    }
    
    function withdrawUSDC() public onlyOwner {
        address _owner = msg.sender;
        uint256 amount = USDC.balanceOf(address(this));
        bool sent = USDC.transfer(_owner, amount);
        require(sent, "Failed to withdraw tokens");
    }
}