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shares.sol

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.9;

import "@openzeppelin/contracts@4.9.3/token/ERC721/ERC721.sol";
import "@openzeppelin/contracts@4.9.3/token/ERC721/extensions/ERC721URIStorage.sol";
import "@openzeppelin/contracts@4.9.3/token/ERC721/extensions/ERC721Burnable.sol";
import "@openzeppelin/contracts@4.9.3/access/Ownable.sol";
import "@openzeppelin/contracts@4.9.3/utils/Counters.sol";
import "@openzeppelin/contracts@4.9.3/token/ERC20/IERC20.sol";

contract SHARES is ERC721, ERC721URIStorage, ERC721Burnable, Ownable {
    using Counters for Counters.Counter;
    Counters.Counter private _tokenIdCounter;
    uint256 public villaCount;
    address public USDT_ADDRESS;
    struct Villa {
        uint256 id;
        string uid;
        string name;
        uint256 buyPrice;
        uint256 sellPrice;
        string uri;
        uint256 max_nft_count;
        uint256 minted_nft;
    }
    mapping(uint256 => Villa) public villa;
    constructor(address _usdt) ERC721("S.H.A.R.E.S", "SHR") {
        USDT_ADDRESS = _usdt;
    }

    function safeMint(address to, string memory uri) public onlyOwner {
        uint256 tokenId = _tokenIdCounter.current();
        _tokenIdCounter.increment();
        _safeMint(to, tokenId);
        _setTokenURI(tokenId, uri);
    }
    //create new villa with nft
    function createVilla(
        string memory uid,
        string memory name, 
        string memory uri,
        uint256 buyPrice, 
        uint256 sellPrice, 
        uint256 max_nft_count) public onlyOwner {
        uint256 villaId = villaCount++;
        villa[villaId] = Villa(villaId, uid, name, buyPrice, sellPrice, uri, max_nft_count, 0);
    }
    function updateVillaBuyPrice(uint256 villaid, uint256 price) public onlyOwner {
        require(villaid < villaCount, "Villa ID does not exist"); 
        require(price > 0, "Invalid Price"); 
        villa[villaid].buyPrice = price;
    } 
    function updateVillaSellPrice(uint256 villaid, uint256 price) public onlyOwner {
        require(villaid < villaCount, "Villa ID does not exist"); 
        require(price > 0, "Invalid Price"); 
        villa[villaid].sellPrice = price;
    }
    function buyShare(uint256 villaid, uint256 share_amount) public returns (uint256[] memory){
        require(villaid < villaCount, "Villa ID does not exist");
        require(villa[villaid].minted_nft + share_amount <= villa[villaid].max_nft_count, "Exceeds maximum NFT count for villa");
        IERC20 usdt_token = IERC20(USDT_ADDRESS); 
        uint256 buyPrice = villa[villaid].buyPrice;
        uint256 totalCost = buyPrice * share_amount;
        require(usdt_token.balanceOf(msg.sender) >= totalCost, "Insufficient USDT balance");
        require(usdt_token.allowance(msg.sender, address(this)) >= totalCost, "Allowance not sufficient");
        usdt_token.transferFrom(msg.sender, address(this), totalCost);
        uint256[] memory mintedTokenIds = new uint256[](share_amount);
        //mint nft 
        for (uint256 i = 0; i < share_amount; i++) {
            villa[villaid].minted_nft++; 
            uint256 tokenId = _tokenIdCounter.current();
            _tokenIdCounter.increment();
            _safeMint(msg.sender, tokenId);
            _setTokenURI(tokenId, villa[villaid].uri);
            mintedTokenIds[i] = tokenId;
        }
        return mintedTokenIds;
    }

    function sellShare(uint256 villaid, uint256[] memory tokenids) public returns (uint256[] memory) {
        require(villaid < villaCount, "Villa ID does not exist");
        require(tokenids.length > 0, "Invalid Token Ids"); 
        IERC20 usdt_token = IERC20(USDT_ADDRESS);
        uint256 sellPrice = villa[villaid].sellPrice * tokenids.length; 
        usdt_token.approve(msg.sender, sellPrice);
        //check all token if approce 
        for (uint256 i = 0; i < tokenids.length; i++) {
            require(getApproved(tokenids[i]) == address(this), "Token Id not approve");
        }
        //send the usdt
        uint256[] memory sellTokenIds = new uint256[](tokenids.length);
        usdt_token.transfer(msg.sender, sellPrice);
        for (uint256 i = 0; i < tokenids.length; i++) {
            //transfer nft 
            //todo save sell share
            villa[villaid].minted_nft--;
            transferFrom(msg.sender, address(this), tokenids[i]);
        }
        return sellTokenIds;
    }
    function usdtBalance() public view onlyOwner returns (uint256) {
        IERC20 usdt_token = IERC20(USDT_ADDRESS);
        return usdt_token.balanceOf(address(this));
    }
    function withdraw() public onlyOwner {
        IERC20 usdt_token = IERC20(USDT_ADDRESS); 
        uint256 balance = usdt_token.balanceOf(address(this));
        require(usdt_token.balanceOf(address(this)) > 0, "not enough usdt"); 
        usdt_token.transfer(msg.sender, balance);
    }

    // The following functions are overrides required by Solidity.

    function _burn(uint256 tokenId) internal override(ERC721, ERC721URIStorage) {
        super._burn(tokenId);
    }

    function tokenURI(uint256 tokenId)
        public
        view
        override(ERC721, ERC721URIStorage)
        returns (string memory)
    {
        return super.tokenURI(tokenId);
    }

    function supportsInterface(bytes4 interfaceId)
        public
        view
        override(ERC721, ERC721URIStorage)
        returns (bool)
    {
        return super.supportsInterface(interfaceId);
    }
}