pragma solidity ^0.8.24;

import "@openzeppelin/contracts/token/ERC20/IERC20.sol";
import "@openzeppelin/contracts/utils/cryptography/MerkleProof.sol";
import "@openzeppelin/contracts/utils/ReentrancyGuard.sol";
import "hardhat/console.sol"; // For debugging purposes, can be removed in production

contract Launchpad is ReentrancyGuard {
	address public owner;
	address public token; // sale token address
	uint256 public totalTokens; // total tokens for sale
	uint256 public tokensSold; // tokens sold so far
	uint256 public startTime; // beginning time of the sale
	uint256 public endTime; // ending time of the sale
	bytes32 public merkleRoot; // Merkle root for whitelisting
	bool public enableClaimToken; // enable claim token
	uint256 public claimStartTime; // start time for claiming tokens
	address public paymentToken; // payment tokens accepted for the sale
	uint256 public salePaymentPrice; //  payment token price in terms of sale token
	mapping(address => uint256) public claimableTokensAmount; // user contributions for claiming tokens
	uint256 public accountsCount; // number of accounts that have contributed
	event SaleCreated(address token, uint256 totalTokens);
	event Contributed(address user, uint256 amount, address paymentToken);
	event TokensClaimed(address user, uint256 amount);
	event SaleCancelled(address token, uint256 refundedAmount);
	event EnableClaimToken(bool enabled, uint256 claimStartTime);
	event DisableClaimToken(bool disabled);
	constructor() {
		owner = msg.sender;
		accountsCount = 0;
	}

	// Modifiers
	modifier onlyOwner() {
		require(msg.sender == owner, "Only owner can call this function");
		_;
	}

	modifier saleActive() {
		require(merkleRoot != bytes32(0), "MerkleRoot not initialized");
		console.log("Claim start time:", startTime);
		console.log("Current time:", block.timestamp);
		console.log("Claiming tokens enabled:", endTime);
		require(block.timestamp >= startTime && block.timestamp <= endTime, "Sale is not active");
		_;
	}
	modifier validClaimTime() {
		require(enableClaimToken, "Claiming tokens is not enabled");
		require(block.timestamp >= claimStartTime, "Claiming tokens not started yet");
		_;
	}

	// Owner Functions
	function createSale(
		address _token,
		uint256 _totalTokens,
		uint256 _startTime,
		uint256 _endTime,
		address _paymentToken,
		uint256 _price
	) public onlyOwner {
		require(_token != address(0), "Invalid token address");
		require(_totalTokens > 0, "Total tokens must be greater than 0");
		require(_startTime < _endTime, "Invalid time range");

		paymentToken = _paymentToken;
		salePaymentPrice = _price;
		token = _token;
		totalTokens = _totalTokens;
		startTime = _startTime;
		endTime = _endTime;
		tokensSold = 0;
		merkleRoot = bytes32(0); // Reset Merkle root
		IERC20(_token).transferFrom(msg.sender, address(this), _totalTokens); // Transfer tokens to the contracts

		emit SaleCreated(token, totalTokens);
	}

	function withdrawRemainingTokens() public onlyOwner {
		require(block.timestamp > endTime, "Sale is still active");
		uint256 remaining = IERC20(token).balanceOf(address(this));
		IERC20(token).transfer(owner, remaining);
	}

	function withdrawPayments() public onlyOwner {
		require(block.timestamp > endTime, "Sale is still active");
		if (paymentToken == address(0)) {
			payable(owner).transfer(address(this).balance);
		} else {
			uint256 balance = IERC20(paymentToken).balanceOf(address(this));
			IERC20(paymentToken).transfer(owner, balance);
		}
	}

	function cancelSale() public onlyOwner {
		require(block.timestamp < startTime, "Sale already started");
		require(token != address(0), "Sale not initialized");
		uint256 balance = IERC20(token).balanceOf(address(this));
		require(balance > 0, "No tokens to refund");
		IERC20(token).transfer(owner, balance); // Refund tokens to owner
		token = address(0);
		totalTokens = 0;
		tokensSold = 0;
		startTime = 0;
		endTime = 0;
		merkleRoot = bytes32(0); // Reset Merkle root
		emit SaleCancelled(token, balance);
	}

	function enableClaimTokens(uint256 _enableClaimTokenTime) public onlyOwner {
		require(_enableClaimTokenTime >= block.timestamp, "Enable claim time must be in the future");
		require(_enableClaimTokenTime >= endTime, "Claiming tokens can only be enabled after the sale ends");
		enableClaimToken = true;
		claimStartTime = _enableClaimTokenTime; // Set claim start time to now
		emit EnableClaimToken(enableClaimToken, claimStartTime);
	}

	function disableClaimTokens() public onlyOwner {
		require(enableClaimToken, "Claiming tokens is already disabled");
		enableClaimToken = false;
		emit DisableClaimToken(enableClaimToken);
	}

	// Setter
	function setOwner(address _newOwner) public onlyOwner {
		require(_newOwner != address(0), "Invalid owner address");
		owner = _newOwner;
	}

	function setSalePayment(address _paymentToken, uint256 _price) public onlyOwner {
		require(_price > 0, "Price must be greater than 0");
		paymentToken = _paymentToken;
		salePaymentPrice = _price;
	}

	function setMerkleRoot(bytes32 _merkleRoot) public onlyOwner {
		merkleRoot = _merkleRoot;
	}

	//Getter

	function getOwner() public view returns (address) {
		return owner;
	}
	function getSaleToken() public view returns (address) {
		return token;
	}
	function getTotalTokens() public view returns (uint256) {
		return totalTokens;
	}
	function getTokensSold() public view returns (uint256) {
		return tokensSold;
	}
	function getStartTime() public view returns (uint256) {
		return startTime;
	}
	function getEndTime() public view returns (uint256) {
		return endTime;
	}
	function getSaleDetails()
		public
		view
		returns (
			address token,
			uint256 totalTokens,
			uint256 tokensSold,
			uint256 startTime,
			uint256 endTime,
			bytes32 merkleRoot,
			address paymentToken,
			uint256 salePaymentPrice
		)
	{
		return (token, totalTokens, tokensSold, startTime, endTime, merkleRoot, paymentToken, salePaymentPrice);
	}

	function getClaimableTokens(address _user) public view returns (uint256) {
		return claimableTokensAmount[_user];
	}

	function getPaymentTokenPrice() public view returns (uint256) {
		return salePaymentPrice;
	}
	function getPaymentTokens() public view returns (address) {
		return paymentToken;
	}
	function getClaimStartTime() public view returns (uint256) {
		return claimStartTime;
	}
	function isClaimEnabled() public view returns (bool) {
		return enableClaimToken;
	}

	//Main Function

	//MUST TEST !
	function contributeETH(
		uint256 _buyAmount,
		uint256 _maxBuyAmount,
		bytes32[] memory _proof
	) public payable saleActive nonReentrant {
		require(paymentToken == address(0), "Payment token must be ETH for this sale");
		require(msg.value > 0, "Must send ETH");
		require(_buyAmount > 0, "Must buy a positive amount");
		require(_buyAmount <= _maxBuyAmount, "Buy amount exceeds max buy amount");
		require(salePaymentPrice > 0, "Payment token not accepted for this sale");

		// 验证 Merkle 证明
		bytes32 leaf = keccak256(bytes.concat(keccak256(abi.encode(msg.sender, _maxBuyAmount))));
		require(MerkleProof.verify(_proof, merkleRoot, leaf), "Invalid proof");

		uint256 cost = (salePaymentPrice / 10 ** 18) * _buyAmount; // Assuming salePaymentPrice is in wei
		require(msg.value >= cost, "Not enough ETH sent");
		tokensSold += _buyAmount;
		if (claimableTokensAmount[msg.sender] == 0) {
			accountsCount++; // Increment accounts count only if this is the first contribution
		}
		claimableTokensAmount[msg.sender] += _buyAmount; // update user's claimable tokens
		require(claimableTokensAmount[msg.sender] <= _maxBuyAmount, "Buy amount exceeds max buy amount");
		payable(msg.sender).transfer(msg.value - cost); //refund excess ETH
		emit Contributed(msg.sender, _buyAmount, address(0));
	}

	function contributeERC20(
		uint256 _buyAmount,
		uint256 _maxBuyAmount,
		bytes32[] memory _proof
	) public saleActive nonReentrant {
		require(_buyAmount > 0, "Must send a positive amount");
		require(_buyAmount <= _maxBuyAmount, "Buy amount exceeds max buy amount");

		bytes32 leaf = keccak256(bytes.concat(keccak256(abi.encode(msg.sender, _maxBuyAmount))));
		require(MerkleProof.verify(_proof, merkleRoot, leaf), "Invalid proof");

		uint256 price = salePaymentPrice;
		require(price > 0, "Payment token not accepted for this sale");
		uint256 cost = (price / 10 ** 18) * _buyAmount; // Assuming salePaymentPrice is in wei
		require(
			IERC20(paymentToken).allowance(msg.sender, address(this)) >= cost,
			"Not enough allowance for payment token"
		);
		tokensSold += _buyAmount;
		if (claimableTokensAmount[msg.sender] == 0) {
			accountsCount++; // Increment accounts count only if this is the first contribution
		}
		claimableTokensAmount[msg.sender] += _buyAmount; // update user's claimable tokens
		console.log("Claimable tokens amount for user:", claimableTokensAmount[msg.sender]);
		require(claimableTokensAmount[msg.sender] <= _maxBuyAmount, "Buy amount exceeds max buy amount");
		IERC20(paymentToken).transferFrom(msg.sender, address(this), cost); // 从用户账户转移支付代币

		emit Contributed(msg.sender, _buyAmount, paymentToken);
	}

	function claimTokens() public validClaimTime {
		require(block.timestamp > endTime, "Sale is still active");
		uint256 amount = claimableTokensAmount[msg.sender];
		require(amount > 0, "No tokens to claim");

		if (tokensSold <= totalTokens) {
			IERC20(token).transfer(msg.sender, amount); // 分发销售代币
			emit TokensClaimed(msg.sender, amount);
		} else {
			uint256 boughtAmountAvg = totalTokens / accountsCount; // 平均每个账户购买的代币数量
			uint256 refundTokenAmount = amount - boughtAmountAvg; // 计算退款金额
			uint256 refundAmount = (refundAmount / 10 ** 18) * salePaymentPrice;
			if (paymentToken == address(0)) {
				payable(msg.sender).transfer(refundAmount); // 退款ETH
			} else {
				IERC20(paymentToken).transfer(msg.sender, refundAmount); // 退款ERC20代币
			}
			IERC20(token).transfer(msg.sender, boughtAmountAvg); // 分发销售代币
		}
	}
}