// SPDX-License-Identifier: MIT

// File: @openzeppelin/contracts/utils/Context.sol


// OpenZeppelin Contracts v4.4.1 (utils/Context.sol)

pragma solidity ^0.8.0;

/**
 * @dev Provides information about the current execution context, including the
 * sender of the transaction and its data. While these are generally available
 * via msg.sender and msg.data, they should not be accessed in such a direct
 * manner, since when dealing with meta-transactions the account sending and
 * paying for execution may not be the actual sender (as far as an application
 * is concerned).
 *
 * This contract is only required for intermediate, library-like contracts.
 */
abstract contract Context {
    function _msgSender() internal view virtual returns (address) {
        return msg.sender;
    }

    function _msgData() internal view virtual returns (bytes calldata) {
        return msg.data;
    }
}

// File: @openzeppelin/contracts/access/Ownable.sol


// OpenZeppelin Contracts (last updated v4.7.0) (access/Ownable.sol)

pragma solidity ^0.8.0;


/**
 * @dev Contract module which provides a basic access control mechanism, where
 * there is an account (an owner) that can be granted exclusive access to
 * specific functions.
 *
 * By default, the owner account will be the one that deploys the contract. This
 * can later be changed with {transferOwnership}.
 *
 * This module is used through inheritance. It will make available the modifier
 * `onlyOwner`, which can be applied to your functions to restrict their use to
 * the owner.
 */
abstract contract Ownable is Context {
    address private _owner;

    event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);

    /**
     * @dev Initializes the contract setting the deployer as the initial owner.
     */
    constructor() {
        _transferOwnership(_msgSender());
    }

    /**
     * @dev Throws if called by any account other than the owner.
     */
    modifier onlyOwner() {
        _checkOwner();
        _;
    }

    /**
     * @dev Returns the address of the current owner.
     */
    function owner() public view virtual returns (address) {
        return _owner;
    }

    /**
     * @dev Throws if the sender is not the owner.
     */
    function _checkOwner() internal view virtual {
        require(owner() == _msgSender(), "Ownable: caller is not the owner");
    }

    /**
     * @dev Leaves the contract without owner. It will not be possible to call
     * `onlyOwner` functions anymore. Can only be called by the current owner.
     *
     * NOTE: Renouncing ownership will leave the contract without an owner,
     * thereby removing any functionality that is only available to the owner.
     */
    function renounceOwnership() public virtual onlyOwner {
        _transferOwnership(address(0));
    }

    /**
     * @dev Transfers ownership of the contract to a new account (`newOwner`).
     * Can only be called by the current owner.
     */
    function transferOwnership(address newOwner) public virtual onlyOwner {
        require(newOwner != address(0), "Ownable: new owner is the zero address");
        _transferOwnership(newOwner);
    }

    /**
     * @dev Transfers ownership of the contract to a new account (`newOwner`).
     * Internal function without access restriction.
     */
    function _transferOwnership(address newOwner) internal virtual {
        address oldOwner = _owner;
        _owner = newOwner;
        emit OwnershipTransferred(oldOwner, newOwner);
    }
}

// File: @openzeppelin/contracts/token/ERC20/IERC20.sol


// OpenZeppelin Contracts (last updated v4.6.0) (token/ERC20/IERC20.sol)

pragma solidity ^0.8.0;

/**
 * @dev Interface of the ERC20 standard as defined in the EIP.
 */
interface IERC20 {
    /**
     * @dev Emitted when `value` tokens are moved from one account (`from`) to
     * another (`to`).
     *
     * Note that `value` may be zero.
     */
    event Transfer(address indexed from, address indexed to, uint256 value);

    /**
     * @dev Emitted when the allowance of a `spender` for an `owner` is set by
     * a call to {approve}. `value` is the new allowance.
     */
    event Approval(address indexed owner, address indexed spender, uint256 value);

    /**
     * @dev Returns the amount of tokens in existence.
     */
    function totalSupply() external view returns (uint256);

    /**
     * @dev Returns the amount of tokens owned by `account`.
     */
    function balanceOf(address account) external view returns (uint256);

    /**
     * @dev Moves `amount` tokens from the caller's account to `to`.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transfer(address to, uint256 amount) external returns (bool);

    /**
     * @dev Returns the remaining number of tokens that `spender` will be
     * allowed to spend on behalf of `owner` through {transferFrom}. This is
     * zero by default.
     *
     * This value changes when {approve} or {transferFrom} are called.
     */
    function allowance(address owner, address spender) external view returns (uint256);

    /**
     * @dev Sets `amount` as the allowance of `spender` over the caller's tokens.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * IMPORTANT: Beware that changing an allowance with this method brings the risk
     * that someone may use both the old and the new allowance by unfortunate
     * transaction ordering. One possible solution to mitigate this race
     * condition is to first reduce the spender's allowance to 0 and set the
     * desired value afterwards:
     * https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
     *
     * Emits an {Approval} event.
     */
    function approve(address spender, uint256 amount) external returns (bool);

    /**
     * @dev Moves `amount` tokens from `from` to `to` using the
     * allowance mechanism. `amount` is then deducted from the caller's
     * allowance.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transferFrom(
        address from,
        address to,
        uint256 amount
    ) external returns (bool);
}

// File: @openzeppelin/contracts/token/ERC20/extensions/IERC20Metadata.sol


// OpenZeppelin Contracts v4.4.1 (token/ERC20/extensions/IERC20Metadata.sol)

pragma solidity ^0.8.0;


/**
 * @dev Interface for the optional metadata functions from the ERC20 standard.
 *
 * _Available since v4.1._
 */
interface IERC20Metadata is IERC20 {
    /**
     * @dev Returns the name of the token.
     */
    function name() external view returns (string memory);

    /**
     * @dev Returns the symbol of the token.
     */
    function symbol() external view returns (string memory);

    /**
     * @dev Returns the decimals places of the token.
     */
    function decimals() external view returns (uint8);
}

// File: contracts/Fundraise.sol


pragma solidity ^0.8.0;



contract Fundraise is Ownable {
    event Setup(address paymentToken, address raiseToken, uint256 lockupDuration, uint256 raiseTokenCap);
    event DepositTokens(address indexed sender, uint256 amount);
    event WithdrawTokens(address indexed sender, uint256 amount);
    event EmergencyWithdrawTokens(address indexed sender, uint256 amount);
    event WithdrawFunds(address indexed sender, uint256 amount);

    IERC20Metadata public paymentToken;
    IERC20Metadata public raiseToken;
    uint256 public lockupDuration;
    uint256 public endedTimestamp;
    uint256 public paymentCap;
    uint256 public sharesPerPaymentToken;
    uint256 public totalDeposits;

    mapping(address => uint256) public deposits;

    function setup(
        address _paymentToken,
        address _raiseToken,
        uint256 _lockupDuration,
        uint256 _paymentCap,
        uint256 _sharesPerPaymentToken
    ) public onlyOwner() {
        require(IERC20Metadata(_raiseToken).balanceOf(address(this)) >= _paymentCap * _sharesPerPaymentToken, "Insufficient raise tokens");

        paymentToken = IERC20Metadata(_paymentToken);
        raiseToken = IERC20Metadata(_raiseToken);
        lockupDuration = _lockupDuration;
        paymentCap = _paymentCap;
        sharesPerPaymentToken = _sharesPerPaymentToken;

        emit Setup(_paymentToken, _raiseToken, _lockupDuration, _paymentCap);
    }

    function depositTokens(uint256 _amount) public {
        require(_amount % (10**paymentToken.decimals()) == 0, "Has to be whole numbers");
        uint256 newTotalDeposits = totalDeposits + _amount;
        require(newTotalDeposits <= paymentCap, "Exceeds payment cap");
        require(paymentToken.transferFrom(msg.sender, address(this), _amount));

        totalDeposits = newTotalDeposits;
        deposits[msg.sender] += _amount;

        if (totalDeposits == paymentCap) {
            endedTimestamp = block.timestamp;
        }

        emit DepositTokens(msg.sender, _amount);
    }

    function withdrawTokens(uint256 _amount) public {
        require(endedTimestamp > 0, "Fundraise not finished");
        require(block.timestamp > endedTimestamp + lockupDuration, "Lockup not finished");
        require(deposits[msg.sender] >= _amount, "Amount not sufficient");

        deposits[msg.sender] -= _amount;
        raiseToken.transfer(msg.sender, _amount * sharesPerPaymentToken);

        emit WithdrawTokens(msg.sender, _amount * sharesPerPaymentToken);
    }

    function emergencyWithdrawTokens(uint256 _amount) public onlyOwner() {
        raiseToken.transfer(msg.sender, _amount);

        emit EmergencyWithdrawTokens(msg.sender, _amount);
    }
    
    function withdrawFunds(uint256 _amount) public onlyOwner() {
        paymentToken.transfer(msg.sender, _amount);

        emit WithdrawFunds(msg.sender, _amount);
    }
}