// File: contracts/FanbasePayment.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.13;

library Address {
    /**
     * @dev Returns true if `account` is a contract.
     *
     * [IMPORTANT]
     * ====
     * It is unsafe to assume that an address for which this function returns
     * false is an externally-owned account (EOA) and not a contract.
     *
     * Among others, `isContract` will return false for the following
     * types of addresses:
     *
     *  - an externally-owned account
     *  - a contract in construction
     *  - an address where a contract will be created
     *  - an address where a contract lived, but was destroyed
     *
     * Furthermore, `isContract` will also return true if the target contract within
     * the same transaction is already scheduled for destruction by `SELFDESTRUCT`,
     * which only has an effect at the end of a transaction.
     * ====
     *
     * [IMPORTANT]
     * ====
     * You shouldn't rely on `isContract` to protect against flash loan attacks!
     *
     * Preventing calls from contracts is highly discouraged. It breaks composability, breaks support for smart wallets
     * like Gnosis Safe, and does not provide security since it can be circumvented by calling from a contract
     * constructor.
     * ====
     */
    function isContract(address account) internal view returns (bool) {
        // This method relies on extcodesize/address.code.length, which returns 0
        // for contracts in construction, since the code is only stored at the end
        // of the constructor execution.

        return account.code.length > 0;
    }

    /**
     * @dev Replacement for Solidity's `transfer`: sends `amount` wei to
     * `recipient`, forwarding all available gas and reverting on errors.
     *
     * https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost
     * of certain opcodes, possibly making contracts go over the 2300 gas limit
     * imposed by `transfer`, making them unable to receive funds via
     * `transfer`. {sendValue} removes this limitation.
     *
     * https://consensys.net/diligence/blog/2019/09/stop-using-soliditys-transfer-now/[Learn more].
     *
     * IMPORTANT: because control is transferred to `recipient`, care must be
     * taken to not create reentrancy vulnerabilities. Consider using
     * {ReentrancyGuard} or the
     * https://solidity.readthedocs.io/en/v0.5.11/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].
     */
    function sendValue(address payable recipient, uint256 amount) internal {
        require(address(this).balance >= amount, "Address: insufficient balance");

        (bool success, ) = recipient.call{value: amount}("");
        require(success, "Address: unable to send value, recipient may have reverted");
    }

    /**
     * @dev Performs a Solidity function call using a low level `call`. A
     * plain `call` is an unsafe replacement for a function call: use this
     * function instead.
     *
     * If `target` reverts with a revert reason, it is bubbled up by this
     * function (like regular Solidity function calls).
     *
     * Returns the raw returned data. To convert to the expected return value,
     * use https://solidity.readthedocs.io/en/latest/units-and-global-variables.html?highlight=abi.decode#abi-encoding-and-decoding-functions[`abi.decode`].
     *
     * Requirements:
     *
     * - `target` must be a contract.
     * - calling `target` with `data` must not revert.
     *
     * _Available since v3.1._
     */
    function functionCall(address target, bytes memory data) internal returns (bytes memory) {
        return functionCallWithValue(target, data, 0, "Address: low-level call failed");
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`], but with
     * `errorMessage` as a fallback revert reason when `target` reverts.
     *
     * _Available since v3.1._
     */
    function functionCall(
        address target,
        bytes memory data,
        string memory errorMessage
    ) internal returns (bytes memory) {
        return functionCallWithValue(target, data, 0, errorMessage);
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but also transferring `value` wei to `target`.
     *
     * Requirements:
     *
     * - the calling contract must have an ETH balance of at least `value`.
     * - the called Solidity function must be `payable`.
     *
     * _Available since v3.1._
     */
    function functionCallWithValue(address target, bytes memory data, uint256 value) internal returns (bytes memory) {
        return functionCallWithValue(target, data, value, "Address: low-level call with value failed");
    }

    /**
     * @dev Same as {xref-Address-functionCallWithValue-address-bytes-uint256-}[`functionCallWithValue`], but
     * with `errorMessage` as a fallback revert reason when `target` reverts.
     *
     * _Available since v3.1._
     */
    function functionCallWithValue(
        address target,
        bytes memory data,
        uint256 value,
        string memory errorMessage
    ) internal returns (bytes memory) {
        require(address(this).balance >= value, "Address: insufficient balance for call");
        (bool success, bytes memory returndata) = target.call{value: value}(data);
        return verifyCallResultFromTarget(target, success, returndata, errorMessage);
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but performing a static call.
     *
     * _Available since v3.3._
     */
    function functionStaticCall(address target, bytes memory data) internal view returns (bytes memory) {
        return functionStaticCall(target, data, "Address: low-level static call failed");
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
     * but performing a static call.
     *
     * _Available since v3.3._
     */
    function functionStaticCall(
        address target,
        bytes memory data,
        string memory errorMessage
    ) internal view returns (bytes memory) {
        (bool success, bytes memory returndata) = target.staticcall(data);
        return verifyCallResultFromTarget(target, success, returndata, errorMessage);
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but performing a delegate call.
     *
     * _Available since v3.4._
     */
    function functionDelegateCall(address target, bytes memory data) internal returns (bytes memory) {
        return functionDelegateCall(target, data, "Address: low-level delegate call failed");
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
     * but performing a delegate call.
     *
     * _Available since v3.4._
     */
    function functionDelegateCall(
        address target,
        bytes memory data,
        string memory errorMessage
    ) internal returns (bytes memory) {
        (bool success, bytes memory returndata) = target.delegatecall(data);
        return verifyCallResultFromTarget(target, success, returndata, errorMessage);
    }

    /**
     * @dev Tool to verify that a low level call to smart-contract was successful, and revert (either by bubbling
     * the revert reason or using the provided one) in case of unsuccessful call or if target was not a contract.
     *
     * _Available since v4.8._
     */
    function verifyCallResultFromTarget(
        address target,
        bool success,
        bytes memory returndata,
        string memory errorMessage
    ) internal view returns (bytes memory) {
        if (success) {
            if (returndata.length == 0) {
                // only check isContract if the call was successful and the return data is empty
                // otherwise we already know that it was a contract
                require(isContract(target), "Address: call to non-contract");
            }
            return returndata;
        } else {
            _revert(returndata, errorMessage);
        }
    }

    /**
     * @dev Tool to verify that a low level call was successful, and revert if it wasn't, either by bubbling the
     * revert reason or using the provided one.
     *
     * _Available since v4.3._
     */
    function verifyCallResult(
        bool success,
        bytes memory returndata,
        string memory errorMessage
    ) internal pure returns (bytes memory) {
        if (success) {
            return returndata;
        } else {
            _revert(returndata, errorMessage);
        }
    }

    function _revert(bytes memory returndata, string memory errorMessage) private pure {
        // Look for revert reason and bubble it up if present
        if (returndata.length > 0) {
            // The easiest way to bubble the revert reason is using memory via assembly
            /// @solidity memory-safe-assembly
            assembly {
                let returndata_size := mload(returndata)
                revert(add(32, returndata), returndata_size)
            }
        } else {
            revert(errorMessage);
        }
    }
}

abstract contract Context {
    function _msgSender() internal view virtual returns (address) {
        return msg.sender;
    }

    function _msgData() internal view virtual returns (bytes calldata) {
        return msg.data;
    }
}

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. Can only be called by the current owner.
     *
     * NOTE: Renouncing ownership will leave the contract without an owner,
     * thereby disabling 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);
    }
}

interface IERC20 {

    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 `recipient`.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transfer(address recipient, 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 `sender` to `recipient` 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 sender, address recipient, uint256 amount) external returns (bool);

    /**
     * @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);
}

interface IERC20Permit {
    /**
     * @dev Sets `value` as the allowance of `spender` over ``owner``'s tokens,
     * given ``owner``'s signed approval.
     *
     * IMPORTANT: The same issues {IERC20-approve} has related to transaction
     * ordering also apply here.
     *
     * Emits an {Approval} event.
     *
     * Requirements:
     *
     * - `spender` cannot be the zero address.
     * - `deadline` must be a timestamp in the future.
     * - `v`, `r` and `s` must be a valid `secp256k1` signature from `owner`
     * over the EIP712-formatted function arguments.
     * - the signature must use ``owner``'s current nonce (see {nonces}).
     *
     * For more information on the signature format, see the
     * https://eips.ethereum.org/EIPS/eip-2612#specification[relevant EIP
     * section].
     */
    function permit(
        address owner,
        address spender,
        uint256 value,
        uint256 deadline,
        uint8 v,
        bytes32 r,
        bytes32 s
    ) external;

    /**
     * @dev Returns the current nonce for `owner`. This value must be
     * included whenever a signature is generated for {permit}.
     *
     * Every successful call to {permit} increases ``owner``'s nonce by one. This
     * prevents a signature from being used multiple times.
     */
    function nonces(address owner) external view returns (uint256);

    /**
     * @dev Returns the domain separator used in the encoding of the signature for {permit}, as defined by {EIP712}.
     */
    // solhint-disable-next-line func-name-mixedcase
    function DOMAIN_SEPARATOR() external view returns (bytes32);
}

library SafeERC20 {
    using Address for address;

    /**
     * @dev Transfer `value` amount of `token` from the calling contract to `to`. If `token` returns no value,
     * non-reverting calls are assumed to be successful.
     */
    function safeTransfer(IERC20 token, address to, uint256 value) internal {
        _callOptionalReturn(token, abi.encodeWithSelector(token.transfer.selector, to, value));
    }

    /**
     * @dev Transfer `value` amount of `token` from `from` to `to`, spending the approval given by `from` to the
     * calling contract. If `token` returns no value, non-reverting calls are assumed to be successful.
     */
    function safeTransferFrom(IERC20 token, address from, address to, uint256 value) internal {
        _callOptionalReturn(token, abi.encodeWithSelector(token.transferFrom.selector, from, to, value));
    }

    /**
     * @dev Deprecated. This function has issues similar to the ones found in
     * {IERC20-approve}, and its usage is discouraged.
     *
     * Whenever possible, use {safeIncreaseAllowance} and
     * {safeDecreaseAllowance} instead.
     */
    function safeApprove(IERC20 token, address spender, uint256 value) internal {
        // safeApprove should only be called when setting an initial allowance,
        // or when resetting it to zero. To increase and decrease it, use
        // 'safeIncreaseAllowance' and 'safeDecreaseAllowance'
        require(
            (value == 0) || (token.allowance(address(this), spender) == 0),
            "SafeERC20: approve from non-zero to non-zero allowance"
        );
        _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, value));
    }

    /**
     * @dev Increase the calling contract's allowance toward `spender` by `value`. If `token` returns no value,
     * non-reverting calls are assumed to be successful.
     */
    function safeIncreaseAllowance(IERC20 token, address spender, uint256 value) internal {
        uint256 oldAllowance = token.allowance(address(this), spender);
        _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, oldAllowance + value));
    }

    /**
     * @dev Decrease the calling contract's allowance toward `spender` by `value`. If `token` returns no value,
     * non-reverting calls are assumed to be successful.
     */
    function safeDecreaseAllowance(IERC20 token, address spender, uint256 value) internal {
        unchecked {
            uint256 oldAllowance = token.allowance(address(this), spender);
            require(oldAllowance >= value, "SafeERC20: decreased allowance below zero");
            _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, oldAllowance - value));
        }
    }

    /**
     * @dev Set the calling contract's allowance toward `spender` to `value`. If `token` returns no value,
     * non-reverting calls are assumed to be successful. Compatible with tokens that require the approval to be set to
     * 0 before setting it to a non-zero value.
     */
    function forceApprove(IERC20 token, address spender, uint256 value) internal {
        bytes memory approvalCall = abi.encodeWithSelector(token.approve.selector, spender, value);

        if (!_callOptionalReturnBool(token, approvalCall)) {
            _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, 0));
            _callOptionalReturn(token, approvalCall);
        }
    }

    /**
     * @dev Use a ERC-2612 signature to set the `owner` approval toward `spender` on `token`.
     * Revert on invalid signature.
     */
    function safePermit(
        IERC20Permit token,
        address owner,
        address spender,
        uint256 value,
        uint256 deadline,
        uint8 v,
        bytes32 r,
        bytes32 s
    ) internal {
        uint256 nonceBefore = token.nonces(owner);
        token.permit(owner, spender, value, deadline, v, r, s);
        uint256 nonceAfter = token.nonces(owner);
        require(nonceAfter == nonceBefore + 1, "SafeERC20: permit did not succeed");
    }

    /**
     * @dev Imitates a Solidity high-level call (i.e. a regular function call to a contract), relaxing the requirement
     * on the return value: the return value is optional (but if data is returned, it must not be false).
     * @param token The token targeted by the call.
     * @param data The call data (encoded using abi.encode or one of its variants).
     */
    function _callOptionalReturn(IERC20 token, bytes memory data) private {
        // We need to perform a low level call here, to bypass Solidity's return data size checking mechanism, since
        // we're implementing it ourselves. We use {Address-functionCall} to perform this call, which verifies that
        // the target address contains contract code and also asserts for success in the low-level call.

        bytes memory returndata = address(token).functionCall(data, "SafeERC20: low-level call failed");
        require(returndata.length == 0 || abi.decode(returndata, (bool)), "SafeERC20: ERC20 operation did not succeed");
    }

    /**
     * @dev Imitates a Solidity high-level call (i.e. a regular function call to a contract), relaxing the requirement
     * on the return value: the return value is optional (but if data is returned, it must not be false).
     * @param token The token targeted by the call.
     * @param data The call data (encoded using abi.encode or one of its variants).
     *
     * This is a variant of {_callOptionalReturn} that silents catches all reverts and returns a bool instead.
     */
    function _callOptionalReturnBool(IERC20 token, bytes memory data) private returns (bool) {
        // We need to perform a low level call here, to bypass Solidity's return data size checking mechanism, since
        // we're implementing it ourselves. We cannot use {Address-functionCall} here since this should return false
        // and not revert is the subcall reverts.

        (bool success, bytes memory returndata) = address(token).call(data);
        return
            success && (returndata.length == 0 || abi.decode(returndata, (bool))) && Address.isContract(address(token));
    }
}

abstract contract ERC20Detailed is IERC20 {
    string private _name;
    string private _symbol;
    uint8 private _decimals;

    /**
     * @dev Sets the values for `name`, `symbol`, and `decimals`. All three of
     * these values are immutable: they can only be set once during
     * construction.
     */
    constructor (string memory __name, string memory __symbol, uint8 __decimals) {
        _name = __name;
        _symbol = __symbol;
        _decimals = __decimals;
    }

    /**
     * @dev Returns the name of the token.
     */
    function name() public view returns (string memory) {
        return _name;
    }

    /**
     * @dev Returns the symbol of the token, usually a shorter version of the
     * name.
     */
    function symbol() public view returns (string memory) {
        return _symbol;
    }

    /**
     * @dev Returns the number of decimals used to get its user representation.
     * For example, if `decimals` equals `2`, a balance of `505` tokens should
     * be displayed to a user as `5,05` (`505 / 10 ** 2`).
     *
     * Tokens usually opt for a value of 18, imitating the relationship between
     * Ether and Wei.
     *
     * NOTE: This information is only used for _display_ purposes: it in
     * no way affects any of the arithmetic of the contract, including
     * {IERC20-balanceOf} and {IERC20-transfer}.
     */
    function decimals() public view returns (uint8) {
        return _decimals;
    }
}

contract FanbasePayment is Ownable {

    using SafeERC20 for IERC20;

    address ZERO_ADDRESS = address(0);

    uint256 public BONUS_PLAN_VALUE = 0;
    uint256 public MONTHLY_PROFESSIONAL_PLAN_VALUE = 19;
    uint256 public ANNUAL_PROFESSIONAL_PLAN_VALUE = 99;

    uint256 public MONTHLY_ADVANCED_PLAN_VALUE = 39;
    uint256 public ANNUAL_ADVANCED_PLAN_VALUE = 249;

    uint256 public MONTHLY_ENTERPRISE_PLAN_VALUE = 59;
    uint256 public ANNUAL_ENTERPRISE_PLAN_VALUE = 499;

    uint256 public MONTHLY_PLAN_DEADLINE = 30 days;
    uint256 public ANNUAL_PLAN_DEADLINE = 365 days;

    enum Plan { Bonus, MonthlyProfessional, MonthlyAdvanced, MonthlyEnterprise, AnnualProfessional, AnnualAdvanced, AnnualEnterprise }

    address public collector;
    address[] private payableTokens;

    mapping(Plan => uint256) public planToValue;
    mapping(Plan => uint256) public planToDeadline;

    mapping(address => Plan) public userToPlan;
    mapping(address => address) public userToPayableToken;
    mapping(address => uint8) public payableTokenToDecimal;

    mapping(bytes32 => Plan) private hashTokenToPlan;
    mapping(bytes32 => string) private hashTokenToDomain;
    mapping(address => uint256) private userToLastCollectedTime;
    mapping(address => bytes32) private userToHashToken;
    mapping(bytes32 => address) private hashTokenToUser;

    constructor(address _collector) Ownable() {
        collector = _collector;

        planToValue[Plan.Bonus] = BONUS_PLAN_VALUE;
        planToValue[Plan.MonthlyProfessional] = MONTHLY_PROFESSIONAL_PLAN_VALUE;
        planToValue[Plan.MonthlyAdvanced] = MONTHLY_ADVANCED_PLAN_VALUE;
        planToValue[Plan.MonthlyEnterprise] = MONTHLY_ENTERPRISE_PLAN_VALUE;
        planToValue[Plan.AnnualProfessional] = ANNUAL_PROFESSIONAL_PLAN_VALUE;
        planToValue[Plan.AnnualAdvanced] = ANNUAL_ADVANCED_PLAN_VALUE;
        planToValue[Plan.AnnualEnterprise] = ANNUAL_ENTERPRISE_PLAN_VALUE;

        planToDeadline[Plan.Bonus] = ANNUAL_PLAN_DEADLINE;
        planToDeadline[Plan.MonthlyProfessional] = MONTHLY_PLAN_DEADLINE;
        planToDeadline[Plan.MonthlyAdvanced] = MONTHLY_PLAN_DEADLINE;
        planToDeadline[Plan.MonthlyEnterprise] = MONTHLY_PLAN_DEADLINE;
        planToDeadline[Plan.AnnualProfessional] = ANNUAL_PLAN_DEADLINE;
        planToDeadline[Plan.AnnualAdvanced] = ANNUAL_PLAN_DEADLINE;
        planToDeadline[Plan.AnnualEnterprise] = ANNUAL_PLAN_DEADLINE;
    }

    ///////////////////////
    /////User Function/////
    ///////////////////////
    function subscribe(Plan _plan, address _payableToken) external returns(bytes32) {
        require(payableTokenToDecimal[_payableToken] > 0, "unregistered token");

        userToPlan[msg.sender] = _plan;
        userToPayableToken[msg.sender] = _payableToken;

        uint256 planValue = planToValue[_plan];
        uint256 decimals = payableTokenToDecimal[_payableToken];
        uint256 amount = planValue * 10 ** decimals;

        if(planValue > 0) {
            IERC20 token = IERC20(_payableToken);
            token.safeTransferFrom(msg.sender, address(this), amount);
        }
        
        bytes32 hashToken = generateHashToken(msg.sender);
        userToHashToken[msg.sender] = hashToken;
        hashTokenToUser[hashToken] = msg.sender;
        hashTokenToPlan[hashToken] = _plan;

        userToLastCollectedTime[msg.sender] = block.timestamp;

        return hashToken;
    }
    
    function pay() external {
        require(userToHashToken[msg.sender] != 0x00, "unsubscribed user");

        address tokenAddress = userToPayableToken[msg.sender];

        Plan userPlan = userToPlan[msg.sender];

        uint256 planValue = planToValue[userPlan];
        uint256 decimals = payableTokenToDecimal[tokenAddress];
        uint256 amount = planValue * 10 ** decimals;

        if(planValue > 0) {
            IERC20 token = IERC20(tokenAddress);
            token.safeTransferFrom(msg.sender, address(this), amount);
        }

        userToLastCollectedTime[msg.sender] = block.timestamp;
    }

    function changePayableToken(address _tokenAddress) external {
        require(userToHashToken[msg.sender] != 0x00, "unsubscribed user");
        require(userToPayableToken[msg.sender] != _tokenAddress, "can't change to same token");

        userToPayableToken[msg.sender] = _tokenAddress;
    }

    function changePlan(Plan _plan) external {
        require(userToHashToken[msg.sender] != 0x00, "unsubscribed user");
        require(userToPlan[msg.sender] != _plan, "can't change to current plan");

        uint256 planValue = planToValue[_plan];
        address tokenAddress = userToPayableToken[msg.sender];
        uint256 decimals = payableTokenToDecimal[tokenAddress];
        uint256 amount = planValue * 10 ** decimals;

        if(planValue > 0) {
            IERC20 token = IERC20(tokenAddress);
            token.safeTransferFrom(msg.sender, address(this), amount);
        }

        userToPlan[msg.sender] = _plan;
        userToLastCollectedTime[msg.sender] = block.timestamp;
    }

    function registerDomain(string memory _domain) external {
        require(userToHashToken[msg.sender] != 0x00, "unsubscribed user");

        bytes32 hashToken = userToHashToken[msg.sender];

        require(bytes32(bytes(hashTokenToDomain[hashToken])) == 0x00, "domain already registered");

        hashTokenToDomain[hashToken] = _domain;
    }

    function changeDomain(string memory _domain) external {
        require(userToHashToken[msg.sender] != 0x00, "unsubscribed user");

        bytes32 hashToken = userToHashToken[msg.sender];

        require(bytes32(bytes(hashTokenToDomain[hashToken])) != 0x00, "domain is not registered");
        require(compareString(hashTokenToDomain[hashToken], _domain) == false, "can't change to same domain");

        hashTokenToDomain[hashToken] = _domain;
    }

    function verifyHashKey(bytes32 _hashToken) external view returns (bool) {
        require(hashTokenToUser[_hashToken] != ZERO_ADDRESS, "unregistered hash token");

        address user = hashTokenToUser[_hashToken];
        Plan userPlan = userToPlan[user];
        uint256 deadline = planToDeadline[userPlan];
        uint256 lastCollectedTime = userToLastCollectedTime[user];

        bool isSubscriptionValid;

        if(block.timestamp < lastCollectedTime + deadline) {
            isSubscriptionValid = true;
        }
        else {
            isSubscriptionValid = false;
        }

        return isSubscriptionValid;
    }

    function getUserHashToken(
        bytes32 _messageHash,
        bytes memory _signature,
        address _signer
    ) external view returns (bytes32) {
        require(isValidSignature(_messageHash, _signature, _signer), "verification failed");
        
        return userToHashToken[_signer];
    }

    function getHashTokenToPlan(bytes32 _hashToken) external view returns (Plan) {
        return hashTokenToPlan[_hashToken];
    }

    function getUserLastPayedTimestamp(address _user) external view returns(uint256) {
        return userToLastCollectedTime[_user];
    }

    function gethashTokenToDomain(bytes32 _hashToken) external view returns(string memory) {
        return hashTokenToDomain[_hashToken];
    }

    function getPayableTokens() external view returns(address[] memory) {
        return payableTokens;
    }

    function getUserToDomain(address _address) external view returns (string memory) {
        bytes32 hashToken = userToHashToken[_address];

        return hashTokenToDomain[hashToken];
    }

    /////////////////////////
    /////Owner Function//////
    /////////////////////////
    function collect(address _tokenAddress) external onlyOwner {
        uint256 tokenBalance = IERC20(_tokenAddress).balanceOf(address(this));
        IERC20(_tokenAddress).transfer(collector, tokenBalance);
    }

    function addPayableToken(address _address) external onlyOwner {
        require(payableTokenToDecimal[_address] == 0, "already added");

        uint8 decimals = ERC20Detailed(_address).decimals();
        payableTokenToDecimal[_address] = decimals;

        payableTokens.push(_address);
    }

    function removePayableToken(address _address) external onlyOwner {
        require(payableTokenToDecimal[_address] > 0, "unregisgered token");

        payableTokenToDecimal[_address] = 0;

        for (uint i = 0; i < payableTokens.length; i++) {
            if (payableTokens[i] == _address) {
                payableTokens[i] = payableTokens[payableTokens.length - 1];
                payableTokens.pop();
                break;
            }
        }
    }

    function setCollector(address _address) external onlyOwner {
        require(collector != _address, "can't change to same address");
        collector = _address;
    }

    ///////////////////////////
    /////Internal Function/////
    ///////////////////////////
    function generateHashToken(
        address _user
    ) internal view returns (bytes32) {
        uint256 randomNum = uint256(keccak256(abi.encodePacked(block.timestamp, _user, block.timestamp)));
        bytes32 hashToken = keccak256(abi.encodePacked(randomNum));

        return hashToken;
    }

    function isValidSignature(
        bytes32 _messageHash,
        bytes memory _signature,
        address _signer
    ) internal pure returns (bool) {
        require(_signature.length == 65, "Invalid signature length");

        bytes32 r;
        bytes32 s;
        uint8 v;

        assembly {
            r := mload(add(_signature, 0x20))
            s := mload(add(_signature, 0x40))
            v := byte(0, mload(add(_signature, 0x60)))
        }

        bytes memory prefix = "\x19Ethereum Signed Message:\n32";
        bytes32 prefixedHash = keccak256(abi.encodePacked(prefix, _messageHash));

        return ecrecover(prefixedHash, v, r, s) == _signer;
    }

    function compareString(string memory _str1, string memory _str2) internal pure returns (bool) {
        return keccak256(abi.encodePacked(_str1)) == keccak256(abi.encodePacked(_str2));
    }
}