// SPDX-License-Identifier: MIT

pragma solidity ^0.8.17;

// ERC20 token implementation

/// @notice Modern and gas efficient ERC20 + EIP-2612 implementation.
/// @author Solmate (https://github.com/transmissions11/solmate/blob/main/src/tokens/ERC20.sol)
/// @author Modified from Uniswap (https://github.com/Uniswap/uniswap-v2-core/blob/master/contracts/UniswapV2ERC20.sol)
/// @dev Do not manually set balances without updating totalSupply, as the sum of all user balances must not exceed it.
abstract contract ERC20 {
    /*//////////////////////////////////////////////////////////////
                                 EVENTS
    //////////////////////////////////////////////////////////////*/

    event Transfer(address indexed from, address indexed to, uint256 amount);

    event Approval(address indexed owner, address indexed spender, uint256 amount);

    /*//////////////////////////////////////////////////////////////
                            METADATA STORAGE
    //////////////////////////////////////////////////////////////*/

    string public name;

    string public symbol;

    uint8 public immutable decimals;

    /*//////////////////////////////////////////////////////////////
                              ERC20 STORAGE
    //////////////////////////////////////////////////////////////*/

    uint256 public totalSupply;

    mapping(address => uint256) public balanceOf;

    mapping(address => mapping(address => uint256)) public allowance;

    /*//////////////////////////////////////////////////////////////
                            EIP-2612 STORAGE
    //////////////////////////////////////////////////////////////*/

    uint256 internal immutable INITIAL_CHAIN_ID;

    bytes32 internal immutable INITIAL_DOMAIN_SEPARATOR;

    mapping(address => uint256) public nonces;

    /*//////////////////////////////////////////////////////////////
                               CONSTRUCTOR
    //////////////////////////////////////////////////////////////*/

    constructor(
        string memory _name,
        string memory _symbol,
        uint8 _decimals
    ) {
        name = _name;
        symbol = _symbol;
        decimals = _decimals;

        INITIAL_CHAIN_ID = block.chainid;
        INITIAL_DOMAIN_SEPARATOR = computeDomainSeparator();
    }

    /*//////////////////////////////////////////////////////////////
                               ERC20 LOGIC
    //////////////////////////////////////////////////////////////*/

    function approve(address spender, uint256 amount) public virtual returns (bool) {
        allowance[msg.sender][spender] = amount;

        emit Approval(msg.sender, spender, amount);

        return true;
    }

    function transfer(address to, uint256 amount) public virtual returns (bool) {
        balanceOf[msg.sender] -= amount;

        // Cannot overflow because the sum of all user
        // balances can't exceed the max uint256 value.
        unchecked {
            balanceOf[to] += amount;
        }

        emit Transfer(msg.sender, to, amount);

        return true;
    }

    function transferFrom(
        address from,
        address to,
        uint256 amount
    ) public virtual returns (bool) {
        uint256 allowed = allowance[from][msg.sender]; // Saves gas for limited approvals.

        if (allowed != type(uint256).max) allowance[from][msg.sender] = allowed - amount;

        balanceOf[from] -= amount;

        // Cannot overflow because the sum of all user
        // balances can't exceed the max uint256 value.
        unchecked {
            balanceOf[to] += amount;
        }

        emit Transfer(from, to, amount);

        return true;
    }

    /*//////////////////////////////////////////////////////////////
                             EIP-2612 LOGIC
    //////////////////////////////////////////////////////////////*/

    function permit(
        address owner,
        address spender,
        uint256 value,
        uint256 deadline,
        uint8 v,
        bytes32 r,
        bytes32 s
    ) public virtual {
        require(deadline >= block.timestamp, "PERMIT_DEADLINE_EXPIRED");

        // Unchecked because the only math done is incrementing
        // the owner's nonce which cannot realistically overflow.
        unchecked {
            address recoveredAddress = ecrecover(
                keccak256(
                    abi.encodePacked(
                        "\x19\x01",
                        DOMAIN_SEPARATOR(),
                        keccak256(
                            abi.encode(
                                keccak256(
                                    "Permit(address owner,address spender,uint256 value,uint256 nonce,uint256 deadline)"
                                ),
                                owner,
                                spender,
                                value,
                                nonces[owner]++,
                                deadline
                            )
                        )
                    )
                ),
                v,
                r,
                s
            );

            require(recoveredAddress != address(0) && recoveredAddress == owner, "INVALID_SIGNER");

            allowance[recoveredAddress][spender] = value;
        }

        emit Approval(owner, spender, value);
    }

    function DOMAIN_SEPARATOR() public view virtual returns (bytes32) {
        return block.chainid == INITIAL_CHAIN_ID ? INITIAL_DOMAIN_SEPARATOR : computeDomainSeparator();
    }

    function computeDomainSeparator() internal view virtual returns (bytes32) {
        return
            keccak256(
                abi.encode(
                    keccak256("EIP712Domain(string name,string version,uint256 chainId,address verifyingContract)"),
                    keccak256(bytes(name)),
                    keccak256("1"),
                    block.chainid,
                    address(this)
                )
            );
    }

    /*//////////////////////////////////////////////////////////////
                        INTERNAL MINT/BURN LOGIC
    //////////////////////////////////////////////////////////////*/

    function _mint(address to, uint256 amount) internal virtual {
        totalSupply += amount;

        // Cannot overflow because the sum of all user
        // balances can't exceed the max uint256 value.
        unchecked {
            balanceOf[to] += amount;
        }

        emit Transfer(address(0), to, amount);
    }

    function _burn(address from, uint256 amount) internal virtual {
        balanceOf[from] -= amount;

        // Cannot underflow because a user's balance
        // will never be larger than the total supply.
        unchecked {
            totalSupply -= amount;
        }

        emit Transfer(from, address(0), amount);
    }
}

// OpenZeppelin Contracts (last updated v4.7.0) (access/Ownable.sol)

// OpenZeppelin Contracts v4.4.1 (utils/Context.sol)

/**
 * @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;
    }
}

/**
 * @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);
    }
}

// Interface for Molecule Protocol Smart Contract
interface IMoleculeController {
    // Human readable name of the controller
    // string public _controllerName;
    // // selected logic combinations
    // uint32[] private _selected;

    // Gated: gated by logic
    // Blocked: always return `false`
    // Bypassed: always return `true`
    enum Status {
        Gated,
        Blocked,
        Bypassed
    }

    // // list id => atomic logic contract address
    // mapping(uint32 => address) private _logicContract;
    // // list id => allow- (true) or block- (false) list
    // mapping(uint32 => bool) private _isAllowList;
    // // list id => list name
    // mapping(uint32 => string) private _name;
    // // list id => logic modifier: add negation if true or false for as-is
    // mapping(uint32 => bool) private _reverseLogic; // NOT used, always false

    // event emitted when the controller name is changed
    event ControllerNameUpdated(string name);
    // event emitted when a new list is added
    event LogicAdded(
        uint32 indexed id,
        address indexed logicContract,
        bool isAllowList,
        string name,
        bool reverseLogic
    );
    // event emitted when a list is removed
    event LogicRemoved(uint32 indexed id);
    // event emitted when a new logic combination is selected
    event Selected(uint32[] ids);
    // event emitted when status changed
    event StatusChanged(Status status);

    // Use default logic combination
    function check(address toCheck) external view returns (bool);

    // Use custom logic combination, passed in as an array of list ids
    function check(
        uint32[] memory ids,
        address toCheck
    ) external view returns (bool);

    // Get the current selected logic combination
    function selected() external view returns (uint32[] memory);

    // Get the current status of the contract
    function status() external view returns (Status);

    // Owner only functions
    // Control the status of the contract
    function setStatus(Status status) external;

    // Preselect logic combinations
    function select(uint32[] memory ids) external;

    // Add a new logic
    function addLogic(
        uint32 id,
        address logicContract,
        string memory name,
        bool reverseLogic
    ) external;

    // Remove a logic
    function removeLogic(uint32 id) external;

    // Add new logics in batch
    function addLogicBatch(
        uint32[] memory ids,
        address[] memory logicContracts,
        string[] memory names,
        bool[] memory reverseLogics
    ) external;

    // Remove logics in batch
    function removeLogicBatch(uint32[] memory ids) external;
}

// custom errors
error AccountNotAllowedToMint(address minter);
error AccountNotAllowedToBurn(address burner);
error SenderNotAllowedToTransfer(address sender);
error RecipientNotAllowedToReceive(address receipient);
error OwnerNotAllowedToApprove(address owner);

// Molecule ERC20 token
contract ERC20m is ERC20, Ownable {
    enum MoleculeType {
        Approve,
        Burn,
        Mint,
        Transfer
    }
    // Molecule address
    address public _moleculeApprove;
    address public _moleculeBurn;
    address public _moleculeMint;
    address public _moleculeTransfer;

    event MoleculeUpdated(address molecule, MoleculeType mtype);

    constructor(
        string memory _tokenName,
        string memory _tokenSymbol,
        uint8 tokenDecimals // 18/9
    ) ERC20(_tokenName, _tokenSymbol, tokenDecimals) {}

    function mint(address account, uint256 amount) external {
        if (_moleculeMint != address(0)) {
            if (!IMoleculeController(_moleculeMint).check(account)) {
                revert AccountNotAllowedToMint(account);
            }
        }
        _mint(account, amount);
    }

    function burn(address account, uint256 amount) external {
        if (_moleculeBurn != address(0)) {
            if (!IMoleculeController(_moleculeBurn).check(account)) {
                revert AccountNotAllowedToBurn(account);
            }
        }
        _burn(account, amount);
    }

    // Transfer function: solmate integration does not use an internal function like OZ
    function transfer(
        address sender,
        address recipient,
        uint256 amount
    ) public virtual {
        if (_moleculeTransfer != address(0)) {
            if (!IMoleculeController(_moleculeTransfer).check(sender)) {
                revert SenderNotAllowedToTransfer(sender);
            }
            if (!IMoleculeController(_moleculeTransfer).check(recipient)) {
                revert RecipientNotAllowedToReceive(recipient);
            }
        }
        super.transfer(recipient, amount);
    }

    // Approve function
    function approve(
        address tokenOwner,
        address spender,
        uint256 amount
    ) public virtual {
        if (_moleculeApprove != address(0)) {
            if (!IMoleculeController(_moleculeApprove).check(tokenOwner)) {
                revert OwnerNotAllowedToApprove(tokenOwner);
            }
            if (!IMoleculeController(_moleculeApprove).check(spender)) {
                revert RecipientNotAllowedToReceive(spender);
            }
        }
        super.approve(spender, amount);
    }

    // Owner only functions
    // Molecule ERC20 token
    function updateMolecule(
        address molecule,
        MoleculeType mtype
    ) external onlyOwner {
        // allows 0x0 address to be set to remove molecule access control
        if (mtype == MoleculeType.Approve) {
            _moleculeApprove = molecule;
        } else if (mtype == MoleculeType.Burn) {
            _moleculeBurn = molecule;
        } else if (mtype == MoleculeType.Mint) {
            _moleculeMint = molecule;
        } else if (mtype == MoleculeType.Transfer) {
            _moleculeTransfer = molecule;
        }
        emit MoleculeUpdated(molecule, mtype);
    }
}