// SPDX-License-Identifier: MIT
// 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;
    }
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.8.0) (token/ERC20/ERC20.sol)

pragma solidity ^0.8.0;

import "./IERC20.sol";
import "./extensions/IERC20Metadata.sol";
import "../../utils/Context.sol";

/**
 * @dev Implementation of the {IERC20} interface.
 *
 * This implementation is agnostic to the way tokens are created. This means
 * that a supply mechanism has to be added in a derived contract using {_mint}.
 * For a generic mechanism see {ERC20PresetMinterPauser}.
 *
 * TIP: For a detailed writeup see our guide
 * https://forum.openzeppelin.com/t/how-to-implement-erc20-supply-mechanisms/226[How
 * to implement supply mechanisms].
 *
 * We have followed general OpenZeppelin Contracts guidelines: functions revert
 * instead returning `false` on failure. This behavior is nonetheless
 * conventional and does not conflict with the expectations of ERC20
 * applications.
 *
 * Additionally, an {Approval} event is emitted on calls to {transferFrom}.
 * This allows applications to reconstruct the allowance for all accounts just
 * by listening to said events. Other implementations of the EIP may not emit
 * these events, as it isn't required by the specification.
 *
 * Finally, the non-standard {decreaseAllowance} and {increaseAllowance}
 * functions have been added to mitigate the well-known issues around setting
 * allowances. See {IERC20-approve}.
 */
contract ERC20 is Context, IERC20, IERC20Metadata {
    mapping(address => uint256) private _balances;

    mapping(address => mapping(address => uint256)) private _allowances;

    uint256 private _totalSupply;

    string private _name;
    string private _symbol;

    /**
     * @dev Sets the values for {name} and {symbol}.
     *
     * The default value of {decimals} is 18. To select a different value for
     * {decimals} you should overload it.
     *
     * All two of these values are immutable: they can only be set once during
     * construction.
     */
    constructor(string memory name_, string memory symbol_) {
        _name = name_;
        _symbol = symbol_;
    }

    /**
     * @dev Returns the name of the token.
     */
    function name() public view virtual override returns (string memory) {
        return _name;
    }

    /**
     * @dev Returns the symbol of the token, usually a shorter version of the
     * name.
     */
    function symbol() public view virtual override 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. This is the value {ERC20} uses, unless this function is
     * overridden;
     *
     * 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 virtual override returns (uint8) {
        return 18;
    }

    /**
     * @dev See {IERC20-totalSupply}.
     */
    function totalSupply() public view virtual override returns (uint256) {
        return _totalSupply;
    }

    /**
     * @dev See {IERC20-balanceOf}.
     */
    function balanceOf(address account) public view virtual override returns (uint256) {
        return _balances[account];
    }

    /**
     * @dev See {IERC20-transfer}.
     *
     * Requirements:
     *
     * - `to` cannot be the zero address.
     * - the caller must have a balance of at least `amount`.
     */
    function transfer(address to, uint256 amount) public virtual override returns (bool) {
        address owner = _msgSender();
        _transfer(owner, to, amount);
        return true;
    }

    /**
     * @dev See {IERC20-allowance}.
     */
    function allowance(address owner, address spender) public view virtual override returns (uint256) {
        return _allowances[owner][spender];
    }

    /**
     * @dev See {IERC20-approve}.
     *
     * NOTE: If `amount` is the maximum `uint256`, the allowance is not updated on
     * `transferFrom`. This is semantically equivalent to an infinite approval.
     *
     * Requirements:
     *
     * - `spender` cannot be the zero address.
     */
    function approve(address spender, uint256 amount) public virtual override returns (bool) {
        address owner = _msgSender();
        _approve(owner, spender, amount);
        return true;
    }

    /**
     * @dev See {IERC20-transferFrom}.
     *
     * Emits an {Approval} event indicating the updated allowance. This is not
     * required by the EIP. See the note at the beginning of {ERC20}.
     *
     * NOTE: Does not update the allowance if the current allowance
     * is the maximum `uint256`.
     *
     * Requirements:
     *
     * - `from` and `to` cannot be the zero address.
     * - `from` must have a balance of at least `amount`.
     * - the caller must have allowance for ``from``'s tokens of at least
     * `amount`.
     */
    function transferFrom(
        address from,
        address to,
        uint256 amount
    ) public virtual override returns (bool) {
        address spender = _msgSender();
        _spendAllowance(from, spender, amount);
        _transfer(from, to, amount);
        return true;
    }

    /**
     * @dev Atomically increases the allowance granted to `spender` by the caller.
     *
     * This is an alternative to {approve} that can be used as a mitigation for
     * problems described in {IERC20-approve}.
     *
     * Emits an {Approval} event indicating the updated allowance.
     *
     * Requirements:
     *
     * - `spender` cannot be the zero address.
     */
    function increaseAllowance(address spender, uint256 addedValue) public virtual returns (bool) {
        address owner = _msgSender();
        _approve(owner, spender, allowance(owner, spender) + addedValue);
        return true;
    }

    /**
     * @dev Atomically decreases the allowance granted to `spender` by the caller.
     *
     * This is an alternative to {approve} that can be used as a mitigation for
     * problems described in {IERC20-approve}.
     *
     * Emits an {Approval} event indicating the updated allowance.
     *
     * Requirements:
     *
     * - `spender` cannot be the zero address.
     * - `spender` must have allowance for the caller of at least
     * `subtractedValue`.
     */
    function decreaseAllowance(address spender, uint256 subtractedValue) public virtual returns (bool) {
        address owner = _msgSender();
        uint256 currentAllowance = allowance(owner, spender);
        require(currentAllowance >= subtractedValue, "ERC20: decreased allowance below zero");
        unchecked {
            _approve(owner, spender, currentAllowance - subtractedValue);
        }

        return true;
    }

    /**
     * @dev Moves `amount` of tokens from `from` to `to`.
     *
     * This internal function is equivalent to {transfer}, and can be used to
     * e.g. implement automatic token fees, slashing mechanisms, etc.
     *
     * Emits a {Transfer} event.
     *
     * Requirements:
     *
     * - `from` cannot be the zero address.
     * - `to` cannot be the zero address.
     * - `from` must have a balance of at least `amount`.
     */
    function _transfer(
        address from,
        address to,
        uint256 amount
    ) internal virtual {
        require(from != address(0), "ERC20: transfer from the zero address");
        require(to != address(0), "ERC20: transfer to the zero address");

        _beforeTokenTransfer(from, to, amount);

        uint256 fromBalance = _balances[from];
        require(fromBalance >= amount, "ERC20: transfer amount exceeds balance");
        unchecked {
            _balances[from] = fromBalance - amount;
            // Overflow not possible: the sum of all balances is capped by totalSupply, and the sum is preserved by
            // decrementing then incrementing.
            _balances[to] += amount;
        }

        emit Transfer(from, to, amount);

        _afterTokenTransfer(from, to, amount);
    }

    /** @dev Creates `amount` tokens and assigns them to `account`, increasing
     * the total supply.
     *
     * Emits a {Transfer} event with `from` set to the zero address.
     *
     * Requirements:
     *
     * - `account` cannot be the zero address.
     */
    function _mint(address account, uint256 amount) internal virtual {
        require(account != address(0), "ERC20: mint to the zero address");

        _beforeTokenTransfer(address(0), account, amount);

        _totalSupply += amount;
        unchecked {
            // Overflow not possible: balance + amount is at most totalSupply + amount, which is checked above.
            _balances[account] += amount;
        }
        emit Transfer(address(0), account, amount);

        _afterTokenTransfer(address(0), account, amount);
    }

    /**
     * @dev Destroys `amount` tokens from `account`, reducing the
     * total supply.
     *
     * Emits a {Transfer} event with `to` set to the zero address.
     *
     * Requirements:
     *
     * - `account` cannot be the zero address.
     * - `account` must have at least `amount` tokens.
     */
    function _burn(address account, uint256 amount) internal virtual {
        require(account != address(0), "ERC20: burn from the zero address");

        _beforeTokenTransfer(account, address(0), amount);

        uint256 accountBalance = _balances[account];
        require(accountBalance >= amount, "ERC20: burn amount exceeds balance");
        unchecked {
            _balances[account] = accountBalance - amount;
            // Overflow not possible: amount <= accountBalance <= totalSupply.
            _totalSupply -= amount;
        }

        emit Transfer(account, address(0), amount);

        _afterTokenTransfer(account, address(0), amount);
    }

    /**
     * @dev Sets `amount` as the allowance of `spender` over the `owner` s tokens.
     *
     * This internal function is equivalent to `approve`, and can be used to
     * e.g. set automatic allowances for certain subsystems, etc.
     *
     * Emits an {Approval} event.
     *
     * Requirements:
     *
     * - `owner` cannot be the zero address.
     * - `spender` cannot be the zero address.
     */
    function _approve(
        address owner,
        address spender,
        uint256 amount
    ) internal virtual {
        require(owner != address(0), "ERC20: approve from the zero address");
        require(spender != address(0), "ERC20: approve to the zero address");

        _allowances[owner][spender] = amount;
        emit Approval(owner, spender, amount);
    }

    /**
     * @dev Updates `owner` s allowance for `spender` based on spent `amount`.
     *
     * Does not update the allowance amount in case of infinite allowance.
     * Revert if not enough allowance is available.
     *
     * Might emit an {Approval} event.
     */
    function _spendAllowance(
        address owner,
        address spender,
        uint256 amount
    ) internal virtual {
        uint256 currentAllowance = allowance(owner, spender);
        if (currentAllowance != type(uint256).max) {
            require(currentAllowance >= amount, "ERC20: insufficient allowance");
            unchecked {
                _approve(owner, spender, currentAllowance - amount);
            }
        }
    }

    /**
     * @dev Hook that is called before any transfer of tokens. This includes
     * minting and burning.
     *
     * Calling conditions:
     *
     * - when `from` and `to` are both non-zero, `amount` of ``from``'s tokens
     * will be transferred to `to`.
     * - when `from` is zero, `amount` tokens will be minted for `to`.
     * - when `to` is zero, `amount` of ``from``'s tokens will be burned.
     * - `from` and `to` are never both zero.
     *
     * To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
     */
    function _beforeTokenTransfer(
        address from,
        address to,
        uint256 amount
    ) internal virtual {}

    /**
     * @dev Hook that is called after any transfer of tokens. This includes
     * minting and burning.
     *
     * Calling conditions:
     *
     * - when `from` and `to` are both non-zero, `amount` of ``from``'s tokens
     * has been transferred to `to`.
     * - when `from` is zero, `amount` tokens have been minted for `to`.
     * - when `to` is zero, `amount` of ``from``'s tokens have been burned.
     * - `from` and `to` are never both zero.
     *
     * To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
     */
    function _afterTokenTransfer(
        address from,
        address to,
        uint256 amount
    ) internal virtual {}
}

// SPDX-License-Identifier: MIT
// 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);
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (token/ERC20/extensions/IERC20Metadata.sol)

pragma solidity ^0.8.0;

import "../IERC20.sol";

/**
 * @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);
}

// SPDX-License-Identifier: AGPL-3.0-only
pragma solidity 0.8.15;

//     ███████    █████       █████ █████ ██████   ██████ ███████████  █████  █████  █████████
//   ███░░░░░███ ░░███       ░░███ ░░███ ░░██████ ██████ ░░███░░░░░███░░███  ░░███  ███░░░░░███
//  ███     ░░███ ░███        ░░███ ███   ░███░█████░███  ░███    ░███ ░███   ░███ ░███    ░░░
// ░███      ░███ ░███         ░░█████    ░███░░███ ░███  ░██████████  ░███   ░███ ░░█████████
// ░███      ░███ ░███          ░░███     ░███ ░░░  ░███  ░███░░░░░░   ░███   ░███  ░░░░░░░░███
// ░░███     ███  ░███      █    ░███     ░███      ░███  ░███         ░███   ░███  ███    ░███
//  ░░░███████░   ███████████    █████    █████     █████ █████        ░░████████  ░░█████████
//    ░░░░░░░    ░░░░░░░░░░░    ░░░░░    ░░░░░     ░░░░░ ░░░░░          ░░░░░░░░    ░░░░░░░░░

//============================================================================================//
//                                        GLOBAL TYPES                                        //
//============================================================================================//

/// @notice Actions to trigger state changes in the kernel. Passed by the executor
enum Actions {
    InstallModule,
    UpgradeModule,
    ActivatePolicy,
    DeactivatePolicy,
    ChangeExecutor,
    MigrateKernel
}

/// @notice Used by executor to select an action and a target contract for a kernel action
struct Instruction {
    Actions action;
    address target;
}

/// @notice Used to define which module functions a policy needs access to
struct Permissions {
    Keycode keycode;
    bytes4 funcSelector;
}

type Keycode is bytes5;

//============================================================================================//
//                                       UTIL FUNCTIONS                                       //
//============================================================================================//

error TargetNotAContract(address target_);
error InvalidKeycode(Keycode keycode_);

// solhint-disable-next-line func-visibility
function toKeycode(bytes5 keycode_) pure returns (Keycode) {
    return Keycode.wrap(keycode_);
}

// solhint-disable-next-line func-visibility
function fromKeycode(Keycode keycode_) pure returns (bytes5) {
    return Keycode.unwrap(keycode_);
}

// solhint-disable-next-line func-visibility
function ensureContract(address target_) view {
    if (target_.code.length == 0) revert TargetNotAContract(target_);
}

// solhint-disable-next-line func-visibility
function ensureValidKeycode(Keycode keycode_) pure {
    bytes5 unwrapped = Keycode.unwrap(keycode_);
    for (uint256 i = 0; i < 5; ) {
        bytes1 char = unwrapped[i];
        if (char < 0x41 || char > 0x5A) revert InvalidKeycode(keycode_); // A-Z only
        unchecked {
            i++;
        }
    }
}

//============================================================================================//
//                                        COMPONENTS                                          //
//============================================================================================//

/// @notice Generic adapter interface for kernel access in modules and policies.
abstract contract KernelAdapter {
    error KernelAdapter_OnlyKernel(address caller_);

    Kernel public kernel;

    constructor(Kernel kernel_) {
        kernel = kernel_;
    }

    /// @notice Modifier to restrict functions to be called only by kernel.
    modifier onlyKernel() {
        if (msg.sender != address(kernel))
            revert KernelAdapter_OnlyKernel(msg.sender);
        _;
    }

    /// @notice Function used by kernel when migrating to a new kernel.
    function changeKernel(Kernel newKernel_) external onlyKernel {
        kernel = newKernel_;
    }
}

/// @notice Base level extension of the kernel. Modules act as independent state components to be
///         interacted with and mutated through policies.
/// @dev    Modules are installed and uninstalled via the executor.
abstract contract Module is KernelAdapter {
    error Module_PolicyNotPermitted(address policy_);

    constructor(Kernel kernel_) KernelAdapter(kernel_) {}

    /// @notice Modifier to restrict which policies have access to module functions.
    modifier permissioned() {
        if (!kernel.modulePermissions(KEYCODE(), Policy(msg.sender), msg.sig))
            revert Module_PolicyNotPermitted(msg.sender);
        _;
    }

    /// @notice 5 byte identifier for a module.
    function KEYCODE() public pure virtual returns (Keycode) {}

    /// @notice Returns which semantic version of a module is being implemented.
    /// @return major - Major version upgrade indicates breaking change to the interface.
    /// @return minor - Minor version change retains backward-compatible interface.
    function VERSION()
        external
        pure
        virtual
        returns (uint8 major, uint8 minor)
    {}

    /// @notice Initialization function for the module
    /// @dev    This function is called when the module is installed or upgraded by the kernel.
    /// @dev    MUST BE GATED BY onlyKernel. Used to encompass any initialization or upgrade logic.
    function INIT() external virtual onlyKernel {}
}

/// @notice Policies are application logic and external interface for the kernel and installed modules.
/// @dev    Policies are activated and deactivated in the kernel by the executor.
/// @dev    Module dependencies and function permissions must be defined in appropriate functions.
abstract contract Policy is KernelAdapter {
    error Policy_ModuleDoesNotExist(Keycode keycode_);

    constructor(Kernel kernel_) KernelAdapter(kernel_) {}

    /// @notice Easily accessible indicator for if a policy is activated or not.
    function isActive() external view returns (bool) {
        return kernel.isPolicyActive(this);
    }

    /// @notice Function to grab module address from a given keycode.
    function getModuleAddress(
        Keycode keycode_
    ) internal view returns (address) {
        address moduleForKeycode = address(
            kernel.getModuleForKeycode(keycode_)
        );
        if (moduleForKeycode == address(0))
            revert Policy_ModuleDoesNotExist(keycode_);
        return moduleForKeycode;
    }

    /// @notice Define module dependencies for this policy.
    /// @return dependencies - Keycode array of module dependencies.
    function configureDependencies()
        external
        virtual
        returns (Keycode[] memory dependencies)
    {}

    /// @notice Function called by kernel to set module function permissions.
    /// @return requests - Array of keycodes and function selectors for requested permissions.
    function requestPermissions()
        external
        view
        virtual
        returns (Permissions[] memory requests)
    {}
}

/// @notice Main contract that acts as a central component registry for the protocol.
/// @dev    The kernel manages modules and policies. The kernel is mutated via predefined Actions,
/// @dev    which are input from any address assigned as the executor. The executor can be changed as needed.
contract Kernel {
    // =========  EVENTS ========= //

    event PermissionsUpdated(
        Keycode indexed keycode_,
        Policy indexed policy_,
        bytes4 funcSelector_,
        bool granted_
    );
    event ActionExecuted(Actions indexed action_, address indexed target_);

    // =========  ERRORS ========= //

    error Kernel_OnlyExecutor(address caller_);
    error Kernel_ModuleAlreadyInstalled(Keycode module_);
    error Kernel_InvalidModuleUpgrade(Keycode module_);
    error Kernel_PolicyAlreadyActivated(address policy_);
    error Kernel_PolicyNotActivated(address policy_);

    // =========  PRIVILEGED ADDRESSES ========= //

    /// @notice Address that is able to initiate Actions in the kernel. Can be assigned to a multisig or governance contract.
    address public executor;

    // =========  MODULE MANAGEMENT ========= //

    /// @notice Array of all modules currently installed.
    Keycode[] public allKeycodes;

    /// @notice Mapping of module address to keycode.
    mapping(Keycode => Module) public getModuleForKeycode;

    /// @notice Mapping of keycode to module address.
    mapping(Module => Keycode) public getKeycodeForModule;

    /// @notice Mapping of a keycode to all of its policy dependents. Used to efficiently reconfigure policy dependencies.
    mapping(Keycode => Policy[]) public moduleDependents;

    /// @notice Helper for module dependent arrays. Prevents the need to loop through array.
    mapping(Keycode => mapping(Policy => uint256)) public getDependentIndex;

    /// @notice Module <> Policy Permissions.
    /// @dev    Keycode -> Policy -> Function Selector -> bool for permission
    mapping(Keycode => mapping(Policy => mapping(bytes4 => bool)))
        public modulePermissions;

    // =========  POLICY MANAGEMENT ========= //

    /// @notice List of all active policies
    Policy[] public activePolicies;

    /// @notice Helper to get active policy quickly. Prevents need to loop through array.
    mapping(Policy => uint256) public getPolicyIndex;

    //============================================================================================//
    //                                       CORE FUNCTIONS                                       //
    //============================================================================================//

    constructor() {
        executor = msg.sender;
    }

    /// @notice Modifier to check if caller is the executor.
    modifier onlyExecutor() {
        if (msg.sender != executor) revert Kernel_OnlyExecutor(msg.sender);
        _;
    }

    function isPolicyActive(Policy policy_) public view returns (bool) {
        return
            activePolicies.length > 0 &&
            activePolicies[getPolicyIndex[policy_]] == policy_;
    }

    /// @notice Main kernel function. Initiates state changes to kernel depending on Action passed in.
    function executeAction(
        Actions action_,
        address target_
    ) external onlyExecutor {
        if (action_ == Actions.InstallModule) {
            ensureContract(target_);
            ensureValidKeycode(Module(target_).KEYCODE());
            _installModule(Module(target_));
        } else if (action_ == Actions.UpgradeModule) {
            ensureContract(target_);
            ensureValidKeycode(Module(target_).KEYCODE());
            _upgradeModule(Module(target_));
        } else if (action_ == Actions.ActivatePolicy) {
            ensureContract(target_);
            _activatePolicy(Policy(target_));
        } else if (action_ == Actions.DeactivatePolicy) {
            ensureContract(target_);
            _deactivatePolicy(Policy(target_));
        } else if (action_ == Actions.ChangeExecutor) {
            executor = target_;
        } else if (action_ == Actions.MigrateKernel) {
            ensureContract(target_);
            _migrateKernel(Kernel(target_));
        }

        emit ActionExecuted(action_, target_);
    }

    function _installModule(Module newModule_) internal {
        Keycode keycode = newModule_.KEYCODE();

        if (address(getModuleForKeycode[keycode]) != address(0))
            revert Kernel_ModuleAlreadyInstalled(keycode);

        getModuleForKeycode[keycode] = newModule_;
        getKeycodeForModule[newModule_] = keycode;
        allKeycodes.push(keycode);

        newModule_.INIT();
    }

    function _upgradeModule(Module newModule_) internal {
        Keycode keycode = newModule_.KEYCODE();
        Module oldModule = getModuleForKeycode[keycode];

        if (address(oldModule) == address(0) || oldModule == newModule_)
            revert Kernel_InvalidModuleUpgrade(keycode);

        getKeycodeForModule[oldModule] = Keycode.wrap(bytes5(0));
        getKeycodeForModule[newModule_] = keycode;
        getModuleForKeycode[keycode] = newModule_;

        newModule_.INIT();

        _reconfigurePolicies(keycode);
    }

    function _activatePolicy(Policy policy_) internal {
        if (isPolicyActive(policy_))
            revert Kernel_PolicyAlreadyActivated(address(policy_));

        // Add policy to list of active policies
        activePolicies.push(policy_);
        getPolicyIndex[policy_] = activePolicies.length - 1;

        // Record module dependencies
        Keycode[] memory dependencies = policy_.configureDependencies();
        uint256 depLength = dependencies.length;

        for (uint256 i; i < depLength; ) {
            Keycode keycode = dependencies[i];

            moduleDependents[keycode].push(policy_);
            getDependentIndex[keycode][policy_] =
                moduleDependents[keycode].length -
                1;

            unchecked {
                ++i;
            }
        }

        // Grant permissions for policy to access restricted module functions
        Permissions[] memory requests = policy_.requestPermissions();
        _setPolicyPermissions(policy_, requests, true);
    }

    function _deactivatePolicy(Policy policy_) internal {
        if (!isPolicyActive(policy_))
            revert Kernel_PolicyNotActivated(address(policy_));

        // Revoke permissions
        Permissions[] memory requests = policy_.requestPermissions();
        _setPolicyPermissions(policy_, requests, false);

        // Remove policy from all policy data structures
        uint256 idx = getPolicyIndex[policy_];
        Policy lastPolicy = activePolicies[activePolicies.length - 1];

        activePolicies[idx] = lastPolicy;
        activePolicies.pop();
        getPolicyIndex[lastPolicy] = idx;
        delete getPolicyIndex[policy_];

        // Remove policy from module dependents
        _pruneFromDependents(policy_);
    }

    /// @notice All functionality will move to the new kernel. WARNING: ACTION WILL BRICK THIS KERNEL.
    /// @dev    New kernel must add in all of the modules and policies via executeAction.
    /// @dev    NOTE: Data does not get cleared from this kernel.
    function _migrateKernel(Kernel newKernel_) internal {
        uint256 keycodeLen = allKeycodes.length;
        for (uint256 i; i < keycodeLen; ) {
            Module module = Module(getModuleForKeycode[allKeycodes[i]]);
            module.changeKernel(newKernel_);
            unchecked {
                ++i;
            }
        }

        uint256 policiesLen = activePolicies.length;
        for (uint256 j; j < policiesLen; ) {
            Policy policy = activePolicies[j];

            // Deactivate before changing kernel
            policy.changeKernel(newKernel_);
            unchecked {
                ++j;
            }
        }
    }

    function _reconfigurePolicies(Keycode keycode_) internal {
        Policy[] memory dependents = moduleDependents[keycode_];
        uint256 depLength = dependents.length;

        for (uint256 i; i < depLength; ) {
            dependents[i].configureDependencies();

            unchecked {
                ++i;
            }
        }
    }

    function _setPolicyPermissions(
        Policy policy_,
        Permissions[] memory requests_,
        bool grant_
    ) internal {
        uint256 reqLength = requests_.length;
        for (uint256 i = 0; i < reqLength; ) {
            Permissions memory request = requests_[i];
            modulePermissions[request.keycode][policy_][
                request.funcSelector
            ] = grant_;

            emit PermissionsUpdated(
                request.keycode,
                policy_,
                request.funcSelector,
                grant_
            );

            unchecked {
                ++i;
            }
        }
    }

    function _pruneFromDependents(Policy policy_) internal {
        Keycode[] memory dependencies = policy_.configureDependencies();
        uint256 depcLength = dependencies.length;

        for (uint256 i; i < depcLength; ) {
            Keycode keycode = dependencies[i];
            Policy[] storage dependents = moduleDependents[keycode];

            uint256 origIndex = getDependentIndex[keycode][policy_];
            Policy lastPolicy = dependents[dependents.length - 1];

            // Swap with last and pop
            dependents[origIndex] = lastPolicy;
            dependents.pop();

            // Record new index and delete deactivated policy index
            getDependentIndex[keycode][lastPolicy] = origIndex;
            delete getDependentIndex[keycode][policy_];

            unchecked {
                ++i;
            }
        }
    }
}

// SPDX-License-Identifier: MIT

pragma solidity 0.8.15;

import "@openzeppelin/contracts/token/ERC20/ERC20.sol";
import "src/Kernel.sol";

/// @title RADToken
/// @notice RADToken is a contract for the RAD token.
contract RADToken is ERC20, Module {
    //============================================================================================//
    //                                        MODULE SETUP                                        //
    //============================================================================================//

    /// @notice Initializes the contract.
    constructor(
        Kernel kernel_ // Why isn't this a Kernel for deploy?
    ) Module(kernel_) ERC20("Radiate Token", "RADT") {}

    /// @inheritdoc Module
    function KEYCODE() public pure override returns (Keycode) {
        return toKeycode("TOKEN");
    }

    uint256 public maxSupply;

    /// @inheritdoc Module
    function VERSION()
        external
        pure
        override
        returns (uint8 major, uint8 minor)
    {
        major = 1;
        minor = 0;
    }

    //============================================================================================//
    //                                       CORE FUNCTIONS                                       //
    //============================================================================================//

    function mint(address _to, uint256 _amount) external permissioned {
        require(
            totalSupply() + _amount <= maxSupply,
            "RADToken: max supply exceeded"
        );
        _mint(_to, _amount);
    }

    function setMaxSupply(uint256 _amount) external permissioned {
        maxSupply = _amount;
    }
}

{
  "compilationTarget": {
    "src/modules/TOKEN/RADToken.sol": "RADToken"
  },
  "evmVersion": "london",
  "libraries": {},
  "metadata": {
    "bytecodeHash": "ipfs"
  },
  "optimizer": {
    "enabled": true,
    "runs": 200
  },
  "remappings": [
    ":@openzeppelin/=lib/openzeppelin-contracts/",
    ":@openzeppelin/upgradeable/=lib/openzeppelin-contracts-upgradeable/",
    ":@solmate/=lib/solmate/src/",
    ":ds-test/=lib/forge-std/lib/ds-test/src/",
    ":forge-std/=lib/forge-std/src/",
    ":openzeppelin-contracts-upgradeable/=lib/openzeppelin-contracts-upgradeable/",
    ":openzeppelin-contracts/=lib/openzeppelin-contracts/",
    ":solmate/=lib/solmate/src/"
  ]
}