// File: @axelar-network/axelar-gmp-sdk-solidity/contracts/interfaces/IAxelarGasService.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

import { IUpgradable } from '../interfaces/IUpgradable.sol';

/**
 * @title IAxelarGasService Interface
 * @notice This is an interface for the AxelarGasService contract which manages gas payments
 * and refunds for cross-chain communication on the Axelar network.
 * @dev This interface inherits IUpgradable
 */
interface IAxelarGasService is IUpgradable {
    error NothingReceived();
    error InvalidAddress();
    error NotCollector();
    error InvalidAmounts();

    event GasPaidForContractCall(
        address indexed sourceAddress,
        string destinationChain,
        string destinationAddress,
        bytes32 indexed payloadHash,
        address gasToken,
        uint256 gasFeeAmount,
        address refundAddress
    );

    event GasPaidForContractCallWithToken(
        address indexed sourceAddress,
        string destinationChain,
        string destinationAddress,
        bytes32 indexed payloadHash,
        string symbol,
        uint256 amount,
        address gasToken,
        uint256 gasFeeAmount,
        address refundAddress
    );

    event NativeGasPaidForContractCall(
        address indexed sourceAddress,
        string destinationChain,
        string destinationAddress,
        bytes32 indexed payloadHash,
        uint256 gasFeeAmount,
        address refundAddress
    );

    event NativeGasPaidForContractCallWithToken(
        address indexed sourceAddress,
        string destinationChain,
        string destinationAddress,
        bytes32 indexed payloadHash,
        string symbol,
        uint256 amount,
        uint256 gasFeeAmount,
        address refundAddress
    );

    event GasPaidForExpressCall(
        address indexed sourceAddress,
        string destinationChain,
        string destinationAddress,
        bytes32 indexed payloadHash,
        address gasToken,
        uint256 gasFeeAmount,
        address refundAddress
    );

    event GasPaidForExpressCallWithToken(
        address indexed sourceAddress,
        string destinationChain,
        string destinationAddress,
        bytes32 indexed payloadHash,
        string symbol,
        uint256 amount,
        address gasToken,
        uint256 gasFeeAmount,
        address refundAddress
    );

    event NativeGasPaidForExpressCall(
        address indexed sourceAddress,
        string destinationChain,
        string destinationAddress,
        bytes32 indexed payloadHash,
        uint256 gasFeeAmount,
        address refundAddress
    );

    event NativeGasPaidForExpressCallWithToken(
        address indexed sourceAddress,
        string destinationChain,
        string destinationAddress,
        bytes32 indexed payloadHash,
        string symbol,
        uint256 amount,
        uint256 gasFeeAmount,
        address refundAddress
    );

    event GasAdded(
        bytes32 indexed txHash,
        uint256 indexed logIndex,
        address gasToken,
        uint256 gasFeeAmount,
        address refundAddress
    );

    event NativeGasAdded(bytes32 indexed txHash, uint256 indexed logIndex, uint256 gasFeeAmount, address refundAddress);

    event ExpressGasAdded(
        bytes32 indexed txHash,
        uint256 indexed logIndex,
        address gasToken,
        uint256 gasFeeAmount,
        address refundAddress
    );

    event NativeExpressGasAdded(
        bytes32 indexed txHash,
        uint256 indexed logIndex,
        uint256 gasFeeAmount,
        address refundAddress
    );

    event Refunded(
        bytes32 indexed txHash,
        uint256 indexed logIndex,
        address payable receiver,
        address token,
        uint256 amount
    );

    /**
     * @notice Pay for gas using ERC20 tokens for a contract call on a destination chain.
     * @dev This function is called on the source chain before calling the gateway to execute a remote contract.
     * @param sender The address making the payment
     * @param destinationChain The target chain where the contract call will be made
     * @param destinationAddress The target address on the destination chain
     * @param payload Data payload for the contract call
     * @param gasToken The address of the ERC20 token used to pay for gas
     * @param gasFeeAmount The amount of tokens to pay for gas
     * @param refundAddress The address where refunds, if any, should be sent
     */
    function payGasForContractCall(
        address sender,
        string calldata destinationChain,
        string calldata destinationAddress,
        bytes calldata payload,
        address gasToken,
        uint256 gasFeeAmount,
        address refundAddress
    ) external;

    /**
     * @notice Pay for gas using ERC20 tokens for a contract call with tokens on a destination chain.
     * @dev This function is called on the source chain before calling the gateway to execute a remote contract.
     * @param sender The address making the payment
     * @param destinationChain The target chain where the contract call with tokens will be made
     * @param destinationAddress The target address on the destination chain
     * @param payload Data payload for the contract call with tokens
     * @param symbol The symbol of the token to be sent with the call
     * @param amount The amount of tokens to be sent with the call
     * @param gasToken The address of the ERC20 token used to pay for gas
     * @param gasFeeAmount The amount of tokens to pay for gas
     * @param refundAddress The address where refunds, if any, should be sent
     */
    function payGasForContractCallWithToken(
        address sender,
        string calldata destinationChain,
        string calldata destinationAddress,
        bytes calldata payload,
        string calldata symbol,
        uint256 amount,
        address gasToken,
        uint256 gasFeeAmount,
        address refundAddress
    ) external;

    /**
     * @notice Pay for gas using native currency for a contract call on a destination chain.
     * @dev This function is called on the source chain before calling the gateway to execute a remote contract.
     * @param sender The address making the payment
     * @param destinationChain The target chain where the contract call will be made
     * @param destinationAddress The target address on the destination chain
     * @param payload Data payload for the contract call
     * @param refundAddress The address where refunds, if any, should be sent
     */
    function payNativeGasForContractCall(
        address sender,
        string calldata destinationChain,
        string calldata destinationAddress,
        bytes calldata payload,
        address refundAddress
    ) external payable;

    /**
     * @notice Pay for gas using native currency for a contract call with tokens on a destination chain.
     * @dev This function is called on the source chain before calling the gateway to execute a remote contract.
     * @param sender The address making the payment
     * @param destinationChain The target chain where the contract call with tokens will be made
     * @param destinationAddress The target address on the destination chain
     * @param payload Data payload for the contract call with tokens
     * @param symbol The symbol of the token to be sent with the call
     * @param amount The amount of tokens to be sent with the call
     * @param refundAddress The address where refunds, if any, should be sent
     */
    function payNativeGasForContractCallWithToken(
        address sender,
        string calldata destinationChain,
        string calldata destinationAddress,
        bytes calldata payload,
        string calldata symbol,
        uint256 amount,
        address refundAddress
    ) external payable;

    /**
     * @notice Pay for gas using ERC20 tokens for an express contract call on a destination chain.
     * @dev This function is called on the source chain before calling the gateway to express execute a remote contract.
     * @param sender The address making the payment
     * @param destinationChain The target chain where the contract call will be made
     * @param destinationAddress The target address on the destination chain
     * @param payload Data payload for the contract call
     * @param gasToken The address of the ERC20 token used to pay for gas
     * @param gasFeeAmount The amount of tokens to pay for gas
     * @param refundAddress The address where refunds, if any, should be sent
     */
    function payGasForExpressCall(
        address sender,
        string calldata destinationChain,
        string calldata destinationAddress,
        bytes calldata payload,
        address gasToken,
        uint256 gasFeeAmount,
        address refundAddress
    ) external;

    /**
     * @notice Pay for gas using ERC20 tokens for an express contract call with tokens on a destination chain.
     * @dev This function is called on the source chain before calling the gateway to express execute a remote contract.
     * @param sender The address making the payment
     * @param destinationChain The target chain where the contract call with tokens will be made
     * @param destinationAddress The target address on the destination chain
     * @param payload Data payload for the contract call with tokens
     * @param symbol The symbol of the token to be sent with the call
     * @param amount The amount of tokens to be sent with the call
     * @param gasToken The address of the ERC20 token used to pay for gas
     * @param gasFeeAmount The amount of tokens to pay for gas
     * @param refundAddress The address where refunds, if any, should be sent
     */
    function payGasForExpressCallWithToken(
        address sender,
        string calldata destinationChain,
        string calldata destinationAddress,
        bytes calldata payload,
        string calldata symbol,
        uint256 amount,
        address gasToken,
        uint256 gasFeeAmount,
        address refundAddress
    ) external;

    /**
     * @notice Pay for gas using native currency for an express contract call on a destination chain.
     * @dev This function is called on the source chain before calling the gateway to express execute a remote contract.
     * @param sender The address making the payment
     * @param destinationChain The target chain where the contract call will be made
     * @param destinationAddress The target address on the destination chain
     * @param payload Data payload for the contract call
     * @param refundAddress The address where refunds, if any, should be sent
     */
    function payNativeGasForExpressCall(
        address sender,
        string calldata destinationChain,
        string calldata destinationAddress,
        bytes calldata payload,
        address refundAddress
    ) external payable;

    /**
     * @notice Pay for gas using native currency for an express contract call with tokens on a destination chain.
     * @dev This function is called on the source chain before calling the gateway to express execute a remote contract.
     * @param sender The address making the payment
     * @param destinationChain The target chain where the contract call with tokens will be made
     * @param destinationAddress The target address on the destination chain
     * @param payload Data payload for the contract call with tokens
     * @param symbol The symbol of the token to be sent with the call
     * @param amount The amount of tokens to be sent with the call
     * @param refundAddress The address where refunds, if any, should be sent
     */
    function payNativeGasForExpressCallWithToken(
        address sender,
        string calldata destinationChain,
        string calldata destinationAddress,
        bytes calldata payload,
        string calldata symbol,
        uint256 amount,
        address refundAddress
    ) external payable;

    /**
     * @notice Add additional gas payment using ERC20 tokens after initiating a cross-chain call.
     * @dev This function can be called on the source chain after calling the gateway to execute a remote contract.
     * @param txHash The transaction hash of the cross-chain call
     * @param logIndex The log index for the cross-chain call
     * @param gasToken The ERC20 token address used to add gas
     * @param gasFeeAmount The amount of tokens to add as gas
     * @param refundAddress The address where refunds, if any, should be sent
     */
    function addGas(
        bytes32 txHash,
        uint256 logIndex,
        address gasToken,
        uint256 gasFeeAmount,
        address refundAddress
    ) external;

    /**
     * @notice Add additional gas payment using native currency after initiating a cross-chain call.
     * @dev This function can be called on the source chain after calling the gateway to execute a remote contract.
     * @param txHash The transaction hash of the cross-chain call
     * @param logIndex The log index for the cross-chain call
     * @param refundAddress The address where refunds, if any, should be sent
     */
    function addNativeGas(
        bytes32 txHash,
        uint256 logIndex,
        address refundAddress
    ) external payable;

    /**
     * @notice Add additional gas payment using ERC20 tokens after initiating an express cross-chain call.
     * @dev This function can be called on the source chain after calling the gateway to express execute a remote contract.
     * @param txHash The transaction hash of the cross-chain call
     * @param logIndex The log index for the cross-chain call
     * @param gasToken The ERC20 token address used to add gas
     * @param gasFeeAmount The amount of tokens to add as gas
     * @param refundAddress The address where refunds, if any, should be sent
     */
    function addExpressGas(
        bytes32 txHash,
        uint256 logIndex,
        address gasToken,
        uint256 gasFeeAmount,
        address refundAddress
    ) external;

    /**
     * @notice Add additional gas payment using native currency after initiating an express cross-chain call.
     * @dev This function can be called on the source chain after calling the gateway to express execute a remote contract.
     * @param txHash The transaction hash of the cross-chain call
     * @param logIndex The log index for the cross-chain call
     * @param refundAddress The address where refunds, if any, should be sent
     */
    function addNativeExpressGas(
        bytes32 txHash,
        uint256 logIndex,
        address refundAddress
    ) external payable;

    /**
     * @notice Allows the gasCollector to collect accumulated fees from the contract.
     * @dev Use address(0) as the token address for native currency.
     * @param receiver The address to receive the collected fees
     * @param tokens Array of token addresses to be collected
     * @param amounts Array of amounts to be collected for each respective token address
     */
    function collectFees(
        address payable receiver,
        address[] calldata tokens,
        uint256[] calldata amounts
    ) external;

    /**
     * @notice Refunds gas payment to the receiver in relation to a specific cross-chain transaction.
     * @dev Only callable by the gasCollector.
     * @dev Use address(0) as the token address to refund native currency.
     * @param txHash The transaction hash of the cross-chain call
     * @param logIndex The log index for the cross-chain call
     * @param receiver The address to receive the refund
     * @param token The token address to be refunded
     * @param amount The amount to refund
     */
    function refund(
        bytes32 txHash,
        uint256 logIndex,
        address payable receiver,
        address token,
        uint256 amount
    ) external;

    /**
     * @notice Returns the address of the designated gas collector.
     * @return address of the gas collector
     */
    function gasCollector() external returns (address);
}

// File: @axelar-network/axelar-gmp-sdk-solidity/contracts/interfaces/IAxelarGateway.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

import { IGovernable } from './IGovernable.sol';

interface IAxelarGateway is IGovernable {
    /**********\
    |* Errors *|
    \**********/

    error NotSelf();
    error NotProxy();
    error InvalidCodeHash();
    error SetupFailed();
    error InvalidAuthModule();
    error InvalidTokenDeployer();
    error InvalidAmount();
    error InvalidChainId();
    error InvalidCommands();
    error TokenDoesNotExist(string symbol);
    error TokenAlreadyExists(string symbol);
    error TokenDeployFailed(string symbol);
    error TokenContractDoesNotExist(address token);
    error BurnFailed(string symbol);
    error MintFailed(string symbol);
    error InvalidSetMintLimitsParams();
    error ExceedMintLimit(string symbol);

    /**********\
    |* Events *|
    \**********/

    event TokenSent(
        address indexed sender,
        string destinationChain,
        string destinationAddress,
        string symbol,
        uint256 amount
    );

    event ContractCall(
        address indexed sender,
        string destinationChain,
        string destinationContractAddress,
        bytes32 indexed payloadHash,
        bytes payload
    );

    event ContractCallWithToken(
        address indexed sender,
        string destinationChain,
        string destinationContractAddress,
        bytes32 indexed payloadHash,
        bytes payload,
        string symbol,
        uint256 amount
    );

    event Executed(bytes32 indexed commandId);

    event TokenDeployed(string symbol, address tokenAddresses);

    event ContractCallApproved(
        bytes32 indexed commandId,
        string sourceChain,
        string sourceAddress,
        address indexed contractAddress,
        bytes32 indexed payloadHash,
        bytes32 sourceTxHash,
        uint256 sourceEventIndex
    );

    event ContractCallApprovedWithMint(
        bytes32 indexed commandId,
        string sourceChain,
        string sourceAddress,
        address indexed contractAddress,
        bytes32 indexed payloadHash,
        string symbol,
        uint256 amount,
        bytes32 sourceTxHash,
        uint256 sourceEventIndex
    );

    event TokenMintLimitUpdated(string symbol, uint256 limit);

    event OperatorshipTransferred(bytes newOperatorsData);

    event Upgraded(address indexed implementation);

    /********************\
    |* Public Functions *|
    \********************/

    function sendToken(
        string calldata destinationChain,
        string calldata destinationAddress,
        string calldata symbol,
        uint256 amount
    ) external;

    function callContract(
        string calldata destinationChain,
        string calldata contractAddress,
        bytes calldata payload
    ) external;

    function callContractWithToken(
        string calldata destinationChain,
        string calldata contractAddress,
        bytes calldata payload,
        string calldata symbol,
        uint256 amount
    ) external;

    function isContractCallApproved(
        bytes32 commandId,
        string calldata sourceChain,
        string calldata sourceAddress,
        address contractAddress,
        bytes32 payloadHash
    ) external view returns (bool);

    function isContractCallAndMintApproved(
        bytes32 commandId,
        string calldata sourceChain,
        string calldata sourceAddress,
        address contractAddress,
        bytes32 payloadHash,
        string calldata symbol,
        uint256 amount
    ) external view returns (bool);

    function validateContractCall(
        bytes32 commandId,
        string calldata sourceChain,
        string calldata sourceAddress,
        bytes32 payloadHash
    ) external returns (bool);

    function validateContractCallAndMint(
        bytes32 commandId,
        string calldata sourceChain,
        string calldata sourceAddress,
        bytes32 payloadHash,
        string calldata symbol,
        uint256 amount
    ) external returns (bool);

    /***********\
    |* Getters *|
    \***********/

    function authModule() external view returns (address);

    function tokenDeployer() external view returns (address);

    function tokenMintLimit(string memory symbol) external view returns (uint256);

    function tokenMintAmount(string memory symbol) external view returns (uint256);

    function allTokensFrozen() external view returns (bool);

    function implementation() external view returns (address);

    function tokenAddresses(string memory symbol) external view returns (address);

    function tokenFrozen(string memory symbol) external view returns (bool);

    function isCommandExecuted(bytes32 commandId) external view returns (bool);

    function adminEpoch() external view returns (uint256);

    function adminThreshold(uint256 epoch) external view returns (uint256);

    function admins(uint256 epoch) external view returns (address[] memory);

    /*******************\
    |* Admin Functions *|
    \*******************/

    function setTokenMintLimits(string[] calldata symbols, uint256[] calldata limits) external;

    function upgrade(
        address newImplementation,
        bytes32 newImplementationCodeHash,
        bytes calldata setupParams
    ) external;

    /**********************\
    |* External Functions *|
    \**********************/

    function setup(bytes calldata params) external;

    function execute(bytes calldata input) external;
}

// File: @axelar-network/axelar-gmp-sdk-solidity/contracts/interfaces/IContractIdentifier.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

// General interface for upgradable contracts
interface IContractIdentifier {
    /**
     * @notice Returns the contract ID. It can be used as a check during upgrades.
     * @dev Meant to be overridden in derived contracts.
     * @return bytes32 The contract ID
     */
    function contractId() external pure returns (bytes32);
}

// File: @axelar-network/axelar-gmp-sdk-solidity/contracts/interfaces/IGovernable.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

/**
 * @title IGovernable Interface
 * @notice This is an interface used by the AxelarGateway contract to manage governance and mint limiter roles.
 */
interface IGovernable {
    error NotGovernance();
    error NotMintLimiter();
    error InvalidGovernance();
    error InvalidMintLimiter();

    event GovernanceTransferred(address indexed previousGovernance, address indexed newGovernance);
    event MintLimiterTransferred(address indexed previousGovernance, address indexed newGovernance);

    /**
     * @notice Returns the governance address.
     * @return address of the governance
     */
    function governance() external view returns (address);

    /**
     * @notice Returns the mint limiter address.
     * @return address of the mint limiter
     */
    function mintLimiter() external view returns (address);

    /**
     * @notice Transfer the governance role to another address.
     * @param newGovernance The new governance address
     */
    function transferGovernance(address newGovernance) external;

    /**
     * @notice Transfer the mint limiter role to another address.
     * @param newGovernance The new mint limiter address
     */
    function transferMintLimiter(address newGovernance) external;
}

// File: @axelar-network/axelar-gmp-sdk-solidity/contracts/interfaces/IOwnable.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

/**
 * @title IOwnable Interface
 * @notice IOwnable is an interface that abstracts the implementation of a
 * contract with ownership control features. It's commonly used in upgradable
 * contracts and includes the functionality to get current owner, transfer
 * ownership, and propose and accept ownership.
 */
interface IOwnable {
    error NotOwner();
    error InvalidOwner();
    error InvalidOwnerAddress();

    event OwnershipTransferStarted(address indexed newOwner);
    event OwnershipTransferred(address indexed newOwner);

    /**
     * @notice Returns the current owner of the contract.
     * @return address The address of the current owner
     */
    function owner() external view returns (address);

    /**
     * @notice Returns the address of the pending owner of the contract.
     * @return address The address of the pending owner
     */
    function pendingOwner() external view returns (address);

    /**
     * @notice Transfers ownership of the contract to a new address
     * @param newOwner The address to transfer ownership to
     */
    function transferOwnership(address newOwner) external;

    /**
     * @notice Proposes to transfer the contract's ownership to a new address.
     * The new owner needs to accept the ownership explicitly.
     * @param newOwner The address to transfer ownership to
     */
    function proposeOwnership(address newOwner) external;

    /**
     * @notice Transfers ownership to the pending owner.
     * @dev Can only be called by the pending owner
     */
    function acceptOwnership() external;
}

// File: @axelar-network/axelar-gmp-sdk-solidity/contracts/interfaces/IUpgradable.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

import { IOwnable } from './IOwnable.sol';
import { IContractIdentifier } from './IContractIdentifier.sol';

// General interface for upgradable contracts
interface IUpgradable is IOwnable, IContractIdentifier {
    error InvalidCodeHash();
    error InvalidImplementation();
    error SetupFailed();
    error NotProxy();

    event Upgraded(address indexed newImplementation);

    function implementation() external view returns (address);

    function upgrade(
        address newImplementation,
        bytes32 newImplementationCodeHash,
        bytes calldata params
    ) external;

    function setup(bytes calldata data) external;
}

// File: @axelar-network/axelar-gmp-sdk-solidity/contracts/libs/AddressString.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

library StringToAddress {
    error InvalidAddressString();

    function toAddress(string memory addressString) internal pure returns (address) {
        bytes memory stringBytes = bytes(addressString);
        uint160 addressNumber = 0;
        uint8 stringByte;

        if (stringBytes.length != 42 || stringBytes[0] != '0' || stringBytes[1] != 'x') revert InvalidAddressString();

        for (uint256 i = 2; i < 42; ++i) {
            stringByte = uint8(stringBytes[i]);

            if ((stringByte >= 97) && (stringByte <= 102)) stringByte -= 87;
            else if ((stringByte >= 65) && (stringByte <= 70)) stringByte -= 55;
            else if ((stringByte >= 48) && (stringByte <= 57)) stringByte -= 48;
            else revert InvalidAddressString();

            addressNumber |= uint160(uint256(stringByte) << ((41 - i) << 2));
        }

        return address(addressNumber);
    }
}

library AddressToString {
    function toString(address address_) internal pure returns (string memory) {
        bytes memory addressBytes = abi.encodePacked(address_);
        bytes memory characters = '0123456789abcdef';
        bytes memory stringBytes = new bytes(42);

        stringBytes[0] = '0';
        stringBytes[1] = 'x';

        for (uint256 i; i < 20; ++i) {
            stringBytes[2 + i * 2] = characters[uint8(addressBytes[i] >> 4)];
            stringBytes[3 + i * 2] = characters[uint8(addressBytes[i] & 0x0f)];
        }

        return string(stringBytes);
    }
}

// File: @openzeppelin-4/contracts/token/ERC20/ERC20.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.0) (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].
 *
 * The default value of {decimals} is 18. To change this, you should override
 * this function so it returns a different value.
 *
 * 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}.
     *
     * 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 default value returned by this function, unless
     * it's 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 {}
}

// File: @openzeppelin-4/contracts/token/ERC20/extensions/IERC20Metadata.sol



// 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);
}

// File: @openzeppelin-4/contracts/token/ERC20/extensions/IERC20Permit.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.0) (token/ERC20/extensions/IERC20Permit.sol)

pragma solidity ^0.8.0;

/**
 * @dev Interface of the ERC20 Permit extension allowing approvals to be made via signatures, as defined in
 * https://eips.ethereum.org/EIPS/eip-2612[EIP-2612].
 *
 * Adds the {permit} method, which can be used to change an account's ERC20 allowance (see {IERC20-allowance}) by
 * presenting a message signed by the account. By not relying on {IERC20-approve}, the token holder account doesn't
 * need to send a transaction, and thus is not required to hold Ether at all.
 */
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);
}

// File: @openzeppelin-4/contracts/token/ERC20/IERC20.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.0) (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-4/contracts/token/ERC20/utils/SafeERC20.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.0) (token/ERC20/utils/SafeERC20.sol)

pragma solidity ^0.8.0;

import "../IERC20.sol";
import "../extensions/IERC20Permit.sol";
import "../../../utils/Address.sol";

/**
 * @title SafeERC20
 * @dev Wrappers around ERC20 operations that throw on failure (when the token
 * contract returns false). Tokens that return no value (and instead revert or
 * throw on failure) are also supported, non-reverting calls are assumed to be
 * successful.
 * To use this library you can add a `using SafeERC20 for IERC20;` statement to your contract,
 * which allows you to call the safe operations as `token.safeTransfer(...)`, etc.
 */
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));
    }
}

// File: @openzeppelin-4/contracts/utils/Address.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.0) (utils/Address.sol)

pragma solidity ^0.8.1;

/**
 * @dev Collection of functions related to the address type
 */
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/v0.8.0/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);
        }
    }
}

// File: @openzeppelin-4/contracts/utils/Context.sol



// 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;
    }
}

// File: @openzeppelin/contracts-upgradeable/access/OwnableUpgradeable.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.0) (access/Ownable.sol)

pragma solidity ^0.8.0;

import "../utils/ContextUpgradeable.sol";
import "../proxy/utils/Initializable.sol";

/**
 * @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 OwnableUpgradeable is Initializable, ContextUpgradeable {
    address private _owner;

    event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);

    /**
     * @dev Initializes the contract setting the deployer as the initial owner.
     */
    function __Ownable_init() internal onlyInitializing {
        __Ownable_init_unchained();
    }

    function __Ownable_init_unchained() internal onlyInitializing {
        _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);
    }

    /**
     * @dev This empty reserved space is put in place to allow future versions to add new
     * variables without shifting down storage in the inheritance chain.
     * See https://docs.openzeppelin.com/contracts/4.x/upgradeable#storage_gaps
     */
    uint256[49] private __gap;
}

// File: @openzeppelin/contracts-upgradeable/proxy/utils/Initializable.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.0) (proxy/utils/Initializable.sol)

pragma solidity ^0.8.2;

import "../../utils/AddressUpgradeable.sol";

/**
 * @dev This is a base contract to aid in writing upgradeable contracts, or any kind of contract that will be deployed
 * behind a proxy. Since proxied contracts do not make use of a constructor, it's common to move constructor logic to an
 * external initializer function, usually called `initialize`. It then becomes necessary to protect this initializer
 * function so it can only be called once. The {initializer} modifier provided by this contract will have this effect.
 *
 * The initialization functions use a version number. Once a version number is used, it is consumed and cannot be
 * reused. This mechanism prevents re-execution of each "step" but allows the creation of new initialization steps in
 * case an upgrade adds a module that needs to be initialized.
 *
 * For example:
 *
 * [.hljs-theme-light.nopadding]
 * ```solidity
 * contract MyToken is ERC20Upgradeable {
 *     function initialize() initializer public {
 *         __ERC20_init("MyToken", "MTK");
 *     }
 * }
 *
 * contract MyTokenV2 is MyToken, ERC20PermitUpgradeable {
 *     function initializeV2() reinitializer(2) public {
 *         __ERC20Permit_init("MyToken");
 *     }
 * }
 * ```
 *
 * TIP: To avoid leaving the proxy in an uninitialized state, the initializer function should be called as early as
 * possible by providing the encoded function call as the `_data` argument to {ERC1967Proxy-constructor}.
 *
 * CAUTION: When used with inheritance, manual care must be taken to not invoke a parent initializer twice, or to ensure
 * that all initializers are idempotent. This is not verified automatically as constructors are by Solidity.
 *
 * [CAUTION]
 * ====
 * Avoid leaving a contract uninitialized.
 *
 * An uninitialized contract can be taken over by an attacker. This applies to both a proxy and its implementation
 * contract, which may impact the proxy. To prevent the implementation contract from being used, you should invoke
 * the {_disableInitializers} function in the constructor to automatically lock it when it is deployed:
 *
 * [.hljs-theme-light.nopadding]
 * ```
 * /// @custom:oz-upgrades-unsafe-allow constructor
 * constructor() {
 *     _disableInitializers();
 * }
 * ```
 * ====
 */
abstract contract Initializable {
    /**
     * @dev Indicates that the contract has been initialized.
     * @custom:oz-retyped-from bool
     */
    uint8 private _initialized;

    /**
     * @dev Indicates that the contract is in the process of being initialized.
     */
    bool private _initializing;

    /**
     * @dev Triggered when the contract has been initialized or reinitialized.
     */
    event Initialized(uint8 version);

    /**
     * @dev A modifier that defines a protected initializer function that can be invoked at most once. In its scope,
     * `onlyInitializing` functions can be used to initialize parent contracts.
     *
     * Similar to `reinitializer(1)`, except that functions marked with `initializer` can be nested in the context of a
     * constructor.
     *
     * Emits an {Initialized} event.
     */
    modifier initializer() {
        bool isTopLevelCall = !_initializing;
        require(
            (isTopLevelCall && _initialized < 1) || (!AddressUpgradeable.isContract(address(this)) && _initialized == 1),
            "Initializable: contract is already initialized"
        );
        _initialized = 1;
        if (isTopLevelCall) {
            _initializing = true;
        }
        _;
        if (isTopLevelCall) {
            _initializing = false;
            emit Initialized(1);
        }
    }

    /**
     * @dev A modifier that defines a protected reinitializer function that can be invoked at most once, and only if the
     * contract hasn't been initialized to a greater version before. In its scope, `onlyInitializing` functions can be
     * used to initialize parent contracts.
     *
     * A reinitializer may be used after the original initialization step. This is essential to configure modules that
     * are added through upgrades and that require initialization.
     *
     * When `version` is 1, this modifier is similar to `initializer`, except that functions marked with `reinitializer`
     * cannot be nested. If one is invoked in the context of another, execution will revert.
     *
     * Note that versions can jump in increments greater than 1; this implies that if multiple reinitializers coexist in
     * a contract, executing them in the right order is up to the developer or operator.
     *
     * WARNING: setting the version to 255 will prevent any future reinitialization.
     *
     * Emits an {Initialized} event.
     */
    modifier reinitializer(uint8 version) {
        require(!_initializing && _initialized < version, "Initializable: contract is already initialized");
        _initialized = version;
        _initializing = true;
        _;
        _initializing = false;
        emit Initialized(version);
    }

    /**
     * @dev Modifier to protect an initialization function so that it can only be invoked by functions with the
     * {initializer} and {reinitializer} modifiers, directly or indirectly.
     */
    modifier onlyInitializing() {
        require(_initializing, "Initializable: contract is not initializing");
        _;
    }

    /**
     * @dev Locks the contract, preventing any future reinitialization. This cannot be part of an initializer call.
     * Calling this in the constructor of a contract will prevent that contract from being initialized or reinitialized
     * to any version. It is recommended to use this to lock implementation contracts that are designed to be called
     * through proxies.
     *
     * Emits an {Initialized} event the first time it is successfully executed.
     */
    function _disableInitializers() internal virtual {
        require(!_initializing, "Initializable: contract is initializing");
        if (_initialized != type(uint8).max) {
            _initialized = type(uint8).max;
            emit Initialized(type(uint8).max);
        }
    }

    /**
     * @dev Returns the highest version that has been initialized. See {reinitializer}.
     */
    function _getInitializedVersion() internal view returns (uint8) {
        return _initialized;
    }

    /**
     * @dev Returns `true` if the contract is currently initializing. See {onlyInitializing}.
     */
    function _isInitializing() internal view returns (bool) {
        return _initializing;
    }
}

// File: @openzeppelin/contracts-upgradeable/utils/AddressUpgradeable.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.0) (utils/Address.sol)

pragma solidity ^0.8.1;

/**
 * @dev Collection of functions related to the address type
 */
library AddressUpgradeable {
    /**
     * @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/v0.8.0/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);
        }
    }
}

// File: @openzeppelin/contracts-upgradeable/utils/ContextUpgradeable.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (utils/Context.sol)

pragma solidity ^0.8.0;
import "../proxy/utils/Initializable.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 ContextUpgradeable is Initializable {
    function __Context_init() internal onlyInitializing {
    }

    function __Context_init_unchained() internal onlyInitializing {
    }
    function _msgSender() internal view virtual returns (address) {
        return msg.sender;
    }

    function _msgData() internal view virtual returns (bytes calldata) {
        return msg.data;
    }

    /**
     * @dev This empty reserved space is put in place to allow future versions to add new
     * variables without shifting down storage in the inheritance chain.
     * See https://docs.openzeppelin.com/contracts/4.x/upgradeable#storage_gaps
     */
    uint256[50] private __gap;
}

// File: contracts/bridgeToken/adapters/axelar/AxelarBridge.sol



// SPDX-License-Identifier: MIT
pragma solidity ^0.8.19; 

import {IERC20} from "@openzeppelin-4/contracts/token/ERC20/ERC20.sol";
import {SafeERC20} from "@openzeppelin-4/contracts/token/ERC20/utils/SafeERC20.sol";
import {OwnableUpgradeable} from "@openzeppelin/contracts-upgradeable/access/OwnableUpgradeable.sol";
import {IXERC20} from  "../../interfaces/IXERC20.sol";
import {IXERC20Lockbox} from "../../interfaces/IXERC20Lockbox.sol";
import {IAxelarGateway} from "@axelar-network/axelar-gmp-sdk-solidity/contracts/interfaces/IAxelarGateway.sol";
import {IAxelarGasService} from "@axelar-network/axelar-gmp-sdk-solidity/contracts/interfaces/IAxelarGasService.sol";
import {StringToAddress} from "@axelar-network/axelar-gmp-sdk-solidity/contracts/libs/AddressString.sol";
import {AddressToString} from "@axelar-network/axelar-gmp-sdk-solidity/contracts/libs/AddressString.sol";

// Axelar Token Bridge adapter for XERC20 tokens
contract AxelarBridge is OwnableUpgradeable {
    using SafeERC20 for IERC20;
    using StringToAddress for string;
    using AddressToString for address;
    
    // Addresses needed for bridging.
    IERC20 public BIFI;
    IXERC20 public xBIFI;
    IXERC20Lockbox public lockbox;
    IAxelarGateway public gateway;
    IAxelarGasService public gasService;

    // Gas limit for bridge calls.
    uint256 public gasLimit;

    // Chain id to axelar id mapping.
    mapping (uint256 => string) public chainIdToAxelarId;
    mapping (string => uint256) public axelarIdToChainId;

    // Errors
    error InvalidChainId();
    error NotGateway();
    error NotApprovedByGateway();
    error WrongSourceAddress();

    // Events
    event BridgedOut(uint256 indexed dstChainId, address indexed bridgeUser, address indexed tokenReceiver, uint256 amount);
    event BridgedIn(uint256 indexed srcChainId, address indexed tokenReceiver, uint256 amount);

    /**@notice Initialize the bridge
     * @param _bifi BIFI token address
     * @param _xbifi xBIFI token address
     * @param _lockbox xBIFI lockbox address
     * @param _gasLimit Gas limit for destination chain execution
     * @param _gateway Axelar gateway address
     * @param _gasService Axelar gas service address
     */
    function initialize(
        IERC20 _bifi,
        IXERC20 _xbifi, 
        IXERC20Lockbox _lockbox,
        uint256 _gasLimit,
        IAxelarGateway _gateway,
        IAxelarGasService _gasService
    ) public initializer {
        __Ownable_init();
        BIFI = _bifi;
        xBIFI = _xbifi;
        lockbox = _lockbox;
        gasLimit = _gasLimit;
        gateway = _gateway;
        gasService = _gasService;

        if (address(lockbox) != address(0)) {
            BIFI.safeApprove(address(lockbox), type(uint).max);
        }
    }

    /**@notice Bridge out to another chain.
     * @param _dstChainId The chain id of the destination chain.
     * @param _amount The amount of tokens to bridge out.
     * @param _to The address to receive the tokens on the other chain.
     */
    function bridge(uint256 _dstChainId, uint256 _amount, address _to) external payable {
        if (abi.encode(chainIdToAxelarId[_dstChainId]).length == 0) revert InvalidChainId();

        // Lock BIFI in lockbox and burn minted tokens. 
        if (address(lockbox) != address(0)) {
            BIFI.safeTransferFrom(msg.sender, address(this), _amount);
            lockbox.deposit(_amount);
            xBIFI.burn(address(this), _amount);
        } else xBIFI.burn(msg.sender, _amount);

        // Send message to receiving bridge to mint tokens to user. 
        bytes memory payload = abi.encode(_to, _amount);
 
        // Pay for our transaction on the other chain.
        gasService.payNativeGasForContractCall{value: msg.value}(
            address(this),
            chainIdToAxelarId[_dstChainId],
            address(this).toString(),
            payload,
            msg.sender
        );

        // Send message to receiving bridge to mint tokens to user.
        gateway.callContract(
            chainIdToAxelarId[_dstChainId],
            address(this).toString(),
            payload
        );

        emit BridgedOut(_dstChainId, msg.sender, _to, _amount);
    }

    // Estimate the gas cost of a bridge call. For axelar this needs to be call via api. 
    function bridgeCost(uint256, uint256, address) external pure returns (uint256 gasCost) {
        // Gas cost needs to be estimated via the axelar api. 
        return 0;
    }

    // Add a new chain id to the mapping. 
    function addChainIds(uint256[] calldata _chainIds, string[] calldata _axelarIds) external onlyOwner {
        for (uint i; i < _chainIds.length; ++i) {
            chainIdToAxelarId[_chainIds[i]] = _axelarIds[i];
            axelarIdToChainId[_axelarIds[i]] = _chainIds[i];
        }
    }

    // Execute a bridge in. Callable only by the gateway.
    function execute(
        bytes32 commandId,
        string calldata sourceChain,
        string calldata sourceAddress,
        bytes calldata payload
    ) external {
        if (msg.sender != address(gateway)) revert NotGateway();
        if (axelarIdToChainId[sourceChain] == 0) revert InvalidChainId();
        if (sourceAddress.toAddress() != address(this)) revert WrongSourceAddress();
        
        bytes32 payloadHash = keccak256(payload);
        if (!gateway.validateContractCall(commandId, sourceChain, sourceAddress, payloadHash)) revert NotApprovedByGateway();
       
        (address user, uint256 amount) = abi.decode(payload, (address,uint256));

        xBIFI.mint(address(this), amount);
        if (address(lockbox) != address(0)) {
            lockbox.withdraw(amount);
            BIFI.transfer(user, amount);
        } else IERC20(address(xBIFI)).transfer(user, amount); 

        emit BridgedIn(axelarIdToChainId[sourceChain], user, amount);      
    }

    // Set the gas limit for the bridge calls.
    function setGasLimit(uint256 _gasLimit) external onlyOwner {
        gasLimit = _gasLimit;
    }
}
// File: contracts/bridgeToken/interfaces/IXERC20.sol



// SPDX-License-Identifier: UNLICENSED
pragma solidity >=0.8.4 <0.9.0;

interface IXERC20 {
  /**
   * @notice Emits when a lockbox is set
   *
   * @param _lockbox The address of the lockbox
   */

  event LockboxSet(address _lockbox);

  /**
   * @notice Emits when a limit is set
   *
   * @param _mintingLimit The updated minting limit we are setting to the bridge
   * @param _burningLimit The updated burning limit we are setting to the bridge
   * @param _bridge The address of the bridge we are setting the limit too
   */
  event BridgeLimitsSet(uint256 _mintingLimit, uint256 _burningLimit, address indexed _bridge);

  /**
   * @notice Reverts when a user with too low of a limit tries to call mint/burn
   */

  error IXERC20_NotHighEnoughLimits();

  /**
   * @notice Reverts when caller is not the factory
   */

  error IXERC20_NotFactory();

  struct Bridge {
    BridgeParameters minterParams;
    BridgeParameters burnerParams;
  }

  struct BridgeParameters {
    uint256 timestamp;
    uint256 ratePerSecond;
    uint256 maxLimit;
    uint256 currentLimit;
  }

  /**
   * @notice Sets the lockbox address
   *
   * @param _lockbox The address of the lockbox
   */

  function setLockbox(address _lockbox) external;

  /**
   * @notice Updates the limits of any bridge
   * @dev Can only be called by the owner
   * @param _mintingLimit The updated minting limit we are setting to the bridge
   * @param _burningLimit The updated burning limit we are setting to the bridge
   * @param _bridge The address of the bridge we are setting the limits too
   */
  function setLimits(address _bridge, uint256 _mintingLimit, uint256 _burningLimit) external;

  /**
   * @notice Returns the max limit of a minter
   *
   * @param _minter The minter we are viewing the limits of
   *  @return _limit The limit the minter has
   */
  function mintingMaxLimitOf(address _minter) external view returns (uint256 _limit);

  /**
   * @notice Returns the max limit of a bridge
   *
   * @param _bridge the bridge we are viewing the limits of
   * @return _limit The limit the bridge has
   */

  function burningMaxLimitOf(address _bridge) external view returns (uint256 _limit);

  /**
   * @notice Returns the current limit of a minter
   *
   * @param _minter The minter we are viewing the limits of
   * @return _limit The limit the minter has
   */

  function mintingCurrentLimitOf(address _minter) external view returns (uint256 _limit);

  /**
   * @notice Returns the current limit of a bridge
   *
   * @param _bridge the bridge we are viewing the limits of
   * @return _limit The limit the bridge has
   */

  function burningCurrentLimitOf(address _bridge) external view returns (uint256 _limit);

  /**
   * @notice Mints tokens for a user
   * @dev Can only be called by a minter
   * @param _user The address of the user who needs tokens minted
   * @param _amount The amount of tokens being minted
   */

  function mint(address _user, uint256 _amount) external;

  /**
   * @notice Burns tokens for a user
   * @dev Can only be called by a minter
   * @param _user The address of the user who needs tokens burned
   * @param _amount The amount of tokens being burned
   */

  function burn(address _user, uint256 _amount) external;
}
// File: contracts/bridgeToken/interfaces/IXERC20Lockbox.sol



// SPDX-License-Identifier: UNLICENSED
pragma solidity >=0.8.4 <0.9.0;

interface IXERC20Lockbox {
  /**
   * @notice Emitted when tokens are deposited into the lockbox
   */

  event Deposit(address _sender, uint256 _amount);

  /**
   * @notice Emitted when tokens are withdrawn from the lockbox
   */

  event Withdraw(address _sender, uint256 _amount);

  /**
   * @notice Reverts when a user tries to deposit native tokens on a non-native lockbox
   */

  error IXERC20Lockbox_NotNative();

  /**
   * @notice Reverts when a user tries to deposit non-native tokens on a native lockbox
   */

  error IXERC20Lockbox_Native();

  /**
   * @notice Reverts when a user tries to withdraw and the call fails
   */

  error IXERC20Lockbox_WithdrawFailed();

  /**
   * @notice Deposit ERC20 tokens into the lockbox
   *
   * @param _amount The amount of tokens to deposit
   */

  function deposit(uint256 _amount) external;

  /**
   * @notice Withdraw ERC20 tokens from the lockbox
   *
   * @param _amount The amount of tokens to withdraw
   */

  function withdraw(uint256 _amount) external;
}