// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

/**
 * @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
     * ====
     */
    function isContract(address account) internal view returns (bool) {
        // This method relies on extcodesize, which returns 0 for contracts in
        // construction, since the code is only stored at the end of the
        // constructor execution.

        uint256 size;
        assembly {
            size := extcodesize(account)
        }
        return size > 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://diligence.consensys.net/posts/2019/09/stop-using-soliditys-transfer-now/[Learn more].
     *
     * IMPORTANT: because control is transferred to `recipient`, care must be
     * taken to not create reentrancy vulnerabilities. Consider using
     * {ReentrancyGuard} or the
     * https://solidity.readthedocs.io/en/v0.5.11/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].
     */
    function sendValue(address payable recipient, uint256 amount) internal {
        require(address(this).balance >= amount, "Address: insufficient balance");

        (bool success, ) = recipient.call{value: amount}("");
        require(success, "Address: unable to send value, recipient may have reverted");
    }

    /**
     * @dev Performs a Solidity function call using a low level `call`. A
     * plain `call` is an unsafe replacement for a function call: use this
     * function instead.
     *
     * If `target` reverts with a revert reason, it is bubbled up by this
     * function (like regular Solidity function calls).
     *
     * Returns the raw returned data. To convert to the expected return value,
     * use https://solidity.readthedocs.io/en/latest/units-and-global-variables.html?highlight=abi.decode#abi-encoding-and-decoding-functions[`abi.decode`].
     *
     * Requirements:
     *
     * - `target` must be a contract.
     * - calling `target` with `data` must not revert.
     *
     * _Available since v3.1._
     */
    function functionCall(address target, bytes memory data) internal returns (bytes memory) {
        return functionCall(target, data, "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");
        require(isContract(target), "Address: call to non-contract");

        (bool success, bytes memory returndata) = target.call{value: value}(data);
        return verifyCallResult(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) {
        require(isContract(target), "Address: static call to non-contract");

        (bool success, bytes memory returndata) = target.staticcall(data);
        return verifyCallResult(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) {
        require(isContract(target), "Address: delegate call to non-contract");

        (bool success, bytes memory returndata) = target.delegatecall(data);
        return verifyCallResult(success, returndata, errorMessage);
    }

    /**
     * @dev Tool to verifies that a low level call was successful, and revert if it wasn't, either by bubbling the
     * revert reason 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 {
            // 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

                assembly {
                    let returndata_size := mload(returndata)
                    revert(add(32, returndata), returndata_size)
                }
            } else {
                revert(errorMessage);
            }
        }
    }
}

// SPDX-License-Identifier: MIT

pragma solidity 0.8.18;

/**
 * @title AirdropErrors
 * @author Non-Fungible Technologies, Inc.
 *
 * This file contains all custom errors for the Arcade Token airdrop contract.
 * All errors are prefixed by  "AA_" for ArcadeAirdrop. Errors located in one place
 * to make it possible to holistically look at all the failure cases.
 */

// ==================================== ARCADE AIRDROP ======================================
/// @notice All errors prefixed with AA_, to separate from other contracts in governance.

/**
 * @notice Ensure airdrop claim period has expired before reclaiming tokens.
 */
error AA_ClaimingNotExpired();

/**
 * @notice Cannot claim tokens after airdrop has expired.
 */
error AA_ClaimingExpired();

/**
 * @notice Cannot claim tokens multiple times.
 */
error AA_AlreadyClaimed();

/**
 * @notice Merkle proof not verified. User is not a participant in the airdrop.
 */
error AA_NonParticipant();

/**
 * @notice Zero address passed in where not allowed.
 *
 * @param addressType                The name of the parameter for which a zero
 *                                   address was provided.
 */
error AA_ZeroAddress(string addressType);

/**
 * @notice Thrown when the merkle root is set to bytes32(0).
 */
error AA_NotInitialized();

// SPDX-License-Identifier: MIT

pragma solidity 0.8.18;

import "@openzeppelin/contracts/token/ERC20/utils/SafeERC20.sol";
import "@openzeppelin/contracts/security/ReentrancyGuard.sol";

import "./ArcadeAirdropBase.sol";

import "../../external/dao-contracts/interfaces/IAirdropSingleSidedStaking.sol";

import { AA_ZeroAddress } from "../../errors/Airdrop.sol";

/**
 * @title Airdrop Season 1
 * @author Non-Fungible Technologies, Inc.
 *
 * This contract is used to distribute tokens to users who have been airdropped
 * tokens. The tokens are distributed to the users directly, or users can choose
 * to have thier allocation staked in the ArcadeSingleSidedStaking contract.
 */
contract AirdropSeason1 is ArcadeAirdropBase, ReentrancyGuard {
    using SafeERC20 for IERC20;

    // ============================================ STATE ==============================================
    /// @notice the voting vault vault which receives airdropped tokens
    IAirdropSingleSidedStaking public immutable votingVault;

    // ============================================ EVENTS =============================================

    event Claimed(address indexed user, uint128 totalGrant);

    // ========================================== CONSTRUCTOR ==========================================
    /**
     * @notice Initiate the contract with a merkle tree root, a token for distribution,
     *         an expiration time for claims, and the voting vault that tokens will be
     *         airdropped into.
     *
     * @param _token                The token to airdrop
     * @param _merkleRoot           The merkle root with deposits encoded into it as hash [address, amount]
     * @param _expiration           The expiration of the airdrop
     * @param _votingVault          The voting vault to deposit tokens to
     */
    constructor(
        IERC20 _token,
        bytes32 _merkleRoot,
        uint256 _expiration,
        IAirdropSingleSidedStaking _votingVault
    ) ArcadeAirdropBase(_token, _merkleRoot, _expiration) {
        if (address(_votingVault) == address(0)) revert AA_ZeroAddress("votingVault");

        votingVault = _votingVault;
    }

    // ===================================== CLAIM FUNCTIONALITY =======================================

    /**
     * @notice Claims an amount of tokens in the tree and stakes the tokens in the ArcadeSingleSidedStaking
     *         contract. The caller can choose who to delegate their voting power to by passing in the
     *         address of their delegate. If a user already has an active stake in the ArcadeSingleSidedStaking
     *         voting vault they must use the same delegate address they are already delegating to.
     *
     * @param delegate               The address the user will delegate to
     * @param totalGrant             The total amount of tokens the user was granted
     * @param merkleProof            The merkle proof showing the user is in the merkle tree
     * @param lock                   The locking period to apply to the staked tokens
     */
    function claimAndStake(
        address delegate,
        uint128 totalGrant,
        bytes32[] calldata merkleProof,
        IAirdropSingleSidedStaking.Lock lock
    ) external {
        _validateWithdraw(totalGrant, merkleProof);

        _setClaimed(msg.sender, totalGrant);

        // approve the voting vault to transfer tokens
        token.approve(address(votingVault), uint256(totalGrant));
        // stake tokens in voting vault for this msg.sender and delegate
        votingVault.airdropReceive(msg.sender, totalGrant, delegate, lock);

        emit Claimed(msg.sender, totalGrant);
    }

    /**
     * @notice Claims an amount of tokens in the tree and send them to the caller.
     *
     * @param totalGrant             The total amount of tokens the user was granted
     * @param merkleProof            The merkle proof showing the user is in the merkle tree
     */
    function claim(uint128 totalGrant, bytes32[] calldata merkleProof) external nonReentrant {
        _validateWithdraw(totalGrant, merkleProof);

        _setClaimed(msg.sender, totalGrant);

        // transfer tokens to the caller
        token.safeTransfer(msg.sender, totalGrant);

        emit Claimed(msg.sender, totalGrant);
    }
}

// SPDX-License-Identifier: MIT

pragma solidity 0.8.18;

import "@openzeppelin/contracts/utils/cryptography/MerkleProof.sol";
import "@openzeppelin/contracts/token/ERC20/utils/SafeERC20.sol";

import "../../external/council/libraries/Authorizable.sol";

import {
    AA_ClaimingNotExpired,
    AA_AlreadyClaimed,
    AA_NonParticipant,
    AA_ClaimingExpired,
    AA_ZeroAddress,
    AA_NotInitialized
} from "../../errors/Airdrop.sol";

/**
 * @title Arcade Airdrop
 * @author Non-Fungible Technologies, Inc.
 *
 * This contract contains the base functionality for an airdrop. The contract is ownable, where the
 * owner can reclaim any remaining tokens once the airdrop is over and also change the merkle root
 * and expiration at their discretion.
 */
abstract contract ArcadeAirdropBase is Authorizable {
    using SafeERC20 for IERC20;
    // ============================================ STATE ==============================================
    /// @notice the token to airdrop
    IERC20 public immutable token;

    /// @notice the merkle root with deposits encoded into it as hash [address, amount]
    bytes32 public rewardsRoot;

    /// @notice the timestamp expiration of the rewards root
    uint256 public expiration;

    /// @notice user claim history by merkle root used to claim
    mapping(address => mapping(bytes32 => uint256)) public claimed;

    // ============================================= EVENTS =============================================

    event SetMerkleRoot(bytes32 indexed merkleRoot, uint256 indexed expiration);

    // ========================================== CONSTRUCTOR ===========================================

    /**
     * @notice Initiate the contract with a merkle tree root, a token for distribution,
     *         an expiration time for claims.
     *
     * @param _token                The token to airdrop
     * @param _rewardsRoot          The merkle root with deposits encoded into it as hash [address, amount]
     * @param _expiration           The expiration of the airdrop
     */
    constructor(IERC20 _token, bytes32 _rewardsRoot, uint256 _expiration) {
        if (address(_token) == address(0)) revert AA_ZeroAddress("token");
        if (_expiration <= block.timestamp) revert AA_ClaimingExpired();

        token = _token;
        rewardsRoot = _rewardsRoot;
        expiration = _expiration;
    }

    // ======================================= REWARDS VALIDATION ========================================

    /**
     * @notice Validate a withdraw attempt by checking merkle proof and ensuring the user has not
     *         previously withdrawn.
     *
     * @param totalGrant             The total amount of tokens the user was granted
     * @param merkleProof            The merkle proof showing the user is in the merkle tree
     */
    function _validateWithdraw(uint256 totalGrant, bytes32[] memory merkleProof) internal view {
        // merkle root must be set
        if (rewardsRoot == bytes32(0)) revert AA_NotInitialized();
        // can only claim before the expiration time
        if (block.timestamp > expiration) revert AA_ClaimingExpired();

        // validate proof and leaf hash
        bytes32 leafHash = keccak256(abi.encodePacked(msg.sender, totalGrant));
        if (!MerkleProof.verify(merkleProof, rewardsRoot, leafHash)) revert AA_NonParticipant();
    }

    // ========================================== HELPERS ===============================================

    /**
     * @notice Get the claimed amount for a user and merkle root
     *
     * @param user                  The user to check
     * @param merkleRoot            The merkle root to check
     *
     * @return claimed              The amount claimed by the user
     */
    function getClaimed(address user, bytes32 merkleRoot) external view returns (uint256) {
        return claimed[user][merkleRoot];
    }

    /**
     * @notice Set the claimed amount for a user and merkle root. The user
     *         cannot claim twice from the same root.
     *
     * @param user                  The user to set
     * @param totalGrant            The total amount claimed
     */
    function _setClaimed(address user, uint256 totalGrant) internal {
        // ensure the user has not already claimed the airdrop for this merkle root
        if (claimed[user][rewardsRoot] != 0) revert AA_AlreadyClaimed();

        claimed[user][rewardsRoot] = totalGrant;
    }

    // ===================================== ADMIN FUNCTIONALITY ========================================

    /**
     * @notice Allows governance to remove the funds in this contract once the airdrop is over.
     *         This function can only be called after the expiration time.
     *
     * @param destination        The address which will receive the remaining tokens
     */
    function reclaim(address destination) external onlyOwner {
        if (block.timestamp <= expiration) revert AA_ClaimingNotExpired();
        if (destination == address(0)) revert AA_ZeroAddress("destination");

        uint256 unclaimed = token.balanceOf(address(this));
        token.safeTransfer(destination, unclaimed);
    }

    /**
     * @notice Allows the owner to set a merkle root and its expiration timestamp. When creating
     *         a merkle trie, a users address should not be associated with multiple leaves.
     *
     * @param _merkleRoot        The new merkle root
     * @param _expiration        The new expiration timestamp for this root
     */
    function setMerkleRoot(bytes32 _merkleRoot, uint256 _expiration) external onlyOwner {
        if (_expiration <= block.timestamp) revert AA_ClaimingExpired();

        rewardsRoot = _merkleRoot;
        expiration = _expiration;

        emit SetMerkleRoot(_merkleRoot, _expiration);
    }
}

// SPDX-License-Identifier: Apache-2.0
pragma solidity >=0.7.0;

contract Authorizable {
    // This contract allows a flexible authorization scheme

    // The owner who can change authorization status
    address public owner;
    // A mapping from an address to its authorization status
    mapping(address => bool) public authorized;

    /// @dev We set the deployer to the owner
    constructor() {
        owner = msg.sender;
    }

    /// @dev This modifier checks if the msg.sender is the owner
    modifier onlyOwner() {

        require(msg.sender == owner, "Sender not owner");
        _;

    }

    /// @dev This modifier checks if an address is authorized
    modifier onlyAuthorized() {
        require(isAuthorized(msg.sender), "Sender not Authorized");
        _;
    }

    /// @dev Returns true if an address is authorized
    /// @param who the address to check
    /// @return true if authorized false if not
    function isAuthorized(address who) public view returns (bool) {
        return authorized[who];
    }

    /// @dev Privileged function authorize an address
    /// @param who the address to authorize
    function authorize(address who) external onlyOwner() {
        _authorize(who);
    }

    /// @dev Privileged function to de authorize an address
    /// @param who The address to remove authorization from
    function deauthorize(address who) external onlyOwner() {
        authorized[who] = false;
    }

    /// @dev Function to change owner
    /// @param who The new owner address
    function setOwner(address who) public onlyOwner() {
        owner = who;
    }

    /// @dev Inheritable function which authorizes someone
    /// @param who the address to authorize
    function _authorize(address who) internal {
        authorized[who] = true;
    }
}

// SPDX-License-Identifier: MIT

pragma solidity 0.8.18;

interface IAirdropSingleSidedStaking {
    enum Lock {
        Short,
        Medium,
        Long
    }

    function airdropReceive(
        address recipient,
        uint256 amount,
        address delegation,
        Lock lock
    ) external;
}

// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

/**
 * @dev Interface of the ERC20 standard as defined in the EIP.
 */
interface IERC20 {
    /**
     * @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 `recipient`.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transfer(address recipient, uint256 amount) external returns (bool);

    /**
     * @dev Returns the remaining number of tokens that `spender` will be
     * allowed to spend on behalf of `owner` through {transferFrom}. This is
     * zero by default.
     *
     * This value changes when {approve} or {transferFrom} are called.
     */
    function allowance(address owner, address spender) external view returns (uint256);

    /**
     * @dev Sets `amount` as the allowance of `spender` over the caller's tokens.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * IMPORTANT: Beware that changing an allowance with this method brings the risk
     * that someone may use both the old and the new allowance by unfortunate
     * transaction ordering. One possible solution to mitigate this race
     * condition is to first reduce the spender's allowance to 0 and set the
     * desired value afterwards:
     * https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
     *
     * Emits an {Approval} event.
     */
    function approve(address spender, uint256 amount) external returns (bool);

    /**
     * @dev Moves `amount` tokens from `sender` to `recipient` using the
     * allowance mechanism. `amount` is then deducted from the caller's
     * allowance.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transferFrom(
        address sender,
        address recipient,
        uint256 amount
    ) external returns (bool);

    /**
     * @dev Emitted when `value` tokens are moved from one account (`from`) to
     * another (`to`).
     *
     * Note that `value` may be zero.
     */
    event Transfer(address indexed from, address indexed to, uint256 value);

    /**
     * @dev Emitted when the allowance of a `spender` for an `owner` is set by
     * a call to {approve}. `value` is the new allowance.
     */
    event Approval(address indexed owner, address indexed spender, uint256 value);
}

// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

/**
 * @dev These functions deal with verification of Merkle Trees proofs.
 *
 * The proofs can be generated using the JavaScript library
 * https://github.com/miguelmota/merkletreejs[merkletreejs].
 * Note: the hashing algorithm should be keccak256 and pair sorting should be enabled.
 *
 * See `test/utils/cryptography/MerkleProof.test.js` for some examples.
 */
library MerkleProof {
    /**
     * @dev Returns true if a `leaf` can be proved to be a part of a Merkle tree
     * defined by `root`. For this, a `proof` must be provided, containing
     * sibling hashes on the branch from the leaf to the root of the tree. Each
     * pair of leaves and each pair of pre-images are assumed to be sorted.
     */
    function verify(
        bytes32[] memory proof,
        bytes32 root,
        bytes32 leaf
    ) internal pure returns (bool) {
        bytes32 computedHash = leaf;

        for (uint256 i = 0; i < proof.length; i++) {
            bytes32 proofElement = proof[i];

            if (computedHash <= proofElement) {
                // Hash(current computed hash + current element of the proof)
                computedHash = keccak256(abi.encodePacked(computedHash, proofElement));
            } else {
                // Hash(current element of the proof + current computed hash)
                computedHash = keccak256(abi.encodePacked(proofElement, computedHash));
            }
        }

        // Check if the computed hash (root) is equal to the provided root
        return computedHash == root;
    }
}

// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

/**
 * @dev Contract module that helps prevent reentrant calls to a function.
 *
 * Inheriting from `ReentrancyGuard` will make the {nonReentrant} modifier
 * available, which can be applied to functions to make sure there are no nested
 * (reentrant) calls to them.
 *
 * Note that because there is a single `nonReentrant` guard, functions marked as
 * `nonReentrant` may not call one another. This can be worked around by making
 * those functions `private`, and then adding `external` `nonReentrant` entry
 * points to them.
 *
 * TIP: If you would like to learn more about reentrancy and alternative ways
 * to protect against it, check out our blog post
 * https://blog.openzeppelin.com/reentrancy-after-istanbul/[Reentrancy After Istanbul].
 */
abstract contract ReentrancyGuard {
    // Booleans are more expensive than uint256 or any type that takes up a full
    // word because each write operation emits an extra SLOAD to first read the
    // slot's contents, replace the bits taken up by the boolean, and then write
    // back. This is the compiler's defense against contract upgrades and
    // pointer aliasing, and it cannot be disabled.

    // The values being non-zero value makes deployment a bit more expensive,
    // but in exchange the refund on every call to nonReentrant will be lower in
    // amount. Since refunds are capped to a percentage of the total
    // transaction's gas, it is best to keep them low in cases like this one, to
    // increase the likelihood of the full refund coming into effect.
    uint256 private constant _NOT_ENTERED = 1;
    uint256 private constant _ENTERED = 2;

    uint256 private _status;

    constructor() {
        _status = _NOT_ENTERED;
    }

    /**
     * @dev Prevents a contract from calling itself, directly or indirectly.
     * Calling a `nonReentrant` function from another `nonReentrant`
     * function is not supported. It is possible to prevent this from happening
     * by making the `nonReentrant` function external, and make it call a
     * `private` function that does the actual work.
     */
    modifier nonReentrant() {
        // On the first call to nonReentrant, _notEntered will be true
        require(_status != _ENTERED, "ReentrancyGuard: reentrant call");

        // Any calls to nonReentrant after this point will fail
        _status = _ENTERED;

        _;

        // By storing the original value once again, a refund is triggered (see
        // https://eips.ethereum.org/EIPS/eip-2200)
        _status = _NOT_ENTERED;
    }
}

// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

import "../IERC20.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;

    function safeTransfer(
        IERC20 token,
        address to,
        uint256 value
    ) internal {
        _callOptionalReturn(token, abi.encodeWithSelector(token.transfer.selector, to, value));
    }

    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));
    }

    function safeIncreaseAllowance(
        IERC20 token,
        address spender,
        uint256 value
    ) internal {
        uint256 newAllowance = token.allowance(address(this), spender) + value;
        _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
    }

    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");
            uint256 newAllowance = oldAllowance - value;
            _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
        }
    }

    /**
     * @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");
        if (returndata.length > 0) {
            // Return data is optional
            require(abi.decode(returndata, (bool)), "SafeERC20: ERC20 operation did not succeed");
        }
    }
}

{
  "compilationTarget": {
    "contracts/token/airdrop/AirdropSeason1.sol": "AirdropSeason1"
  },
  "evmVersion": "paris",
  "libraries": {},
  "metadata": {
    "bytecodeHash": "none"
  },
  "optimizer": {
    "enabled": true,
    "runs": 999999
  },
  "remappings": []
}