// File: @openzeppelin/contracts/access/Ownable.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

import "../utils/Context.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 Ownable is Context {
    address private _owner;

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

    /**
     * @dev Initializes the contract setting the deployer as the initial owner.
     */
    constructor() {
        _setOwner(_msgSender());
    }

    /**
     * @dev Returns the address of the current owner.
     */
    function owner() public view virtual returns (address) {
        return _owner;
    }

    /**
     * @dev Throws if called by any account other than the owner.
     */
    modifier onlyOwner() {
        require(owner() == _msgSender(), "Ownable: caller is not the owner");
        _;
    }

    /**
     * @dev Leaves the contract without owner. It will not be possible to call
     * `onlyOwner` functions anymore. Can only be called by the current owner.
     *
     * NOTE: Renouncing ownership will leave the contract without an owner,
     * thereby removing any functionality that is only available to the owner.
     */
    function renounceOwnership() public virtual onlyOwner {
        _setOwner(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");
        _setOwner(newOwner);
    }

    function _setOwner(address newOwner) private {
        address oldOwner = _owner;
        _owner = newOwner;
        emit OwnershipTransferred(oldOwner, newOwner);
    }
}

// File: @openzeppelin/contracts/security/ReentrancyGuard.sol



// 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;
    }
}

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



// 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);
}

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



// SPDX-License-Identifier: MIT

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/contracts/utils/Context.sol



// SPDX-License-Identifier: MIT

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/utils/cryptography/MerkleProof.sol



// 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;
    }
}

// File: contracts/MerkleProofUnoClaim.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

import {ReentrancyGuard} from "@openzeppelin/contracts/security/ReentrancyGuard.sol";
import {Ownable} from "@openzeppelin/contracts/access/Ownable.sol";
import {IERC20Metadata} from "@openzeppelin/contracts/token/ERC20/extensions/IERC20Metadata.sol";
import {MerkleProof} from "@openzeppelin/contracts/utils/cryptography/MerkleProof.sol";
import {IMerkleProofUnoClaim} from "./interfaces/IMerkleProofUnoClaim.sol";
import {TransferHelper} from "./libraries/TransferHelper.sol";

contract MerkleProofUnoClaim is IMerkleProofUnoClaim, Ownable, ReentrancyGuard {
    address public immutable claimToken;
    uint128 public constant cohortStartTime = 1633046401;
    bytes32 public merkleRoot;

    mapping(address => UserInfo) public userInfo;

    constructor(address _token) {
        claimToken = _token;
    }

    function airdropUNO(
        uint128 _index,
        address _account,
        uint128 _amount,
        bytes32[] calldata _merkleProof
    ) external override nonReentrant {
        require(msg.sender == _account, "UnoRe: No msg sender.");
        // Verify the merkle proof.
        bytes32 node = keccak256(abi.encodePacked(uint256(_index), _account, uint256(_amount)));
        require(MerkleProof.verify(_merkleProof, merkleRoot, node), "UnoRe: Invalid proof.");
        uint128 lastClaimTime = userInfo[_account].lastClaimTime;
        require(lastClaimTime < cohortStartTime + 365 days, "UnoRe: Last claim time over");
        require(block.timestamp >= cohortStartTime, "UnoRe: Cohort not started yet");
        require(block.timestamp > lastClaimTime, "UnoRe: Too short time diff ");
        uint128 diffTime = lastClaimTime > 0
            ? uint128(block.timestamp) - lastClaimTime
            : uint128(block.timestamp) - cohortStartTime;
        if (diffTime > 365 days) {
            diffTime = 365 days;
        }
        uint128 amountForClaim = (_amount * diffTime) / 365 days;
        require(userInfo[_account].claimedAmount + amountForClaim <= _amount, "UnoRe: Claimed amount overflow");
        TransferHelper.safeTransfer(claimToken, _account, amountForClaim);

        // Update claimed amount.
        userInfo[_account].claimedAmount += amountForClaim;
        userInfo[_account].lastClaimTime = uint128(block.timestamp);

        emit LogAirdropUNO(_index, _account, _amount, amountForClaim);
    }

    function setMerkleRoot(bytes32 _merkleRoot) external onlyOwner nonReentrant {
        require(_merkleRoot != bytes32(0), "UnoRe: Zero merkleRoot bytes.");
        merkleRoot = _merkleRoot;
        emit LogSetMerkleRoot(address(this), _merkleRoot);
    }

    function emergencyWithdraw(
        address _currency,
        address _to,
        uint256 _amount
    ) external onlyOwner {
        require(_to != address(0), "UnoRe: zero address reward");
        if (_currency == address(0)) {
            if (address(this).balance >= _amount) {
                TransferHelper.safeTransferETH(_to, _amount);
                emit LogEmergencyWithdraw(address(this), _currency, _to, _amount);
            } else {
                if (address(this).balance > 0) {
                    uint256 withdrawAmount = address(this).balance;
                    TransferHelper.safeTransferETH(_to, withdrawAmount);
                    emit LogEmergencyWithdraw(address(this), _currency, _to, withdrawAmount);
                }
            }
        } else {
            if (IERC20Metadata(_currency).balanceOf(address(this)) >= _amount) {
                TransferHelper.safeTransfer(_currency, _to, _amount);
                emit LogEmergencyWithdraw(address(this), _currency, _to, _amount);
            } else {
                if (IERC20Metadata(_currency).balanceOf(address(this)) > 0) {
                    uint256 withdrawAmount = IERC20Metadata(_currency).balanceOf(address(this));
                    TransferHelper.safeTransfer(_currency, _to, withdrawAmount);
                    emit LogEmergencyWithdraw(address(this), _currency, _to, withdrawAmount);
                }
            }
        }
    }
}

// File: contracts/interfaces/IMerkleProofUnoClaim.sol



// SPDX-License-Identifier: UNLICENSED
pragma solidity ^0.8.0;

// Allows anyone to claim a token if they exist in a merkle root.
interface IMerkleProofUnoClaim {
    struct UserInfo {
        uint128 claimedAmount;
        uint128 lastClaimTime;
    }

    // Claim the given amount of the token to the given address. Reverts if the inputs are invalid.
    function airdropUNO(
        uint128 _index,
        address _account,
        uint128 _amount,
        bytes32[] calldata _merkleProof
    ) external;

    // This event is triggered whenever a call to #claim succeeds.
    event LogAirdropUNO(uint128 _index, address _account, uint128 _totalClaimAmount, uint128 _claimAmount);
    event LogSetMerkleRoot(address indexed _contract, bytes32 _merkleRoot);
    event LogEmergencyWithdraw(address indexed _from, address indexed _currency, address _to, uint256 _amount);
}

// File: contracts/libraries/TransferHelper.sol



// SPDX-License-Identifier: GPL-3.0-or-later
pragma solidity ^0.8.0;

// from Uniswap TransferHelper library
library TransferHelper {
    function safeApprove(
        address token,
        address to,
        uint256 value
    ) internal {
        // bytes4(keccak256(bytes('approve(address,uint256)')));
        (bool success, bytes memory data) = token.call(abi.encodeWithSelector(0x095ea7b3, to, value));
        require(success && (data.length == 0 || abi.decode(data, (bool))), "TransferHelper::safeApprove: approve failed");
    }

    function safeTransfer(
        address token,
        address to,
        uint256 value
    ) internal {
        // bytes4(keccak256(bytes('transfer(address,uint256)')));
        (bool success, bytes memory data) = token.call(abi.encodeWithSelector(0xa9059cbb, to, value));
        require(success && (data.length == 0 || abi.decode(data, (bool))), "TransferHelper::safeTransfer: transfer failed");
    }

    function safeTransferFrom(
        address token,
        address from,
        address to,
        uint256 value
    ) internal {
        // bytes4(keccak256(bytes('transferFrom(address,address,uint256)')));
        (bool success, bytes memory data) = token.call(abi.encodeWithSelector(0x23b872dd, from, to, value));
        require(success && (data.length == 0 || abi.decode(data, (bool))), "TransferHelper::transferFrom: transferFrom failed");
    }

    function safeTransferETH(address to, uint256 value) internal {
        (bool success, ) = to.call{value: value}(new bytes(0));
        require(success, "TransferHelper::safeTransferETH: ETH transfer failed");
    }
}