// File: contracts/MerkleDrop.sol



// SPDX-License-Identifier: AGPL-3.0-or-later

pragma solidity ^0.8.6;

import { MerkleProof } from "@openzeppelin/contracts/utils/cryptography/MerkleProof.sol";
import { IERC20 } from "@openzeppelin/contracts/token/ERC20/IERC20.sol";
import { SafeERC20 } from "@openzeppelin/contracts/token/ERC20/utils/SafeERC20.sol";

import { Ownable } from "@openzeppelin/contracts/access/Ownable.sol";
import { PackedBooleanArray } from "packed-solidity-arrays/contracts/PackedBooleanArray.sol";

contract MerkleDrop is Ownable {
  using SafeERC20 for IERC20;
  using PackedBooleanArray for PackedBooleanArray.PackedArray;

  event Claimed(address claimant, uint256 tranche, uint256 balance);
  event TrancheAdded(uint256 tranche, bytes32 merkleRoot, uint256 totalAmount, string uri);
  event TrancheExpired(uint256 tranche);
  event FunderAdded(address indexed _address);
  event FunderRemoved(address indexed _address);

  IERC20 public immutable token;

  mapping(uint256 => bytes32) public merkleRoots;
  mapping(address => PackedBooleanArray.PackedArray) internal claimed;
  mapping(address => bool) public funders;
  uint256 tranches;

  /**
   * @dev Modifier to allow function calls only from funder addresses.
   */
  modifier onlyFunder() {
    require(funders[msg.sender], "Must be a funder");
    _;
  }

  constructor(IERC20 _token) {
    token = _token;
  }

  function hasClaimed(address _user, uint256 _tranche) external view returns (bool) {
    return claimed[_user].getValue(_tranche);
  }

  /***************************************
                    ADMIN
  ****************************************/

  /**
   * @dev Add a tranche with new allocations to claim.
   * @param _merkleRoot  Merkle root of the tree of accounts/balances
   * @param _totalAllocation Total tokens allocated in the tranche
   * @param _uri URI representing the tranche, e.g. an IPFS hash of the allocations
   */
  function seedNewAllocations(
    bytes32 _merkleRoot,
    uint256 _totalAllocation,
    string memory _uri
  ) public onlyFunder returns (uint256 trancheId) {
    token.safeTransferFrom(msg.sender, address(this), _totalAllocation);

    trancheId = tranches;
    merkleRoots[trancheId] = _merkleRoot;

    tranches += 1;

    emit TrancheAdded(trancheId, _merkleRoot, _totalAllocation, _uri);
  }

  function expireTranche(uint256 _trancheId) public onlyFunder {
    merkleRoots[_trancheId] = bytes32(0);

    emit TrancheExpired(_trancheId);
  }

  /**
   * @dev Allows the owner to add a new funder
   * @param _address  Funder to add
   */
  function addFunder(address _address) public onlyOwner {
    require(_address != address(0), "Address is zero");
    require(!funders[_address], "Already a funder");

    funders[_address] = true;

    emit FunderAdded(_address);
  }

  /**
   * @dev Allows the owner to remove an inactive funder
   * @param _address  Funder to remove
   */
  function removeFunder(address _address) external onlyOwner {
    require(_address != address(0), "Address is zero");
    require(funders[_address], "Address is not a funder");

    funders[_address] = false;

    emit FunderRemoved(_address);
  }

  /***************************************
                  CLAIMING
  ****************************************/

  function claimTranche(
    address _claimer,
    uint256 _tranche,
    uint256 _balance,
    bytes32[] memory _merkleProof
  ) public {
    _claimTranche(_claimer, _tranche, _balance, _merkleProof);
    _disburse(_claimer, _balance);
  }

  function claimTranches(
    address _claimer,
    uint256[] memory _ids,
    uint256[] memory _balances,
    bytes32[][] memory _merkleProofs
  ) public {
    uint256 len = _ids.length;

    require(len > 0, "Must claim some tranches");
    require(len == _balances.length && len == _merkleProofs.length, "Mismatching inputs");

    uint256 totalBalance = 0;
    for (uint256 i = 0; i < len; i++) {
      _claimTranche(_claimer, _ids[i], _balances[i], _merkleProofs[i]);
      totalBalance += _balances[i];
    }

    _disburse(_claimer, totalBalance);
  }

  function verifyClaim(
    address _claimer,
    uint256 _tranche,
    uint256 _balance,
    bytes32[] memory _merkleProof
  ) public view returns (bool valid) {
    return _verifyClaim(_claimer, _tranche, _balance, _merkleProof);
  }

  /***************************************
              CLAIMING - INTERNAL
  ****************************************/

  function _claimTranche(
    address _claimer,
    uint256 _tranche,
    uint256 _balance,
    bytes32[] memory _merkleProof
  ) private {
    require(_tranche < tranches, "Tranche cannot be in the future");
    require(!claimed[_claimer].getValue(_tranche), "Address has already claimed");
    require(_verifyClaim(_claimer, _tranche, _balance, _merkleProof), "Incorrect merkle proof");
    claimed[_claimer].setValue(_tranche, true);
    emit Claimed(_claimer, _tranche, _balance);
  }

  function _verifyClaim(
    address _claimer,
    uint256 _tranche,
    uint256 _balance,
    bytes32[] memory _merkleProof
  ) private view returns (bool valid) {
    bytes32 leaf = keccak256(abi.encodePacked(_claimer, _balance));
    return MerkleProof.verify(_merkleProof, merkleRoots[_tranche], leaf);
  }

  function _disburse(address _claimer, uint256 _balance) private {
    if (_balance > 0) {
      token.safeTransfer(_claimer, _balance);
    } else {
      revert("No balance would be transferred - not going to waste your gas");
    }
  }
}

// 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: @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/utils/SafeERC20.sol



// 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'
        // solhint-disable-next-line max-line-length
        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
            // solhint-disable-next-line max-line-length
            require(abi.decode(returndata, (bool)), "SafeERC20: ERC20 operation did not succeed");
        }
    }
}

// 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 () {
        address msgSender = _msgSender();
        _owner = msgSender;
        emit OwnershipTransferred(address(0), 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 {
        emit OwnershipTransferred(_owner, address(0));
        _owner = 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");
        emit OwnershipTransferred(_owner, newOwner);
        _owner = newOwner;
    }
}

// File: packed-solidity-arrays/contracts/PackedBooleanArray.sol



// SPDX-License-Identifier: GPL-3.0

pragma solidity ^0.8.0;

/// @title PackedBooleanArray
/// @author alsco77
library PackedBooleanArray {
    using PackedBooleanArray for PackedBooleanArray.PackedArray;

    struct PackedArray {
        uint256[] array;
    }

    // Verifies that the higher level count is correct, and that the last uint256 is left packed with 0's
    function initStruct(uint256[] memory _arr, uint256 _len)
        internal
        pure
        returns (PackedArray memory)
    {
        uint256 actualLength = _arr.length;
        uint256 len0 = _len / 256;
        require(actualLength == len0 + 1, "Invalid arr length");

        uint256 len1 = _len % 256;
        uint256 leftPacked = uint256(_arr[len0] >> len1);
        require(leftPacked == 0, "Invalid uint256 packing");

        return PackedArray(_arr);
    }

    // Gets the value at _index, or returns false if the _index does not exist
    function getValue(PackedArray storage ref, uint256 _index) internal view returns (bool) {
        uint256 aid = _index / 256;
        if(aid >= ref.array.length) return false;

        uint256 iid = _index % 256;
        return (ref.array[aid] >> iid) & 1 == 1 ? true : false;
    }

    // Sets the value at a given _index, adding a new entry to the array and updating length if necessary
    function setValue(
        PackedArray storage ref,
        uint256 _index,
        bool _value
    ) internal {
        // 0. Ensure array is long enough, and extend if necessary
        uint256 aid = _index / 256;
        if(aid >= ref.array.length) {
            uint256 delta = aid - ref.array.length + 1;
            for(uint256 i = 0; i < delta; i++){
                ref.array.push(0);
            }
        }

        uint256 iid = _index % 256;

        // 1. Do an & between old value and a mask
        uint256 mask = uint256(~(uint256(1) << iid));
        uint256 masked = ref.array[aid] & mask;

        // 2. Do an |= between (1) and positioned _value
        mask = uint256(_value ? 1 : 0) << (iid);
        ref.array[aid] = masked | mask;
    }
}

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



// 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;
        // solhint-disable-next-line no-inline-assembly
        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");

        // solhint-disable-next-line avoid-low-level-calls, avoid-call-value
        (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");

        // solhint-disable-next-line avoid-low-level-calls
        (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");

        // solhint-disable-next-line avoid-low-level-calls
        (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");

        // solhint-disable-next-line avoid-low-level-calls
        (bool success, bytes memory returndata) = target.delegatecall(data);
        return _verifyCallResult(success, returndata, errorMessage);
    }

    function _verifyCallResult(bool success, bytes memory returndata, string memory errorMessage) private 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

                // solhint-disable-next-line no-inline-assembly
                assembly {
                    let returndata_size := mload(returndata)
                    revert(add(32, returndata), returndata_size)
                }
            } else {
                revert(errorMessage);
            }
        }
    }
}

// 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) {
        this; // silence state mutability warning without generating bytecode - see https://github.com/ethereum/solidity/issues/2691
        return msg.data;
    }
}