pragma solidity 0.6.6;

/*
 * @title Multisignature wallet - Allows multiple parties to agree on transactions before execution.
 * @author Stefan George - <stefan.george@consensys.net>
 */
contract MultiSigWallet {

    /*
     *  Events
     */
    event Confirmation(address indexed sender, uint indexed transactionId);
    event Revocation(address indexed sender, uint indexed transactionId);
    event Submission(uint indexed transactionId);
    event Execution(uint indexed transactionId);
    event ExecutionFailure(uint indexed transactionId);
    event Deposit(address indexed sender, uint value);
    event OwnerAddition(address indexed owner);
    event OwnerRemoval(address indexed owner);
    event RequirementChange(uint required);

    uint constant public MAX_OWNER_COUNT = 50;
    bytes32  constant internal projectHash = keccak256(abi.encodePacked("CLAIM"));

    mapping (uint => Transaction) public transactions;
    mapping (uint => mapping (address => bool)) public confirmations;
    mapping (address => bool) public isOwner;
    address[] public owners;
    uint public required;
    uint public transactionCount;

    struct Transaction {
        address destination;
        uint value;
        bytes data;
        bool executed;
        uint submitTime;
    }

    /*
     *  Modifiers
     */
    modifier onlyWallet() {
        require(msg.sender == address(this), "msg.sender != address(this)");
        _;
    }

    modifier ownerDoesNotExist(address owner) {
        require(!isOwner[owner], "is already owner");
        _;
    }

    modifier ownerExists(address owner) {
        require(isOwner[owner],"is not owner");
        _;
    }

    modifier transactionExists(uint transactionId) {
        require(transactions[transactionId].destination != address(0),"transactionId is not exists");
        _;
    }

    modifier confirmed(uint transactionId, address owner) {
        require(confirmations[transactionId][owner],"is not confirmed");
        _;
    }

    modifier notConfirmed(uint transactionId, address owner) {
        require(!confirmations[transactionId][owner],"already confirmed");
        _;
    }

    modifier notExecuted(uint transactionId) {
        require(!transactions[transactionId].executed,"already executed");
        _;
    }

    modifier notNull(address _address) {
        require(_address != address(0),"_address == address(0)");
        _;
    }

    modifier validRequirement(uint ownerCount, uint _required) {
        require(ownerCount <= MAX_OWNER_COUNT
            && _required <= ownerCount
            && _required != 0
            && ownerCount != 0,"error: validRequirement()");
        _;
    }

    /// @dev Fallback function allows to deposit ether.
    fallback() external {
    }

    receive() external payable { 
        if (msg.value > 0)
            emit Deposit(msg.sender, msg.value);
    }

    /*
     * Public functions
     */
    /// @dev Contract constructor sets initial owners and required number of confirmations.
    /// @param _owners List of initial owners.
    /// @param _required Number of required confirmations.
    constructor(address[] memory _owners, uint _required)
        public
        validRequirement(_owners.length, _required)
    {
        for (uint i=0; i<_owners.length; i++) {
            require(!isOwner[_owners[i]] && _owners[i] != address(0));
            isOwner[_owners[i]] = true;
        }
        owners = _owners;
        required = _required;
    }

    /// @dev Allows to add a new owner. Transaction has to be sent by wallet.
    /// @param owner Address of new owner.
    function addOwner(address owner)
        public
        onlyWallet
        ownerDoesNotExist(owner)
        notNull(owner)
        validRequirement(owners.length + 1, required)
    {
        isOwner[owner] = true;
        owners.push(owner);
        OwnerAddition(owner);
    }

    /// @dev Allows to remove an owner. Transaction has to be sent by wallet.
    /// @param owner Address of owner.
    function removeOwner(address owner)
        public
        onlyWallet
        ownerExists(owner)
    {
        isOwner[owner] = false;
        for (uint i=0; i<owners.length - 1; i++)
            if (owners[i] == owner) {
                owners[i] = owners[owners.length - 1];
                break;
            }
        if (required > (owners.length - 1))
            changeRequirement(owners.length - 1);
        OwnerRemoval(owner);
    }

    /// @dev Allows to replace an owner with a new owner. Transaction has to be sent by wallet.
    /// @param owner Address of owner to be replaced.
    /// @param newOwner Address of new owner.
    function replaceOwner(address owner, address newOwner)
        public
        onlyWallet
        ownerExists(owner)
        ownerDoesNotExist(newOwner)
    {
        for (uint i=0; i<owners.length; i++)
            if (owners[i] == owner) {
                owners[i] = newOwner;
                break;
            }
        isOwner[owner] = false;
        isOwner[newOwner] = true;
        OwnerRemoval(owner);
        OwnerAddition(newOwner);
    }

    /// @dev Allows to change the number of required confirmations. Transaction has to be sent by wallet.
    /// @param _required Number of required confirmations.
    function changeRequirement(uint _required)
        public
        onlyWallet
        validRequirement(owners.length, _required)
    {
        required = _required;
        RequirementChange(_required);
    }

    /*@dev Allows an owner to submit and confirm a transaction.
    @param destination Transaction target address.
    @param value Transaction ether value.
    @param data Transaction data payload.
    @return Returns transaction ID.*/
    function submitTransaction(address destination, uint value, bytes memory data)
        public
        returns (uint transactionId)
    {
        transactionId = addTransaction(destination, value, data);
        confirmTransaction(transactionId);
    }

    /// @dev Allows an owner to batch confirm  transactions.
    /// @param transactionIdArray Transaction ID array.
    function batchConfirmTransaction(uint[] memory transactionIdArray) public
    {
        for(uint i = 0; i < transactionIdArray.length; i++ ) {
            confirmTransaction(transactionIdArray[i]);
        }
    }
    
    /// @dev Allows an owner to confirm a transaction.
    /// @param transactionId Transaction ID.
    function confirmTransaction(uint transactionId) 
        public 
        ownerExists(msg.sender)
        transactionExists(transactionId)
        notConfirmed(transactionId, msg.sender)
    {
        confirmations[transactionId][msg.sender] = true;
        Confirmation(msg.sender, transactionId);
        executeTransaction(transactionId);
    }

    /// @dev Allows an owner to revoke a confirmation for a transaction.
    /// @param transactionId Transaction ID.
    function revokeConfirmation(uint transactionId)
        public
        ownerExists(msg.sender)
        confirmed(transactionId, msg.sender)
        notExecuted(transactionId)
    {
        confirmations[transactionId][msg.sender] = false;
        Revocation(msg.sender, transactionId);
    }

    /// @dev Allows anyone to execute a confirmed transaction.
    /// @param transactionId Transaction ID.
    function executeTransaction(uint transactionId)
        public
        ownerExists(msg.sender)
        confirmed(transactionId, msg.sender)
        notExecuted(transactionId)
    {
        if (isConfirmed(transactionId)) {
            Transaction storage txn = transactions[transactionId];
            txn.executed = true;
            // address(txn.destination).call(abi.encodeWithSignature(txn.data))
            (bool success, bytes memory data) = txn.destination.call{value: txn.value}(txn.data);
            if (success)
                emit Execution(transactionId);
            else {
                emit ExecutionFailure(transactionId);
                txn.executed = false;
            }
        }
    }

    /// @dev Returns the confirmation status of a transaction.
    /// @param transactionId Transaction ID.
    /// @return Confirmation status.
    function isConfirmed(uint transactionId)
        public
        view
        returns (bool)
    {
        uint count = 0;
        for (uint i=0; i<owners.length; i++) {
            if (confirmations[transactionId][owners[i]])
                count += 1;
            if (count == required)
                return true;
        }
        return false;
    }

    /*
     * Internal functions
     */
    /*@dev Adds a new transaction to the transaction mapping, if transaction does not exist yet.
    @param destination Transaction target address.
    @param value Transaction ether value.
    @param data Transaction data payload.
    @return Returns transaction ID.*/
    function addTransaction(address destination, uint value, bytes memory data)
        internal
        notNull(destination)
        returns (uint transactionId)
    {
        transactionId = transactionCount;
        transactions[transactionId] = Transaction({
            destination: destination,
            value: value,
            data: data,
            executed: false,
            submitTime: block.timestamp
        });
        transactionCount += 1;
        Submission(transactionId);
    }

    /*
     * Web3 call functions
     */
    /*@dev Returns number of confirmations of a transaction.
    @param transactionId Transaction ID.
    @return Number of confirmations.*/
    function getConfirmationCount(uint transactionId)
        public
        view
        returns (uint count)
    {
        count = 0;
        for (uint i=0; i<owners.length; i++)
            if (confirmations[transactionId][owners[i]])
                count += 1;
    }

    /*@dev Returns total number of transactions after filers are applied.
    @param pending Include pending transactions.
    @param executed Include executed transactions.
    @return Total number of transactions after filters are applied.*/
    function getTransactionCount(bool pending, bool executed)
        public
        view
        returns (uint count)
    {
        count = 0;
        for (uint i=0; i<transactionCount; i++)
            if (   pending && !transactions[i].executed
                || executed && transactions[i].executed)
                count += 1;
    }

    /// @dev Returns list of owners.
    /// @return List of owner addresses.
    function getOwners()
        public
        view
        returns (address[] memory)
    {
        return owners;
    }

    /*@dev Returns array with owner addresses, which confirmed transaction.
    @param transactionId Transaction ID.
    @return Returns array of owner addresses.*/
    function getConfirmations(uint transactionId)
        public
        view
        returns (address[] memory _confirmations)
    {
        address[] memory confirmationsTemp = new address[](owners.length);
        uint count = 0;
        uint i;
        for (i=0; i<owners.length; i++)
            if (confirmations[transactionId][owners[i]]) {
                confirmationsTemp[count] = owners[i];
                count += 1;
            }
        _confirmations = new address[](count);
        for (i=0; i<count; i++)
            _confirmations[i] = confirmationsTemp[i];
    }

    /*@dev Returns list of transaction IDs in defined range.
    @param from Index start position of transaction array.
    @param to Index end position of transaction array.
    @param pending Include pending transactions.
    @param executed Include executed transactions.
    @return Returns array of transaction IDs.*/
    function getTransactionIds(uint from, uint to, bool pending, bool executed)
        public
        view
        returns (uint[] memory _transactionIds)
    {
        uint[] memory transactionIdsTemp = new uint[](transactionCount);
        uint count = 0;
        uint i;
        for (i=0; i<transactionCount; i++)
            if (   pending && !transactions[i].executed
                || executed && transactions[i].executed)
            {
                transactionIdsTemp[count] = i;
                count += 1;
            }
        _transactionIds = new uint[](to - from);
        for (i=from; i<to; i++)
            _transactionIds[i - from] = transactionIdsTemp[i];
    }

    function getBlockTimestamp() view internal returns (uint) {
        return block.timestamp;
    }
}