pragma solidity ^0.4.15;


/// @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);

  /*
   *  Constants
   */
  uint constant public MAX_OWNER_COUNT = 50;

  /*
   *  Storage
   */
  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;
  }

  /*
   *  Modifiers
   */
  modifier onlyWallet() {
    require(msg.sender == address(this));
    _;
  }

  modifier ownerDoesNotExist(address owner) {
    require(!isOwner[owner]);
    _;
  }

  modifier ownerExists(address owner) {
    require(isOwner[owner]);
    _;
  }

  modifier transactionExists(uint transactionId) {
    require(transactions[transactionId].destination != 0);
    _;
  }

  modifier confirmed(uint transactionId, address owner) {
    require(confirmations[transactionId][owner]);
    _;
  }

  modifier notConfirmed(uint transactionId, address owner) {
    require(!confirmations[transactionId][owner]);
    _;
  }

  modifier notExecuted(uint transactionId) {
    require(!transactions[transactionId].executed);
    _;
  }

  modifier notNull(address _address) {
    require(_address != 0);
    _;
  }

  modifier validRequirement(uint ownerCount, uint _required) {
    require(ownerCount <= MAX_OWNER_COUNT
    && _required <= ownerCount
    && _required != 0
    && ownerCount != 0);
    _;
  }

  /// @dev Fallback function allows to deposit ether.
  function()
  payable
  {
    if (msg.value > 0)
      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.
  function MultiSigWallet(address[] _owners, uint _required)
  public
  validRequirement(_owners.length, _required)
  {
    for (uint i=0; i<_owners.length; i++) {
      require(!isOwner[_owners[i]] && _owners[i] != 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;
      }
    owners.length -= 1;
    if (required > owners.length)
      changeRequirement(owners.length);
    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 data)
  public
  returns (uint transactionId)
  {
    transactionId = addTransaction(destination, value, data);
    confirmTransaction(transactionId);
  }

  /// @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;
      if (external_call(txn.destination, txn.value, txn.data.length, txn.data))
        Execution(transactionId);
      else {
        ExecutionFailure(transactionId);
        txn.executed = false;
      }
    }
  }

  // call has been separated into its own function in order to take advantage
  // of the Solidity's code generator to produce a loop that copies tx.data into memory.
  function external_call(address destination, uint value, uint dataLength, bytes data) private returns (bool) {
    bool result;
    assembly {
      let x := mload(0x40)   // "Allocate" memory for output (0x40 is where "free memory" pointer is stored by convention)
      let d := add(data, 32) // First 32 bytes are the padded length of data, so exclude that
      result := call(
      sub(gas, 34710),   // 34710 is the value that solidity is currently emitting
      // It includes callGas (700) + callVeryLow (3, to pay for SUB) + callValueTransferGas (9000) +
      // callNewAccountGas (25000, in case the destination address does not exist and needs creating)
      destination,
      value,
      d,
      dataLength,        // Size of the input (in bytes) - this is what fixes the padding problem
      x,
      0                  // Output is ignored, therefore the output size is zero
      )
    }
    return result;
  }

  /// @dev Returns the confirmation status of a transaction.
  /// @param transactionId Transaction ID.
  /// @return Confirmation status.
  function isConfirmed(uint transactionId)
  public
  constant
  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;
    }
  }

  /*
   * 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 data)
  internal
  notNull(destination)
  returns (uint transactionId)
  {
    transactionId = transactionCount;
    transactions[transactionId] = Transaction({
      destination: destination,
      value: value,
      data: data,
      executed: false
      });
    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
  constant
  returns (uint count)
  {
    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
  constant
  returns (uint count)
  {
    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
  constant
  returns (address[])
  {
    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
  constant
  returns (address[] _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
  constant
  returns (uint[] _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];
  }
}