// Contract: WalletSimple
// Target function: function sendMultiSig(
// SPDX-License-Identifier: Apache-2.0
pragma solidity 0.7.5;

/**
 * Contract that exposes the needed erc20 token functions
 */

abstract contract ERC20Interface {
  // Send _value amount of tokens to address _to
  function transfer(address _to, uint256 _value)
    public
    virtual
    returns (bool success);

  // Get the account balance of another account with address _owner
  function balanceOf(address _owner)
    public
    virtual
    view
    returns (uint256 balance);
}

/**
 * Contract that will forward any incoming Ether to the creator of the contract
 *
 */
contract Forwarder {
  // Address to which any funds sent to this contract will be forwarded
  address public parentAddress;
  event ForwarderDeposited(address from, uint256 value, bytes data);

  /**
   * Initialize the contract, and sets the destination address to that of the creator
   */
  function init(address _parentAddress) external onlyUninitialized {
    parentAddress = _parentAddress;
    this.flush();
  }

  /**
   * Modifier that will execute internal code block only if the sender is the parent address
   */
  modifier onlyParent {
    require(msg.sender == parentAddress, "Only Parent");
    _;
  }

  /**
   * Modifier that will execute internal code block only if the contract has not been initialized yet
   */
  modifier onlyUninitialized {
    require(parentAddress == address(0x0), "Already initialized");
    _;
  }

  /**
   * Default function; Gets called when data is sent but does not match any other function
   */
  fallback() external payable {
    this.flush();
  }

  /**
   * Default function; Gets called when Ether is deposited with no data, and forwards it to the parent address
   */
  receive() external payable {
    this.flush();
  }

  /**
   * Execute a token transfer of the full balance from the forwarder token to the parent address
   * @param tokenContractAddress the address of the erc20 token contract
   */
  function flushTokens(address tokenContractAddress) external onlyParent {
    ERC20Interface instance = ERC20Interface(tokenContractAddress);
    address forwarderAddress = address(this);
    uint256 forwarderBalance = instance.balanceOf(forwarderAddress);
    if (forwarderBalance == 0) {
      return;
    }

    require(
      instance.transfer(parentAddress, forwarderBalance),
      "Token flush failed"
    );
  }

  /**
   * Flush the entire balance of the contract to the parent address.
   */
  function flush() external {
    uint256 value = address(this).balance;

    if (value == 0) {
      return;
    }

    (bool success, ) = parentAddress.call{ value: value }("");
    require(success, "Flush failed");
    emit ForwarderDeposited(msg.sender, value, msg.data);
  }
}

/**
 *
 * WalletSimple
 * ============
 *
 * Basic multi-signer wallet designed for use in a co-signing environment where 2 signatures are required to move funds.
 * Typically used in a 2-of-3 signing configuration. Uses ecrecover to allow for 2 signatures in a single transaction.
 *
 * The first signature is created on the operation hash (see Data Formats) and passed to sendMultiSig/sendMultiSigToken
 * The signer is determined by verifyMultiSig().
 *
 * The second signature is created by the submitter of the transaction and determined by msg.signer.
 *
 * Data Formats
 * ============
 *
 * The signature is created with ethereumjs-util.ecsign(operationHash).
 * Like the eth_sign RPC call, it packs the values as a 65-byte array of [r, s, v].
 * Unlike eth_sign, the message is not prefixed.
 *
 * The operationHash the result of keccak256(prefix, toAddress, value, data, expireTime).
 * For ether transactions, `prefix` is "ETHER".
 * For token transaction, `prefix` is "ERC20" and `data` is the tokenContractAddress.
 *
 *
 */
contract WalletSimple {
  // Events
  event Deposited(address from, uint256 value, bytes data);
  event SafeModeActivated(address msgSender);
  event Transacted(
    address msgSender, // Address of the sender of the message initiating the transaction
    address otherSigner, // Address of the signer (second signature) used to initiate the transaction
    bytes32 operation, // Operation hash (see Data Formats)
    address toAddress, // The address the transaction was sent to
    uint256 value, // Amount of Wei sent to the address
    bytes data // Data sent when invoking the transaction
  );

  event BatchTransfer(address sender, address recipient, uint256 value);
  // this event shows the other signer and the operation hash that they signed
  // specific batch transfer events are emitted in Batcher
  event BatchTransacted(
    address msgSender, // Address of the sender of the message initiating the transaction
    address otherSigner, // Address of the signer (second signature) used to initiate the transaction
    bytes32 operation // Operation hash (see Data Formats)
  );

  // Public fields
  mapping(address => bool) public signers; // The addresses that can co-sign transactions on the wallet
  bool public safeMode = false; // When active, wallet may only send to signer addresses
  bool public initialized = false; // True if the contract has been initialized

  // Internal fields
  uint256 private lastSequenceId;
  uint256 private constant MAX_SEQUENCE_ID_INCREASE = 10000;

  /**
   * Set up a simple multi-sig wallet by specifying the signers allowed to be used on this wallet.
   * 2 signers will be required to send a transaction from this wallet.
   * Note: The sender is NOT automatically added to the list of signers.
   * Signers CANNOT be changed once they are set
   *
   * @param allowedSigners An array of signers on the wallet
   */
  function init(address[] calldata allowedSigners) external onlyUninitialized {
    require(allowedSigners.length == 3, "Invalid number of signers");

    for (uint8 i = 0; i < allowedSigners.length; i++) {
      require(allowedSigners[i] != address(0), "Invalid signer");
      signers[allowedSigners[i]] = true;
    }
    initialized = true;
  }

  /**
   * Get the network identifier that signers must sign over
   * This provides protection signatures being replayed on other chains
   * This must be a virtual function because chain-specific contracts will need
   *    to override with their own network ids. It also can't be a field
   *    to allow this contract to be used by proxy with delegatecall, which will
   *    not pick up on state variables
   */
  function getNetworkId() internal virtual pure returns (string memory) {
    return "ETHER";
  }

  /**
   * Get the network identifier that signers must sign over for token transfers
   * This provides protection signatures being replayed on other chains
   * This must be a virtual function because chain-specific contracts will need
   *    to override with their own network ids. It also can't be a field
   *    to allow this contract to be used by proxy with delegatecall, which will
   *    not pick up on state variables
   */
  function getTokenNetworkId() internal virtual pure returns (string memory) {
    return "ERC20";
  }

  /**
   * Get the network identifier that signers must sign over for batch transfers
   * This provides protection signatures being replayed on other chains
   * This must be a virtual function because chain-specific contracts will need
   *    to override with their own network ids. It also can't be a field
   *    to allow this contract to be used by proxy with delegatecall, which will
   *    not pick up on state variables
   */
  function getBatchNetworkId() internal virtual pure returns (string memory) {
    return "ETHER-Batch";
  }

  /**
   * Determine if an address is a signer on this wallet
   * @param signer address to check
   * returns boolean indicating whether address is signer or not
   */
  function isSigner(address signer) public view returns (bool) {
    return signers[signer];
  }

  /**
   * Modifier that will execute internal code block only if the sender is an authorized signer on this wallet
   */
  modifier onlySigner {
    require(isSigner(msg.sender), "Non-signer in onlySigner method");
    _;
  }

  /**
   * Modifier that will execute internal code block only if the contract has not been initialized yet
   */
  modifier onlyUninitialized {
    require(!initialized, "Contract already initialized");
    _;
  }

  /**
   * Gets called when a transaction is received with data that does not match any other method
   */
  fallback() external payable {
    if (msg.value > 0) {
      // Fire deposited event if we are receiving funds
      Deposited(msg.sender, msg.value, msg.data);
    }
  }

  /**
   * Gets called when a transaction is received with ether and no data
   */
  receive() external payable {
    if (msg.value > 0) {
      // Fire deposited event if we are receiving funds
      Deposited(msg.sender, msg.value, msg.data);
    }
  }