@b0dhidharma/yswaps/deployments/polygon/solcInputs/0eb7107d651f51015c988e0c3d67565f.json

Yearn strategy swappers

{
  "language": "Solidity",
  "sources": {
    "contracts/mock/ERC20Mock.sol": {
      "content": "// SPDX-License-Identifier: MIT\npragma solidity ^0.8.4;\n\nimport '@openzeppelin/contracts/token/ERC20/ERC20.sol';\n\ncontract ERC20Mock is ERC20 {\n  constructor(\n    string memory name,\n    string memory symbol,\n    address initialAccount,\n    uint256 initialBalance\n  ) ERC20(name, symbol) {\n    _mint(initialAccount, initialBalance);\n  }\n\n  function mint(address account, uint256 amount) public {\n    _mint(account, amount);\n  }\n\n  function burn(address account, uint256 amount) public {\n    _burn(account, amount);\n  }\n\n  function transferInternal(\n    address from,\n    address to,\n    uint256 value\n  ) public {\n    _transfer(from, to, value);\n  }\n\n  function approveInternal(\n    address owner,\n    address spender,\n    uint256 value\n  ) public {\n    _approve(owner, spender, value);\n  }\n}\n"
    },
    "@openzeppelin/contracts/token/ERC20/ERC20.sol": {
      "content": "// SPDX-License-Identifier: MIT\n\npragma solidity ^0.8.0;\n\nimport \"./IERC20.sol\";\nimport \"./extensions/IERC20Metadata.sol\";\nimport \"../../utils/Context.sol\";\n\n/**\n * @dev Implementation of the {IERC20} interface.\n *\n * This implementation is agnostic to the way tokens are created. This means\n * that a supply mechanism has to be added in a derived contract using {_mint}.\n * For a generic mechanism see {ERC20PresetMinterPauser}.\n *\n * TIP: For a detailed writeup see our guide\n * https://forum.zeppelin.solutions/t/how-to-implement-erc20-supply-mechanisms/226[How\n * to implement supply mechanisms].\n *\n * We have followed general OpenZeppelin guidelines: functions revert instead\n * of returning `false` on failure. This behavior is nonetheless conventional\n * and does not conflict with the expectations of ERC20 applications.\n *\n * Additionally, an {Approval} event is emitted on calls to {transferFrom}.\n * This allows applications to reconstruct the allowance for all accounts just\n * by listening to said events. Other implementations of the EIP may not emit\n * these events, as it isn't required by the specification.\n *\n * Finally, the non-standard {decreaseAllowance} and {increaseAllowance}\n * functions have been added to mitigate the well-known issues around setting\n * allowances. See {IERC20-approve}.\n */\ncontract ERC20 is Context, IERC20, IERC20Metadata {\n    mapping(address => uint256) private _balances;\n\n    mapping(address => mapping(address => uint256)) private _allowances;\n\n    uint256 private _totalSupply;\n\n    string private _name;\n    string private _symbol;\n\n    /**\n     * @dev Sets the values for {name} and {symbol}.\n     *\n     * The default value of {decimals} is 18. To select a different value for\n     * {decimals} you should overload it.\n     *\n     * All two of these values are immutable: they can only be set once during\n     * construction.\n     */\n    constructor(string memory name_, string memory symbol_) {\n        _name = name_;\n        _symbol = symbol_;\n    }\n\n    /**\n     * @dev Returns the name of the token.\n     */\n    function name() public view virtual override returns (string memory) {\n        return _name;\n    }\n\n    /**\n     * @dev Returns the symbol of the token, usually a shorter version of the\n     * name.\n     */\n    function symbol() public view virtual override returns (string memory) {\n        return _symbol;\n    }\n\n    /**\n     * @dev Returns the number of decimals used to get its user representation.\n     * For example, if `decimals` equals `2`, a balance of `505` tokens should\n     * be displayed to a user as `5,05` (`505 / 10 ** 2`).\n     *\n     * Tokens usually opt for a value of 18, imitating the relationship between\n     * Ether and Wei. This is the value {ERC20} uses, unless this function is\n     * overridden;\n     *\n     * NOTE: This information is only used for _display_ purposes: it in\n     * no way affects any of the arithmetic of the contract, including\n     * {IERC20-balanceOf} and {IERC20-transfer}.\n     */\n    function decimals() public view virtual override returns (uint8) {\n        return 18;\n    }\n\n    /**\n     * @dev See {IERC20-totalSupply}.\n     */\n    function totalSupply() public view virtual override returns (uint256) {\n        return _totalSupply;\n    }\n\n    /**\n     * @dev See {IERC20-balanceOf}.\n     */\n    function balanceOf(address account) public view virtual override returns (uint256) {\n        return _balances[account];\n    }\n\n    /**\n     * @dev See {IERC20-transfer}.\n     *\n     * Requirements:\n     *\n     * - `recipient` cannot be the zero address.\n     * - the caller must have a balance of at least `amount`.\n     */\n    function transfer(address recipient, uint256 amount) public virtual override returns (bool) {\n        _transfer(_msgSender(), recipient, amount);\n        return true;\n    }\n\n    /**\n     * @dev See {IERC20-allowance}.\n     */\n    function allowance(address owner, address spender) public view virtual override returns (uint256) {\n        return _allowances[owner][spender];\n    }\n\n    /**\n     * @dev See {IERC20-approve}.\n     *\n     * Requirements:\n     *\n     * - `spender` cannot be the zero address.\n     */\n    function approve(address spender, uint256 amount) public virtual override returns (bool) {\n        _approve(_msgSender(), spender, amount);\n        return true;\n    }\n\n    /**\n     * @dev See {IERC20-transferFrom}.\n     *\n     * Emits an {Approval} event indicating the updated allowance. This is not\n     * required by the EIP. See the note at the beginning of {ERC20}.\n     *\n     * Requirements:\n     *\n     * - `sender` and `recipient` cannot be the zero address.\n     * - `sender` must have a balance of at least `amount`.\n     * - the caller must have allowance for ``sender``'s tokens of at least\n     * `amount`.\n     */\n    function transferFrom(\n        address sender,\n        address recipient,\n        uint256 amount\n    ) public virtual override returns (bool) {\n        _transfer(sender, recipient, amount);\n\n        uint256 currentAllowance = _allowances[sender][_msgSender()];\n        require(currentAllowance >= amount, \"ERC20: transfer amount exceeds allowance\");\n        unchecked {\n            _approve(sender, _msgSender(), currentAllowance - amount);\n        }\n\n        return true;\n    }\n\n    /**\n     * @dev Atomically increases the allowance granted to `spender` by the caller.\n     *\n     * This is an alternative to {approve} that can be used as a mitigation for\n     * problems described in {IERC20-approve}.\n     *\n     * Emits an {Approval} event indicating the updated allowance.\n     *\n     * Requirements:\n     *\n     * - `spender` cannot be the zero address.\n     */\n    function increaseAllowance(address spender, uint256 addedValue) public virtual returns (bool) {\n        _approve(_msgSender(), spender, _allowances[_msgSender()][spender] + addedValue);\n        return true;\n    }\n\n    /**\n     * @dev Atomically decreases the allowance granted to `spender` by the caller.\n     *\n     * This is an alternative to {approve} that can be used as a mitigation for\n     * problems described in {IERC20-approve}.\n     *\n     * Emits an {Approval} event indicating the updated allowance.\n     *\n     * Requirements:\n     *\n     * - `spender` cannot be the zero address.\n     * - `spender` must have allowance for the caller of at least\n     * `subtractedValue`.\n     */\n    function decreaseAllowance(address spender, uint256 subtractedValue) public virtual returns (bool) {\n        uint256 currentAllowance = _allowances[_msgSender()][spender];\n        require(currentAllowance >= subtractedValue, \"ERC20: decreased allowance below zero\");\n        unchecked {\n            _approve(_msgSender(), spender, currentAllowance - subtractedValue);\n        }\n\n        return true;\n    }\n\n    /**\n     * @dev Moves `amount` of tokens from `sender` to `recipient`.\n     *\n     * This internal function is equivalent to {transfer}, and can be used to\n     * e.g. implement automatic token fees, slashing mechanisms, etc.\n     *\n     * Emits a {Transfer} event.\n     *\n     * Requirements:\n     *\n     * - `sender` cannot be the zero address.\n     * - `recipient` cannot be the zero address.\n     * - `sender` must have a balance of at least `amount`.\n     */\n    function _transfer(\n        address sender,\n        address recipient,\n        uint256 amount\n    ) internal virtual {\n        require(sender != address(0), \"ERC20: transfer from the zero address\");\n        require(recipient != address(0), \"ERC20: transfer to the zero address\");\n\n        _beforeTokenTransfer(sender, recipient, amount);\n\n        uint256 senderBalance = _balances[sender];\n        require(senderBalance >= amount, \"ERC20: transfer amount exceeds balance\");\n        unchecked {\n            _balances[sender] = senderBalance - amount;\n        }\n        _balances[recipient] += amount;\n\n        emit Transfer(sender, recipient, amount);\n\n        _afterTokenTransfer(sender, recipient, amount);\n    }\n\n    /** @dev Creates `amount` tokens and assigns them to `account`, increasing\n     * the total supply.\n     *\n     * Emits a {Transfer} event with `from` set to the zero address.\n     *\n     * Requirements:\n     *\n     * - `account` cannot be the zero address.\n     */\n    function _mint(address account, uint256 amount) internal virtual {\n        require(account != address(0), \"ERC20: mint to the zero address\");\n\n        _beforeTokenTransfer(address(0), account, amount);\n\n        _totalSupply += amount;\n        _balances[account] += amount;\n        emit Transfer(address(0), account, amount);\n\n        _afterTokenTransfer(address(0), account, amount);\n    }\n\n    /**\n     * @dev Destroys `amount` tokens from `account`, reducing the\n     * total supply.\n     *\n     * Emits a {Transfer} event with `to` set to the zero address.\n     *\n     * Requirements:\n     *\n     * - `account` cannot be the zero address.\n     * - `account` must have at least `amount` tokens.\n     */\n    function _burn(address account, uint256 amount) internal virtual {\n        require(account != address(0), \"ERC20: burn from the zero address\");\n\n        _beforeTokenTransfer(account, address(0), amount);\n\n        uint256 accountBalance = _balances[account];\n        require(accountBalance >= amount, \"ERC20: burn amount exceeds balance\");\n        unchecked {\n            _balances[account] = accountBalance - amount;\n        }\n        _totalSupply -= amount;\n\n        emit Transfer(account, address(0), amount);\n\n        _afterTokenTransfer(account, address(0), amount);\n    }\n\n    /**\n     * @dev Sets `amount` as the allowance of `spender` over the `owner` s tokens.\n     *\n     * This internal function is equivalent to `approve`, and can be used to\n     * e.g. set automatic allowances for certain subsystems, etc.\n     *\n     * Emits an {Approval} event.\n     *\n     * Requirements:\n     *\n     * - `owner` cannot be the zero address.\n     * - `spender` cannot be the zero address.\n     */\n    function _approve(\n        address owner,\n        address spender,\n        uint256 amount\n    ) internal virtual {\n        require(owner != address(0), \"ERC20: approve from the zero address\");\n        require(spender != address(0), \"ERC20: approve to the zero address\");\n\n        _allowances[owner][spender] = amount;\n        emit Approval(owner, spender, amount);\n    }\n\n    /**\n     * @dev Hook that is called before any transfer of tokens. This includes\n     * minting and burning.\n     *\n     * Calling conditions:\n     *\n     * - when `from` and `to` are both non-zero, `amount` of ``from``'s tokens\n     * will be transferred to `to`.\n     * - when `from` is zero, `amount` tokens will be minted for `to`.\n     * - when `to` is zero, `amount` of ``from``'s tokens will be burned.\n     * - `from` and `to` are never both zero.\n     *\n     * To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].\n     */\n    function _beforeTokenTransfer(\n        address from,\n        address to,\n        uint256 amount\n    ) internal virtual {}\n\n    /**\n     * @dev Hook that is called after any transfer of tokens. This includes\n     * minting and burning.\n     *\n     * Calling conditions:\n     *\n     * - when `from` and `to` are both non-zero, `amount` of ``from``'s tokens\n     * has been transferred to `to`.\n     * - when `from` is zero, `amount` tokens have been minted for `to`.\n     * - when `to` is zero, `amount` of ``from``'s tokens have been burned.\n     * - `from` and `to` are never both zero.\n     *\n     * To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].\n     */\n    function _afterTokenTransfer(\n        address from,\n        address to,\n        uint256 amount\n    ) internal virtual {}\n}\n"
    },
    "@openzeppelin/contracts/token/ERC20/IERC20.sol": {
      "content": "// SPDX-License-Identifier: MIT\n\npragma solidity ^0.8.0;\n\n/**\n * @dev Interface of the ERC20 standard as defined in the EIP.\n */\ninterface IERC20 {\n    /**\n     * @dev Returns the amount of tokens in existence.\n     */\n    function totalSupply() external view returns (uint256);\n\n    /**\n     * @dev Returns the amount of tokens owned by `account`.\n     */\n    function balanceOf(address account) external view returns (uint256);\n\n    /**\n     * @dev Moves `amount` tokens from the caller's account to `recipient`.\n     *\n     * Returns a boolean value indicating whether the operation succeeded.\n     *\n     * Emits a {Transfer} event.\n     */\n    function transfer(address recipient, uint256 amount) external returns (bool);\n\n    /**\n     * @dev Returns the remaining number of tokens that `spender` will be\n     * allowed to spend on behalf of `owner` through {transferFrom}. This is\n     * zero by default.\n     *\n     * This value changes when {approve} or {transferFrom} are called.\n     */\n    function allowance(address owner, address spender) external view returns (uint256);\n\n    /**\n     * @dev Sets `amount` as the allowance of `spender` over the caller's tokens.\n     *\n     * Returns a boolean value indicating whether the operation succeeded.\n     *\n     * IMPORTANT: Beware that changing an allowance with this method brings the risk\n     * that someone may use both the old and the new allowance by unfortunate\n     * transaction ordering. One possible solution to mitigate this race\n     * condition is to first reduce the spender's allowance to 0 and set the\n     * desired value afterwards:\n     * https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729\n     *\n     * Emits an {Approval} event.\n     */\n    function approve(address spender, uint256 amount) external returns (bool);\n\n    /**\n     * @dev Moves `amount` tokens from `sender` to `recipient` using the\n     * allowance mechanism. `amount` is then deducted from the caller's\n     * allowance.\n     *\n     * Returns a boolean value indicating whether the operation succeeded.\n     *\n     * Emits a {Transfer} event.\n     */\n    function transferFrom(\n        address sender,\n        address recipient,\n        uint256 amount\n    ) external returns (bool);\n\n    /**\n     * @dev Emitted when `value` tokens are moved from one account (`from`) to\n     * another (`to`).\n     *\n     * Note that `value` may be zero.\n     */\n    event Transfer(address indexed from, address indexed to, uint256 value);\n\n    /**\n     * @dev Emitted when the allowance of a `spender` for an `owner` is set by\n     * a call to {approve}. `value` is the new allowance.\n     */\n    event Approval(address indexed owner, address indexed spender, uint256 value);\n}\n"
    },
    "@openzeppelin/contracts/token/ERC20/extensions/IERC20Metadata.sol": {
      "content": "// SPDX-License-Identifier: MIT\n\npragma solidity ^0.8.0;\n\nimport \"../IERC20.sol\";\n\n/**\n * @dev Interface for the optional metadata functions from the ERC20 standard.\n *\n * _Available since v4.1._\n */\ninterface IERC20Metadata is IERC20 {\n    /**\n     * @dev Returns the name of the token.\n     */\n    function name() external view returns (string memory);\n\n    /**\n     * @dev Returns the symbol of the token.\n     */\n    function symbol() external view returns (string memory);\n\n    /**\n     * @dev Returns the decimals places of the token.\n     */\n    function decimals() external view returns (uint8);\n}\n"
    },
    "@openzeppelin/contracts/utils/Context.sol": {
      "content": "// SPDX-License-Identifier: MIT\n\npragma solidity ^0.8.0;\n\n/*\n * @dev Provides information about the current execution context, including the\n * sender of the transaction and its data. While these are generally available\n * via msg.sender and msg.data, they should not be accessed in such a direct\n * manner, since when dealing with meta-transactions the account sending and\n * paying for execution may not be the actual sender (as far as an application\n * is concerned).\n *\n * This contract is only required for intermediate, library-like contracts.\n */\nabstract contract Context {\n    function _msgSender() internal view virtual returns (address) {\n        return msg.sender;\n    }\n\n    function _msgData() internal view virtual returns (bytes calldata) {\n        return msg.data;\n    }\n}\n"
    },
    "contracts/utils/BaseStrategy.sol": {
      "content": "// SPDX-License-Identifier: GPL-3.0\npragma solidity >=0.8.0 <0.9.0;\n\nimport '@openzeppelin/contracts/token/ERC20/IERC20.sol';\nimport '@openzeppelin/contracts/token/ERC20/ERC20.sol';\nimport '@openzeppelin/contracts/token/ERC20/utils/SafeERC20.sol';\n\nstruct StrategyParams {\n  uint256 performanceFee;\n  uint256 activation;\n  uint256 debtRatio;\n  uint256 minDebtPerHarvest;\n  uint256 maxDebtPerHarvest;\n  uint256 lastReport;\n  uint256 totalDebt;\n  uint256 totalGain;\n  uint256 totalLoss;\n  bool enforceChangeLimit;\n  uint256 profitLimitRatio;\n  uint256 lossLimitRatio;\n  address customCheck;\n}\n\ninterface VaultAPI is IERC20 {\n  function name() external view returns (string calldata);\n\n  function symbol() external view returns (string calldata);\n\n  function decimals() external view returns (uint256);\n\n  function apiVersion() external pure returns (string memory);\n\n  function permit(\n    address owner,\n    address spender,\n    uint256 amount,\n    uint256 expiry,\n    bytes calldata signature\n  ) external returns (bool);\n\n  // NOTE: Vyper produces multiple signatures for a given function with \"default\" args\n  function deposit() external returns (uint256);\n\n  function deposit(uint256 amount) external returns (uint256);\n\n  function deposit(uint256 amount, address recipient) external returns (uint256);\n\n  // NOTE: Vyper produces multiple signatures for a given function with \"default\" args\n  function withdraw() external returns (uint256);\n\n  function withdraw(uint256 maxShares) external returns (uint256);\n\n  function withdraw(uint256 maxShares, address recipient) external returns (uint256);\n\n  function token() external view returns (address);\n\n  function strategies(address _strategy) external view returns (StrategyParams memory);\n\n  function pricePerShare() external view returns (uint256);\n\n  function totalAssets() external view returns (uint256);\n\n  function depositLimit() external view returns (uint256);\n\n  function maxAvailableShares() external view returns (uint256);\n\n  /**\n   * View how much the Vault would increase this Strategy's borrow limit,\n   * based on its present performance (since its last report). Can be used to\n   * determine expectedReturn in your Strategy.\n   */\n  function creditAvailable() external view returns (uint256);\n\n  /**\n   * View how much the Vault would like to pull back from the Strategy,\n   * based on its present performance (since its last report). Can be used to\n   * determine expectedReturn in your Strategy.\n   */\n  function debtOutstanding() external view returns (uint256);\n\n  /**\n   * View how much the Vault expect this Strategy to return at the current\n   * block, based on its present performance (since its last report). Can be\n   * used to determine expectedReturn in your Strategy.\n   */\n  function expectedReturn() external view returns (uint256);\n\n  /**\n   * This is the main contact point where the Strategy interacts with the\n   * Vault. It is critical that this call is handled as intended by the\n   * Strategy. Therefore, this function will be called by BaseStrategy to\n   * make sure the integration is correct.\n   */\n  function report(\n    uint256 _gain,\n    uint256 _loss,\n    uint256 _debtPayment\n  ) external returns (uint256);\n\n  /**\n   * This function should only be used in the scenario where the Strategy is\n   * being retired but no migration of the positions are possible, or in the\n   * extreme scenario that the Strategy needs to be put into \"Emergency Exit\"\n   * mode in order for it to exit as quickly as possible. The latter scenario\n   * could be for any reason that is considered \"critical\" that the Strategy\n   * exits its position as fast as possible, such as a sudden change in\n   * market conditions leading to losses, or an imminent failure in an\n   * external dependency.\n   */\n  function revokeStrategy() external;\n\n  /**\n   * View the governance address of the Vault to assert privileged functions\n   * can only be called by governance. The Strategy serves the Vault, so it\n   * is subject to governance defined by the Vault.\n   */\n  function governance() external view returns (address);\n\n  /**\n   * View the management address of the Vault to assert privileged functions\n   * can only be called by management. The Strategy serves the Vault, so it\n   * is subject to management defined by the Vault.\n   */\n  function management() external view returns (address);\n\n  /**\n   * View the guardian address of the Vault to assert privileged functions\n   * can only be called by guardian. The Strategy serves the Vault, so it\n   * is subject to guardian defined by the Vault.\n   */\n  function guardian() external view returns (address);\n}\n\n/**\n * This interface is here for the keeper bot to use.\n */\ninterface StrategyAPI {\n  function name() external view returns (string memory);\n\n  function vault() external view returns (address);\n\n  function want() external view returns (address);\n\n  function apiVersion() external pure returns (string memory);\n\n  function keeper() external view returns (address);\n\n  function isActive() external view returns (bool);\n\n  function delegatedAssets() external view returns (uint256);\n\n  function estimatedTotalAssets() external view returns (uint256);\n\n  function tendTrigger(uint256 callCost) external view returns (bool);\n\n  function tend() external;\n\n  function harvestTrigger(uint256 callCost) external view returns (bool);\n\n  function harvest() external;\n\n  event Harvested(uint256 profit, uint256 loss, uint256 debtPayment, uint256 debtOutstanding);\n}\n\n/**\n * @title Yearn Base Strategy\n * @author yearn.finance\n * @notice\n *  BaseStrategy implements all of the required functionality to interoperate\n *  closely with the Vault contract. This contract should be inherited and the\n *  abstract methods implemented to adapt the Strategy to the particular needs\n *  it has to create a return.\n *\n *  Of special interest is the relationship between `harvest()` and\n *  `vault.report()'. `harvest()` may be called simply because enough time has\n *  elapsed since the last report, and not because any funds need to be moved\n *  or positions adjusted. This is critical so that the Vault may maintain an\n *  accurate picture of the Strategy's performance. See  `vault.report()`,\n *  `harvest()`, and `harvestTrigger()` for further details.\n */\n\nabstract contract BaseStrategy {\n  using SafeERC20 for IERC20;\n  string public metadataURI;\n\n  /**\n   * @notice\n   *  Used to track which version of `StrategyAPI` this Strategy\n   *  implements.\n   * @dev The Strategy's version must match the Vault's `API_VERSION`.\n   * @return A string which holds the current API version of this contract.\n   */\n  function apiVersion() public pure returns (string memory) {\n    return '0.4.2';\n  }\n\n  /**\n   * @notice This Strategy's name.\n   * @dev\n   *  You can use this field to manage the \"version\" of this Strategy, e.g.\n   *  `StrategySomethingOrOtherV1`. However, \"API Version\" is managed by\n   *  `apiVersion()` function above.\n   * @return This Strategy's name.\n   */\n  function name() external view virtual returns (string memory);\n\n  /**\n   * @notice\n   *  The amount (priced in want) of the total assets managed by this strategy should not count\n   *  towards Yearn's TVL calculations.\n   * @dev\n   *  You can override this field to set it to a non-zero value if some of the assets of this\n   *  Strategy is somehow delegated inside another part of of Yearn's ecosystem e.g. another Vault.\n   *  Note that this value must be strictly less than or equal to the amount provided by\n   *  `estimatedTotalAssets()` below, as the TVL calc will be total assets minus delegated assets.\n   *  Also note that this value is used to determine the total assets under management by this\n   *  strategy, for the purposes of computing the management fee in `Vault`\n   * @return\n   *  The amount of assets this strategy manages that should not be included in Yearn's Total Value\n   *  Locked (TVL) calculation across it's ecosystem.\n   */\n  function delegatedAssets() external view virtual returns (uint256) {\n    return 0;\n  }\n\n  VaultAPI public vault;\n  address public strategist;\n  address public rewards;\n  address public keeper;\n\n  IERC20 public want;\n\n  // So indexers can keep track of this\n  event Harvested(uint256 profit, uint256 loss, uint256 debtPayment, uint256 debtOutstanding);\n\n  event UpdatedStrategist(address newStrategist);\n\n  event UpdatedKeeper(address newKeeper);\n\n  event UpdatedRewards(address rewards);\n\n  event UpdatedMinReportDelay(uint256 delay);\n\n  event UpdatedMaxReportDelay(uint256 delay);\n\n  event UpdatedProfitFactor(uint256 profitFactor);\n\n  event UpdatedDebtThreshold(uint256 debtThreshold);\n\n  event EmergencyExitEnabled();\n\n  event UpdatedMetadataURI(string metadataURI);\n\n  // The minimum number of seconds between harvest calls. See\n  // `setMinReportDelay()` for more details.\n  uint256 public minReportDelay;\n\n  // The maximum number of seconds between harvest calls. See\n  // `setMaxReportDelay()` for more details.\n  uint256 public maxReportDelay;\n\n  // The minimum multiple that `callCost` must be above the credit/profit to\n  // be \"justifiable\". See `setProfitFactor()` for more details.\n  uint256 public profitFactor;\n\n  // Use this to adjust the threshold at which running a debt causes a\n  // harvest trigger. See `setDebtThreshold()` for more details.\n  uint256 public debtThreshold;\n\n  // See note on `setEmergencyExit()`.\n  bool public emergencyExit;\n\n  // modifiers\n  modifier onlyAuthorized() {\n    require(msg.sender == strategist || msg.sender == governance(), '!authorized');\n    _;\n  }\n\n  modifier onlyEmergencyAuthorized() {\n    require(\n      msg.sender == strategist || msg.sender == governance() || msg.sender == vault.guardian() || msg.sender == vault.management(),\n      '!authorized'\n    );\n    _;\n  }\n\n  modifier onlyStrategist() {\n    require(msg.sender == strategist, '!strategist');\n    _;\n  }\n\n  modifier onlyGovernance() {\n    require(msg.sender == governance(), '!authorized');\n    _;\n  }\n\n  modifier onlyKeepers() {\n    require(\n      msg.sender == keeper ||\n        msg.sender == strategist ||\n        msg.sender == governance() ||\n        msg.sender == vault.guardian() ||\n        msg.sender == vault.management(),\n      '!authorized'\n    );\n    _;\n  }\n\n  constructor(address _vault) {\n    _initialize(_vault, msg.sender, msg.sender, msg.sender);\n  }\n\n  /**\n   * @notice\n   *  Initializes the Strategy, this is called only once, when the\n   *  contract is deployed.\n   * @dev `_vault` should implement `VaultAPI`.\n   * @param _vault The address of the Vault responsible for this Strategy.\n   * @param _strategist The address to assign as `strategist`.\n   * The strategist is able to change the reward address\n   * @param _rewards  The address to use for pulling rewards.\n   * @param _keeper The adddress of the _keeper. _keeper\n   * can harvest and tend a strategy.\n   */\n  function _initialize(\n    address _vault,\n    address _strategist,\n    address _rewards,\n    address _keeper\n  ) internal {\n    require(address(want) == address(0), 'Strategy already initialized');\n\n    vault = VaultAPI(_vault);\n    want = IERC20(vault.token());\n    want.safeApprove(_vault, type(uint256).max); // Give Vault unlimited access (might save gas)\n    strategist = _strategist;\n    rewards = _rewards;\n    keeper = _keeper;\n    // initialize variables\n    minReportDelay = 0;\n    maxReportDelay = 86400;\n    profitFactor = 100;\n    debtThreshold = 0;\n\n    vault.approve(rewards, type(uint256).max); // Allow rewards to be pulled\n  }\n\n  /**\n   * @notice\n   *  Used to change `strategist`.\n   *\n   *  This may only be called by governance or the existing strategist.\n   * @param _strategist The new address to assign as `strategist`.\n   */\n  function setStrategist(address _strategist) external onlyAuthorized {\n    require(_strategist != address(0));\n    strategist = _strategist;\n    emit UpdatedStrategist(_strategist);\n  }\n\n  /**\n   * @notice\n   *  Used to change `keeper`.\n   *\n   *  `keeper` is the only address that may call `tend()` or `harvest()`,\n   *  other than `governance()` or `strategist`. However, unlike\n   *  `governance()` or `strategist`, `keeper` may *only* call `tend()`\n   *  and `harvest()`, and no other authorized functions, following the\n   *  principle of least privilege.\n   *\n   *  This may only be called by governance or the strategist.\n   * @param _keeper The new address to assign as `keeper`.\n   */\n  function setKeeper(address _keeper) external onlyAuthorized {\n    require(_keeper != address(0));\n    keeper = _keeper;\n    emit UpdatedKeeper(_keeper);\n  }\n\n  /**\n   * @notice\n   *  Used to change `rewards`. EOA or smart contract which has the permission\n   *  to pull rewards from the vault.\n   *\n   *  This may only be called by the strategist.\n   * @param _rewards The address to use for pulling rewards.\n   */\n  function setRewards(address _rewards) external onlyStrategist {\n    require(_rewards != address(0));\n    vault.approve(rewards, 0);\n    rewards = _rewards;\n    vault.approve(rewards, type(uint256).max);\n    emit UpdatedRewards(_rewards);\n  }\n\n  /**\n   * @notice\n   *  Used to change `minReportDelay`. `minReportDelay` is the minimum number\n   *  of blocks that should pass for `harvest()` to be called.\n   *\n   *  For external keepers (such as the Keep3r network), this is the minimum\n   *  time between jobs to wait. (see `harvestTrigger()`\n   *  for more details.)\n   *\n   *  This may only be called by governance or the strategist.\n   * @param _delay The minimum number of seconds to wait between harvests.\n   */\n  function setMinReportDelay(uint256 _delay) external onlyAuthorized {\n    minReportDelay = _delay;\n    emit UpdatedMinReportDelay(_delay);\n  }\n\n  /**\n   * @notice\n   *  Used to change `maxReportDelay`. `maxReportDelay` is the maximum number\n   *  of blocks that should pass for `harvest()` to be called.\n   *\n   *  For external keepers (such as the Keep3r network), this is the maximum\n   *  time between jobs to wait. (see `harvestTrigger()`\n   *  for more details.)\n   *\n   *  This may only be called by governance or the strategist.\n   * @param _delay The maximum number of seconds to wait between harvests.\n   */\n  function setMaxReportDelay(uint256 _delay) external onlyAuthorized {\n    maxReportDelay = _delay;\n    emit UpdatedMaxReportDelay(_delay);\n  }\n\n  /**\n   * @notice\n   *  Used to change `profitFactor`. `profitFactor` is used to determine\n   *  if it's worthwhile to harvest, given gas costs. (See `harvestTrigger()`\n   *  for more details.)\n   *\n   *  This may only be called by governance or the strategist.\n   * @param _profitFactor A ratio to multiply anticipated\n   * `harvest()` gas cost against.\n   */\n  function setProfitFactor(uint256 _profitFactor) external onlyAuthorized {\n    profitFactor = _profitFactor;\n    emit UpdatedProfitFactor(_profitFactor);\n  }\n\n  /**\n   * @notice\n   *  Sets how far the Strategy can go into loss without a harvest and report\n   *  being required.\n   *\n   *  By default this is 0, meaning any losses would cause a harvest which\n   *  will subsequently report the loss to the Vault for tracking. (See\n   *  `harvestTrigger()` for more details.)\n   *\n   *  This may only be called by governance or the strategist.\n   * @param _debtThreshold How big of a loss this Strategy may carry without\n   * being required to report to the Vault.\n   */\n  function setDebtThreshold(uint256 _debtThreshold) external onlyAuthorized {\n    debtThreshold = _debtThreshold;\n    emit UpdatedDebtThreshold(_debtThreshold);\n  }\n\n  /**\n   * @notice\n   *  Used to change `metadataURI`. `metadataURI` is used to store the URI\n   * of the file describing the strategy.\n   *\n   *  This may only be called by governance or the strategist.\n   * @param _metadataURI The URI that describe the strategy.\n   */\n  function setMetadataURI(string calldata _metadataURI) external onlyAuthorized {\n    metadataURI = _metadataURI;\n    emit UpdatedMetadataURI(_metadataURI);\n  }\n\n  /**\n   * Resolve governance address from Vault contract, used to make assertions\n   * on protected functions in the Strategy.\n   */\n  function governance() internal view returns (address) {\n    return vault.governance();\n  }\n\n  /**\n   * @notice\n   *  Provide an accurate conversion from `_amtInWei` (denominated in wei)\n   *  to `want` (using the native decimal characteristics of `want`).\n   * @dev\n   *  Care must be taken when working with decimals to assure that the conversion\n   *  is compatible. As an example:\n   *\n   *      given 1e17 wei (0.1 ETH) as input, and want is USDC (6 decimals),\n   *      with USDC/ETH = 1800, this should give back 1800000000 (180 USDC)\n   *\n   * @param _amtInWei The amount (in wei/1e-18 ETH) to convert to `want`\n   * @return The amount in `want` of `_amtInEth` converted to `want`\n   **/\n  function ethToWant(uint256 _amtInWei) public view virtual returns (uint256);\n\n  /**\n   * @notice\n   *  Provide an accurate estimate for the total amount of assets\n   *  (principle + return) that this Strategy is currently managing,\n   *  denominated in terms of `want` tokens.\n   *\n   *  This total should be \"realizable\" e.g. the total value that could\n   *  *actually* be obtained from this Strategy if it were to divest its\n   *  entire position based on current on-chain conditions.\n   * @dev\n   *  Care must be taken in using this function, since it relies on external\n   *  systems, which could be manipulated by the attacker to give an inflated\n   *  (or reduced) value produced by this function, based on current on-chain\n   *  conditions (e.g. this function is possible to influence through\n   *  flashloan attacks, oracle manipulations, or other DeFi attack\n   *  mechanisms).\n   *\n   *  It is up to governance to use this function to correctly order this\n   *  Strategy relative to its peers in the withdrawal queue to minimize\n   *  losses for the Vault based on sudden withdrawals. This value should be\n   *  higher than the total debt of the Strategy and higher than its expected\n   *  value to be \"safe\".\n   * @return The estimated total assets in this Strategy.\n   */\n  function estimatedTotalAssets() public view virtual returns (uint256);\n\n  /*\n   * @notice\n   *  Provide an indication of whether this strategy is currently \"active\"\n   *  in that it is managing an active position, or will manage a position in\n   *  the future. This should correlate to `harvest()` activity, so that Harvest\n   *  events can be tracked externally by indexing agents.\n   * @return True if the strategy is actively managing a position.\n   */\n  function isActive() public view returns (bool) {\n    return vault.strategies(address(this)).debtRatio > 0 || estimatedTotalAssets() > 0;\n  }\n\n  /**\n   * Perform any Strategy unwinding or other calls necessary to capture the\n   * \"free return\" this Strategy has generated since the last time its core\n   * position(s) were adjusted. Examples include unwrapping extra rewards.\n   * This call is only used during \"normal operation\" of a Strategy, and\n   * should be optimized to minimize losses as much as possible.\n   *\n   * This method returns any realized profits and/or realized losses\n   * incurred, and should return the total amounts of profits/losses/debt\n   * payments (in `want` tokens) for the Vault's accounting (e.g.\n   * `want.balanceOf(this) >= _debtPayment + _profit`).\n   *\n   * `_debtOutstanding` will be 0 if the Strategy is not past the configured\n   * debt limit, otherwise its value will be how far past the debt limit\n   * the Strategy is. The Strategy's debt limit is configured in the Vault.\n   *\n   * NOTE: `_debtPayment` should be less than or equal to `_debtOutstanding`.\n   *       It is okay for it to be less than `_debtOutstanding`, as that\n   *       should only used as a guide for how much is left to pay back.\n   *       Payments should be made to minimize loss from slippage, debt,\n   *       withdrawal fees, etc.\n   *\n   * See `vault.debtOutstanding()`.\n   */\n  function prepareReturn(uint256 _debtOutstanding)\n    internal\n    virtual\n    returns (\n      uint256 _profit,\n      uint256 _loss,\n      uint256 _debtPayment\n    );\n\n  /**\n   * Perform any adjustments to the core position(s) of this Strategy given\n   * what change the Vault made in the \"investable capital\" available to the\n   * Strategy. Note that all \"free capital\" in the Strategy after the report\n   * was made is available for reinvestment. Also note that this number\n   * could be 0, and you should handle that scenario accordingly.\n   *\n   * See comments regarding `_debtOutstanding` on `prepareReturn()`.\n   */\n  function adjustPosition(uint256 _debtOutstanding) internal virtual;\n\n  /**\n   * Liquidate up to `_amountNeeded` of `want` of this strategy's positions,\n   * irregardless of slippage. Any excess will be re-invested with `adjustPosition()`.\n   * This function should return the amount of `want` tokens made available by the\n   * liquidation. If there is a difference between them, `_loss` indicates whether the\n   * difference is due to a realized loss, or if there is some other sitution at play\n   * (e.g. locked funds) where the amount made available is less than what is needed.\n   *\n   * NOTE: The invariant `_liquidatedAmount + _loss <= _amountNeeded` should always be maintained\n   */\n  function liquidatePosition(uint256 _amountNeeded) internal virtual returns (uint256 _liquidatedAmount, uint256 _loss);\n\n  /**\n   * Liquidate everything and returns the amount that got freed.\n   * This function is used during emergency exit instead of `prepareReturn()` to\n   * liquidate all of the Strategy's positions back to the Vault.\n   */\n\n  function liquidateAllPositions() internal virtual returns (uint256 _amountFreed);\n\n  /**\n   * @notice\n   *  Provide a signal to the keeper that `tend()` should be called. The\n   *  keeper will provide the estimated gas cost that they would pay to call\n   *  `tend()`, and this function should use that estimate to make a\n   *  determination if calling it is \"worth it\" for the keeper. This is not\n   *  the only consideration into issuing this trigger, for example if the\n   *  position would be negatively affected if `tend()` is not called\n   *  shortly, then this can return `true` even if the keeper might be\n   *  \"at a loss\" (keepers are always reimbursed by Yearn).\n   * @dev\n   *  `callCostInWei` must be priced in terms of `wei` (1e-18 ETH).\n   *\n   *  This call and `harvestTrigger()` should never return `true` at the same\n   *  time.\n   * @param callCostInWei The keeper's estimated gas cost to call `tend()` (in wei).\n   * @return `true` if `tend()` should be called, `false` otherwise.\n   */\n  function tendTrigger(uint256 callCostInWei) public view virtual returns (bool) {\n    // We usually don't need tend, but if there are positions that need\n    // active maintainence, overriding this function is how you would\n    // signal for that.\n    // If your implementation uses the cost of the call in want, you can\n    // use uint256 callCost = ethToWant(callCostInWei);\n\n    return false;\n  }\n\n  /**\n   * @notice\n   *  Adjust the Strategy's position. The purpose of tending isn't to\n   *  realize gains, but to maximize yield by reinvesting any returns.\n   *\n   *  See comments on `adjustPosition()`.\n   *\n   *  This may only be called by governance, the strategist, or the keeper.\n   */\n  function tend() external onlyKeepers {\n    // Don't take profits with this call, but adjust for better gains\n    adjustPosition(vault.debtOutstanding());\n  }\n\n  /**\n   * @notice\n   *  Provide a signal to the keeper that `harvest()` should be called. The\n   *  keeper will provide the estimated gas cost that they would pay to call\n   *  `harvest()`, and this function should use that estimate to make a\n   *  determination if calling it is \"worth it\" for the keeper. This is not\n   *  the only consideration into issuing this trigger, for example if the\n   *  position would be negatively affected if `harvest()` is not called\n   *  shortly, then this can return `true` even if the keeper might be \"at a\n   *  loss\" (keepers are always reimbursed by Yearn).\n   * @dev\n   *  `callCostInWei` must be priced in terms of `wei` (1e-18 ETH).\n   *\n   *  This call and `tendTrigger` should never return `true` at the\n   *  same time.\n   *\n   *  See `min/maxReportDelay`, `profitFactor`, `debtThreshold` to adjust the\n   *  strategist-controlled parameters that will influence whether this call\n   *  returns `true` or not. These parameters will be used in conjunction\n   *  with the parameters reported to the Vault (see `params`) to determine\n   *  if calling `harvest()` is merited.\n   *\n   *  It is expected that an external system will check `harvestTrigger()`.\n   *  This could be a script run off a desktop or cloud bot (e.g.\n   *  https://github.com/iearn-finance/yearn-vaults/blob/master/scripts/keep.py),\n   *  or via an integration with the Keep3r network (e.g.\n   *  https://github.com/Macarse/GenericKeep3rV2/blob/master/contracts/keep3r/GenericKeep3rV2.sol).\n   * @param callCostInWei The keeper's estimated gas cost to call `harvest()` (in wei).\n   * @return `true` if `harvest()` should be called, `false` otherwise.\n   */\n  function harvestTrigger(uint256 callCostInWei) public view virtual returns (bool) {\n    uint256 callCost = ethToWant(callCostInWei);\n    StrategyParams memory params = vault.strategies(address(this));\n\n    // Should not trigger if Strategy is not activated\n    if (params.activation == 0) return false;\n\n    // Should not trigger if we haven't waited long enough since previous harvest\n    if ((block.timestamp - params.lastReport) < minReportDelay) return false;\n\n    // Should trigger if hasn't been called in a while\n    if ((block.timestamp - params.lastReport) >= maxReportDelay) return true;\n\n    // If some amount is owed, pay it back\n    // NOTE: Since debt is based on deposits, it makes sense to guard against large\n    //       changes to the value from triggering a harvest directly through user\n    //       behavior. This should ensure reasonable resistance to manipulation\n    //       from user-initiated withdrawals as the outstanding debt fluctuates.\n    uint256 outstanding = vault.debtOutstanding();\n    if (outstanding > debtThreshold) return true;\n\n    // Check for profits and losses\n    uint256 total = estimatedTotalAssets();\n    // Trigger if we have a loss to report\n    if ((total + debtThreshold) < params.totalDebt) return true;\n\n    uint256 profit = 0;\n    if (total > params.totalDebt) profit = total - params.totalDebt; // We've earned a profit!\n\n    // Otherwise, only trigger if it \"makes sense\" economically (gas cost\n    // is <N% of value moved)\n    uint256 credit = vault.creditAvailable();\n    return ((profitFactor * callCost) < (credit + profit));\n  }\n\n  /**\n   * @notice\n   *  Harvests the Strategy, recognizing any profits or losses and adjusting\n   *  the Strategy's position.\n   *\n   *  In the rare case the Strategy is in emergency shutdown, this will exit\n   *  the Strategy's position.\n   *\n   *  This may only be called by governance, the strategist, or the keeper.\n   * @dev\n   *  When `harvest()` is called, the Strategy reports to the Vault (via\n   *  `vault.report()`), so in some cases `harvest()` must be called in order\n   *  to take in profits, to borrow newly available funds from the Vault, or\n   *  otherwise adjust its position. In other cases `harvest()` must be\n   *  called to report to the Vault on the Strategy's position, especially if\n   *  any losses have occurred.\n   */\n  function harvest() external onlyKeepers {\n    uint256 profit = 0;\n    uint256 loss = 0;\n    uint256 debtOutstanding = vault.debtOutstanding();\n    uint256 debtPayment = 0;\n    if (emergencyExit) {\n      // Free up as much capital as possible\n      uint256 amountFreed = liquidateAllPositions();\n      if (amountFreed < debtOutstanding) {\n        loss = debtOutstanding - amountFreed;\n      } else if (amountFreed > debtOutstanding) {\n        profit = amountFreed - debtOutstanding;\n      }\n      debtPayment = debtOutstanding - loss;\n    } else {\n      // Free up returns for Vault to pull\n      (profit, loss, debtPayment) = prepareReturn(debtOutstanding);\n    }\n\n    // Allow Vault to take up to the \"harvested\" balance of this contract,\n    // which is the amount it has earned since the last time it reported to\n    // the Vault.\n    debtOutstanding = vault.report(profit, loss, debtPayment);\n\n    // Check if free returns are left, and re-invest them\n    adjustPosition(debtOutstanding);\n\n    emit Harvested(profit, loss, debtPayment, debtOutstanding);\n  }\n\n  /**\n   * @notice\n   *  Withdraws `_amountNeeded` to `vault`.\n   *\n   *  This may only be called by the Vault.\n   * @param _amountNeeded How much `want` to withdraw.\n   * @return _loss Any realized losses\n   */\n  function withdraw(uint256 _amountNeeded) external returns (uint256 _loss) {\n    require(msg.sender == address(vault), '!vault');\n    // Liquidate as much as possible to `want`, up to `_amountNeeded`\n    uint256 amountFreed;\n    (amountFreed, _loss) = liquidatePosition(_amountNeeded);\n    // Send it directly back (NOTE: Using `msg.sender` saves some gas here)\n    SafeERC20.safeTransfer(want, msg.sender, amountFreed);\n    // NOTE: Reinvest anything leftover on next `tend`/`harvest`\n  }\n\n  /**\n   * Do anything necessary to prepare this Strategy for migration, such as\n   * transferring any reserve or LP tokens, CDPs, or other tokens or stores of\n   * value.\n   */\n  function prepareMigration(address _newStrategy) internal virtual;\n\n  /**\n   * @notice\n   *  Transfers all `want` from this Strategy to `_newStrategy`.\n   *\n   *  This may only be called by the Vault.\n   * @dev\n   * The new Strategy's Vault must be the same as this Strategy's Vault.\n   *  The migration process should be carefully performed to make sure all\n   * the assets are migrated to the new address, which should have never\n   * interacted with the vault before.\n   * @param _newStrategy The Strategy to migrate to.\n   */\n  function migrate(address _newStrategy) external {\n    require(msg.sender == address(vault));\n    require(BaseStrategy(_newStrategy).vault() == vault);\n    prepareMigration(_newStrategy);\n    SafeERC20.safeTransfer(want, _newStrategy, want.balanceOf(address(this)));\n  }\n\n  /**\n   * @notice\n   *  Activates emergency exit. Once activated, the Strategy will exit its\n   *  position upon the next harvest, depositing all funds into the Vault as\n   *  quickly as is reasonable given on-chain conditions.\n   *\n   *  This may only be called by governance or the strategist.\n   * @dev\n   *  See `vault.setEmergencyShutdown()` and `harvest()` for further details.\n   */\n  function setEmergencyExit() external onlyEmergencyAuthorized {\n    emergencyExit = true;\n    vault.revokeStrategy();\n\n    emit EmergencyExitEnabled();\n  }\n\n  /**\n   * Override this to add all tokens/tokenized positions this contract\n   * manages on a *persistent* basis (e.g. not just for swapping back to\n   * want ephemerally).\n   *\n   * NOTE: Do *not* include `want`, already included in `sweep` below.\n   *\n   * Example:\n   * ```\n   *    function protectedTokens() internal override view returns (address[] memory) {\n   *      address[] memory protected = new address[](3);\n   *      protected[0] = tokenA;\n   *      protected[1] = tokenB;\n   *      protected[2] = tokenC;\n   *      return protected;\n   *    }\n   * ```\n   */\n  function protectedTokens() internal view virtual returns (address[] memory);\n\n  /**\n