// File: src/token/Burn.sol



// SPDX-License-Identifier: MIT
pragma solidity 0.8.19;

import "@openzeppelin/token/ERC20/IERC20.sol";
/// @title Pitch Token Burner
/// @notice This contract is used to burn Pitch tokens as it has no "burn" functionality & cannot send to address(0).
/// @notice There is no way to transfer out of this contract.
/// @author Hourglass Foundation - ZrowGz

contract PitchBurner {

    IERC20 internal constant _CONVERT_TOKEN = IERC20(0x1b5bb61F958A418Bf173f6f56090dC0a00a897aA);
    address internal _time;

    /// @notice this pulls in the covert token & there's no way to get it out.
    function burnAmount(address _from, uint256 _amount) external {
        require(msg.sender == _time, "!hourglass");
        // check that balance of this + amount is less than total supply of convert token
        require(
            _CONVERT_TOKEN.balanceOf(address(this)) + _amount <= _CONVERT_TOKEN.totalSupply(), 
            "!burnableSupply"
        );

        // pull convert token from caller & send to burn contract (cannot transfer to address(0))
        _CONVERT_TOKEN.transferFrom(_from, address(this), _amount);

        emit TokensBurned(address(_CONVERT_TOKEN), _from, _amount);
    }

    function setHourglassToken(address _token) external {
        require(_time == address(0), "already set");
        _time = _token;
    }

    event TokensBurned(address indexed destroyedToken, address indexed from, uint256 indexed amount);
}
// File: lib/openzeppelin-contracts/contracts/token/ERC20/IERC20.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.0) (token/ERC20/IERC20.sol)

pragma solidity ^0.8.0;

/**
 * @dev Interface of the ERC20 standard as defined in the EIP.
 */
interface IERC20 {
    /**
     * @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);

    /**
     * @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 `to`.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transfer(address to, 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 `from` to `to` 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 from, address to, uint256 amount) external returns (bool);
}