// File: contracts/BaseMinter.sol



// SPDX-License-Identifier: MIT

pragma solidity >=0.8.0;

import "@openzeppelin/contracts/token/ERC20/IERC20.sol";
import "./interfaces/IBridgeReserve.sol";
import "./interfaces/IArtBridge.sol";
import "./BridgeContext.sol";

///
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/// ╚═════╝ ╚═╝  ╚═╝╚══════╝╚══════╝
///
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/// ██║╚██╔╝██║██║██║╚██╗██║   ██║   ██╔══╝  ██╔══██╗
/// ██║ ╚═╝ ██║██║██║ ╚████║   ██║   ███████╗██║  ██║
/// ╚═╝     ╚═╝╚═╝╚═╝  ╚═══╝   ╚═╝   ╚══════╝╚═╝  ╚═╝
///
/// @title Base Minter
/// @author artbridge.eth
/// @notice Provide project validated minting interface
contract BaseMinter is BridgeContext {
  IArtBridge public immutable bridge;
  IBridgeReserve public immutable reserve;

  /// @dev financial checks are not enforced, deferred to minter implementation
  /// @notice ensures attempted mint is for a valid project
  /// @param _id target bridge project id
  /// @param _amount number of tokens to mint
  modifier onlyValidMint(uint256 _id, uint256 _amount) {
    require(_id < bridge.nextProjectId(), "!registered");
    require(bridge.minters(address(this)), "!minter");
    require(reserve.projectToMinters(_id, address(this)), "!minter");
    BridgeBeams.ReserveParameters memory params = reserve.projectToParameters(
      _id
    );
    require(_amount <= params.maxMintPerInvocation, "exceed mint max");
    _;
  }

  /// @param _bridge art bridge deployment address
  /// @param _reserve bridge reserve deployment address
  constructor(address _bridge, address _reserve) {
    bridge = IArtBridge(_bridge);
    reserve = IBridgeReserve(_reserve);
  }

  /// @dev extensions of base minter can override mint for custom pricing
  /// @dev base minter provides single price validation
  /// @notice mints the requested amount of project tokens
  /// @param _id target bridge project id
  /// @param _amount number of tokens to mint
  /// @param _to address to mint tokens to
  function mint(
    uint256 _id,
    uint256 _amount,
    address _to
  ) external payable virtual onlyValidMint(_id, _amount) {
    require(
      _amount * bridge.projectToTokenPrice(_id) == msg.value,
      "invalid payment amount"
    );
    bridge.mint(_id, _amount, _to);
  }
}

// File: @openzeppelin/contracts/token/ERC20/IERC20.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

/**
 * @dev Interface of the ERC20 standard as defined in the EIP.
 */
interface IERC20 {
    /**
     * @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 `recipient`.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transfer(address recipient, 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 `sender` to `recipient` 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 sender,
        address recipient,
        uint256 amount
    ) external returns (bool);

    /**
     * @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);
}

// File: contracts/interfaces/IBridgeReserve.sol



// SPDX-License-Identifier: MIT

pragma solidity >=0.8.0;

import {BridgeBeams} from "../libraries/BridgeBeams.sol";

interface IBridgeReserve {
  function projectToParameters(uint256 _id)
    external
    view
    returns (BridgeBeams.ReserveParameters memory);

  function projectToMinters(uint256 _id, address _minter)
    external
    view
    returns (bool);
}

// File: contracts/interfaces/IArtBridge.sol



// SPDX-License-Identifier: MIT

pragma solidity >=0.8.0;

import {BridgeBeams} from "../libraries/BridgeBeams.sol";

interface IArtBridge {
  function mint(
    uint256 _id,
    uint256 _amount,
    address _to
  ) external;

  function reserve(
    uint256 _id,
    uint256 _amount,
    address _to
  ) external;

  function nextProjectId() external view returns (uint256);

  function projects(uint256 _id)
    external
    view
    returns (
      uint256 id,
      string memory name,
      string memory artist,
      string memory description,
      string memory website,
      uint256 supply,
      uint256 maxSupply,
      uint256 startBlock
    );

  function minters(address _minter) external view returns (bool);

  function projectToTokenPrice(uint256 _id) external view returns (uint256);

  function projectState(uint256 _id)
    external
    view
    returns (BridgeBeams.ProjectState memory);
}

// File: contracts/BridgeContext.sol



// SPDX-License-Identifier: MIT

pragma solidity >=0.8.0;

import {BridgeBeams} from "./libraries/BridgeBeams.sol";
import "./Extractable.sol";

contract BridgeContext is Extractable {
  using BridgeBeams for BridgeBeams.Project;
  using BridgeBeams for BridgeBeams.ProjectState;
  using BridgeBeams for BridgeBeams.ReserveParameters;
}

// File: contracts/libraries/BridgeBeams.sol



// SPDX-License-Identifier: MIT

pragma solidity >=0.8.0;

/// BridgeBeams.sol
/// @title BEAMS token helper functions
/// @author artbridge.eth
/// @dev Library assists requirement checks across contracts
library BridgeBeams {
  struct Project {
    uint256 id;
    string name;
    string artist;
    string description;
    string website;
    uint256 supply;
    uint256 maxSupply;
    uint256 startBlock;
  }

  struct ProjectState {
    bool initialized;
    bool mintable;
    bool released;
    uint256 remaining;
  }

  struct ReserveParameters {
    uint256 maxMintPerInvocation;
    uint256 reservedMints;
    bytes32 reserveRoot;
  }

  /// @param _project Target project struct
  /// @return Project state struct derived from given input
  function projectState(Project memory _project)
    external
    view
    returns (BridgeBeams.ProjectState memory)
  {
    return
      ProjectState({
        initialized: isInitialized(_project),
        mintable: isMintable(_project),
        released: isReleased(_project),
        remaining: _project.maxSupply - _project.supply
      });
  }

  /// @param _project Target project struct
  /// @return True if project has required initial parameters, false if not
  function isInitialized(Project memory _project) internal pure returns (bool) {
    if (
      bytes(_project.artist).length == 0 ||
      bytes(_project.description).length == 0
    ) {
      return false;
    }
    return true;
  }

  /// @param _project Target project struct
  /// @return True if project is past mint start block, false if not
  function isReleased(Project memory _project) internal view returns (bool) {
    return _project.startBlock > 0 && _project.startBlock <= block.number;
  }

  /// @param _project Target project struct
  /// @return True if project is available for public mint, false if not
  function isMintable(Project memory _project) internal view returns (bool) {
    if (!isInitialized(_project)) {
      return false;
    }
    return isReleased(_project) && _project.supply < _project.maxSupply;
  }
}

// File: contracts/Extractable.sol



// SPDX-License-Identifier: MIT

pragma solidity >=0.8.0;

import "@openzeppelin/contracts/token/ERC20/IERC20.sol";
import "@openzeppelin/contracts/access/Ownable.sol";

contract Extractable is Ownable {
  function withdraw() external payable onlyOwner {
    require(payable(owner()).send(address(this).balance), "!transfer");
  }

  function extract(address _token) external onlyOwner {
    IERC20 token = IERC20(_token);
    token.transfer(owner(), token.balanceOf(address(this)));
  }
}

// File: @openzeppelin/contracts/access/Ownable.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

import "../utils/Context.sol";

/**
 * @dev Contract module which provides a basic access control mechanism, where
 * there is an account (an owner) that can be granted exclusive access to
 * specific functions.
 *
 * By default, the owner account will be the one that deploys the contract. This
 * can later be changed with {transferOwnership}.
 *
 * This module is used through inheritance. It will make available the modifier
 * `onlyOwner`, which can be applied to your functions to restrict their use to
 * the owner.
 */
abstract contract Ownable is Context {
    address private _owner;

    event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);

    /**
     * @dev Initializes the contract setting the deployer as the initial owner.
     */
    constructor() {
        _setOwner(_msgSender());
    }

    /**
     * @dev Returns the address of the current owner.
     */
    function owner() public view virtual returns (address) {
        return _owner;
    }

    /**
     * @dev Throws if called by any account other than the owner.
     */
    modifier onlyOwner() {
        require(owner() == _msgSender(), "Ownable: caller is not the owner");
        _;
    }

    /**
     * @dev Leaves the contract without owner. It will not be possible to call
     * `onlyOwner` functions anymore. Can only be called by the current owner.
     *
     * NOTE: Renouncing ownership will leave the contract without an owner,
     * thereby removing any functionality that is only available to the owner.
     */
    function renounceOwnership() public virtual onlyOwner {
        _setOwner(address(0));
    }

    /**
     * @dev Transfers ownership of the contract to a new account (`newOwner`).
     * Can only be called by the current owner.
     */
    function transferOwnership(address newOwner) public virtual onlyOwner {
        require(newOwner != address(0), "Ownable: new owner is the zero address");
        _setOwner(newOwner);
    }

    function _setOwner(address newOwner) private {
        address oldOwner = _owner;
        _owner = newOwner;
        emit OwnershipTransferred(oldOwner, newOwner);
    }
}

// File: @openzeppelin/contracts/utils/Context.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

/**
 * @dev Provides information about the current execution context, including the
 * sender of the transaction and its data. While these are generally available
 * via msg.sender and msg.data, they should not be accessed in such a direct
 * manner, since when dealing with meta-transactions the account sending and
 * paying for execution may not be the actual sender (as far as an application
 * is concerned).
 *
 * This contract is only required for intermediate, library-like contracts.
 */
abstract contract Context {
    function _msgSender() internal view virtual returns (address) {
        return msg.sender;
    }

    function _msgData() internal view virtual returns (bytes calldata) {
        return msg.data;
    }
}