// SPDX-License-Identifier: AGPL-3.0-or-later
// Copyright (C) 2018 Rain <rainbreak@riseup.net>
pragma solidity ^0.8.4;

interface ICodex {
    function init(address vault) external;

    function setParam(bytes32 param, uint256 data) external;

    function setParam(
        address,
        bytes32,
        uint256
    ) external;

    function credit(address) external view returns (uint256);

    function unbackedDebt(address) external view returns (uint256);

    function balances(
        address,
        uint256,
        address
    ) external view returns (uint256);

    function vaults(address vault)
        external
        view
        returns (
            uint256 totalNormalDebt,
            uint256 rate,
            uint256 debtCeiling,
            uint256 debtFloor
        );

    function positions(
        address vault,
        uint256 tokenId,
        address position
    ) external view returns (uint256 collateral, uint256 normalDebt);

    function globalDebt() external view returns (uint256);

    function globalUnbackedDebt() external view returns (uint256);

    function globalDebtCeiling() external view returns (uint256);

    function delegates(address, address) external view returns (uint256);

    function grantDelegate(address) external;

    function revokeDelegate(address) external;

    function modifyBalance(
        address,
        uint256,
        address,
        int256
    ) external;

    function transferBalance(
        address vault,
        uint256 tokenId,
        address src,
        address dst,
        uint256 amount
    ) external;

    function transferCredit(
        address src,
        address dst,
        uint256 amount
    ) external;

    function modifyCollateralAndDebt(
        address vault,
        uint256 tokenId,
        address user,
        address collateralizer,
        address debtor,
        int256 deltaCollateral,
        int256 deltaNormalDebt
    ) external;

    function transferCollateralAndDebt(
        address vault,
        uint256 tokenId,
        address src,
        address dst,
        int256 deltaCollateral,
        int256 deltaNormalDebt
    ) external;

    function confiscateCollateralAndDebt(
        address vault,
        uint256 tokenId,
        address user,
        address collateralizer,
        address debtor,
        int256 deltaCollateral,
        int256 deltaNormalDebt
    ) external;

    function settleUnbackedDebt(uint256 debt) external;

    function createUnbackedDebt(
        address debtor,
        address creditor,
        uint256 debt
    ) external;

    function modifyRate(
        address vault,
        address creditor,
        int256 rate
    ) external;

    function lock() external;
}
// OpenZeppelin Contracts (last updated v4.5.0) (token/ERC20/IERC20.sol)



/**
 * @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 `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);

    /**
     * @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);
}



interface IDebtAuction {
    function auctions(uint256)
        external
        view
        returns (
            uint256,
            uint256,
            address,
            uint48,
            uint48
        );

    function codex() external view returns (ICodex);

    function token() external view returns (IERC20);

    function minBidBump() external view returns (uint256);

    function tokenToSellBump() external view returns (uint256);

    function bidDuration() external view returns (uint48);

    function auctionDuration() external view returns (uint48);

    function auctionCounter() external view returns (uint256);

    function live() external view returns (uint256);

    function aer() external view returns (address);

    function setParam(bytes32 param, uint256 data) external;

    function startAuction(
        address recipient,
        uint256 tokensToSell,
        uint256 bid
    ) external returns (uint256 id);

    function redoAuction(uint256 id) external;

    function submitBid(
        uint256 id,
        uint256 tokensToSell,
        uint256 bid
    ) external;

    function closeAuction(uint256 id) external;

    function lock() external;

    function cancelAuction(uint256 id) external;
}
interface ISurplusAuction {
    function auctions(uint256)
        external
        view
        returns (
            uint256,
            uint256,
            address,
            uint48,
            uint48
        );

    function codex() external view returns (ICodex);

    function token() external view returns (IERC20);

    function minBidBump() external view returns (uint256);

    function bidDuration() external view returns (uint48);

    function auctionDuration() external view returns (uint48);

    function auctionCounter() external view returns (uint256);

    function live() external view returns (uint256);

    function setParam(bytes32 param, uint256 data) external;

    function startAuction(uint256 creditToSell, uint256 bid) external returns (uint256 id);

    function redoAuction(uint256 id) external;

    function submitBid(
        uint256 id,
        uint256 creditToSell,
        uint256 bid
    ) external;

    function closeAuction(uint256 id) external;

    function lock(uint256 credit) external;

    function cancelAuction(uint256 id) external;
}

interface IAer {
    function codex() external view returns (ICodex);

    function surplusAuction() external view returns (ISurplusAuction);

    function debtAuction() external view returns (IDebtAuction);

    function debtQueue(uint256) external view returns (uint256);

    function queuedDebt() external view returns (uint256);

    function debtOnAuction() external view returns (uint256);

    function auctionDelay() external view returns (uint256);

    function debtAuctionSellSize() external view returns (uint256);

    function debtAuctionBidSize() external view returns (uint256);

    function surplusAuctionSellSize() external view returns (uint256);

    function surplusBuffer() external view returns (uint256);

    function live() external view returns (uint256);

    function setParam(bytes32 param, uint256 data) external;

    function setParam(bytes32 param, address data) external;

    function queueDebt(uint256 debt) external;

    function unqueueDebt(uint256 queuedAt) external;

    function settleDebtWithSurplus(uint256 debt) external;

    function settleAuctionedDebt(uint256 debt) external;

    function startDebtAuction() external returns (uint256 auctionId);

    function startSurplusAuction() external returns (uint256 auctionId);

    function transferCredit(address to, uint256 credit) external;

    function lock() external;
}interface IPublican {
    function vaults(address vault) external view returns (uint256, uint256);

    function codex() external view returns (ICodex);

    function aer() external view returns (IAer);

    function baseInterest() external view returns (uint256);

    function init(address vault) external;

    function setParam(
        address vault,
        bytes32 param,
        uint256 data
    ) external;

    function setParam(bytes32 param, uint256 data) external;

    function setParam(bytes32 param, address data) external;

    function virtualRate(address vault) external returns (uint256 rate);

    function collect(address vault) external returns (uint256 rate);
}
interface IGuarded {
    function ANY_SIG() external view returns (bytes32);

    function ANY_CALLER() external view returns (address);

    function allowCaller(bytes32 sig, address who) external;

    function blockCaller(bytes32 sig, address who) external;

    function canCall(bytes32 sig, address who) external view returns (bool);
}
/// @title Guarded
/// @notice Mixin implementing an authentication scheme on a method level
abstract contract Guarded is IGuarded {
    /// ======== Custom Errors ======== ///

    error Guarded__notRoot();
    error Guarded__notGranted();

    /// ======== Storage ======== ///

    /// @notice Wildcard for granting a caller to call every guarded method
    bytes32 public constant override ANY_SIG = keccak256("ANY_SIG");
    /// @notice Wildcard for granting a caller to call every guarded method
    address public constant override ANY_CALLER = address(uint160(uint256(bytes32(keccak256("ANY_CALLER")))));

    /// @notice Mapping storing who is granted to which method
    /// @dev Method Signature => Caller => Bool
    mapping(bytes32 => mapping(address => bool)) private _canCall;

    /// ======== Events ======== ///

    event AllowCaller(bytes32 sig, address who);
    event BlockCaller(bytes32 sig, address who);

    constructor() {
        // set root
        _setRoot(msg.sender);
    }

    /// ======== Auth ======== ///

    modifier callerIsRoot() {
        if (_canCall[ANY_SIG][msg.sender]) {
            _;
        } else revert Guarded__notRoot();
    }

    modifier checkCaller() {
        if (canCall(msg.sig, msg.sender)) {
            _;
        } else revert Guarded__notGranted();
    }

    /// @notice Grant the right to call method `sig` to `who`
    /// @dev Only the root user (granted `ANY_SIG`) is able to call this method
    /// @param sig Method signature (4Byte)
    /// @param who Address of who should be able to call `sig`
    function allowCaller(bytes32 sig, address who) public override callerIsRoot {
        _canCall[sig][who] = true;
        emit AllowCaller(sig, who);
    }

    /// @notice Revoke the right to call method `sig` from `who`
    /// @dev Only the root user (granted `ANY_SIG`) is able to call this method
    /// @param sig Method signature (4Byte)
    /// @param who Address of who should not be able to call `sig` anymore
    function blockCaller(bytes32 sig, address who) public override callerIsRoot {
        _canCall[sig][who] = false;
        emit BlockCaller(sig, who);
    }

    /// @notice Returns if `who` can call `sig`
    /// @param sig Method signature (4Byte)
    /// @param who Address of who should be able to call `sig`
    function canCall(bytes32 sig, address who) public view override returns (bool) {
        return (_canCall[sig][who] || _canCall[ANY_SIG][who] || _canCall[sig][ANY_CALLER]);
    }

    /// @notice Sets the root user (granted `ANY_SIG`)
    /// @param root Address of who should be set as root
    function _setRoot(address root) internal {
        _canCall[ANY_SIG][root] = true;
        emit AllowCaller(ANY_SIG, root);
    }

    /// @notice Unsets the root user (granted `ANY_SIG`)
    /// @param root Address of who should be unset as root
    function _unsetRoot(address root) internal {
        _canCall[ANY_SIG][root] = false;
        emit AllowCaller(ANY_SIG, root);
    }
}// Copyright (C) 2020 Maker Ecosystem Growth Holdings, INC.

uint256 constant MLN = 10**6;
uint256 constant BLN = 10**9;
uint256 constant WAD = 10**18;
uint256 constant RAY = 10**18;
uint256 constant RAD = 10**18;

/* solhint-disable func-visibility, no-inline-assembly */

error Math__toInt256_overflow(uint256 x);

function toInt256(uint256 x) pure returns (int256) {
    if (x > uint256(type(int256).max)) revert Math__toInt256_overflow(x);
    return int256(x);
}

function min(uint256 x, uint256 y) pure returns (uint256 z) {
    unchecked {
        z = x <= y ? x : y;
    }
}

function max(uint256 x, uint256 y) pure returns (uint256 z) {
    unchecked {
        z = x >= y ? x : y;
    }
}

error Math__diff_overflow(uint256 x, uint256 y);

function diff(uint256 x, uint256 y) pure returns (int256 z) {
    unchecked {
        z = int256(x) - int256(y);
        if (!(int256(x) >= 0 && int256(y) >= 0)) revert Math__diff_overflow(x, y);
    }
}

error Math__add_overflow(uint256 x, uint256 y);

function add(uint256 x, uint256 y) pure returns (uint256 z) {
    unchecked {
        if ((z = x + y) < x) revert Math__add_overflow(x, y);
    }
}

error Math__add48_overflow(uint256 x, uint256 y);

function add48(uint48 x, uint48 y) pure returns (uint48 z) {
    unchecked {
        if ((z = x + y) < x) revert Math__add48_overflow(x, y);
    }
}

error Math__add_overflow_signed(uint256 x, int256 y);

function add(uint256 x, int256 y) pure returns (uint256 z) {
    unchecked {
        z = x + uint256(y);
        if (!(y >= 0 || z <= x)) revert Math__add_overflow_signed(x, y);
        if (!(y <= 0 || z >= x)) revert Math__add_overflow_signed(x, y);
    }
}

error Math__sub_overflow(uint256 x, uint256 y);

function sub(uint256 x, uint256 y) pure returns (uint256 z) {
    unchecked {
        if ((z = x - y) > x) revert Math__sub_overflow(x, y);
    }
}

error Math__sub_overflow_signed(uint256 x, int256 y);

function sub(uint256 x, int256 y) pure returns (uint256 z) {
    unchecked {
        z = x - uint256(y);
        if (!(y <= 0 || z <= x)) revert Math__sub_overflow_signed(x, y);
        if (!(y >= 0 || z >= x)) revert Math__sub_overflow_signed(x, y);
    }
}

error Math__mul_overflow(uint256 x, uint256 y);

function mul(uint256 x, uint256 y) pure returns (uint256 z) {
    unchecked {
        if (!(y == 0 || (z = x * y) / y == x)) revert Math__mul_overflow(x, y);
    }
}

error Math__mul_overflow_signed(uint256 x, int256 y);

function mul(uint256 x, int256 y) pure returns (int256 z) {
    unchecked {
        z = int256(x) * y;
        if (int256(x) < 0) revert Math__mul_overflow_signed(x, y);
        if (!(y == 0 || z / y == int256(x))) revert Math__mul_overflow_signed(x, y);
    }
}

function wmul(uint256 x, uint256 y) pure returns (uint256 z) {
    unchecked {
        z = mul(x, y) / WAD;
    }
}

function wmul(uint256 x, int256 y) pure returns (int256 z) {
    unchecked {
        z = mul(x, y) / int256(WAD);
    }
}

error Math__div_overflow(uint256 x, uint256 y);

function div(uint256 x, uint256 y) pure returns (uint256 z) {
    unchecked {
        if (y == 0) revert Math__div_overflow(x, y);
        return x / y;
    }
}

function wdiv(uint256 x, uint256 y) pure returns (uint256 z) {
    unchecked {
        z = mul(x, WAD) / y;
    }
}

// optimized version from dss PR #78
function wpow(
    uint256 x,
    uint256 n,
    uint256 b
) pure returns (uint256 z) {
    unchecked {
        assembly {
            switch n
            case 0 {
                z := b
            }
            default {
                switch x
                case 0 {
                    z := 0
                }
                default {
                    switch mod(n, 2)
                    case 0 {
                        z := b
                    }
                    default {
                        z := x
                    }
                    let half := div(b, 2) // for rounding.
                    for {
                        n := div(n, 2)
                    } n {
                        n := div(n, 2)
                    } {
                        let xx := mul(x, x)
                        if shr(128, x) {
                            revert(0, 0)
                        }
                        let xxRound := add(xx, half)
                        if lt(xxRound, xx) {
                            revert(0, 0)
                        }
                        x := div(xxRound, b)
                        if mod(n, 2) {
                            let zx := mul(z, x)
                            if and(iszero(iszero(x)), iszero(eq(div(zx, x), z))) {
                                revert(0, 0)
                            }
                            let zxRound := add(zx, half)
                            if lt(zxRound, zx) {
                                revert(0, 0)
                            }
                            z := div(zxRound, b)
                        }
                    }
                }
            }
        }
    }
}

/* solhint-disable func-visibility, no-inline-assembly */
/// @title Publican
/// @notice `Publican` is responsible for setting the debt interest rate and collecting interest
/// Uses Jug.sol from DSS (MakerDAO) / TaxCollector.sol from GEB (Reflexer Labs) as a blueprint
/// Changes from Jug.sol / TaxCollector.sol:
/// - only WAD precision is used (no RAD and RAY)
/// - uses a method signature based authentication scheme
/// - configuration by Vaults
contract Publican is Guarded, IPublican {
    /// ======== Custom Errors ======== ///

    error Publican__init_vaultAlreadyInit();
    error Publican__setParam_notCollected();
    error Publican__setParam_unrecognizedParam();
    error Publican__collect_invalidBlockTimestamp();

    /// ======== Storage ======== ///

    // Vault specific configuration data
    struct VaultConfig {
        // Collateral-specific, per-second stability fee contribution [wad]
        uint256 interestPerSecond;
        // Time of last drip [unix epoch time]
        uint256 lastCollected;
    }

    /// @notice Vault Configs
    /// @dev Vault => Vault Config
    mapping(address => VaultConfig) public override vaults;

    /// @notice Codex
    ICodex public immutable override codex;
    /// @notice Aer
    IAer public override aer;

    /// @notice Global, per-second stability fee contribution [wad]
    uint256 public override baseInterest;

    /// ======== Events ======== ///
    event Init(address indexed vault);
    event SetParam(address indexed vault, bytes32 indexed param, uint256 data);
    event SetParam(bytes32 indexed param, address indexed data);
    event Collect(address indexed vault);

    constructor(address codex_) Guarded() {
        codex = ICodex(codex_);
    }

    /// ======== Configuration ======== ///

    /// @notice Initializes a new Vault
    /// @dev Sender has to be allowed to call this method
    /// @param vault Address of the Vault
    function init(address vault) external override checkCaller {
        VaultConfig storage v = vaults[vault];
        if (v.interestPerSecond != 0) revert Publican__init_vaultAlreadyInit();
        v.interestPerSecond = WAD;
        v.lastCollected = block.timestamp;
        emit Init(vault);
    }

    /// @notice Sets various variables for a Vault
    /// @dev Sender has to be allowed to call this method
    /// @param vault Address of the Vault
    /// @param param Name of the variable to set
    /// @param data New value to set for the variable [wad]
    function setParam(
        address vault,
        bytes32 param,
        uint256 data
    ) external override checkCaller {
        if (block.timestamp != vaults[vault].lastCollected) revert Publican__setParam_notCollected();
        if (param == "interestPerSecond") vaults[vault].interestPerSecond = data;
        else revert Publican__setParam_unrecognizedParam();
        emit SetParam(vault, param, data);
    }

    /// @notice Sets various variables for this contract
    /// @dev Sender has to be allowed to call this method
    /// @param param Name of the variable to set
    /// @param data New value to set for the variable [wad]
    function setParam(bytes32 param, uint256 data) external override checkCaller {
        if (param == "baseInterest") baseInterest = data;
        else revert Publican__setParam_unrecognizedParam();
        emit SetParam(address(0), param, data);
    }

    /// @notice Sets various variables for this contract
    /// @dev Sender has to be allowed to call this method
    /// @param param Name of the variable to set
    /// @param data New value to set for the variable [address]
    function setParam(bytes32 param, address data) external override checkCaller {
        if (param == "aer") aer = IAer(data);
        else revert Publican__setParam_unrecognizedParam();
        emit SetParam(param, data);
    }

    /// ======== Interest Rates ======== ///

    /// @notice Returns the up to date rate (virtual rate) for a given vault as the rate stored in Codex
    /// might be outdated
    /// @param vault Address of the Vault
    /// @return rate Virtual rate
    function virtualRate(address vault) external view override returns (uint256 rate) {
        (, uint256 prev, , ) = codex.vaults(vault);
        if (block.timestamp < vaults[vault].lastCollected) return prev;
        rate = wmul(
            wpow(
                add(baseInterest, vaults[vault].interestPerSecond),
                sub(block.timestamp, vaults[vault].lastCollected),
                WAD
            ),
            prev
        );
    }

    /// @notice Collects accrued interest from all Position on a Vault by updating the Vault's rate
    /// @param vault Address of the Vault
    /// @return rate Set rate
    function collect(address vault) public override returns (uint256 rate) {
        if (block.timestamp < vaults[vault].lastCollected) revert Publican__collect_invalidBlockTimestamp();
        (, uint256 prev, , ) = codex.vaults(vault);
        rate = wmul(
            wpow(
                add(baseInterest, vaults[vault].interestPerSecond),
                sub(block.timestamp, vaults[vault].lastCollected),
                WAD
            ),
            prev
        );
        codex.modifyRate(vault, address(aer), diff(rate, prev));
        vaults[vault].lastCollected = block.timestamp;
        emit Collect(vault);
    }

    /// @notice Batches interest collection. See `collect(address vault)`.
    /// @param vaults_ Array of Vault addresses
    /// @return rates Set rates for each updated Vault
    function collectMany(address[] memory vaults_) external returns (uint256[] memory) {
        uint256[] memory rates = new uint256[](vaults_.length);
        for (uint256 i = 0; i < vaults_.length; i++) {
            rates[i] = collect(vaults_[i]);
        }
        return rates;
    }
}