// osm.sol - Oracle Security Module

// Copyright (C) 2019 Maker Foundation

// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.

// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License
// along with this program. If not, see <http://www.gnu.org/licenses/>.

contract DSAuthority {
    function canCall(
        address src, address dst, bytes4 sig
    ) public view returns (bool);
}

contract DSAuthEvents {
    event LogSetAuthority (address indexed authority);
    event LogSetOwner     (address indexed owner);
}

contract DSAuth is DSAuthEvents {
    DSAuthority  public  authority;
    address      public  owner;

    constructor() public {
        owner = msg.sender;
        emit LogSetOwner(msg.sender);
    }

    function setOwner(address owner_)
        public
        auth
    {
        owner = owner_;
        emit LogSetOwner(owner);
    }

    function setAuthority(DSAuthority authority_)
        public
        auth
    {
        authority = authority_;
        emit LogSetAuthority(address(authority));
    }

    modifier auth {
        require(isAuthorized(msg.sender, msg.sig), "ds-auth-unauthorized");
        _;
    }

    function isAuthorized(address src, bytes4 sig) internal view returns (bool) {
        if (src == address(this)) {
            return true;
        } else if (src == owner) {
            return true;
        } else if (authority == DSAuthority(0)) {
            return false;
        } else {
            return authority.canCall(src, address(this), sig);
        }
    }
}

////// lib/ds-stop/lib/ds-note/src/note.sol
/// note.sol -- the `note' modifier, for logging calls as events

// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.

// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

/* pragma solidity >=0.4.23; */

contract DSNote {
    event LogNote(
        bytes4   indexed  sig,
        address  indexed  guy,
        bytes32  indexed  foo,
        bytes32  indexed  bar,
        uint256           wad,
        bytes             fax
    ) anonymous;

    modifier note {
        bytes32 foo;
        bytes32 bar;
        uint256 wad;

        assembly {
            foo := calldataload(4)
            bar := calldataload(36)
            wad := callvalue
        }

        emit LogNote(msg.sig, msg.sender, foo, bar, wad, msg.data);

        _;
    }
}

////// lib/ds-value/lib/ds-thing/lib/ds-math/src/math.sol
/// math.sol -- mixin for inline numerical wizardry

// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.

// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

/* pragma solidity >0.4.13; */

contract DSMath {
    function add(uint x, uint y) internal pure returns (uint z) {
        require((z = x + y) >= x, "ds-math-add-overflow");
    }
    function sub(uint x, uint y) internal pure returns (uint z) {
        require((z = x - y) <= x, "ds-math-sub-underflow");
    }
    function mul(uint x, uint y) internal pure returns (uint z) {
        require(y == 0 || (z = x * y) / y == x, "ds-math-mul-overflow");
    }

    function min(uint x, uint y) internal pure returns (uint z) {
        return x <= y ? x : y;
    }
    function max(uint x, uint y) internal pure returns (uint z) {
        return x >= y ? x : y;
    }
    function imin(int x, int y) internal pure returns (int z) {
        return x <= y ? x : y;
    }
    function imax(int x, int y) internal pure returns (int z) {
        return x >= y ? x : y;
    }

    uint constant WAD = 10 ** 18;
    uint constant RAY = 10 ** 27;

    function wmul(uint x, uint y) internal pure returns (uint z) {
        z = add(mul(x, y), WAD / 2) / WAD;
    }
    function rmul(uint x, uint y) internal pure returns (uint z) {
        z = add(mul(x, y), RAY / 2) / RAY;
    }
    function wdiv(uint x, uint y) internal pure returns (uint z) {
        z = add(mul(x, WAD), y / 2) / y;
    }
    function rdiv(uint x, uint y) internal pure returns (uint z) {
        z = add(mul(x, RAY), y / 2) / y;
    }

    // This famous algorithm is called "exponentiation by squaring"
    // and calculates x^n with x as fixed-point and n as regular unsigned.
    //
    // It's O(log n), instead of O(n) for naive repeated multiplication.
    //
    // These facts are why it works:
    //
    //  If n is even, then x^n = (x^2)^(n/2).
    //  If n is odd,  then x^n = x * x^(n-1),
    //   and applying the equation for even x gives
    //    x^n = x * (x^2)^((n-1) / 2).
    //
    //  Also, EVM division is flooring and
    //    floor[(n-1) / 2] = floor[n / 2].
    //
    function rpow(uint x, uint n) internal pure returns (uint z) {
        z = n % 2 != 0 ? x : RAY;

        for (n /= 2; n != 0; n /= 2) {
            x = rmul(x, x);

            if (n % 2 != 0) {
                z = rmul(z, x);
            }
        }
    }
}

////// lib/ds-value/lib/ds-thing/src/thing.sol
// thing.sol - `auth` with handy mixins. your things should be DSThings

// Copyright (C) 2017  DappHub, LLC

// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.

// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

/* pragma solidity >=0.4.23; */

/* import 'ds-auth/auth.sol'; */
/* import 'ds-note/note.sol'; */
/* import 'ds-math/math.sol'; */

contract DSThing is DSAuth, DSNote, DSMath {
    function S(string memory s) internal pure returns (bytes4) {
        return bytes4(keccak256(abi.encodePacked(s)));
    }

}

////// lib/ds-value/src/value.sol
/// value.sol - a value is a simple thing, it can be get and set

// Copyright (C) 2017  DappHub, LLC

// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.

// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

/* pragma solidity >=0.4.23; */

/* import 'ds-thing/thing.sol'; */

contract DSValue is DSThing {
    bool    has;
    bytes32 val;
    function peek() public view returns (bytes32, bool) {
        return (val,has);
    }
    function read() public view returns (bytes32) {
        bytes32 wut; bool haz;
        (wut, haz) = peek();
        require(haz, "haz-not");
        return wut;
    }
    function poke(bytes32 wut) public note auth {
        val = wut;
        has = true;
    }
    function void() public note auth {  // unset the value
        has = false;
    }
}

////// src/osm.sol
/* pragma solidity >=0.5.10; */

/* import "ds-value/value.sol"; */

contract LibNote {
    event LogNote(
        bytes4   indexed  sig,
        address  indexed  usr,
        bytes32  indexed  arg1,
        bytes32  indexed  arg2,
        bytes             data
    ) anonymous;

    modifier note {
        _;
        assembly {
            // log an 'anonymous' event with a constant 6 words of calldata
            // and four indexed topics: selector, caller, arg1 and arg2
            let mark := msize                         // end of memory ensures zero
            mstore(0x40, add(mark, 288))              // update free memory pointer
            mstore(mark, 0x20)                        // bytes type data offset
            mstore(add(mark, 0x20), 224)              // bytes size (padded)
            calldatacopy(add(mark, 0x40), 0, 224)     // bytes payload
            log4(mark, 288,                           // calldata
                 shl(224, shr(224, calldataload(0))), // msg.sig
                 caller,                              // msg.sender
                 calldataload(4),                     // arg1
                 calldataload(36)                     // arg2
                )
        }
    }
}

contract OSM is LibNote {

    // --- Auth ---
    mapping (address => uint) public wards;
    function rely(address usr) external note auth { wards[usr] = 1; }
    function deny(address usr) external note auth { wards[usr] = 0; }
    modifier auth {
        require(wards[msg.sender] == 1, "OSM/not-authorized");
        _;
    }

    // --- Stop ---
    uint256 public stopped;
    modifier stoppable { require(stopped == 0, "OSM/is-stopped"); _; }

    // --- Math ---
    function add(uint64 x, uint64 y) internal pure returns (uint64 z) {
        z = x + y;
        require(z >= x);
    }

    address public src;
    uint16  constant ONE_HOUR = uint16(3600);
    uint16  public hop = ONE_HOUR;
    uint64  public zzz;

    struct Feed {
        uint128 val;
        uint128 has;
    }

    Feed cur;
    Feed nxt;

    // Whitelisted contracts, set by an auth
    mapping (address => uint256) public bud;

    modifier toll { require(bud[msg.sender] == 1, "OSM/contract-not-whitelisted"); _; }

    event LogValue(bytes32 val);

    constructor (address src_) public {
        wards[msg.sender] = 1;
        src = src_;
    }

    function stop() external note auth {
        stopped = 1;
    }
    function start() external note auth {
        stopped = 0;
    }

    function change(address src_) external note auth {
        src = src_;
    }

    function era() internal view returns (uint) {
        return block.timestamp;
    }

    function prev(uint ts) internal view returns (uint64) {
        require(hop != 0, "OSM/hop-is-zero");
        return uint64(ts - (ts % hop));
    }

    function step(uint16 ts) external auth {
        require(ts > 0, "OSM/ts-is-zero");
        hop = ts;
    }

    function void() external note auth {
        cur = nxt = Feed(0, 0);
        stopped = 1;
    }

    function pass() public view returns (bool ok) {
        return era() >= add(zzz, hop);
    }

    function poke() external note stoppable {
        require(pass(), "OSM/not-passed");
        (bytes32 wut, bool ok) = DSValue(src).peek();
        if (ok) {
            cur = nxt;
            nxt = Feed(uint128(uint(wut)), 1);
            zzz = prev(era());
            emit LogValue(bytes32(uint(cur.val)));
        }
    }

    function peek() external view toll returns (bytes32,bool) {
        return (bytes32(uint(cur.val)), cur.has == 1);
    }

    function peep() external view toll returns (bytes32,bool) {
        return (bytes32(uint(nxt.val)), nxt.has == 1);
    }

    function read() external view toll returns (bytes32) {
        require(cur.has == 1, "OSM/no-current-value");
        return (bytes32(uint(cur.val)));
    }



    function kiss(address a) external note auth {
        require(a != address(0), "OSM/no-contract-0");
        bud[a] = 1;
    }

    function diss(address a) external note auth {
        bud[a] = 0;
    }

    function kiss(address[] calldata a) external note auth {
        for(uint i = 0; i < a.length; i++) {
            require(a[i] != address(0), "OSM/no-contract-0");
            bud[a[i]] = 1;
        }
    }

    function diss(address[] calldata a) external note auth {
        for(uint i = 0; i < a.length; i++) {
            bud[a[i]] = 0;
        }
    }
}

{
  "compilationTarget": {
    "OSM.sol": "OSM"
  },
  "evmVersion": "petersburg",
  "libraries": {},
  "optimizer": {
    "enabled": true,
    "runs": 200
  },
  "remappings": []
}