contract DssProxyActions is Common {
    // Internal functions

    function sub(uint x, uint y) internal pure returns (uint z) {
        require((z = x - y) <= x, "sub-overflow");
    }

    function toInt(uint x) internal pure returns (int y) {
        y = int(x);
        require(y >= 0, "int-overflow");
    }

    function toRad(uint wad) internal pure returns (uint rad) {
        rad = mul(wad, 10 ** 27);
    }

    function convertTo18(address gemJoin, uint256 amt) internal returns (uint256 wad) {
        // For those collaterals that have less than 18 decimals precision we need to do the conversion before passing to frob function
        // Adapters will automatically handle the difference of precision
        wad = mul(
            amt,
            10 ** (18 - GemJoinLike(gemJoin).dec())
        );
    }

    function _getDrawDart(
        address vat,
        address jug,
        address urn,
        bytes32 ilk,
        uint wad
    ) internal returns (int dart) {
        // Updates stability fee rate
        uint rate = JugLike(jug).drip(ilk);

        // Gets DAI balance of the urn in the vat
        uint dai = VatLike(vat).dai(urn);

        // If there was already enough DAI in the vat balance, just exits it without adding more debt
        if (dai < mul(wad, RAY)) {
            // Calculates the needed dart so together with the existing dai in the vat is enough to exit wad amount of DAI tokens
            dart = toInt(sub(mul(wad, RAY), dai) / rate);
            // This is neeeded due lack of precision. It might need to sum an extra dart wei (for the given DAI wad amount)
            dart = mul(uint(dart), rate) < mul(wad, RAY) ? dart + 1 : dart;
        }
    }

    function _getWipeDart(
        address vat,
        uint dai,
        address urn,
        bytes32 ilk
    ) internal view returns (int dart) {
        // Gets actual rate from the vat
        (, uint rate,,,) = VatLike(vat).ilks(ilk);
        // Gets actual art value of the urn
        (, uint art) = VatLike(vat).urns(ilk, urn);

        // Uses the whole dai balance in the vat to reduce the debt
        dart = toInt(dai / rate);
        // Checks the calculated dart is not higher than urn.art (total debt), otherwise uses its value
        dart = uint(dart) <= art ? - dart : - toInt(art);
    }

    function open(
        address manager,
        bytes32 ilk,
        address usr
    ) public returns (uint cdp) {
        cdp = ManagerLike(manager).open(ilk, usr);
    }

    function give(
        address manager,
        uint cdp,
        address usr
    ) public {
        ManagerLike(manager).give(cdp, usr);
    }

    function giveToProxy(
        address proxyRegistry,
        address manager,
        uint cdp,
        address dst
    ) public {
        // Gets actual proxy address
        address proxy = ProxyRegistryLike(proxyRegistry).proxies(dst);
        // Checks if the proxy address already existed and dst address is still the owner
        if (proxy == address(0) || ProxyLike(proxy).owner() != dst) {
            uint csize;
            assembly {
                csize := extcodesize(dst)
            }
            // We want to avoid creating a proxy for a contract address that might not be able to handle proxies, then losing the CDP
            require(csize == 0, "Dst-is-a-contract");
            // Creates the proxy for the dst address
            proxy = ProxyRegistryLike(proxyRegistry).build(dst);
        }
        // Transfers CDP to the dst proxy
        give(manager, cdp, proxy);
    }

    function flux(
        address manager,
        uint cdp,
        address dst,
        uint wad
    ) public {
        ManagerLike(manager).flux(cdp, dst, wad);
    }

    function move(
        address manager,
        uint cdp,
        address dst,
        uint rad
    ) public {
        ManagerLike(manager).move(cdp, dst, rad);
    }

    function frob(
        address manager,
        uint cdp,
        int dink,
        int dart
    ) public {
        ManagerLike(manager).frob(cdp, dink, dart);
    }

    function gemJoin_join(address apt, address urn, uint wad) public {
      // Approves adapter to take the token amount
      GemJoinLike(apt).gem().approve(apt, wad);
      // Joins token collateral into the vat
      GemJoinLike(apt).join(urn, wad);
    }

    function lockGemAndDraw(
        address manager,
        address jug,
        address gemJoin,
        address daiJoin,
        uint cdp,
        uint wadC,
        uint wadD
    ) public {
        address urn = ManagerLike(manager).urns(cdp);
        address vat = ManagerLike(manager).vat();
        bytes32 ilk = ManagerLike(manager).ilks(cdp);
        // Takes token amount from user's wallet and joins into the vat
        gemJoin_join(gemJoin, urn, wadC);
        // Locks token amount into the CDP and generates debt
        frob(manager, cdp, toInt(convertTo18(gemJoin, wadC)), _getDrawDart(vat, jug, urn, ilk, wadD));
        // Moves the DAI amount (balance in the vat in rad) to proxy's address
        move(manager, cdp, address(this), toRad(wadD));
        // Allows adapter to access to proxy's DAI balance in the vat
        if (VatLike(vat).can(address(this), address(daiJoin)) == 0) {
            VatLike(vat).hope(daiJoin);
        }
        // Exits DAI to the user's wallet as a token
        DaiJoinLike(daiJoin).exit(address(this), wadD);
    }

    function openLockGemAndDraw(
        address manager,
        address jug,
        address gemJoin,
        address daiJoin,
        bytes32 ilk,
        uint wadC,
        uint wadD
    ) public returns (uint cdp) {
        cdp = open(manager, ilk, address(this));
        lockGemAndDraw(manager, jug, gemJoin, daiJoin, cdp, wadC, wadD);
    }

    function wipeAndFreeGem(
        address manager,
        address gemJoin,
        address daiJoin,
        uint cdp,
        uint wadC,
        uint wadD
    ) public {
        address urn = ManagerLike(manager).urns(cdp);
        // Joins DAI amount into the vat
        daiJoin_join(daiJoin, urn, wadD);
        uint wad18 = convertTo18(gemJoin, wadC);
        // Paybacks debt to the CDP and unlocks token amount from it
        frob(
            manager,
            cdp,
            -toInt(wad18),
            _getWipeDart(ManagerLike(manager).vat(), VatLike(ManagerLike(manager).vat()).dai(urn), urn, ManagerLike(manager).ilks(cdp))
        );
        // Moves the amount from the CDP urn to proxy's address
        flux(manager, cdp, address(this), wad18);
        // Exits token amount to the user's wallet as a token
        GemJoinLike(gemJoin).exit(address(this), wadC);
    }
}
function sub(uint x, uint y) internal pure returns (uint z) {
    require((z = x - y) <= x, "sub-overflow");
}

// Internal functions