/*

    /     |  __    / ____|
   /      | |__) | | |
  / /    |  _  /  | |
 / ____   | |    | |____
/_/    _ |_|  _  _____|

* ARC: v1/StateV1.sol
*
* Latest source (may be newer): https://github.com/arcxgame/contracts/blob/master/contracts/v1/StateV1.sol
*
* Contract Dependencies: 
*	- Context
*	- Ownable
* Libraries: 
*	- Address
*	- Decimal
*	- Math
*	- SafeERC20
*	- SafeMath
*	- TypesV1
*
* MIT License
* ===========
*
* Copyright (c) 2020 ARC
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in all
* copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
*/

pragma experimental ABIEncoderV2;

/* ===============================================
* Flattened with Solidifier by Coinage
* 
* https://solidifier.coina.ge
* ===============================================
*/


pragma solidity ^0.5.0;

/**
 * @dev Wrappers over Solidity's arithmetic operations with added overflow
 * checks.
 *
 * Arithmetic operations in Solidity wrap on overflow. This can easily result
 * in bugs, because programmers usually assume that an overflow raises an
 * error, which is the standard behavior in high level programming languages.
 * `SafeMath` restores this intuition by reverting the transaction when an
 * operation overflows.
 *
 * Using this library instead of the unchecked operations eliminates an entire
 * class of bugs, so it's recommended to use it always.
 */
library SafeMath {
    /**
     * @dev Returns the addition of two unsigned integers, reverting on
     * overflow.
     *
     * Counterpart to Solidity's `+` operator.
     *
     * Requirements:
     * - Addition cannot overflow.
     */
    function add(uint256 a, uint256 b) internal pure returns (uint256) {
        uint256 c = a + b;
        require(c >= a, "SafeMath: addition overflow");

        return c;
    }

    /**
     * @dev Returns the subtraction of two unsigned integers, reverting on
     * overflow (when the result is negative).
     *
     * Counterpart to Solidity's `-` operator.
     *
     * Requirements:
     * - Subtraction cannot overflow.
     */
    function sub(uint256 a, uint256 b) internal pure returns (uint256) {
        return sub(a, b, "SafeMath: subtraction overflow");
    }

    /**
     * @dev Returns the subtraction of two unsigned integers, reverting with custom message on
     * overflow (when the result is negative).
     *
     * Counterpart to Solidity's `-` operator.
     *
     * Requirements:
     * - Subtraction cannot overflow.
     *
     * _Available since v2.4.0._
     */
    function sub(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        require(b <= a, errorMessage);
        uint256 c = a - b;

        return c;
    }

    /**
     * @dev Returns the multiplication of two unsigned integers, reverting on
     * overflow.
     *
     * Counterpart to Solidity's `*` operator.
     *
     * Requirements:
     * - Multiplication cannot overflow.
     */
    function mul(uint256 a, uint256 b) internal pure returns (uint256) {
        // Gas optimization: this is cheaper than requiring 'a' not being zero, but the
        // benefit is lost if 'b' is also tested.
        // See: https://github.com/OpenZeppelin/openzeppelin-contracts/pull/522
        if (a == 0) {
            return 0;
        }

        uint256 c = a * b;
        require(c / a == b, "SafeMath: multiplication overflow");

        return c;
    }

    /**
     * @dev Returns the integer division of two unsigned integers. Reverts on
     * division by zero. The result is rounded towards zero.
     *
     * Counterpart to Solidity's `/` operator. Note: this function uses a
     * `revert` opcode (which leaves remaining gas untouched) while Solidity
     * uses an invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     * - The divisor cannot be zero.
     */
    function div(uint256 a, uint256 b) internal pure returns (uint256) {
        return div(a, b, "SafeMath: division by zero");
    }

    /**
     * @dev Returns the integer division of two unsigned integers. Reverts with custom message on
     * division by zero. The result is rounded towards zero.
     *
     * Counterpart to Solidity's `/` operator. Note: this function uses a
     * `revert` opcode (which leaves remaining gas untouched) while Solidity
     * uses an invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     * - The divisor cannot be zero.
     *
     * _Available since v2.4.0._
     */
    function div(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        // Solidity only automatically asserts when dividing by 0
        require(b > 0, errorMessage);
        uint256 c = a / b;
        // assert(a == b * c + a % b); // There is no case in which this doesn't hold

        return c;
    }

    /**
     * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
     * Reverts when dividing by zero.
     *
     * Counterpart to Solidity's `%` operator. This function uses a `revert`
     * opcode (which leaves remaining gas untouched) while Solidity uses an
     * invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     * - The divisor cannot be zero.
     */
    function mod(uint256 a, uint256 b) internal pure returns (uint256) {
        return mod(a, b, "SafeMath: modulo by zero");
    }

    /**
     * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
     * Reverts with custom message when dividing by zero.
     *
     * Counterpart to Solidity's `%` operator. This function uses a `revert`
     * opcode (which leaves remaining gas untouched) while Solidity uses an
     * invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     * - The divisor cannot be zero.
     *
     * _Available since v2.4.0._
     */
    function mod(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        require(b != 0, errorMessage);
        return a % b;
    }
}


/**
 * @dev Interface of the ERC20 standard as defined in the EIP. Does not include
 * the optional functions; to access them see {ERC20Detailed}.
 */
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);
}


/**
 * @dev Collection of functions related to the address type
 */
library Address {
    /**
     * @dev Returns true if `account` is a contract.
     *
     * [IMPORTANT]
     * ====
     * It is unsafe to assume that an address for which this function returns
     * false is an externally-owned account (EOA) and not a contract.
     *
     * Among others, `isContract` will return false for the following 
     * types of addresses:
     *
     *  - an externally-owned account
     *  - a contract in construction
     *  - an address where a contract will be created
     *  - an address where a contract lived, but was destroyed
     * ====
     */
    function isContract(address account) internal view returns (bool) {
        // According to EIP-1052, 0x0 is the value returned for not-yet created accounts
        // and 0xc5d2460186f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470 is returned
        // for accounts without code, i.e. `keccak256('')`
        bytes32 codehash;
        bytes32 accountHash = 0xc5d2460186f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470;
        // solhint-disable-next-line no-inline-assembly
        assembly { codehash := extcodehash(account) }
        return (codehash != accountHash && codehash != 0x0);
    }

    /**
     * @dev Converts an `address` into `address payable`. Note that this is
     * simply a type cast: the actual underlying value is not changed.
     *
     * _Available since v2.4.0._
     */
    function toPayable(address account) internal pure returns (address payable) {
        return address(uint160(account));
    }

    /**
     * @dev Replacement for Solidity's `transfer`: sends `amount` wei to
     * `recipient`, forwarding all available gas and reverting on errors.
     *
     * https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost
     * of certain opcodes, possibly making contracts go over the 2300 gas limit
     * imposed by `transfer`, making them unable to receive funds via
     * `transfer`. {sendValue} removes this limitation.
     *
     * https://diligence.consensys.net/posts/2019/09/stop-using-soliditys-transfer-now/[Learn more].
     *
     * IMPORTANT: because control is transferred to `recipient`, care must be
     * taken to not create reentrancy vulnerabilities. Consider using
     * {ReentrancyGuard} or the
     * https://solidity.readthedocs.io/en/v0.5.11/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].
     *
     * _Available since v2.4.0._
     */
    function sendValue(address payable recipient, uint256 amount) internal {
        require(address(this).balance >= amount, "Address: insufficient balance");

        // solhint-disable-next-line avoid-call-value
        (bool success, ) = recipient.call.value(amount)("");
        require(success, "Address: unable to send value, recipient may have reverted");
    }
}


/**
 * @title SafeERC20
 * @dev Wrappers around ERC20 operations that throw on failure (when the token
 * contract returns false). Tokens that return no value (and instead revert or
 * throw on failure) are also supported, non-reverting calls are assumed to be
 * successful.
 * To use this library you can add a `using SafeERC20 for ERC20;` statement to your contract,
 * which allows you to call the safe operations as `token.safeTransfer(...)`, etc.
 */
library SafeERC20 {
    using SafeMath for uint256;
    using Address for address;

    function safeTransfer(IERC20 token, address to, uint256 value) internal {
        callOptionalReturn(token, abi.encodeWithSelector(token.transfer.selector, to, value));
    }

    function safeTransferFrom(IERC20 token, address from, address to, uint256 value) internal {
        callOptionalReturn(token, abi.encodeWithSelector(token.transferFrom.selector, from, to, value));
    }

    function safeApprove(IERC20 token, address spender, uint256 value) internal {
        // safeApprove should only be called when setting an initial allowance,
        // or when resetting it to zero. To increase and decrease it, use
        // 'safeIncreaseAllowance' and 'safeDecreaseAllowance'
        // solhint-disable-next-line max-line-length
        require((value == 0) || (token.allowance(address(this), spender) == 0),
            "SafeERC20: approve from non-zero to non-zero allowance"
        );
        callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, value));
    }

    function safeIncreaseAllowance(IERC20 token, address spender, uint256 value) internal {
        uint256 newAllowance = token.allowance(address(this), spender).add(value);
        callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
    }

    function safeDecreaseAllowance(IERC20 token, address spender, uint256 value) internal {
        uint256 newAllowance = token.allowance(address(this), spender).sub(value, "SafeERC20: decreased allowance below zero");
        callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
    }

    /**
     * @dev Imitates a Solidity high-level call (i.e. a regular function call to a contract), relaxing the requirement
     * on the return value: the return value is optional (but if data is returned, it must not be false).
     * @param token The token targeted by the call.
     * @param data The call data (encoded using abi.encode or one of its variants).
     */
    function callOptionalReturn(IERC20 token, bytes memory data) private {
        // We need to perform a low level call here, to bypass Solidity's return data size checking mechanism, since
        // we're implementing it ourselves.

        // A Solidity high level call has three parts:
        //  1. The target address is checked to verify it contains contract code
        //  2. The call itself is made, and success asserted
        //  3. The return value is decoded, which in turn checks the size of the returned data.
        // solhint-disable-next-line max-line-length
        require(address(token).isContract(), "SafeERC20: call to non-contract");

        // solhint-disable-next-line avoid-low-level-calls
        (bool success, bytes memory returndata) = address(token).call(data);
        require(success, "SafeERC20: low-level call failed");

        if (returndata.length > 0) { // Return data is optional
            // solhint-disable-next-line max-line-length
            require(abi.decode(returndata, (bool)), "SafeERC20: ERC20 operation did not succeed");
        }
    }
}


/*
 * @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 GSN 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.
 */
contract Context {
    // Empty internal constructor, to prevent people from mistakenly deploying
    // an instance of this contract, which should be used via inheritance.
    constructor () internal { }
    // solhint-disable-previous-line no-empty-blocks

    function _msgSender() internal view returns (address payable) {
        return msg.sender;
    }

    function _msgData() internal view returns (bytes memory) {
        this; // silence state mutability warning without generating bytecode - see https://github.com/ethereum/solidity/issues/2691
        return msg.data;
    }
}


/**
 * @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.
 *
 * 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.
 */
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 () internal {
        address msgSender = _msgSender();
        _owner = msgSender;
        emit OwnershipTransferred(address(0), msgSender);
    }

    /**
     * @dev Returns the address of the current owner.
     */
    function owner() public view returns (address) {
        return _owner;
    }

    /**
     * @dev Throws if called by any account other than the owner.
     */
    modifier onlyOwner() {
        require(isOwner(), "Ownable: caller is not the owner");
        _;
    }

    /**
     * @dev Returns true if the caller is the current owner.
     */
    function isOwner() public view returns (bool) {
        return _msgSender() == _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 onlyOwner {
        emit OwnershipTransferred(_owner, address(0));
        _owner = 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 onlyOwner {
        _transferOwnership(newOwner);
    }

    /**
     * @dev Transfers ownership of the contract to a new account (`newOwner`).
     */
    function _transferOwnership(address newOwner) internal {
        require(newOwner != address(0), "Ownable: new owner is the zero address");
        emit OwnershipTransferred(_owner, newOwner);
        _owner = newOwner;
    }
}


// SPDX-License-Identifier: MIT


/**
 * @title Math
 *
 * Library for non-standard Math functions
 */
library Math {
    using SafeMath for uint256;

    // ============ Library Functions ============

    /*
     * Return target * (numerator / denominator).
     */
    function getPartial(
        uint256 target,
        uint256 numerator,
        uint256 denominator
    )
        internal
        pure
        returns (uint256)
    {
        return target.mul(numerator).div(denominator);
    }

    function to128(
        uint256 number
    )
        internal
        pure
        returns (uint128)
    {
        uint128 result = uint128(number);
        require(
            result == number,
            "Math: Unsafe cast to uint128"
        );
        return result;
    }

    function to96(
        uint256 number
    )
        internal
        pure
        returns (uint96)
    {
        uint96 result = uint96(number);
        require(
            result == number,
            "Math: Unsafe cast to uint96"
        );
        return result;
    }

    function to32(
        uint256 number
    )
        internal
        pure
        returns (uint32)
    {
        uint32 result = uint32(number);
        require(
            result == number,
            "Math: Unsafe cast to uint32"
        );
        return result;
    }

    function min(
        uint256 a,
        uint256 b
    )
        internal
        pure
        returns (uint256)
    {
        return a < b ? a : b;
    }

    function max(
        uint256 a,
        uint256 b
    )
        internal
        pure
        returns (uint256)
    {
        return a > b ? a : b;
    }
}

// SPDX-License-Identifier: MIT


/**
 * @title Decimal
 *
 * Library that defines a fixed-point number with 18 decimal places.
 */
library Decimal {
    using SafeMath for uint256;

    // ============ Constants ============

    uint256 constant BASE = 10**18;

    // ============ Structs ============

    struct D256 {
        uint256 value;
    }

    // ============ Functions ============

    function one()
        internal
        pure
        returns (D256 memory)
    {
        return D256({ value: BASE });
    }

    function onePlus(
        D256 memory d
    )
        internal
        pure
        returns (D256 memory)
    {
        return D256({ value: d.value.add(BASE) });
    }

    function mul(
        uint256 target,
        D256 memory d
    )
        internal
        pure
        returns (uint256)
    {
        return Math.getPartial(target, d.value, BASE);
    }

    function mul(
        D256 memory d1,
        D256 memory d2
    )
        internal
        pure
        returns (D256 memory)
    {
        return Decimal.D256({ value: Math.getPartial(d1.value, d2.value, BASE) });
    }

    function div(
        uint256 target,
        D256 memory d
    )
        internal
        pure
        returns (uint256)
    {
        return Math.getPartial(target, BASE, d.value);
    }

    function add(
        D256 memory d,
        uint256 amount
    )
        internal
        pure
        returns (D256 memory)
    {
        return D256({ value: d.value.add(amount) });
    }

    function sub(
        D256 memory d,
        uint256 amount
    )
        internal
        pure
        returns (D256 memory)
    {
        return D256({ value: d.value.sub(amount) });
    }

}

// SPDX-License-Identifier: MIT


interface IOracle {

    function fetchCurrentPrice()
        external
        view
        returns (Decimal.D256 memory);

}


// SPDX-License-Identifier: MIT


interface ISyntheticToken {

    function symbolKey()
        external
        view
        returns (bytes32);

    function mint(
        address to,
        uint256 value
    )
        external;

    function burn(
        address to,
        uint256 value
    )
        external;

    function transferCollateral(
        address token,
        address to,
        uint256 value
    )
        external
        returns (bool);


}


// SPDX-License-Identifier: MIT


interface IMintableToken {

    function mint(
        address to,
        uint256 value
    )
        external;

    function burn(
        address to,
        uint256 value
    )
        external;

}


// SPDX-License-Identifier: MIT


library TypesV1 {

    using Math for uint256;
    using SafeMath for uint256;

    // ============ Enums ============

    enum AssetType {
        Collateral,
        Synthetic
    }

    // ============ Structs ============

    struct MarketParams {
        Decimal.D256 collateralRatio;
        Decimal.D256 liquidationUserFee;
        Decimal.D256 liquidationArcFee;
    }

    struct Position {
        address owner;
        AssetType collateralAsset;
        AssetType borrowedAsset;
        Par collateralAmount;
        Par borrowedAmount;
    }

    struct RiskParams {
        uint256 collateralLimit;
        uint256 syntheticLimit;
        uint256 positionCollateralMinimum;
    }

    // ============ AssetAmount ============

    enum AssetDenomination {
        Wei, // the amount is denominated in wei
        Par  // the amount is denominated in par
    }

    enum AssetReference {
        Delta, // the amount is given as a delta from the current value
        Target // the amount is given as an exact number to end up at
    }

    struct AssetAmount {
        bool sign; // true if positive
        AssetDenomination denomination;
        AssetReference ref;
        uint256 value;
    }

    // ============ ArcAsset ============

    function oppositeAsset(
        AssetType assetType
    )
        internal
        pure
        returns (AssetType)
    {
        return assetType == AssetType.Collateral ? AssetType.Synthetic : AssetType.Collateral;
    }

    // ============ Par (Principal Amount) ============

    // Individual principal amount for an account
    struct Par {
        bool sign; // true if positive
        uint128 value;
    }

    function zeroPar()
        internal
        pure
        returns (Par memory)
    {
        return Par({
            sign: false,
            value: 0
        });
    }

    function positiveZeroPar()
        internal
        pure
        returns (Par memory)
    {
        return Par({
            sign: true,
            value: 0
        });
    }

    function sub(
        Par memory a,
        Par memory b
    )
        internal
        pure
        returns (Par memory)
    {
        return add(a, negative(b));
    }

    function add(
        Par memory a,
        Par memory b
    )
        internal
        pure
        returns (Par memory)
    {
        Par memory result;
        if (a.sign == b.sign) {
            result.sign = a.sign;
            result.value = SafeMath.add(a.value, b.value).to128();
        } else {
            if (a.value >= b.value) {
                result.sign = a.sign;
                result.value = SafeMath.sub(a.value, b.value).to128();
            } else {
                result.sign = b.sign;
                result.value = SafeMath.sub(b.value, a.value).to128();
            }
        }
        return result;
    }

    function equals(
        Par memory a,
        Par memory b
    )
        internal
        pure
        returns (bool)
    {
        if (a.value == b.value) {
            if (a.value == 0) {
                return true;
            }
            return a.sign == b.sign;
        }
        return false;
    }

    function negative(
        Par memory a
    )
        internal
        pure
        returns (Par memory)
    {
        return Par({
            sign: !a.sign,
            value: a.value
        });
    }

    function isNegative(
        Par memory a
    )
        internal
        pure
        returns (bool)
    {
        return !a.sign && a.value > 0;
    }

    function isPositive(
        Par memory a
    )
        internal
        pure
        returns (bool)
    {
        return a.sign && a.value > 0;
    }

    function isZero(
        Par memory a
    )
        internal
        pure
        returns (bool)
    {
        return a.value == 0;
    }

}


// SPDX-License-Identifier: MIT


/**
 * @title StateV1
 * @author Kerman Kohli
 * @notice This contract holds all the state regarding a sythetic asset protocol.
 *         The contract has an owner and core address which can call certain functions.
 */
contract StateV1 is Ownable {

    using Math for uint256;
    using SafeMath for uint256;
    using TypesV1 for TypesV1.Par;

    // ============ Variables ============

    address public core;

    TypesV1.MarketParams public market;
    TypesV1.RiskParams public risk;

    IOracle public oracle;
    address public collateralAsset;
    address public syntheticAsset;

    uint256 public positionCount;
    uint256 public totalSupplied;

    mapping (uint256 => TypesV1.Position) public positions;

    // ============ Events ============

    event MarketParamsUpdated(TypesV1.MarketParams updatedMarket);
    event RiskParamsUpdated(TypesV1.RiskParams updatedParams);
    event OracleUpdated(address updatedOracle);

    // ============ Constructor ============

    constructor(
        address _core,
        address _collateralAsset,
        address _syntheticAsset,
        address _oracle,
        TypesV1.MarketParams memory _marketParams,
        TypesV1.RiskParams memory _riskParams
    )
        public
    {
        core = _core;
        collateralAsset = _collateralAsset;
        syntheticAsset = _syntheticAsset;

        setOracle(_oracle);
        setMarketParams(_marketParams);
        setRiskParams(_riskParams);
    }

    // ============ Modifiers ============

    modifier onlyCore() {
        require(
            msg.sender == core,
            "StateV1: only core can call"
        );
        _;
    }

    // ============ Admin Setters ============

    /**
     * @dev Set the address of the oracle
     *
     * @param _oracle Address of the oracle to set
     */
    function setOracle(
        address _oracle
    )
        public
        onlyOwner
    {
        require(
            _oracle != address(0),
            "StateV1: cannot set 0 for oracle address"
        );

        oracle = IOracle(_oracle);
        emit OracleUpdated(_oracle);
    }

    /**
     * @dev Set the parameters of the market
     *
     * @param _marketParams Set the new market params
     */
    function setMarketParams(
        TypesV1.MarketParams memory _marketParams
    )
        public
        onlyOwner
    {
        market = _marketParams;
        emit MarketParamsUpdated(market);
    }

    /**
     * @dev Set the risk parameters of the market
     *
     * @param _riskParams Set the risk levels of the market
     */
    function setRiskParams(
        TypesV1.RiskParams memory _riskParams
    )
        public
        onlyOwner
    {
        risk = _riskParams;
        emit RiskParamsUpdated(risk);
    }

    // ============ Core Setters ============

    function updateTotalSupplied(
        uint256 amount
    )
        public
        onlyCore
    {
        totalSupplied = totalSupplied.add(amount);
    }

    function savePosition(
        TypesV1.Position memory position
    )
        public
        onlyCore
        returns (uint256)
    {
        uint256 idToAllocate = positionCount;
        positions[positionCount] = position;
        positionCount = positionCount.add(1);

        return idToAllocate;
    }

    function setAmount(
        uint256 id,
        TypesV1.AssetType asset,
        TypesV1.Par memory amount
    )
        public
        onlyCore
        returns (TypesV1.Position memory)
    {
        TypesV1.Position storage position = positions[id];

        if (position.collateralAsset == asset) {
            position.collateralAmount = amount;
        } else {
            position.borrowedAmount = amount;
        }

        return position;
    }

    function updatePositionAmount(
        uint256 id,
        TypesV1.AssetType asset,
        TypesV1.Par memory amount
    )
        public
        onlyCore
        returns (TypesV1.Position memory)
    {
        TypesV1.Position storage position = positions[id];

        if (position.collateralAsset == asset) {
            position.collateralAmount = position.collateralAmount.add(amount);
        } else {
            position.borrowedAmount = position.borrowedAmount.add(amount);
        }

        return position;
    }

    // ============ Public Getters ============

    function getAddress(
        TypesV1.AssetType asset
    )
        public
        view
        returns (address)
    {
        return asset == TypesV1.AssetType.Collateral ?
            address(collateralAsset) :
            address(syntheticAsset);
    }

    function getPosition(
        uint256 id
    )
        public
        view
        returns (TypesV1.Position memory)
    {
        return positions[id];
    }

    function getCurrentPrice()
        public
        view
        returns (Decimal.D256 memory)
    {
        return oracle.fetchCurrentPrice();
    }

    // ============ Calculation Getters ============

    function isCollateralized(
        TypesV1.Position memory position
    )
        public
        view
        returns (bool)
    {
        if (position.borrowedAmount.value == 0) {
            return true;
        }

        Decimal.D256 memory currentPrice = oracle.fetchCurrentPrice();

        (TypesV1.Par memory collateralDelta) = calculateCollateralDelta(
            position.borrowedAsset,
            position.collateralAmount,
            position.borrowedAmount,
            currentPrice
        );

        return collateralDelta.sign || collateralDelta.value == 0;
    }

    /**
     * @dev Given an asset, calculate the inverse amount of that asset
     *
     * @param asset The asset in question here
     * @param amount The amount of this asset
     * @param price What price do you want to calculate the inverse at
     */
    function calculateInverseAmount(
        TypesV1.AssetType asset,
        uint256 amount,
        Decimal.D256 memory price
    )
        public
        pure
        returns (uint256)
    {
        uint256 borrowRequired;

        if (asset == TypesV1.AssetType.Collateral) {
            borrowRequired = Decimal.mul(
                amount,
                price
            );
        } else if (asset == TypesV1.AssetType.Synthetic) {
            borrowRequired = Decimal.div(
                amount,
                price
            );
        }

        return borrowRequired;
    }

    /**
     * @dev Similar to calculateInverseAmount although the difference being
     *      that this factors in the collateral ratio.
     *
     * @param asset The asset in question here
     * @param amount The amount of this asset
     * @param price What price do you want to calculate the inverse at
     */
    function calculateInverseRequired(
        TypesV1.AssetType asset,
        uint256 amount,
        Decimal.D256 memory price
    )
        public
        view
        returns (TypesV1.Par memory)
    {

        uint256 inverseRequired = calculateInverseAmount(
            asset,
            amount,
            price
        );

        if (asset == TypesV1.AssetType.Collateral) {
            inverseRequired = Decimal.div(
                inverseRequired,
                market.collateralRatio
            );

        } else if (asset == TypesV1.AssetType.Synthetic) {
            inverseRequired = Decimal.mul(
                inverseRequired,
                market.collateralRatio
            );
        }

        return TypesV1.Par({
            sign: true,
            value: inverseRequired.to128()
        });
    }

    /**
     * @dev When executing a liqudation, the price of the asset has to be calculated
     *      at a discount in order for it to be profitable for the liquidator. This function
     *      will get the current oracle price for the asset and find the discounted price.
     *
     * @param asset The asset in question here
     */
    function calculateLiquidationPrice(
        TypesV1.AssetType asset
    )
        public
        view
        returns (Decimal.D256 memory)
    {
        Decimal.D256 memory result;
        Decimal.D256 memory currentPrice = oracle.fetchCurrentPrice();

        uint256 totalSpread = market.liquidationUserFee.value.add(
            market.liquidationArcFee.value
        );

        if (asset == TypesV1.AssetType.Collateral) {
            result = Decimal.sub(
                Decimal.one(),
                totalSpread
            );
        } else if (asset == TypesV1.AssetType.Synthetic) {
            result = Decimal.add(
                Decimal.one(),
                totalSpread
            );
        }

        result = Decimal.mul(
            currentPrice,
            result
        );

        return result;
    }

    /**
     * @dev Given an asset being borrowed, figure out how much collateral can this still borrow or
     *      is in the red by. This function is used to check if a position is undercolalteralised and
     *      also to calculate how much can a position be liquidated by.
     *
     * @param borrowedAsset The asset which is being borrowed
     * @param parSupply The amount being supplied
     * @param parBorrow The amount being borrowed
     * @param price The price to calculate this difference by
     */
    function calculateCollateralDelta(
        TypesV1.AssetType borrowedAsset,
        TypesV1.Par memory parSupply,
        TypesV1.Par memory parBorrow,
        Decimal.D256 memory price
    )
        public
        view
        returns (TypesV1.Par memory)
    {
        TypesV1.Par memory collateralDelta;
        TypesV1.Par memory collateralRequired;

        if (borrowedAsset == TypesV1.AssetType.Collateral) {
            collateralRequired = calculateInverseRequired(
                borrowedAsset,
                parBorrow.value,
                price
            );
        } else if (borrowedAsset == TypesV1.AssetType.Synthetic) {
            collateralRequired = calculateInverseRequired(
                borrowedAsset,
                parBorrow.value,
                price
            );
        }

        collateralDelta = parSupply.sub(collateralRequired);

        return collateralDelta;
    }

    /**
     * @dev Add the user liqudation fee with the arc liquidation fee
     */
    function totalLiquidationSpread()
        public
        view
        returns (Decimal.D256 memory)
    {
        return Decimal.D256({
            value: market.liquidationUserFee.value.add(
                market.liquidationArcFee.value
            )
        });
    }

    /**
     * @dev Calculate the liquidation ratio between the user and ARC.
     *
     * @return First parameter it the user ratio, second is ARC's ratio
     */
    function calculateLiquidationSplit()
        public
        view
        returns (
            Decimal.D256 memory,
            Decimal.D256 memory
        )
    {
        Decimal.D256 memory total = Decimal.D256({
            value: market.liquidationUserFee.value.add(
                market.liquidationArcFee.value
            )
        });

        Decimal.D256 memory userRatio = Decimal.D256({
            value: Decimal.div(
                market.liquidationUserFee.value,
                total
            )
        });

        return (
            userRatio,
            Decimal.sub(
                Decimal.one(),
                userRatio.value
            )
        );
    }

}