Add interfaces (#10)

contracts/OverlayV1State.sol

@@ -1,6 +1,8 @@
 // SPDX-License-Identifier: MIT
 pragma solidity 0.8.10;
 
+import "./interfaces/IOverlayV1State.sol";
+
 import "./state/OverlayV1BaseState.sol";
 import "./state/OverlayV1OIState.sol";
 import "./state/OverlayV1PositionState.sol";
@@ -9,6 +11,7 @@ import "./state/OverlayV1PriceState.sol";
 /// @title A market state contract to view the current state of
 /// @title an Overlay market
 contract OverlayV1State is
+    IOverlayV1State,
     OverlayV1BaseState,
     OverlayV1PriceState,
     OverlayV1OIState,

contracts/interfaces/IOverlayV1State.sol

@@ -0,0 +1,14 @@
+// SPDX-License-Identifier: MIT
+pragma solidity 0.8.10;
+
+import "./state/IOverlayV1BaseState.sol";
+import "./state/IOverlayV1PriceState.sol";
+import "./state/IOverlayV1OIState.sol";
+import "./state/IOverlayV1PositionState.sol";
+
+interface IOverlayV1State is
+    IOverlayV1BaseState,
+    IOverlayV1PriceState,
+    IOverlayV1OIState,
+    IOverlayV1PositionState
+{}

contracts/interfaces/state/IOverlayV1BaseState.sol

@@ -0,0 +1,17 @@
+// SPDX-License-Identifier: MIT
+pragma solidity 0.8.10;
+
+import "@overlay/v1-core/contracts/interfaces/IOverlayV1Factory.sol";
+import "@overlay/v1-core/contracts/interfaces/IOverlayV1Market.sol";
+import "@overlay/v1-core/contracts/libraries/Oracle.sol";
+
+interface IOverlayV1BaseState {
+    // immutables
+    function factory() external view returns (IOverlayV1Factory);
+
+    // market associated with given feed
+    function market(address feed) external view returns (IOverlayV1Market market_);
+
+    // latest oracle data associated with given feed
+    function data(address feed) external view returns (Oracle.Data memory data_);
+}

contracts/interfaces/state/IOverlayV1OIState.sol

@@ -0,0 +1,31 @@
+// SPDX-License-Identifier: MIT
+pragma solidity 0.8.10;
+
+import "./IOverlayV1BaseState.sol";
+import "./IOverlayV1PriceState.sol";
+
+interface IOverlayV1OIState is IOverlayV1BaseState, IOverlayV1PriceState {
+    // aggregate open interest values on market associated with feed
+    function ois(address feed) external view returns (uint256 oiLong_, uint256 oiShort_);
+
+    // cap on aggregate open interest on market associated with feed
+    function capOi(address feed) external view returns (uint256 capOi_);
+
+    // fraction of cap on aggregate open interest given oi amount
+    function fractionOfCapOi(address feed, uint256 oi)
+        external
+        view
+        returns (uint256 fractionOfCapOi_);
+
+    // funding rate on market associated with feed
+    function fundingRate(address feed) external view returns (int256 fundingRate_);
+
+    // circuit breaker level on market associated with feed
+    function circuitBreakerLevel(address feed)
+        external
+        view
+        returns (uint256 circuitBreakerLevel_);
+
+    // rolling minted amount on market associated with feed
+    function minted(address feed) external view returns (int256 minted_);
+}

contracts/interfaces/state/IOverlayV1PositionState.sol

@@ -0,0 +1,103 @@
+// SPDX-License-Identifier: MIT
+pragma solidity 0.8.10;
+
+import "@overlay/v1-core/contracts/libraries/Position.sol";
+
+import "./IOverlayV1BaseState.sol";
+import "./IOverlayV1OIState.sol";
+import "./IOverlayV1PriceState.sol";
+
+interface IOverlayV1PositionState is IOverlayV1BaseState, IOverlayV1PriceState, IOverlayV1OIState {
+    // position on the market associated with feed
+    function position(
+        address feed,
+        address owner,
+        uint256 id
+    ) external view returns (Position.Info memory position_);
+
+    // debt of position on the market associated with feed
+    function debt(
+        address feed,
+        address owner,
+        uint256 id
+    ) external view returns (uint256 debt_);
+
+    // cost basis of position on the market associated with feed
+    function cost(
+        address feed,
+        address owner,
+        uint256 id
+    ) external view returns (uint256 cost_);
+
+    // open interest of position on the market associated with feed
+    function oi(
+        address feed,
+        address owner,
+        uint256 id
+    ) external view returns (uint256 oi_);
+
+    // collateral backing position on the market associated with feed
+    function collateral(
+        address feed,
+        address owner,
+        uint256 id
+    ) external view returns (uint256 collateral_);
+
+    // value of position on the market associated with feed
+    function value(
+        address feed,
+        address owner,
+        uint256 id
+    ) external view returns (uint256 value_);
+
+    // notional of position on the market associated with feed
+    function notional(
+        address feed,
+        address owner,
+        uint256 id
+    ) external view returns (uint256 notional_);
+
+    // trading fee charged to unwind position on the market associated with feed
+    function tradingFee(
+        address feed,
+        address owner,
+        uint256 id
+    ) external view returns (uint256 tradingFee_);
+
+    // whether position is liquidatable on the market associated with feed
+    function liquidatable(
+        address feed,
+        address owner,
+        uint256 id
+    ) external view returns (bool liquidatable_);
+
+    // liquidation fee rewarded to liquidator for position on market associated
+    // with feed
+    function liquidationFee(
+        address feed,
+        address owner,
+        uint256 id
+    ) external view returns (uint256 liquidationFee_);
+
+    // maintenance margin requirement for position on market associated with feed
+    function maintenanceMargin(
+        address feed,
+        address owner,
+        uint256 id
+    ) external view returns (uint256 maintenanceMargin_);
+
+    // remaining margin before liquidation for position on market associated
+    // with feed
+    function marginExcessBeforeLiquidation(
+        address feed,
+        address owner,
+        uint256 id
+    ) external view returns (int256 excess_);
+
+    // liquidation price for position on market associated with feed
+    function liquidationPrice(
+        address feed,
+        address owner,
+        uint256 id
+    ) external view returns (uint256 liquidationPrice_);
+}

contracts/interfaces/state/IOverlayV1PriceState.sol

@@ -0,0 +1,42 @@
+// SPDX-License-Identifier: MIT
+pragma solidity 0.8.10;
+
+import "./IOverlayV1BaseState.sol";
+
+interface IOverlayV1PriceState is IOverlayV1BaseState {
+    // bid on the market associated with the feed given new volume from fractionOfCapOi
+    function bid(address feed, uint256 fractionOfCapOi) external view returns (uint256 bid_);
+
+    // ask on the market associated with the feed given new volume from fractionOfCapOi
+    function ask(address feed, uint256 fractionOfCapOi) external view returns (uint256 ask_);
+
+    // mid on the market associated with the feed
+    function mid(address feed) external view returns (uint256 mid_);
+
+    // volume on the bid of the market associated with the feed given
+    // new volume from fractionOfCapOi
+    function volumeBid(address feed, uint256 fractionOfCapOi)
+        external
+        view
+        returns (uint256 volumeBid_);
+
+    // volume on the ask of the market associated with the feed given
+    // new volume from fractionOfCapOi
+    function volumeAsk(address feed, uint256 fractionOfCapOi)
+        external
+        view
+        returns (uint256 volumeAsk_);
+
+    // bid, ask, mid prices of the market associated with the feed
+    function prices(address feed)
+        external
+        view
+        returns (
+            uint256 bid_,
+            uint256 ask_,
+            uint256 mid_
+        );
+
+    // bid, ask volumes of the market associated with the feed
+    function volumes(address feed) external view returns (uint256 volumeBid_, uint256 volumeAsk_);
+}

contracts/state/OverlayV1BaseState.sol

@@ -5,11 +5,11 @@ import "@overlay/v1-core/contracts/interfaces/IOverlayV1Factory.sol";
 import "@overlay/v1-core/contracts/interfaces/IOverlayV1Market.sol";
 import "@overlay/v1-core/contracts/interfaces/feeds/IOverlayV1Feed.sol";
 
-import "@overlay/v1-core/contracts/libraries/FixedPoint.sol";
 import "@overlay/v1-core/contracts/libraries/Oracle.sol";
-import "@overlay/v1-core/contracts/libraries/Position.sol";
 
-abstract contract OverlayV1BaseState {
+import "../interfaces/state/IOverlayV1BaseState.sol";
+
+abstract contract OverlayV1BaseState is IOverlayV1BaseState {
     // immutables
     IOverlayV1Factory public immutable factory;
 

contracts/state/OverlayV1OIState.sol

@@ -6,10 +6,12 @@ import "@overlay/v1-core/contracts/libraries/FixedPoint.sol";
 import "@overlay/v1-core/contracts/libraries/Oracle.sol";
 import "@overlay/v1-core/contracts/libraries/Roller.sol";
 
+import "../interfaces/state/IOverlayV1OIState.sol";
+
 import "./OverlayV1BaseState.sol";
 import "./OverlayV1PriceState.sol";
 
-abstract contract OverlayV1OIState is OverlayV1BaseState, OverlayV1PriceState {
+abstract contract OverlayV1OIState is IOverlayV1OIState, OverlayV1BaseState, OverlayV1PriceState {
     using FixedPoint for uint256;
     using Roller for Roller.Snapshot;
 

contracts/state/OverlayV1PositionState.sol

@@ -4,13 +4,16 @@ pragma solidity 0.8.10;
 import "@overlay/v1-core/contracts/interfaces/IOverlayV1Market.sol";
 import "@overlay/v1-core/contracts/libraries/FixedPoint.sol";
 import "@overlay/v1-core/contracts/libraries/Oracle.sol";
-import "@overlay/v1-core/contracts/libraries/Roller.sol";
+import "@overlay/v1-core/contracts/libraries/Position.sol";
+
+import "../interfaces/state/IOverlayV1PositionState.sol";
 
 import "./OverlayV1BaseState.sol";
 import "./OverlayV1OIState.sol";
 import "./OverlayV1PriceState.sol";
 
 abstract contract OverlayV1PositionState is
+    IOverlayV1PositionState,
     OverlayV1BaseState,
     OverlayV1PriceState,
     OverlayV1OIState

contracts/state/OverlayV1PriceState.sol

@@ -4,12 +4,14 @@ pragma solidity 0.8.10;
 import "@openzeppelin/contracts/utils/math/Math.sol";
 
 import "@overlay/v1-core/contracts/interfaces/IOverlayV1Market.sol";
-import "@overlay/v1-core/contracts/libraries/FixedPoint.sol";
 import "@overlay/v1-core/contracts/libraries/Oracle.sol";
+import "@overlay/v1-core/contracts/libraries/Roller.sol";
+
+import "../interfaces/state/IOverlayV1PriceState.sol";
 
 import "./OverlayV1BaseState.sol";
 
-abstract contract OverlayV1PriceState is OverlayV1BaseState {
+abstract contract OverlayV1PriceState is IOverlayV1PriceState, OverlayV1BaseState {
     using Roller for Roller.Snapshot;
 
     function _bid(