feat: add getter for provision tracker free tokens

packages/horizon/contracts/data-service/libraries/ProvisionTracker.sol

@@ -72,4 +72,21 @@ library ProvisionTracker {
         uint256 tokensAvailable = graphStaking.getTokensAvailable(serviceProvider, address(this), delegationRatio);
         return self[serviceProvider] <= tokensAvailable;
     }
+
+    /**
+     * @notice Returns the number of free tokens for a service provider. Free tokens are those currently available to lock.
+     * @param self The provision tracker mapping
+     * @param graphStaking The HorizonStaking contract
+     * @param serviceProvider The service provider address
+     * @param delegationRatio A delegation ratio to limit the amount of delegation that's usable
+     */
+    function getTokensFree(
+        mapping(address => uint256) storage self,
+        IHorizonStaking graphStaking,
+        address serviceProvider,
+        uint32 delegationRatio
+    ) internal view returns (uint256) {
+        uint256 tokensAvailable = graphStaking.getTokensAvailable(serviceProvider, address(this), delegationRatio);
+        return tokensAvailable > self[serviceProvider] ? tokensAvailable - self[serviceProvider] : 0;
+    }
 }

packages/subgraph-service/contracts/SubgraphService.sol

@@ -21,6 +21,7 @@ import { TokenUtils } from "@graphprotocol/contracts/contracts/utils/TokenUtils.
 import { PPMMath } from "@graphprotocol/horizon/contracts/libraries/PPMMath.sol";
 import { Allocation } from "./libraries/Allocation.sol";
 import { LegacyAllocation } from "./libraries/LegacyAllocation.sol";
+import { ProvisionTracker } from "@graphprotocol/horizon/contracts/data-service/libraries/ProvisionTracker.sol";
 
 /**
  * @title SubgraphService contract
@@ -40,6 +41,7 @@ contract SubgraphService is
     IRewardsIssuer,
     ISubgraphService
 {
+    using ProvisionTracker for mapping(address => uint256);
     using PPMMath for uint256;
     using Allocation for mapping(address => Allocation.State);
     using Allocation for Allocation.State;
@@ -489,6 +491,14 @@ contract SubgraphService is
         return _isOverAllocated(indexer, delegationRatio);
     }
 
+    function getAllocationTokensFree(address indexer) external view override returns (uint256) {
+        return _getAllocationTokensFree(indexer, delegationRatio);
+    }
+
+    function getFeesTokensFree(address indexer) external view override returns (uint256) {
+        return feesProvisionTracker.getTokensFree(_graphStaking(), indexer, delegationRatio);
+    }
+
     // -- Data service parameter getters --
     /**
      * @notice Getter for the accepted thawing period range for provisions
@@ -579,6 +589,10 @@ contract SubgraphService is
         return tokensCollected;
     }
 
+    /**
+     * @notice Set the stake to fees ratio
+     * @param _stakeToFeesRatio The new stake to fees ratio
+     */
     function _setStakeToFeesRatio(uint256 _stakeToFeesRatio) private {
         require(_stakeToFeesRatio != 0, SubgraphServiceInvalidZeroStakeToFeesRatio());
         stakeToFeesRatio = _stakeToFeesRatio;

packages/subgraph-service/contracts/interfaces/ISubgraphService.sol

@@ -228,6 +228,29 @@ interface ISubgraphService is IDataServiceFees {
      */
     function getLegacyAllocation(address allocationId) external view returns (LegacyAllocation.State memory);
 
+    /**
+     * @notice Returns the number of free tokens for an indexer.
+     * Free tokens are those that can be immediately used to lock as economic security.
+     * @param indexer The address of the indexer
+     * @param paymentType The type of payment to consider
+     * @return The number of free tokens
+     */
+    // function getTokensFree(address indexer, IGraphPayments.PaymentTypes paymentType) external view returns (uint256);
+
+    /**
+     * @notice Returns the number of free tokens for an indexer for indexing rewards
+     * @param indexer The address of the indexer
+     * @return The number of free tokens
+     */
+    function getAllocationTokensFree(address indexer) external view returns (uint256);
+
+    /**
+     * @notice Returns the number of free tokens for an indexer for query fees
+     * @param indexer The address of the indexer
+     * @return The number of free tokens
+     */
+    function getFeesTokensFree(address indexer) external view returns (uint256);
+
     /**
      * @notice Encodes the allocation proof for EIP712 signing
      * @param indexer The address of the indexer

packages/subgraph-service/contracts/utilities/AllocationManager.sol

@@ -476,6 +476,16 @@ abstract contract AllocationManager is EIP712Upgradeable, GraphDirectory, Alloca
         return !allocationProvisionTracker.check(_graphStaking(), _indexer, _delegationRatio);
     }
 
+    /**
+     * @notice Returns the number of free tokens for an indexer
+     * @param _indexer The address of the indexer
+     * @param _delegationRatio The delegation ratio to consider when locking tokens
+     * @return The number of free tokens
+     */
+    function _getAllocationTokensFree(address _indexer, uint32 _delegationRatio) internal view returns (uint256) {
+        return allocationProvisionTracker.getTokensFree(_graphStaking(), _indexer, _delegationRatio);
+    }
+
     /**
      * @notice Verifies ownership of an allocation id by verifying an EIP712 allocation proof
      * @dev Requirements: