add getActivePayers paginated

Author: fbac

contracts/src/Payer.sol

@@ -459,6 +459,34 @@ contract Payer is Initializable, AccessControlUpgradeable, UUPSUpgradeable, Paus
         return _getPayerStorage().payers[payer];
     }
 
+    /**
+     * @inheritdoc IPayer
+     */
+    function getActivePayers(uint256 offset, uint256 limit) external view returns (Payer[] memory payers, bool hasMore) {
+        PayerStorage storage $ = _getPayerStorage();
+        
+        uint256 totalCount = $.activePayers.length();
+
+        if (offset >= totalCount) revert OutOfBounds();
+
+        uint256 count = totalCount - offset;
+        if (count > limit) {
+            count = limit;
+            hasMore = true;
+        } else {
+            hasMore = false;
+        }
+
+        payers = new Payer[](count);
+
+        for (uint256 i = 0; i < count; i++) {
+            address payerAddress = $.activePayers.at(offset + i);
+            payers[i] = $.payers[payerAddress];
+        }
+        
+        return (payers, hasMore);
+    }
+
     /**
      * @inheritdoc IPayer
      */

contracts/src/interfaces/IPayer.sol

@@ -162,6 +162,9 @@ interface IPayerErrors {
 
     /// @notice Error thrown when deleting a payer has failed.
     error FailedToDeletePayer();
+
+    /// @notice Error thrown when the offset is out of bounds.
+    error OutOfBounds();
 }
 
 /**
@@ -405,6 +408,18 @@ interface IPayer is IERC165, IPayerEvents, IPayerErrors {
      */
     function getPayer(address payer) external view returns (Payer memory payerInfo);
 
+    /**
+     * @notice Returns all active payers in a paginated response.
+     * @param  offset Number of payers to skip before starting to return results.
+     * @param  limit  Maximum number of payers to return.
+     * @return payers The payer information.
+     * @return hasMore True if there are more payers to retrieve.
+     */
+    function getActivePayers(uint256 offset, uint256 limit)
+        external
+        view
+        returns (Payer[] memory payers, bool hasMore);
+
     /**
      * @notice Checks if a given address is an active payer.
      * @param  payer    The address to check.