setup

contracts/common/Errors.sol

@@ -0,0 +1,16 @@
+// SPDX-License-Identifier: LGPL-3.0-only
+pragma solidity ^0.8.24;
+
+contract BiconomySponsorshipPaymasterErrors {
+
+    /**
+     * @notice Throws when the paymaster address provided is address(0)
+     */
+    error PaymasterIdCannotBeZero();
+
+    /**
+     * @notice Throws when the 0 has been provided as deposit
+     */
+    error DepositCanNotBeZero();
+
+}

contracts/interfaces/IBiconomySponsorshipPaymaster.sol

@@ -0,0 +1,16 @@
+// SPDX-License-Identifier: MIT
+pragma solidity ^0.8.24;
+
+interface IBiconomySponsorshipPaymaster {
+    event FixedPriceMarkupChanged(uint32 indexed _oldValue, uint32 indexed _newValue);
+
+    event VerifyingSignerChanged(address indexed _oldSigner, address indexed _newSigner, address indexed _actor);
+
+    event FeeCollectorChanged(
+        address indexed _oldFeeCollector, address indexed _newFeeCollector, address indexed _actor
+    );
+    event GasDeposited(address indexed _paymasterId, uint256 indexed _value);
+    event GasWithdrawn(address indexed _paymasterId, address indexed _to, uint256 indexed _value);
+    event GasBalanceDeducted(address indexed _paymasterId, uint256 indexed _charge, bytes32 indexed userOpHash);
+    event PremiumCollected(address indexed _paymasterId, uint256 indexed _premium);
+}

contracts/sponsorship/SponsorshipPaymasterWithPremium.sol

@@ -9,4 +9,63 @@ import "account-abstraction/contracts/core/Helpers.sol";
 import "@openzeppelin/contracts/utils/cryptography/ECDSA.sol";
 import "@openzeppelin/contracts/utils/cryptography/MessageHashUtils.sol";
 import { SignatureCheckerLib } from "solady/src/utils/SignatureCheckerLib.sol";
-import { ECDSA as ECDSA_solady } from "solady/src/utils/ECDSA.sol";
+import { ECDSA as ECDSA_solady } from "solady/src/utils/ECDSA.sol";
+import { BiconomySponsorshipPaymasterErrors } from "../common/Errors.sol";
+import { ReentrancyGuard } from "@openzeppelin/contracts/utils/ReentrancyGuard.sol";
+import { IBiconomySponsorshipPaymaster } from "../interfaces/IBiconomySponsorshipPaymaster.sol";
+
+// possiblity (conflicts with BasePaymaster which is also Ownbale) // either make BasePaymaster SoladyOwnable
+// import { SoladyOwnable } from "../utils/SoladyOwnable.sol";
+
+/**
+ * @title BiconomySponsorshipPaymaster
+ * @author livingrockrises<[email protected]>
+ * @notice Based on Infinitism 'VerifyingPaymaster' contract
+ * @dev This contract is used to sponsor the transaction fees of the user operations
+ * Uses a verifying signer to provide the signature if predetermined conditions are met 
+ * regarding the user operation calldata. Also this paymaster is Singleton in nature which 
+ * means multiple Dapps/Wallet clients willing to sponsor the transactions can share this paymaster.
+ * Maintains it's own accounting of the gas balance for each Dapp/Wallet client 
+ * and Manages it's own deposit on the EntryPoint.
+ */
+
+// Todo: Add more methods in interface
+// Todo: Add methods to withdraw stuck erc20 tokens and native tokens
+
+abstract contract BiconomySponsorshipPaymaster is BasePaymaster, ReentrancyGuard, BiconomySponsorshipPaymasterErrors, IBiconomySponsorshipPaymaster {
+    using UserOperationLib for PackedUserOperation;
+
+    address public verifyingSigner;
+    address public feeCollector;
+    uint32 private constant PRICE_DENOMINATOR = 1e6;
+
+    // note: could rename to PAYMASTER_ID_OFFSET
+    uint256 private constant VALID_PND_OFFSET = PAYMASTER_DATA_OFFSET;
+
+    // temp
+    // paymasterAndData: paymaster address + paymaster gas limits + paymasterData
+    // paymasterData: concat of [paymasterId(20 bytes), validUntil(6 bytes), validAfter(6 bytes), priceMarkup(4 bytes), signature]
+
+    mapping(address => uint256) public paymasterIdBalances;
+
+    constructor(address _owner, IEntryPoint _entryPoint, address _verifyingSigner, address _feeCollector) BasePaymaster(_entryPoint) {
+        // TODO
+        // Check for zero address
+        verifyingSigner = _verifyingSigner;
+        feeCollector = _feeCollector;
+        _transferOwnership(_owner);
+    }
+
+    /**
+     * @dev Add a deposit for this paymaster and given paymasterId (Dapp Depositor address), used for paying for transaction fees
+     * @param paymasterId dapp identifier for which deposit is being made
+     */
+    function depositFor(address paymasterId) external payable nonReentrant {
+        if (paymasterId == address(0)) revert PaymasterIdCannotBeZero();
+        if (msg.value == 0) revert DepositCanNotBeZero();
+        paymasterIdBalances[paymasterId] += msg.value;
+        entryPoint.depositTo{value: msg.value}(address(this));
+        emit GasDeposited(paymasterId, msg.value);
+    }
+
+}

contracts/utils/SoladyOwnable.sol

@@ -0,0 +1,10 @@
+// SPDX-License-Identifier: MIT
+pragma solidity ^0.8.24;
+
+import {Ownable} from "solady/src/auth/Ownable.sol";
+
+contract SoladyOwnable is Ownable {
+    constructor(address _owner) Ownable() {
+        _initializeOwner(_owner);
+    }
+}