feat(story-nft): add cachable functionality to StoryBadgeNFT

Author: sebsadface

contracts/story-nft/CachableNFT.sol

@@ -24,11 +24,15 @@ abstract contract CachableNFT is OwnableUpgradeable {
     bytes32 private constant CacheableNFTStorageLocation =
         0xb2c28ba4bb2a3f74a63ac2785b5af0c41313804d8b65acc69c0b2736a57e5f00;
 
+    /// @notice Sets the cache mode.
+    /// @param useCache The new cache mode, true for cache mode, false for passthrough mode.
     function setCacheMode(bool useCache) external onlyOwner {
         CacheableNFTStorage storage $ = _getCacheableNFTStorage();
         $.cacheMode = useCache;
     }
 
+    /// @notice Mints NFTs to the cache.
+    /// @param amount The number of NFTs to mint.
     function mintToCache(uint256 amount) external onlyOwner {
         // mint NFT to cache
         for (uint256 i = 0; i < amount; i++) {
@@ -38,21 +42,37 @@ abstract contract CachableNFT is OwnableUpgradeable {
         }
     }
 
+    /// @notice Returns the number of NFTs in the cache.
+    /// @return The number of NFTs in the cache.
     function cacheSize() external view returns (uint256) {
         CacheableNFTStorage storage $ = _getCacheableNFTStorage();
         return $.cache.length();
     }
 
+    /// @notice Transfers the first NFT from the cache to the recipient.
+    /// @param recipient The recipient of the NFT.
+    /// @return tokenId The token ID of the transferred NFT.
+    /// @return ipId The IP ID of the transferred NFT.
     function _transferFromCache(address recipient) internal returns (uint256 tokenId, address ipId) {
         CacheableNFTStorage storage $ = _getCacheableNFTStorage();
         if (!$.cacheMode || $.cache.length() == 0) {
             return (0, address(0));
         }
         (tokenId, ipId) = $.cache.at(0);
+        $.cache.remove(0);
+
         _transferFrom(address(this), recipient, tokenId);
     }
 
+    /// @notice Mints an NFT to the contract itself.
+    /// @return tokenId The token ID of the minted NFT.
+    /// @return ipId The IP ID of the minted NFT.
     function _mintToSelf() internal virtual returns (uint256 tokenId, address ipId);
+
+    /// @notice Transfers an NFT from one address to another.
+    /// @param from The address to transfer the NFT from.
+    /// @param to The address to transfer the NFT to.
+    /// @param tokenId The token ID of the NFT to transfer.
     function _transferFrom(address from, address to, uint256 tokenId) internal virtual;
 
     /// @dev Returns the storage struct of CacheableNFT.

contracts/story-nft/StoryBadgeNFT.sol

@@ -11,11 +11,12 @@ import { MessageHashUtils } from "@openzeppelin/contracts/utils/cryptography/Mes
 import { SignatureChecker } from "@openzeppelin/contracts/utils/cryptography/SignatureChecker.sol";
 
 import { BaseOrgStoryNFT } from "./BaseOrgStoryNFT.sol";
+import { CachableNFT } from "./CachableNFT.sol";
 import { IStoryBadgeNFT } from "../interfaces/story-nft/IStoryBadgeNFT.sol";
 
 /// @title Story Badge NFT
 /// @notice A Story Badge is a soulbound NFT that has an unified token URI for all tokens.
-contract StoryBadgeNFT is IStoryBadgeNFT, BaseOrgStoryNFT, ERC721Holder {
+contract StoryBadgeNFT is IStoryBadgeNFT, BaseOrgStoryNFT, CachableNFT, ERC721Holder {
     using MessageHashUtils for bytes32;
 
     /// @notice Story Proof-of-Creativity PILicense Template address.
@@ -97,25 +98,16 @@ contract StoryBadgeNFT is IStoryBadgeNFT, BaseOrgStoryNFT, ERC721Holder {
         if (!SignatureChecker.isValidSignatureNow($.signer, digest, signature))
             revert StoryBadgeNFT__InvalidSignature();
 
-        // Mint the badge and register it as an IP
-        (tokenId, ipId) = _mintAndRegisterIp(
-            address(this),
-            $.tokenURI,
-            $.ipMetadataURI,
-            $.ipMetadataHash,
-            $.nftMetadataHash
-        );
+        // Try to transfer from cache first
+        (tokenId, ipId) = _transferFromCache(recipient);
 
-        address[] memory parentIpIds = new address[](1);
-        uint256[] memory licenseTermsIds = new uint256[](1);
-        parentIpIds[0] = orgIpId();
-        licenseTermsIds[0] = DEFAULT_LICENSE_TERMS_ID;
-
-        // Make the badge a derivative of the organization IP
-        _makeDerivative(ipId, parentIpIds, PIL_TEMPLATE, licenseTermsIds, "", 0);
+        if (ipId == address(0)) {
+            // cache miss or cache mode is disabled, mint directly
+            (tokenId, ipId) = _mintToSelf();
 
-        // Transfer the badge to the recipient
-        _safeTransfer(address(this), recipient, tokenId);
+            // Transfer the badge to the recipient
+            _transfer(address(this), recipient, tokenId);
+        }
 
         emit StoryBadgeNFTMinted(recipient, tokenId, ipId);
     }
@@ -164,6 +156,38 @@ contract StoryBadgeNFT is IStoryBadgeNFT, BaseOrgStoryNFT, ERC721Holder {
         return "";
     }
 
+    /// @notice Mints an NFT to the contract itself.
+    /// @return tokenId The token ID of the minted NFT.
+    /// @return ipId The IP ID of the minted NFT.
+    function _mintToSelf() internal override returns (uint256 tokenId, address ipId) {
+        StoryBadgeNFTStorage storage $ = _getStoryBadgeNFTStorage();
+
+        // Mint the badge and register it as an IP
+        (tokenId, ipId) = _mintAndRegisterIp(
+            address(this),
+            $.tokenURI,
+            $.ipMetadataURI,
+            $.ipMetadataHash,
+            $.nftMetadataHash
+        );
+
+        address[] memory parentIpIds = new address[](1);
+        uint256[] memory licenseTermsIds = new uint256[](1);
+        parentIpIds[0] = orgIpId();
+        licenseTermsIds[0] = DEFAULT_LICENSE_TERMS_ID;
+
+        // Make the badge a derivative of the organization IP
+        _makeDerivative(ipId, parentIpIds, PIL_TEMPLATE, licenseTermsIds, "", 0);
+    }
+
+    /// @notice Transfers an NFT from one address to another.
+    /// @param from The address to transfer the NFT from.
+    /// @param to The address to transfer the NFT to.
+    /// @param tokenId The token ID of the NFT to transfer.
+    function _transferFrom(address from, address to, uint256 tokenId) internal override {
+        _transfer(from, to, tokenId);
+    }
+
     /// @dev Returns the storage struct of StoryBadgeNFT.
     function _getStoryBadgeNFTStorage() private pure returns (StoryBadgeNFTStorage storage $) {
         assembly {

test/story-nft/StoryBadgeNFT.t.sol

@@ -212,6 +212,34 @@ contract StoryBadgeNFTTest is BaseTest {
         assertEq(rootOrgStoryNft.tokenURI(0), "New Token URI");
     }
 
+    function test_StoryBadgeNFT_cachedMint() public {
+        vm.startPrank(rootOrgStoryNftOwner);
+        rootOrgStoryNft.mintToCache(1);
+        assertEq(rootOrgStoryNft.cacheSize(), 1); // 1 cached
+        rootOrgStoryNft.mintToCache(100);
+        assertEq(rootOrgStoryNft.cacheSize(), 101); // 100 cached + 1 minted
+        rootOrgStoryNft.setCacheMode(true); // enable cache mode
+        vm.stopPrank();
+
+        bytes memory signature = _signAddress(rootOrgStoryNftSignerSk, u.carl);
+        vm.startPrank(u.carl);
+        (uint256 tokenId, ) = rootOrgStoryNft.mint(u.carl, signature);
+        assertEq(rootOrgStoryNft.ownerOf(tokenId), u.carl); // minted from cache
+        vm.stopPrank();
+        assertEq(rootOrgStoryNft.cacheSize(), 100); // cache size is reduced by 1
+
+        vm.startPrank(rootOrgStoryNftOwner);
+        rootOrgStoryNft.setCacheMode(false); // disable cache mode
+        vm.stopPrank();
+
+        signature = _signAddress(rootOrgStoryNftSignerSk, u.bob);
+        vm.startPrank(u.bob);
+        (tokenId, ) = rootOrgStoryNft.mint(u.bob, signature);
+        assertEq(rootOrgStoryNft.ownerOf(tokenId), u.bob); // minted directly
+        vm.stopPrank();
+        assertEq(rootOrgStoryNft.cacheSize(), 100); // cache size is unchanged
+    }
+
     function test_StoryBadgeNFT_revert_setSigner_CallerIsNotOwner() public {
         vm.startPrank(u.carl);
         vm.expectRevert(abi.encodeWithSelector(Ownable.OwnableUnauthorizedAccount.selector, u.carl));