Add wrapper functionality & bridge integration

Makefile

@@ -1,6 +1,3 @@
-export GOFLAGS :=-tags=no_cgo
-export CGO_ENABLED := 0
-
 .PHONY: test
 test:
 	$(MAKE) generate -C lib/go

contracts/TopShot.cdc

@@ -48,6 +48,8 @@ import NonFungibleToken from 0xNFTADDRESS
 import MetadataViews from 0xMETADATAVIEWSADDRESS
 import TopShotLocking from 0xTOPSHOTLOCKINGADDRESS
 import ViewResolver from 0xVIEWRESOLVERADDRESS
+import CrossVMMetadataViews from 0xCROSSVMMETADATAVIEWSADDRESS
+import EVM from 0xEVMADDRESS
 
 access(all) contract TopShot: NonFungibleToken {
     // -----------------------------------------------------------------------
@@ -727,6 +729,7 @@ access(all) contract TopShot: NonFungibleToken {
                 Type<MetadataViews.ExternalURL>(),
                 Type<MetadataViews.NFTCollectionData>(),
                 Type<MetadataViews.NFTCollectionDisplay>(),
+                Type<CrossVMMetadataViews.EVMPointer>(),
                 Type<MetadataViews.Serial>(),
                 Type<MetadataViews.Traits>(),
                 Type<MetadataViews.Medias>()
@@ -796,6 +799,8 @@ access(all) contract TopShot: NonFungibleToken {
                     return TopShot.resolveContractView(resourceType: nil, viewType: Type<MetadataViews.NFTCollectionData>())
                 case Type<MetadataViews.NFTCollectionDisplay>():
                     return TopShot.resolveContractView(resourceType: nil, viewType: Type<MetadataViews.NFTCollectionDisplay>())
+                case Type<CrossVMMetadataViews.EVMPointer>():
+                    return TopShot.resolveContractView(resourceType: nil, viewType: Type<CrossVMMetadataViews.EVMPointer>())
                 case Type<MetadataViews.Traits>():
                     return self.resolveTraitsView()
                 case Type<MetadataViews.Medias>():
@@ -1673,11 +1678,16 @@ access(all) contract TopShot: NonFungibleToken {
 
     // getContractViews returns the metadata view types available for this contract
     access(all) view fun getContractViews(resourceType: Type?): [Type] {
-        return [Type<MetadataViews.NFTCollectionData>(), Type<MetadataViews.NFTCollectionDisplay>(), Type<MetadataViews.Royalties>()]
+        return [
+            Type<MetadataViews.NFTCollectionData>(),
+            Type<MetadataViews.NFTCollectionDisplay>(),
+            Type<CrossVMMetadataViews.EVMPointer>(),
+            Type<MetadataViews.Royalties>()
+        ]
     }
 
     // resolveContractView resolves this contract's metadata views
-    access(all) view fun resolveContractView(resourceType: Type?, viewType: Type): AnyStruct? {
+    access(all) fun resolveContractView(resourceType: Type?, viewType: Type): AnyStruct? {
         post {
             result == nil || result!.getType() == viewType: "The returned view must be of the given type or nil"
         }
@@ -1717,18 +1727,26 @@ access(all) contract TopShot: NonFungibleToken {
                         "instagram": MetadataViews.ExternalURL("https://www.instagram.com/nbatopshot")
                     }
                 )
-                case Type<MetadataViews.Royalties>():
-                    let royaltyReceiver: Capability<&{FungibleToken.Receiver}> =
-                        getAccount(TopShot.RoyaltyAddress()).capabilities.get<&{FungibleToken.Receiver}>(MetadataViews.getRoyaltyReceiverPublicPath())!
-                    return MetadataViews.Royalties(
-                        [
-                            MetadataViews.Royalty(
-                                receiver: royaltyReceiver,
-                                cut: 0.05,
-                                description: "NBATopShot marketplace royalty"
-                            )
-                        ]
-                    )
+            case Type<MetadataViews.Royalties>():
+                let royaltyReceiver: Capability<&{FungibleToken.Receiver}> =
+                    getAccount(TopShot.RoyaltyAddress()).capabilities.get<&{FungibleToken.Receiver}>(MetadataViews.getRoyaltyReceiverPublicPath())!
+                return MetadataViews.Royalties(
+                    [
+                        MetadataViews.Royalty(
+                            receiver: royaltyReceiver,
+                            cut: 0.05,
+                            description: "NBATopShot marketplace royalty"
+                        )
+                    ]
+                )
+            case Type<CrossVMMetadataViews.EVMPointer>():
+                return CrossVMMetadataViews.EVMPointer(
+                    cadenceType: Type<@TopShot.NFT>(),
+                    cadenceContractAddress: self.account.address,
+                    // TODO: Replace with actual EVM contract address
+                    evmContractAddress: EVM.addressFromString("0x1234565789012345657890123456578901234565"),
+                    nativeVM: CrossVMMetadataViews.VM.Cadence
+                )
         }
         return nil
     }

contracts/imports/CrossVMMetadataViews.cdc

@@ -0,0 +1,83 @@
+import ViewResolver from 0xVIEWRESOLVERADDRESS
+import EVM from 0xEVMADDRESS
+
+/// This contract implements views originally proposed in FLIP-318 supporting NFT collections
+/// with project-defined implementations across both Cadence & EVM.
+/// The View structs in this contract should be implemented in the same way that views from `MetadataViews` are implemented
+///
+access(all) contract CrossVMMetadataViews {
+
+    /// An enum denoting a VM. For now, there are only two VMs on Flow, but this enum could be
+    /// expanded in the event other VMs are supported on the network.
+    ///
+    access(all) enum VM : UInt8 {
+        access(all) case Cadence
+        access(all) case EVM
+    }
+
+    /// View resolved at contract & resource level pointing to the associated EVM implementation.
+    /// NOTE: This view alone is not sufficient to validate an association across Cadence & EVM!
+    /// Both the Cadence Type/contract *and* the EVM contract should point to each other, with the
+    /// EVM pointer being facilitated by ICrossVM.sol contract interface methods. For more
+    /// information and context, see FLIP-318: https://github.com/onflow/flips/issues/318
+    ///
+    access(all) struct EVMPointer {
+        /// The associated Cadence Type defined in the contract that this view is returned from
+        access(all) let cadenceType: Type
+        /// The defining Cadence contract address
+        access(all) let cadenceContractAddress: Address
+        /// The associated EVM contract address that the Cadence contract will bridge to
+        access(all) let evmContractAddress: EVM.EVMAddress
+        /// Whether the asset is Cadence- or EVM-native. Native here meaning the VM in which the
+        /// asset is originally distributed.
+        access(all) let nativeVM: VM
+
+        init(
+            cadenceType: Type,
+            cadenceContractAddress: Address,
+            evmContractAddress: EVM.EVMAddress,
+            nativeVM: VM
+        ) {
+            self.cadenceType = cadenceType
+            self.cadenceContractAddress = cadenceContractAddress
+            self.evmContractAddress = evmContractAddress
+            self.nativeVM = nativeVM
+        }
+    }
+
+    access(all) fun getEVMPointer(_ viewResolver: &{ViewResolver.Resolver}): EVMPointer? {
+        if let view = viewResolver.resolveView(Type<EVMPointer>()) {
+            if let v = view as? EVMPointer {
+                return v
+            }
+        }
+        return nil
+    }
+
+    /// View resolved at resource level denoting any metadata to be passed to the associated EVM
+    /// contract at the time of bridging. This optional view would allow EVM side metadata to be
+    /// updated based on current Cadence state. If the view is not supported, no bytes will be
+    /// passed into EVM when bridging.
+    ///
+    access(all) struct EVMBytesMetadata {
+        /// Returns the bytes to be passed to the EVM contract on `fulfillToEVM` call, allowing the
+        /// EVM contract to update the metadata associated with the NFT. The corresponding Solidity
+        /// `bytes` type allows the implementer greater flexibility by enabling them to pass
+        /// arbitrary data between VMs.
+        access(all) let bytes: EVM.EVMBytes
+
+        init(bytes: EVM.EVMBytes) {
+            self.bytes = bytes
+        }
+    }
+
+    access(all) fun getEVMBytesMetadata(_ viewResolver: &{ViewResolver.Resolver}): EVMBytesMetadata? {
+        if let view = viewResolver.resolveView(Type<EVMBytesMetadata>()) {
+            if let v = view as? EVMBytesMetadata {
+                return v
+            }
+        }
+        return nil
+    }
+
+}

evm-bridging/README.md

@@ -1,76 +1,139 @@
-# <h1 align="center"> NBA TopShot on FlowEVM [Initial Draft Version] </h1>
-
-**! This directory currently contains work in progress only !**
+# <h1 align="center"> NBA TopShot on FlowEVM </h1>
 
 ## Introduction
 
-The `BridgedTopShotMoments` smart contract facilitates the creation of 1:1 ERC721 references for existing Cadence-native NBA Top Shot moments. By associating these references with the same metadata, it ensures seamless integration and interaction between Cadence and FlowEVM environments. This allows users to enjoy the benefits of both ecosystems while maintaining the integrity and uniqueness of their NBA Top Shot moments.
+The `BridgedTopShotMoments` smart contract enables NBA Top Shot moments to exist on FlowEVM as ERC721 tokens. Each ERC721 token is a 1:1 reference to a Cadence-native NBA Top Shot moment, maintaining the same metadata and uniqueness while allowing users to leverage both Flow and EVM ecosystems.
+
+### Core Features
+
+1. **ERC721 Implementation**
+   - Full ERC721 compliance with enumeration and burning capabilities
+   - NFT metadata support with customizable base URI
+   - Ownable contract for admin operations
+   - Upgradeable via UUPS proxy
+
+2. **Bridge Integration**
+   - Wrapper functionality for ERC721s from bridged-deployed contract
+   - Cross-VM compatibility for Flow ↔ EVM bridging (after [FLIP-318](https://github.com/onflow/flips/pull/319) implementation allowing custom associations, and after contract is onboarded to the bridge)
+     - Fulfillment of ERC721s from Flow to EVM
+     - Bridge permissions management
+     - Cadence-specific identifiers tracking
+
+3. **Royalty Management**
+   - ERC2981 royalty standard implementation
+   - Transfer validation for royalty enforcement via ERC721C/Token Creator Standard
+   - Configurable royalty rates (in basis points)
+   - Updatable royalty receiver address
 
-## Getting Started
+> **Note**: This contract is under active development. Features and implementations may change.
 
-Install Foundry:
+
+## Prerequisites
+
+1. Install Foundry:
 
 ```sh
 curl -L https://foundry.paradigm.xyz | bash
 foundryup
 ```
 
-Compile contracts and run tests:
+2. Install Flow CLI: [Instructions](https://developers.flow.com/tools/flow-cli/install)
+
+## Development
+
+1. Compile and test contracts:
+
 ```sh
 forge test --force -vvv
 ```
 
-### Deploy & Verify Contracts
+2. Set up environment:
 
-Load environment variables after populating address and key details:
 
 ```sh
-cp .env.example.testnet .env
+cp .env.flowevm.testnet.example .env
+# Add your account details to .env and source it
 source .env
 ```
 
-Run script to deploy and verify contracts (proxy and implementation):
+3. Deploy and verify contracts:
 
 ```sh
+# Deploy both proxy and implementation contracts
 forge script --rpc-url $RPC_URL --private-key $DEPLOYER_PRIVATE_KEY --legacy script/Deploy.s.sol:DeployScript --broadcast --verify --verifier $VERIFIER_PROVIDER --verifier-url $VERIFIER_URL
-```
 
-If verification fails for one or both contracts, verify separately:
-
-```sh
+# If verification fails, verify individually
 forge verify-contract --rpc-url $RPC_URL --verifier $VERIFIER_PROVIDER --verifier-url $VERIFIER_URL <address-of-contract-to-verify>
 ```
 
-## Run Transactions
+## Usage
 
-Set NFT symbol (admin):
+### EVM Operations
 
 ```sh
-cast send $DEPLOYED_PROXY_CONTRACT_ADDRESS --rpc-url $RPC_URL --private-key $DEPLOYER_PRIVATE_KEY --legacy "setSymbol(string)" <new-nft-symbol>
-```
+# Approve operator for a NFT
+cast send $DEPLOYED_PROXY_CONTRACT_ADDRESS --rpc-url $RPC_URL --private-key <private-key> --legacy "approve(address,uint256)" <operator-address> <token-id>
 
-## Execute Queries
+# Approve operator for all NFTs
+cast send $DEPLOYED_PROXY_CONTRACT_ADDRESS --rpc-url $RPC_URL --private-key <private-key> --legacy "setApprovalForAll(address,bool)" <operator-address> <true>
 
-BalanceOf:
-```sh
+# Transfer NFT
+cast send $DEPLOYED_PROXY_CONTRACT_ADDRESS --rpc-url $RPC_URL --private-key <private-key> --legacy "safeTransferFrom(address,address,uint256)" <from-address> <to-address> <token-id>
+
+# Query balance
 cast call $DEPLOYED_PROXY_CONTRACT_ADDRESS --rpc-url $RPC_URL "balanceOf(address)(uint256)" $DEPLOYER_ADDRESS
-```
 
-OwnerOf:
-```sh
+# Query owner
 cast call $DEPLOYED_PROXY_CONTRACT_ADDRESS --rpc-url $RPC_URL "ownerOf(uint256)(address)" <nft-id>
+
+# Query token URI
+cast call $DEPLOYED_PROXY_CONTRACT_ADDRESS --rpc-url $RPC_URL "tokenURI(uint256)(string)" <nft-id>
+
+# Set NFT symbol (admin only)
+cast send $DEPLOYED_PROXY_CONTRACT_ADDRESS --rpc-url $RPC_URL --private-key $DEPLOYER_PRIVATE_KEY --legacy "setSymbol(string)" <new-nft-symbol>
+
+# Set transfer validator (admin only)
+cast send $DEPLOYED_PROXY_CONTRACT_ADDRESS --rpc-url $RPC_URL --private-key $DEPLOYER_PRIVATE_KEY --legacy "setTransferValidator(address)" <validator-address>
+
+# Set royalty info (admin only)
+cast send $DEPLOYED_PROXY_CONTRACT_ADDRESS --rpc-url $RPC_URL --private-key $DEPLOYER_PRIVATE_KEY --legacy "setRoyaltyInfo((address,uint96))" "(<royalty-receiver-address>,<royalty-basis-points>)"
 ```
 
-## Misc
+### Cadence Operations
+
+> **Note**: Populate arguments in json file before submitting the transactions.
+
+```sh
+# Transfer erc721 NFTs
+flow transactions send ./evm-bridging/cadence/transactions/transfer_erc721s_to_evm_address.cdc --args-json "$(cat ./evm-bridging/cadence/transactions/transfer_erc721s_to_evm_address_args.json)" --network <network> --signer <signer>
+
+# Bridge and wrap NFTs
+flow transactions send ./evm-bridging/cadence/transactions/bridge_nfts_to_evm_and_wrap.cdc --args-json "$(cat ./evm-bridging/cadence/transactions/bridge_nfts_to_evm_and_wrap_args.json)" --network <network> --signer <signer> --gas-limit 8000
+
+# Wrap already-bridged NFTs
+flow transactions send ./evm-bridging/cadence/transactions/wrap_nfts.cdc --args-json "$(cat ./evm-bridging/cadence/transactions/wrap_nfts_args.json)" --network <network> --signer <signer>
+
+# Unwrap and bridge back NFTs
+flow transactions send ./evm-bridging/cadence/transactions/unwrap_nfts_and_bridge_from_evm.cdc --args-json "$(cat ./evm-bridging/cadence/transactions/unwrap_nfts_and_bridge_from_evm_args.json)" --network <network> --signer <signer> --gas-limit 8000
+
+# Unwrap NFTs
+flow transactions send ./evm-bridging/cadence/transactions/unwrap_nfts.cdc --args-json "$(cat ./evm-bridging/cadence/transactions/unwrap_nfts_args.json)" --network <network> --signer <signer>
+
+# Query ERC721 address
+flow scripts execute ./evm-bridging/cadence/scripts/get_underlying_erc721_address.cdc <nft_contract_flow_address> <nft_contract_evm_address> --network testnet
+
+# Set up royalty management (admin only)
+flow transactions send ./evm-bridging/cadence/transactions/admin/set_up_royalty_management.cdc --args-json "$(cat ./evm-bridging/cadence/transactions/admin/set_up_royalty_management_args.json)" --network <network> --signer <signer>
+```
 
-Fund testnet Flow EVM account:
+### Testnet Setup
 
-1. Use Flow Faucet: https://faucet.flow.com/fund-account
+1. Get testnet FLOW from [Flow Faucet](https://faucet.flow.com/fund-account)
 
 2. Transfer FLOW to EVM address:
 
 ```sh
-flow transactions send ./cadence/transfer_flow_to_evm_address.cdc <evm_address_hex> <ufix64_amount> --network testnet --signer testnet-account
+flow transactions send ./evm-bridging/cadence/transactions/transfer_flow_to_evm_address.cdc <evm_address_hex> <ufix64_amount> --network testnet --signer testnet-account
 ```
 
 ## Useful links
@@ -83,3 +146,4 @@ flow transactions send ./cadence/transfer_flow_to_evm_address.cdc <evm_address_h
 - [OpenZeppelin Doc - ERC721 Contracts v5](https://docs.openzeppelin.com/contracts/5.x/api/token/erc721)
 - [GitHub - OpenZeppelin Upgradeable Contracts](https://github.com/OpenZeppelin/openzeppelin-contracts-upgradeable)
 - [GitHub - LimitBreak Creator Token Standards](https://github.com/limitbreakinc/creator-token-standards)
+- [OpenSea Doc - Creator Fee Enforcement](https://docs.opensea.io/docs/creator-fee-enforcement)

evm-bridging/cadence/scripts/get_evm_address_string.cdc

@@ -0,0 +1,11 @@
+import "EVM"
+
+/// Returns the hex encoded address of the COA in the given Flow address
+///
+access(all) fun main(flowAddress: Address): String? {
+    return getAuthAccount<auth(BorrowValue) &Account>(flowAddress)
+        .storage.borrow<&EVM.CadenceOwnedAccount>(from: /storage/evm)
+        ?.address()
+        ?.toString()
+        ?? nil
+}

evm-bridging/cadence/scripts/get_underlying_erc721_address.cdc

@@ -0,0 +1,33 @@
+import "EVM"
+
+/// Returns the hex encoded address of the underlying ERC721 contract
+///
+access(all) fun main(flowNftAddress: Address, wrapperERC721Address: String): String? {
+    let coa = getAuthAccount<auth(BorrowValue) &Account>(flowNftAddress)
+        .storage.borrow<auth(EVM.Call) &EVM.CadenceOwnedAccount>(from: /storage/evm)
+            ?? panic("No COA found in signer's account")
+
+    return getUnderlyingERC721Address(coa,
+        EVM.addressFromString(wrapperERC721Address)
+    ).toString()
+}
+
+/// Gets the underlying ERC721 address
+///
+access(all) fun getUnderlyingERC721Address(
+    _ coa: auth(EVM.Call) &EVM.CadenceOwnedAccount,
+    _ wrapperAddress: EVM.EVMAddress
+): EVM.EVMAddress {
+    let res = coa.call(
+        to: wrapperAddress,
+        data: EVM.encodeABIWithSignature("underlying()", []),
+        gasLimit: 100_000,
+        value: EVM.Balance(attoflow: 0)
+    )
+
+    assert(res.status == EVM.Status.successful, message: "Call to get underlying ERC721 address failed")
+    let decodedResult = EVM.decodeABI(types: [Type<EVM.EVMAddress>()], data: res.data)
+    assert(decodedResult.length == 1, message: "Invalid response length")
+
+    return decodedResult[0] as! EVM.EVMAddress
+}