package core import ( "github.com/ethereum/go-ethereum" "github.com/ethereum/go-ethereum/core/types" "math/big" ) type BlockChain interface { ContractDataFetcher GetBlockByNumber(blockNumber int64) (Block, error) GetHeaderByNumber(blockNumber int64) (Header, error) GetLogs(contract Contract, startingBlockNumber *big.Int, endingBlockNumber *big.Int) ([]Log, error) GetEthLogsWithCustomQuery(query ethereum.FilterQuery) ([]types.Log, error) LastBlock() *big.Int Node() Node } type ContractDataFetcher interface { FetchContractData(abiJSON string, address string, method string, methodArg interface{}, result interface{}, blockNumber int64) error }