contract.service.ts

import networkMapping from '../deployments.json';
import { Contract, ethers, Wallet } from 'ethers';
import { CeloWallet, CeloProvider } from '@celo-tools/celo-ethers-wrapper';
import logger from '../util/logger';

class ContractService {
    private static instance: ContractService;

    // establish contract parameters based on environment
    private CELO_RPC_ENDPOINT = process.env.NODE_ENV === 'test' ?
        process.env.CELO_LOCAL_RPC_ENDPOINT : process.env.NODE_ENV === 'production' ?
            process.env.CELO_ALFAJORES_RPC_ENDPOINT : process.env.NODE_ENV === 'cloud' ?
                process.env.CELO_MAINNET_RPC_ENDPOINT : 'error';

    private CHAIN_ID = process.env.NODE_ENV === 'test' ?
        process.env.CELO_LOCAL_CHAIN_ID : process.env.NODE_ENV === 'production' ?
            process.env.CELO_ALFAJORES_CHAIN_ID : process.env.NODE_ENV === 'cloud' ?
                process.env.CELO_MAINNET_CHAIN_ID : 'error';

    private CELO_PRIV_KEY = process.env.NODE_ENV === 'test' ?
        process.env.CELO_LOCAL_PRIVKEY : process.env.NODE_ENV === 'production' ?
            process.env.CELO_ALFAJORES_PRIVKEY : process.env.NODE_ENV === 'cloud' ?
                process.env.CELO_MAINNET_PRIVKEY : 'error';

    private contract: Contract;
    private constructor() {
        logger.info({ level: 'error', message: `ContractService init, CELO endpoint: ${this.CELO_RPC_ENDPOINT}` });
        try {
            const networkMappingForChain =
                networkMapping[this.CHAIN_ID as keyof typeof networkMapping];
            const geodataContractMapping = networkMappingForChain[0]['contracts']['GeodataAnchor'];

            // localnode vs. alfajores/mainnet provider/wallet:
            let signer: Wallet;
            if (process.env.NODE_ENV === 'test') {
                signer = new Wallet(this.CELO_PRIV_KEY, new ethers.providers.JsonRpcProvider(this.CELO_RPC_ENDPOINT));
            } else {
                signer = new CeloWallet(this.CELO_PRIV_KEY, new CeloProvider(this.CELO_RPC_ENDPOINT));
            }

            this.contract = new Contract(
                geodataContractMapping.address,
                geodataContractMapping.abi,
                signer
            );
        } catch (error) {
            logger.log({ level: 'error', message: `ContractService init contract failed: ${error}` });
        }
    }

    public static getInstance(): ContractService {
        if (!ContractService.instance) {
            ContractService.instance = new ContractService();
        }

        return ContractService.instance;
    }

    public getContract(): Contract {
        return this.contract;
    }
}

export default ContractService;