import Web3 from "web3";
import BigNumber from "bignumber.js"
import { AbiItem } from 'web3-utils';
import { EthAddress, IStaker } from "./@types/staker";

import * as dotenv from "dotenv";
import { governanceAddress, governanceRewardsProposalBlock, hackBlock, oldStakingAddress } from "./config";

import GovernanceAbi from "../abi/GovernanceAbi.json";
import StakingAbi from "../abi/StakingABI.json";

dotenv.config();

const web3 = new Web3(process.env.MAINNET_RPC_URL as string);

function getGovernanceFunctionSelector(functionName: string): string {
    const lockFunctionAbi = GovernanceAbi.find(item => item.name == functionName);
    if (!lockFunctionAbi) throw new Error(`Cannot find function ${functionName} in Governance contract ABI`);

    const selector = web3.eth.abi.encodeFunctionSignature(lockFunctionAbi as AbiItem);

    return selector;
}

async function getAddressesStakersWithProssibleRewards(): Promise<Array<EthAddress>> {
    const governanceContract = new web3.eth.Contract(GovernanceAbi as AbiItem[], governanceAddress);

    /* Don't need to fetch all "lock" or "lockAndApproval" transactions from Governance contract,
     * because user rewards start updating only when RewardUpdateSuccessful events is emitted.
     */
    const rewardsUpdateEvents =
        await governanceContract.getPastEvents("RewardUpdateSuccessful", { fromBlock: governanceRewardsProposalBlock });

    const governanceStakers = rewardsUpdateEvents.map(event => event.returnValues.account as string);

    return [...new Set(governanceStakers)];
}

export async function getStakersWithRewardsBeforeHack(): Promise<Array<IStaker>> {
    const stakingContract = new web3.eth.Contract(StakingAbi as AbiItem[], oldStakingAddress);
    const stakersAddresses = await getAddressesStakersWithProssibleRewards();

    let stakersWithRewardsBeforeHack: Array<IStaker> = [];
    for (const address of stakersAddresses) {
        // Check stakers rewards on previous block before hack
        const rewardsBeforeHack = await stakingContract.methods.checkReward(address).call({}, hackBlock - 1);
        // Discard stakers with rewards less than 1 TORN, because accruing each reward requires paying gas
        if (BigNumber(rewardsBeforeHack).div(1e18).isGreaterThan(1))
            stakersWithRewardsBeforeHack.push({ address, rewardBalance: BigNumber(rewardsBeforeHack) });
    }

    return stakersWithRewardsBeforeHack;
}