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, multicallContractAddress } from "./config";

import GovernanceAbi from "../abi/GovernanceAbi.json";
import StakingAbi from "../abi/StakingABI.json";
import MulticallABI from "../abi/MultiCallABI.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();

    const multiCallQuery: Array<[string, object]> = stakersAddresses.map((stakerAddress) =>
        stakingContract.methods.checkReward(stakerAddress).encodeABI()
    );
    const stakersWithRewardsBeforeHackRawData = await useMultiCall(oldStakingAddress, multiCallQuery, hackBlock - 1);
    const stakersWithRewardsBeforeHack: Array<IStaker> = stakersWithRewardsBeforeHackRawData.map((reward, index) => ({
        address: stakersAddresses[index],
        rewardBalance: BigNumber(reward),
    }));

    // 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.filter((staker) => staker.rewardBalance.div(1e18).isGreaterThan(1));
}

export async function getStakersWithdrawedAfterHack(): Promise<Array<EthAddress>> {
    const stakingContract = new web3.eth.Contract(StakingAbi as AbiItem[], oldStakingAddress);

    const withdrawRewardEvents = await stakingContract.getPastEvents("RewardsClaimed", { fromBlock: hackBlock });
    const stakersWithdrawedAfterHack = withdrawRewardEvents.map((event) => event.returnValues.account as string);

    return stakersWithdrawedAfterHack;
}

async function useMultiCall(contractAddress: EthAddress, queryArray: Array<Object>, callBlock?: number): Promise<any[]> {
    const multiCallContract = new web3.eth.Contract(MulticallABI as AbiItem[], multicallContractAddress);
    const multicallQueryArray = queryArray.map((query) => [contractAddress, query]);
    const { returnData } = await multiCallContract.methods.aggregate(multicallQueryArray).call({}, callBlock);
    return returnData;
}

export async function getStakersLockedBalancesSum(block: number): Promise<BigNumber> {
    const governanceContract = new web3.eth.Contract(GovernanceAbi as AbiItem[], governanceAddress);

    // All stakers who had more than 1 TORN in rewards at the time of the hack
    const stakersWithRewardsBeforeHack = await getStakersWithRewardsBeforeHack();
    // Stakers who withdrew rewards from the time of hack until the balance of the old Staking contract was nullified
    const stakersWithdrawedAfterHack = await getStakersWithdrawedAfterHack();

    // It makes no sense to restore awards to those who already withdrew them from the old Staking contract
    const stakersToRestoreRewards = stakersWithRewardsBeforeHack.filter((staker) => !stakersWithdrawedAfterHack.includes(staker.address));

    const lockedBalances: Array<string> = await useMultiCall(
        governanceAddress,
        stakersToRestoreRewards.map((staker) => governanceContract.methods.lockedBalance(staker.address).encodeABI()),
        block
    );

    return lockedBalances.reduce((acc, cur) => acc.plus(BigNumber(cur)), BigNumber(0));
}