import {
    HexUInt,
    Transaction,
    TransactionBody,
    TransactionClause,
} from '@vechain/sdk-core';
import { TESTNET_URL, ThorClient } from '@vechain/sdk-network';

const thorClient = ThorClient.at(TESTNET_URL);

let chainTag: number;

export const getBestBlockRef = async (): Promise<string> => {
    const blockRef = await thorClient.blocks.getBestBlockRef();

    if (!blockRef) {
        throw new Error('Block ref not found');
    }

    return blockRef;
};

export const getChainTag = async (): Promise<number> => {
    if (chainTag) {
        return chainTag;
    }

    const genesisBlock = await thorClient.blocks.getGenesisBlock();

    if (!genesisBlock) {
        throw new Error('Genesis block not found');
    }

    chainTag = Number(`0x${genesisBlock.id.slice(64)}`);
    return chainTag;
};

export const buildTxBody = async (
    clauses: TransactionClause[],
    senderAddress: string,
    expiration: number,
    gas?: number,
): Promise<TransactionBody> => {
    if (!gas) {
        // Get gas estimate
        const gasResult = await thorClient.gas.estimateGas(
            clauses,
            senderAddress,
        );

        if (gasResult.reverted) {
            throw new Error(
                `Gas estimation failed: ${gasResult.revertReasons} - ${gasResult.vmErrors}`,
            );
        }

        gas = gasResult.totalGas + 200_000;
    }

    const body: TransactionBody = {
        chainTag: await getChainTag(),
        blockRef: await getBestBlockRef(),
        expiration,
        clauses,
        gasPriceCoef: 0,
        gas,
        dependsOn: null,
        nonce: Math.floor(Math.random() * 10000000),
    };

    return body;
};

export const signAndSendTx = async (body: TransactionBody, pk: Uint8Array) => {
    const encodedTx = Transaction.of(body).sign(pk).encoded;
    const raw = HexUInt.of(encodedTx).toString();

    const sendTransactionResult =
        await thorClient.transactions.sendRawTransaction(raw);

    const txReceipt = await thorClient.transactions.waitForTransaction(
        sendTransactionResult.id,
    );
    // console.log(`Transaction receipt: ${JSON.stringify(txReceipt)}`)

    if (!txReceipt) {
        throw new Error('Transaction failed');
    }
    if (txReceipt.reverted) {
        throw new Error('Transaction reverted');
    }
};