metamask.js

import { hashMessage } from '@ethersproject/hash'
import {
    computePublicKey,
    recoverPublicKey,
} from '@ethersproject/signing-key'
import { altheaToEth, gravityToEth } from '@gravity-bridge/address-converter'
import { signatureToWeb3Extension } from '@gravity-bridge/transactions';
import { createTxRaw, createAnyMessage } from '@gravity-bridge/proto';

let mmAccounts;
let currPubkey;

const verifyPubKeyMsg = 'Verify Public Key';

export function metamaskInstalled() {
    return typeof window.ethereum !== 'undefined';
}

export async function connectMetamask() {
    mmAccounts = await window?.ethereum?.request({
        method: 'eth_requestAccounts',
    });
    console.log("Discovered accounts: ", mmAccounts);
}

export async function verifyPubKey() {
    const signature = await window?.ethereum?.request({
        method: 'personal_sign',
        params: [verifyPubKeyMsg, mmAccounts[0], ''],
    })

    // Compress the key, since the client expects
    // public keys to be compressed.
    const uncompressedPk = recoverPublicKey(
        hashMessage(verifyPubKeyMsg),
        signature,
    )

    const hexPk = computePublicKey(uncompressedPk, true)
    const pk = Buffer.from(
        hexPk.replace('0x', ''), 'hex',
    ).toString('base64')
    currPubkey = pk
}

export function GetCurrPubkey() {
    return currPubkey;
}

export function GetCurrAccount() {
    if (mmAccounts && mmAccounts.length > 0) {
        return mmAccounts[0];
    } else {
        return undefined;
    }
}

export async function SignEIP712CosmosTx(context, tx) {
    const { sender, chain } = context

    var senderHexAddress
    if (sender.accountAddress.startsWith("althea")) {
        senderHexAddress = altheaToEth(sender.accountAddress)
    } else if (sender.accountAddress.startsWith("gravity")) {
        senderHexAddress = gravityToEth(sender.accountAddress)
    }
    const eip712Payload = JSON.stringify(tx.eipToSign);
    console.log("EIP712 payload: ", eip712Payload);

    const mmArgs = {
        method: 'eth_signTypedData_v4',
        params: [senderHexAddress, eip712Payload],
    }
    const signature = await window.ethereum.request(mmArgs);
    const extension = signatureToWeb3Extension(chain, sender, signature);

    const { legacyAmino } = tx;
    legacyAmino.body.extensionOptions.push(createAnyMessage(extension));

    const bodyBytes = legacyAmino.body.toBinary();
    const authInfoBytes = legacyAmino.authInfo.toBinary();

    const signedTx = createTxRaw(bodyBytes, authInfoBytes, [new Uint8Array()]);

    return signedTx
}