import { createPublicClient, createWalletClient, http, parseAbi } from 'viem';
import { privateKeyToAccount } from 'viem/accounts';
import { sei } from 'viem/chains';

const client = createPublicClient({ chain: sei, transport: http() });
const account = privateKeyToAccount('0xYourPrivateKey');
const walletClient = createWalletClient({ account, chain: sei, transport: http() });

const ERC20_ABI = parseAbi([
  'function name() view returns (string)',
  'function symbol() view returns (string)',
  'function decimals() view returns (uint8)',
  'function totalSupply() view returns (uint256)',
  'function balanceOf(address owner) view returns (uint256)',
  'function allowance(address owner, address spender) view returns (uint256)',
  'function transfer(address to, uint256 amount) returns (bool)',
  'function approve(address spender, uint256 amount) returns (bool)',
  'function transferFrom(address from, address to, uint256 amount) returns (bool)',
  'event Transfer(address indexed from, address indexed to, uint256 value)',
  'event Approval(address indexed owner, address indexed spender, uint256 value)',
]);

const TOKEN = '0xTokenAddress';

import { ethers } from 'ethers';

const provider = new ethers.JsonRpcProvider('https://evm-rpc.sei-apis.com');
const wallet = new ethers.Wallet('0xYourPrivateKey', provider);

const ERC20_ABI = [
  'function name() view returns (string)',
  'function symbol() view returns (string)',
  'function decimals() view returns (uint8)',
  'function totalSupply() view returns (uint256)',
  'function balanceOf(address owner) view returns (uint256)',
  'function allowance(address owner, address spender) view returns (uint256)',
  'function transfer(address to, uint256 amount) returns (bool)',
  'function approve(address spender, uint256 amount) returns (bool)',
  'function transferFrom(address from, address to, uint256 amount) returns (bool)',
  'event Transfer(address indexed from, address indexed to, uint256 value)',
  'event Approval(address indexed owner, address indexed spender, uint256 value)',
];

const TOKEN = '0xTokenAddress';
const readContract = new ethers.Contract(TOKEN, ERC20_ABI, provider);
const writeContract = new ethers.Contract(TOKEN, ERC20_ABI, wallet);

const [name, symbol, decimals, totalSupply] = await Promise.all([
  client.readContract({ address: TOKEN, abi: ERC20_ABI, functionName: 'name' }),
  client.readContract({ address: TOKEN, abi: ERC20_ABI, functionName: 'symbol' }),
  client.readContract({ address: TOKEN, abi: ERC20_ABI, functionName: 'decimals' }),
  client.readContract({ address: TOKEN, abi: ERC20_ABI, functionName: 'totalSupply' }),
]);

const [name, symbol, decimals, totalSupply] = await Promise.all([
  readContract.name(),
  readContract.symbol(),
  readContract.decimals(),
  readContract.totalSupply(),
]);

const balance = await client.readContract({
  address: TOKEN,
  abi: ERC20_ABI,
  functionName: 'balanceOf',
  args: ['0xOwnerAddress'],
});

const allowance = await client.readContract({
  address: TOKEN,
  abi: ERC20_ABI,
  functionName: 'allowance',
  args: ['0xOwnerAddress', '0xSpenderAddress'],
});

const balance = await readContract.balanceOf('0xOwnerAddress');
const allowance = await readContract.allowance('0xOwnerAddress', '0xSpenderAddress');

import { parseUnits } from 'viem';

const hash = await walletClient.writeContract({
  address: TOKEN,
  abi: ERC20_ABI,
  functionName: 'transfer',
  args: ['0xRecipient', parseUnits('10', 18)],
});

const receipt = await client.waitForTransactionReceipt({ hash });

const tx = await writeContract.transfer('0xRecipient', ethers.parseUnits('10', 18));
const receipt = await tx.wait();

import { parseUnits, maxUint256 } from 'viem';

// Approve a specific amount
const hash = await walletClient.writeContract({
  address: TOKEN,
  abi: ERC20_ABI,
  functionName: 'approve',
  args: ['0xSpenderAddress', parseUnits('100', 18)],
});

// Or approve max (unlimited)
const hashMax = await walletClient.writeContract({
  address: TOKEN,
  abi: ERC20_ABI,
  functionName: 'approve',
  args: ['0xSpenderAddress', maxUint256],
});

// Approve a specific amount
const tx = await writeContract.approve('0xSpenderAddress', ethers.parseUnits('100', 18));

// Or approve max (unlimited)
const txMax = await writeContract.approve('0xSpenderAddress', ethers.MaxUint256);

const unwatch = client.watchContractEvent({
  address: TOKEN,
  abi: ERC20_ABI,
  eventName: 'Transfer',
  onLogs: (logs) => {
    logs.forEach(({ args }) => {
      console.log(`${args.from} → ${args.to}: ${args.value}`);
    });
  },
});

// Stop watching
unwatch();

readContract.on('Transfer', (from, to, value) => {
  console.log(`${from} → ${to}: ${value}`);
});

// Stop watching
readContract.off('Transfer');

const logs = await client.getContractEvents({
  address: TOKEN,
  abi: ERC20_ABI,
  eventName: 'Transfer',
  fromBlock: 0n,
  toBlock: 'latest',
});

const filter = readContract.filters.Transfer();
const logs = await readContract.queryFilter(filter, 0, 'latest');