/**
 * Uniswap: Permit2 signature-based approvals
 * 
 * This example demonstrates how to use Permit2 for signature-based token approvals.
 * Permit2 allows users to approve tokens via signatures instead of on-chain transactions.
 */

import { createWalletRpcClient } from '../../src/utils/chain-config.js';
import { getPermit2Address, getUniswapSwapRouter02 } from '../../src/utils/addresses.js';
import { getTokenMetadata, parseTokenAmount } from '../../src/utils/tokens.js';
import { getPermit2Domain, getPermit2TransferTypes, createPermit2Deadline } from '../../src/utils/permit2.js';
import { waitForTransaction } from '../../src/utils/rpc.js';
import { signTypedData } from 'viem';
import type { Address } from 'viem';

const CHAIN_ID = 1; // Mainnet
const PRIVATE_KEY = process.env.PRIVATE_KEY as `0x${string}`;

// Permit2 ABI for permit transfer
const PERMIT2_ABI = [
  {
    name: 'permitTransferFrom',
    type: 'function',
    stateMutability: 'nonpayable',
    inputs: [
      {
        components: [
          {
            components: [
              { name: 'token', type: 'address' },
              { name: 'amount', type: 'uint256' },
            ],
            name: 'permitted',
            type: 'tuple',
          },
          { name: 'nonce', type: 'uint256' },
          { name: 'deadline', type: 'uint256' },
        ],
        name: 'permit',
        type: 'tuple',
      },
      {
        components: [
          { name: 'to', type: 'address' },
          { name: 'requestedAmount', type: 'uint256' },
        ],
        name: 'transferDetails',
        type: 'tuple',
      },
      { name: 'signature', type: 'bytes' },
    ],
    outputs: [],
  },
] as const;

async function permit2Approval() {
  const walletClient = createWalletRpcClient(CHAIN_ID, PRIVATE_KEY);
  const publicClient = walletClient as any;
  const account = walletClient.account?.address;
  
  if (!account) {
    throw new Error('No account available');
  }

  const permit2Address = getPermit2Address(CHAIN_ID);
  const token = getTokenMetadata(CHAIN_ID, 'USDC');
  const amount = parseTokenAmount('1000', token.decimals);
  const spender = getUniswapSwapRouter02(CHAIN_ID); // Example: approve Uniswap router
  
  console.log(`Creating Permit2 signature for ${amount} ${token.symbol}`);
  console.log(`Permit2: ${permit2Address}`);
  console.log(`Spender: ${spender}`);
  console.log(`Account: ${account}`);

  // Step 1: Get nonce from Permit2
  // In production, query the Permit2 contract for the user's current nonce
  const nonce = 0n; // TODO: Read from Permit2 contract
  
  // Step 2: Create permit data
  const deadline = createPermit2Deadline(3600); // 1 hour
  const domain = getPermit2Domain(CHAIN_ID);
  const types = getPermit2TransferTypes();
  
  const permit = {
    permitted: {
      token: token.address,
      amount,
    },
    nonce,
    deadline,
  };

  const transferDetails = {
    to: spender,
    requestedAmount: amount,
  };

  // Step 3: Sign the permit
  console.log('\n1. Signing Permit2 permit...');
  const signature = await signTypedData(walletClient, {
    domain,
    types,
    primaryType: 'PermitTransferFrom',
    message: {
      permitted: permit.permitted,
      spender,
      nonce: permit.nonce,
      deadline: permit.deadline,
    },
  });
  
  console.log(`Signature: ${signature}`);

  // Step 4: Execute permitTransferFrom (this would typically be done by a router/contract)
  // Note: In practice, Permit2 permits are usually used within larger transaction flows
  // (e.g., Universal Router uses them automatically)
  console.log('\n2. Permit2 signature created successfully!');
  console.log('Use this signature in your transaction (e.g., Universal Router)');
  console.log('\nExample usage with Universal Router:');
  console.log('  - Universal Router will call permitTransferFrom on Permit2');
  console.log('  - Then execute the swap/transfer');
  console.log('  - All in one transaction');
}

// Run if executed directly
if (import.meta.url === `file://${process.argv[1]}`) {
  permit2Approval().catch(console.error);
}

export { permit2Approval };