// Wallet plumbing: EIP-1193 connect, chain add/switch, SIWE sign-in, and raw
// calldata builders for the contract's tx functions (no library needed).
window.IAPWallet = (function () {
  const SEL_BUY = '0xfd095e97';      // buy(uint32,uint32)
  const SEL_ACTIVATE = '0x1a93ec95'; // activate(uint32)
  const pad = v => BigInt(v).toString(16).padStart(64, '0');

  function eth() {
    if (!window.ethereum) throw new Error('No wallet found. Open this page in a browser with MetaMask (or a wallet browser).');
    return window.ethereum;
  }
  async function ensureChain(c) {
    const want = '0x' + Number(c.chainId).toString(16);
    const cur = await eth().request({ method: 'eth_chainId' });
    if (cur === want) return;
    try {
      await eth().request({ method: 'wallet_switchEthereumChain', params: [{ chainId: want }] });
    } catch (e) {
      if (e.code !== 4902) throw e;
      await eth().request({ method: 'wallet_addEthereumChain', params: [{
        chainId: want, chainName: c.chainName, nativeCurrency: { name: 'POL', symbol: 'POL', decimals: 18 },
        rpcUrls: [c.rpc], blockExplorerUrls: [c.explorer] }] });
    }
  }
  async function connect() {
    const c = await IAP.getConfig();
    const [addr] = await eth().request({ method: 'eth_requestAccounts' });
    await ensureChain(c);
    return addr;
  }
  // SIWE: challenge -> personal_sign -> verify (server sets the session cookie)
  async function signIn() {
    const addr = await connect();
    const ch = await (await fetch('/api/auth/challenge', { method: 'POST',
      headers: { 'Content-Type': 'application/json' }, body: JSON.stringify({ address: addr }) })).json();
    if (ch.error) throw new Error(ch.error);
    const sig = await eth().request({ method: 'personal_sign', params: [ch.message, addr] });
    const r = await (await fetch('/api/auth/verify', { method: 'POST',
      headers: { 'Content-Type': 'application/json' }, body: JSON.stringify({ address: addr, signature: sig }) })).json();
    if (r.error) throw new Error(r.error);
    return r; // {address, memberId, sponsorId}
  }
  async function sendTx(data, valueWei) {
    const c = await IAP.getConfig();
    const [addr] = await eth().request({ method: 'eth_requestAccounts' });
    await ensureChain(c);
    const tx = { from: addr, to: c.contract, data };
    if (valueWei) tx.value = '0x' + BigInt(valueWei).toString(16);
    return eth().request({ method: 'eth_sendTransaction', params: [tx] });
  }
  async function waitTx(hash) {
    // poll our own server (CSP-friendly); it relays the receipt from the RPC
    for (let i = 0; i < 60; i++) {
      const r = await (await fetch('/api/tx/' + hash)).json();
      if (r.found) return { status: r.status, blockNumber: r.blockNumber };
      await new Promise(res => setTimeout(res, 2500));
    }
    throw new Error('Timed out waiting for the transaction. Check the explorer.');
  }
  // buy: quote is read live server-side; pad 2% for oracle drift, contract
  // refunds every wei of excess in the same transaction.
  async function buy(productId, sponsorId, costWei) {
    const value = BigInt(costWei) + BigInt(costWei) / 50n;
    const data = SEL_BUY + pad(productId) + pad(sponsorId || 0);
    const hash = await sendTx(data, value);
    return { hash, receipt: await waitTx(hash) };
  }
  async function activate(sponsorId) {
    const data = SEL_ACTIVATE + pad(sponsorId || 0);
    const hash = await sendTx(data, null);
    return { hash, receipt: await waitTx(hash) };
  }
  return { connect, signIn, buy, activate, waitTx };
})();