Buy flow: balance pre-flight; Trust Wallet users get a drain-warning heads-up

Stops early when the wallet lacks the POL. Only Trust Wallet users see the
proportion warning (smaller package / add POL / other wallet); everyone else
goes straight to the wallet confirmation. Buy-pane tip + chatbot reworded.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

public/assets/my.js

@@ -1227,6 +1227,23 @@
             await IAPWallet.signIn();
           }
           const spNow = await jretry('/api/sponsor');
+          // pre-flight: stop early if the POL is not there. Trust Wallet also hard-blocks any
+          // transaction that spends most of the balance ("drain your wallet"), so Trust users
+          // get a heads-up first; other wallets go straight to the confirmation.
+          try {
+            const need = BigInt(b.dataset.cost) + BigInt(b.dataset.cost) / 50n; // same 2% pad as buy()
+            const bal = await IAPWallet.balance(IAPWallet.address() || meNow.address);
+            if (bal < need) {
+              IAP.status('That wallet holds ' + IAP.fmtPol(bal.toString()) + ' POL, but this package needs about ' + IAP.fmtPol(need.toString()) + ' POL plus a little for gas. Top it up and try again.', 'bad');
+              return;
+            }
+            const pct = Number(need * 100n / bal);
+            const isTrust = /trust/i.test(IAPWallet.walletName() || '');
+            if (isTrust && pct > 55 && !confirm('Heads up for Trust Wallet users: this purchase uses about ' + pct + '% of the POL in your wallet, and Trust Wallet refuses transactions that spend most of the balance (it shows a "drain your wallet" warning with only Stop and go back).' + '\n\n' + 'Options: pick a smaller package first, add some POL, or connect a different wallet (MetaMask, Phantom, SafePal). Extra POL always stays yours.' + '\n\n' + 'Try it anyway?')) {
+              IAP.status('Purchase paused. Pick a smaller package, add POL, or connect another wallet, then try again.', 'ok');
+              return;
+            }
+          } catch (e) { /* balance read failed: let the wallet decide */ }
           IAP.status('Confirm the purchase in your wallet…');
           const r = await IAPWallet.buy(Number(b.dataset.id), spNow.sponsorId || 0, b.dataset.cost);
           if (r.status !== '0x1' && r.receipt && r.receipt.status !== '0x1') throw new Error('Transaction reverted.');

public/assets/wallet.js

@@ -221,5 +221,12 @@ window.IAPWallet = (function () {
     try { Object.keys(localStorage).forEach(k => { if (/wc@2|walletconnect|w3m|wcm|reown|wagmi|appkit/i.test(k)) localStorage.removeItem(k); }); } catch (e) {}
   }
 
-  return { connect, signIn, buy, activate, waitTx, disconnect };
+  // native balance of the connected wallet (pre-flight check before a buy)
+  async function balance(addr) {
+    await connect();
+    const h = await eth().request({ method: 'eth_getBalance', params: [addr || currentAddress(), 'latest'] });
+    return BigInt(h);
+  }
+  function walletName() { try { const w = modal && modal.getWalletInfo && modal.getWalletInfo(); return (w && w.name) || ''; } catch (e) { return ''; } }
+  return { connect, signIn, buy, activate, waitTx, disconnect, balance, address: currentAddress, walletName };
 })();