update buy handler

lib/buyHandler.ts

@@ -0,0 +1,65 @@
+import { ethers } from 'ethers';
+import { getContract } from '@/lib/ethers';
+
+declare global {
+  interface Window {
+    ethereumProvider?: ethers.providers.ExternalProvider & {
+      isMetaMask?: boolean;
+      request?: (method: string, params?: unknown[]) => Promise<unknown>;
+    };
+  }
+}
+
+type ToastFunction = (options: {
+  title: string;
+  variant?: 'default' | 'destructive' | null | undefined;
+}) => void;
+
+export const buyHandler = async (
+  eventId: number,
+  toast: ToastFunction
+): Promise<void> => {
+  if (eventId < 0) {
+    toast({ title: 'Please enter a valid Event ID.', variant: 'destructive' });
+    return;
+  }
+
+  try {
+    if (typeof window.ethereum === 'undefined') {
+      toast({
+        title: 'Please install MetaMask or another Ethereum wallet',
+        variant: 'destructive',
+      });
+      return;
+    }
+
+    // @ts-expect-error: window.ethereum might not match ExternalProvider exactly
+    const provider = new ethers.providers.Web3Provider(window.ethereum);
+    const signer = provider.getSigner();
+    const contract = getContract().connect(signer);
+
+    const ticketCost = await contract.getEventPriceFlare(eventId);
+    const balance = await provider.getBalance(await signer.getAddress());
+
+    if (balance.lt(ticketCost)) {
+      toast({
+        title: 'Insufficient balance to cover ticket cost and gas fees.',
+        variant: 'destructive',
+      });
+      return;
+    }
+
+    const tx = await contract.buyTicket(eventId, { value: ticketCost });
+    const receipt = await tx.wait();
+
+    toast({
+      title: `Ticket purchased successfully! Transaction Hash: ${receipt.transactionHash}`,
+    });
+  } catch (error) {
+    console.error('Error buying ticket:', error);
+    toast({
+      title: 'Transaction failed. Please try again.',
+      variant: 'destructive',
+    });
+  }
+};