import { useAccount, useClient } from "@getpara/react-sdk";
import { createPublicClient, http, type WalletClient, type PublicClient, type LocalAccount } from "viem";
import { createParaAccount, createParaViemClient } from "@getpara/viem-v2-integration";
import { Chain } from "viem/chains";
import { useState, useEffect, useMemo } from "react";

/**
 * Hook to create viem clients for Para wallet integration
 * Provides publicClient, walletClient, and account information for signing
 */
export function useParaViem(chain: Chain, rpcUrl: string) {
  const { isConnected } = useAccount();
  const para = useClient();

  // Stable public client across renders unless chain/rpc changes
  const publicClient = useMemo(() => createPublicClient({
    chain,
    transport: http(rpcUrl)
  }), [chain.id, rpcUrl]);

  const [clients, setClients] = useState<{
    publicClient: PublicClient;
    walletClient: WalletClient | null;
    account: LocalAccount | null;
  } | null>(null);
  const [isLoading, setIsLoading] = useState(false);
  const [error, setError] = useState<Error | null>(null);

  useEffect(() => {
    let isMounted = true;
    const setup = async () => {
      setIsLoading(true);
      setError(null);
      try {
        if (isConnected && para) {
          const viemAccount = createParaAccount(para);
          const walletClient = createParaViemClient(para, {
            account: viemAccount,
            chain,
            transport: http(rpcUrl)
          });
          if (isMounted) {
            setClients({ publicClient, walletClient, account: viemAccount });
          }
        } else if (isMounted) {
          setClients({ publicClient, walletClient: null, account: null });
        }
      } catch (err) {
        if (isMounted) setError(err instanceof Error ? err : new Error('Failed to setup Para viem clients'));
      } finally {
        if (isMounted) setIsLoading(false);
      }
    };
    setup();
    return () => { isMounted = false; };
  }, [chain.id, rpcUrl, isConnected]);

  return { clients, isLoading, error };
}