package com.library;

import com.facebook.react.bridge.ReactApplicationContext;
import com.facebook.react.bridge.ReactContextBaseJavaModule;
import com.facebook.react.bridge.ReactMethod;
import com.facebook.react.bridge.Promise;
import org.bitcoinj.core.*;
import org.bitcoinj.params.TestNet3Params;
import org.bitcoinj.script.Script;
import org.bitcoinj.wallet.Wallet;

public class PayjoinModule extends ReactContextBaseJavaModule {
    private static final NetworkParameters PARAMS = TestNet3Params.get();

    public PayjoinModule(ReactApplicationContext reactContext) {
        super(reactContext);
    }

    @Override
    public String getName() {
        return "PayjoinModule";
    }

    @ReactMethod
    public void createInitialPsbt(String senderAddress, String receiverAddress, int amount, int feeRate, Promise promise) {
        try {
            Wallet wallet = new Wallet(PARAMS);
            Transaction tx = new Transaction(PARAMS);

            // Fetch UTXOs (simplified, assuming a helper method)
            List<Utxo> utxos = fetchUtxos(senderAddress);

            long totalInput = 0;
            for (Utxo utxo : utxos) {
                Sha256Hash txid = Sha256Hash.wrap(utxo.getTxid());
                tx.addInput(txid, utxo.getVout(), new Script(Hex.decode(utxo.getScriptPubKey())));
                totalInput += utxo.getAmount();
            }

            // Add receiver output
            Address receiverAddr = Address.fromString(PARAMS, receiverAddress);
            tx.addOutput(Coin.valueOf(amount), receiverAddr);

            // Add change output
            long estimatedFee = feeRate * 200 + 10000; // Max fee contribution
            long change = totalInput - amount - estimatedFee;
            if (change > 546) { // Dust threshold
                Address changeAddr = Address.fromString(PARAMS, senderAddress);
                tx.addOutput(Coin.valueOf(change), changeAddr);
            }

            // Convert to PSBT (simplified, assumes conversion utility)
            String psbtBase64 = convertToPsbt(tx);
            promise.resolve(psbtBase64);
        } catch (Exception e) {
            promise.reject("PSBT_CREATION_FAILED", e);
        }
    }

    @ReactMethod
    public void signAndFinalizePsbt(String psbtBase64, String privateKeyWif, Promise promise) {
        try {
            // Parse PSBT (simplified, assumes conversion utility)
            Transaction tx = convertFromPsbt(psbtBase64);

            // Sign transaction
            ECKey key = DumpedPrivateKey.fromBase58(PARAMS, privateKeyWif).getKey();
            for (TransactionInput input : tx.getInputs()) {
                input.sign(key, input.getConnectedOutput().getScriptPubKey());
            }

            // Finalize and return transaction hex
            promise.resolve(tx.bitcoinSerialize().toString());
        } catch (Exception e) {
            promise.reject("SIGNING_FAILED", e);
        }
    }

    private List<Utxo> fetchUtxos(String senderAddress) {
        // Implement network request to fetch UTXOs (e.g., using OkHttp)
        // This is a placeholder; replace with actual API call
        return new ArrayList<>();
    }

    private String convertToPsbt(Transaction tx) {
        // Placeholder: Implement PSBT conversion
        return "";
    }

    private Transaction convertFromPsbt(String psbtBase64) {
        // Placeholder: Implement PSBT parsing
        return new Transaction(PARAMS);
    }
}