/*
 * This file is part of the Flowee project
 * Copyright (C) 2024-2025 Tom Zander <tom@flowee.org>
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
#include "QMLSweepHandler.h"
#include "IndexerServices.h"
#include <FloweePay.h>
#include <QDir>
#include <QFile>
#include <QTimer>
#include <base58.h>
#include <cashaddr.h>
#include <streaming/BufferPools.h>


QMLSweepHandler::QMLSweepHandler(QObject *parent)
    : QObject(parent),
    m_fetcher(new TransactionsFetcher(this))
{
    // make sure that we'll have a list of indexer services when we
    // need them later.
    FloweePay::instance()->indexerServices()->populate();

    m_builder.setAnonimize(true);

    connect (m_fetcher, &TransactionsFetcher::failed, this, [=]() {
        auto score = m_fetcher->serviceFailureLevel();
        if (score) {
            auto services = FloweePay::instance()->indexerServices();
            services->punish(m_fetcher->service(), score);
            // try again
            this->start();
        }
    }, Qt::QueuedConnection);

    connect (m_fetcher, &TransactionsFetcher::searchComplete, this, [=]() {
        auto f = m_fetcher;
        if (f) {
            setNumOutputsFound(m_fetcher->numOutputsFound());
            setNumTokensFound(m_fetcher->numTokensFound());
        }
    });

    connect (m_fetcher, &TransactionsFetcher::finished, this, &QMLSweepHandler::startTxBuilder);

    connect (m_fetcher, &TransactionsFetcher::fetched, this, [=](int utxoCount) {
        int progress = 1000;
        auto f = m_fetcher;
        if (f)
            progress = std::round(utxoCount / (float) m_fetcher->numOutputsFound() * 1000);
        setDownloadProgress(progress);
    });
}

QString QMLSweepHandler::privKey() const
{
    return m_privKey;
}

void QMLSweepHandler::setPrivKey(const QString &newPrivKey)
{
    if (m_privKey == newPrivKey)
        return;
    m_privKey = newPrivKey;
    m_addressHash.clear();
    emit privKeyChanged();

    // if the private key is valid, find the address and outputscript hash which
    // we'll use to ask electrum-cash for content.
    CBase58Data string;
    if (string.SetString(newPrivKey.toStdString())) {
        auto chain = FloweePay::instance()->chain();
        if ((chain == P2PNet::MainChain && string.isMainnetPrivKey())
                || (chain == P2PNet::Testnet4Chain && string.isTestnetPrivKey())) {
            m_key.set(string.data().begin(), string.data().begin() + 32,
                string.data().size() > 32 && string.data().at(32) == 1);
        }
    }
    if (!m_key.isValid()) {
        setError(InvalidInput);
        return;
    }
    const auto id = m_key.getPubKey().getKeyId();
    assert(id.size() == 20);
    CashAddress::Content cashContent;
    cashContent.type = CashAddress::PubkeyType;
    cashContent.hash = std::vector<uint8_t>(id.begin(), id.end());
    m_addressHash = CashAddress::createHashedOutputScript(cashContent);

    const std::string &chainPref = FloweePay::instance()->chainPrefix();
    auto s = CashAddress::encode(chainPref, cashContent);
    const auto size = chainPref.size();
    setSweepAddress(QString::fromLatin1(s.c_str() + size + 1, s.size() - size -1)); // the 1 is for the colon

    QTimer::singleShot(10, this, SLOT(start()));
}

QMLSweepHandler::Error QMLSweepHandler::error() const
{
    return m_error;
}

void QMLSweepHandler::setError(Error err)
{
    if (m_error == err)
        return;
    m_error = err;
    emit errorChanged();
}

AccountInfo *QMLSweepHandler::currentAccount() const
{
    return m_account;
}

void QMLSweepHandler::setCurrentAccount(AccountInfo *account)
{
    if (m_account == account)
        return;
    assert(!m_txBroadcastStarted);
    if (m_txBroadcastStarted)
        return;
    m_account = account;
    emit currentAccountChanged();
}

void QMLSweepHandler::markUserApproved()
{
    if (m_txBroadcastStarted)
        return;
    assert(m_account);
    if (!m_account) {
        logFatal(10051) << "Missing account";
        return;
    }
    if (m_builder.outputCount() == 0 || m_builder.inputCount() == 0) {
        logFatal(10051) << "No Tx to approve";
        return;
    }

    KeyId address;
    /*int privKeyId = */ m_account->wallet()->reserveUnusedAddress(address, Wallet::ChangePath);
    // ignore the returned value as we have no intention of ever 'unreserving' the key
    // as we just broadcast in this same flow.
    m_builder.selectOutput(0);
    m_builder.pushOutputPay2Address(address);
    setTargetAddress(renderAddress(address));

    const auto tx = m_builder.createTransaction();
    m_account->wallet()->addTransaction(tx, Wallet::NoNotification);
    m_account->wallet()->setTransactionComment(tx, tr("Swept funds"));

    m_infoObject = std::make_shared<TxInfoObject>(m_account->wallet(), tx);
    connect(m_infoObject.get(), SIGNAL(broadcastStatusChanged()), this, SIGNAL(broadcastStatusChanged()));
    FloweePay::instance()->broadcastTransaction(m_infoObject);
    m_txBroadcastStarted = true;
    emit broadcastStatusChanged();

    // the transactions we spent were stored in a subdir.
    // lets clean up after ourselves.
    QDir subdir("sweep");
    if (subdir.exists())
        subdir.removeRecursively();
}

FloweePay::BroadcastStatus QMLSweepHandler::broadcastStatus() const
{
#if 0
    // This default-disabled code-snippet is fun to allow developing the UX/GUI by stepping through the steps.
    // Alter the 'i == 4' to another value to make it stop at the step you want to see longer.
    static int i = 0;
    static QTimer *timer = nullptr;
    if (timer == nullptr) {
        timer = new QTimer(const_cast<QMLSweepHandler*>(this));
        timer->start(3000);
        connect(timer, &QTimer::timeout, [=]() {
            if (++i == 4)
                timer->stop();
            emit const_cast<QMLSweepHandler*>(this)->broadcastStatusChanged();
        });
    }
    switch (i) {
        case 0: return FloweePay::NotStarted;
        case 1: return FloweePay::TxOffered;
        case 3: return FloweePay::TxRejected;
        case 4: return FloweePay::TxBroadcastSuccess;
        default: return FloweePay::TxWaiting;
    }
#else
    if (!m_txBroadcastStarted)
        return FloweePay::NotStarted;
#endif
    auto infoObject = m_infoObject;
    if (infoObject.get() == nullptr)
        return FloweePay::TxBroadcastSuccess;
    return infoObject->broadcastStatus();
}

void QMLSweepHandler::start()
{
    auto service = FloweePay::instance()->indexerServices()->service();
    if (service.hostname.empty()) {
        // lets not translate this, since this is likely an
        // internal error (aka bug) or simply a lack of Internet.
        setError(NoBackendFound);
        return;
    }

    m_fetcher->setService(service);
    m_fetcher->start(m_addressHash);
}

void QMLSweepHandler::startTxBuilder(const QList<TransactionsFetcher::Output> &result)
{
    assert(m_fetcher);
    assert(m_builder.inputCount() == 0);
    assert(m_builder.outputCount() == 0);
    assert(m_key.isValid());
    setNumOutputsFound(m_fetcher->numOutputsFound());
    setNumTokensFound(m_fetcher->numTokensFound());
    m_fetcher->deleteLater();
    m_fetcher = nullptr;

    int64_t inputs = 0;
    for (const auto &prevOut : result) {
        logDebug(10051) << "Using input:" << prevOut.txid << prevOut.outIndex;
        uint256 txid = uint256S(prevOut.txid.toStdString());
        m_builder.appendInput(txid, prevOut.outIndex);

        QFile txIn(prevOut.filename);
        if (!txIn.open(QIODevice::ReadOnly)) {
            logCritical(10051) << "Failed to open file" << prevOut.filename;
            setError(FileError);
            return;
        }
        auto pool = Streaming::pool(txIn.size());
        txIn.read(pool->begin(), txIn.size());
        Tx tx(pool->commit(txIn.size()));
        Tx::Iterator iter(tx);
        Tx::Output out;
        for (int index = 0; index <= prevOut.outIndex; ++index) {
            out = iter.nextOutput();
        }
        if (out.outputValue < 0) {
            logCritical(10051) << "Invalid indexer data";
            setError(DataInconsistency);
            return;
        }
        inputs += out.outputValue;
        m_builder.pushInputSignature(m_key, out.outputScript(), out.outputValue, TransactionBuilder::Schnorr);
    }
    m_builder.appendOutput(inputs);
    m_builder.setOutputFeeSource(0);
    // We're not doing the last step here of assigning our address since the user may change account before we send.

    logInfo(10051) << "Built a transaction with" << m_builder.inputCount() << " => " << m_builder.outputCount();
    logInfo(10051) << "Total sats:" << inputs;
    setSweepTotal(inputs);
    setPrepared(true);
}

int QMLSweepHandler::downloadProgress() const
{
    return m_downloadProgress;
}

void QMLSweepHandler::setDownloadProgress(int progress)
{
    if (m_downloadProgress == progress)
        return;
    m_downloadProgress = progress;
    emit downloadProgressChanged();
}

QString QMLSweepHandler::sweepAddress() const
{
    return m_sweepAddress;
}

void QMLSweepHandler::setSweepAddress(const QString &newSweepAddress)
{
    if (m_sweepAddress == newSweepAddress)
        return;
    m_sweepAddress = newSweepAddress;
    emit sweepAddressChanged();
}

int QMLSweepHandler::numOutputsFound() const
{
    return m_numOutputsFound;
}

void QMLSweepHandler::setNumOutputsFound(int newNumOutputsFound)
{
    if (m_numOutputsFound == newNumOutputsFound)
        return;
    m_numOutputsFound = newNumOutputsFound;
    emit numOutputsFoundChanged();
}

int QMLSweepHandler::numTokensFound() const
{
    return m_numTokensFound;
}

void QMLSweepHandler::setNumTokensFound(int newNumTokensFound)
{
    if (m_numTokensFound == newNumTokensFound)
        return;
    m_numTokensFound = newNumTokensFound;
    emit numTokensFoundChanged();
}

double QMLSweepHandler::sweepTotal() const
{
    return m_sweepTotal;
}

void QMLSweepHandler::setSweepTotal(double newSweepTotal)
{
    if (qFuzzyCompare(m_sweepTotal, newSweepTotal))
        return;
    m_sweepTotal = newSweepTotal;
    emit sweepTotalChanged();
}

bool QMLSweepHandler::prepared() const
{
    return m_prepared;
}

void QMLSweepHandler::setPrepared(bool newPrepared)
{
    if (m_prepared == newPrepared)
        return;
    m_prepared = newPrepared;
    emit preparedChanged();
}

QString QMLSweepHandler::targetAddress() const
{
    return m_targetAddress;
}

void QMLSweepHandler::setTargetAddress(const QString &newTargetAddress)
{
    if (m_targetAddress == newTargetAddress)
        return;
    m_targetAddress = newTargetAddress;
    emit targetAddressChanged();
}