#include "BlockchainBackend.h"
#include "logos_api.h"
#include "logos_api_client.h"

#include <QByteArray>
#include <QClipboard>
#include <QCoreApplication>
#include <QDateTime>
#include <QDebug>
#include <QDir>
#include <QGuiApplication>
#include <QJsonDocument>
#include <QJsonObject>
#include <QSettings>
#include <QSignalBlocker>
#include <QTimer>
#include <QUrl>
#include <QVariant>

#include <algorithm>

const QString BlockchainBackend::BLOCKCHAIN_MODULE_NAME =
    QStringLiteral("liblogos_blockchain_module");

void BlockchainBackend::setError(const QString& message)
{
    setLastErrorMessage(message);
    setStatus(Error);
}

static QString toLocalPath(const QString& pathInput)
{
    if (pathInput.trimmed().isEmpty())
        return pathInput;
    return QUrl::fromUserInput(pathInput).toLocalFile();
}

// invokeRemoteMethod() returns an invalid QVariant (not a LogosResult) when
// the call itself fails to get a reply (timeout, disconnected module, etc.),
// as opposed to the remote method running and reporting failure normally.
static LogosResult toLogosResult(const QVariant& reply)
{
    if (!reply.isValid())
        return LogosResult{false, QVariant(), QStringLiteral("Call failed.")};
    return reply.value<LogosResult>();
}

static QString toErrorMessage(const LogosResult& result)
{
    return QStringLiteral("Error: %1").arg(result.error.toString());
}

// QML callers distinguish success from failure by sniffing for an "Error"
// prefix (see BlockchainView.qml), so both branches must share this type.
// TODO: Currently functions are returning a string (for ok and ko cases), which is later re-parsed to know if the call
//  succeeded or failed. We can simplify this by returning the result itself upward.
static QString toDisplayMessage(const LogosResult& result)
{
    return result.success ? result.value.toString() : toErrorMessage(result);
}

// Decode a base58 (Bitcoin alphabet) string to raw bytes. On an invalid
// character *ok is set to false and an empty array is returned.
static QByteArray decodeBase58(const QString& input, bool* ok)
{
    static const QByteArray kAlphabet =
        "123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz";

    const QByteArray s = input.trimmed().toLatin1();
    QByteArray bytes; // little-endian while building, reversed at the end
    bytes.append('\0');

    for (const char c : s) {
        const int value = kAlphabet.indexOf(c);
        if (value < 0) {
            if (ok) *ok = false;
            return {};
        }
        int carry = value;
        for (int j = 0; j < bytes.size(); ++j) {
            carry += static_cast<unsigned char>(bytes[j]) * 58;
            bytes[j] = static_cast<char>(carry & 0xff);
            carry >>= 8;
        }
        while (carry > 0) {
            bytes.append(static_cast<char>(carry & 0xff));
            carry >>= 8;
        }
    }

    // Each leading '1' maps to a leading zero byte.
    for (int i = 0; i < s.size() && s[i] == '1'; ++i)
        bytes.append('\0');

    std::reverse(bytes.begin(), bytes.end());
    if (ok) *ok = true;
    return bytes;
}

BlockchainBackend::BlockchainBackend(LogosAPI* logosAPI, QObject* parent)
    : BlockchainBackendSimpleSource(parent)
    , m_logosAPI(logosAPI)
    , m_accountsModel(new AccountsModel(this))
    , m_logModel(new LogModel(this))
{
    setStatus(NotStarted);
    setUseGeneratedConfig(false);
    setGeneratedUserConfigPath(
        QDir::currentPath() + QStringLiteral("/user_config.yaml"));

    // Restore saved config paths
    QSettings s("Logos", "BlockchainUI");
    const QString envConfigPath =
        QString::fromUtf8(qgetenv("LB_CONFIG_PATH"));
    const QString savedUserConfig =
        s.value("userConfigPath").toString();
    const QString savedDeploymentConfig =
        s.value("deploymentConfigPath").toString();

    if (!envConfigPath.isEmpty())
        setUserConfig(toLocalPath(envConfigPath));
    else if (!savedUserConfig.isEmpty())
        setUserConfig(toLocalPath(savedUserConfig));

    if (!savedDeploymentConfig.isEmpty())
        setDeploymentConfig(toLocalPath(savedDeploymentConfig));

    // Re-apply pre-.rep behavior: normalize file URLs, then persist (as master did in setters).
    connect(this, &BlockchainBackendSimpleSource::userConfigChanged, this, [this]() {
        const QString p = userConfig();
        const QString n = toLocalPath(p);
        if (n != p) {
            QSignalBlocker b(this);
            setUserConfig(n);
        }
        QSettings("Logos", "BlockchainUI")
            .setValue("userConfigPath", userConfig());
    });
    connect(this, &BlockchainBackendSimpleSource::deploymentConfigChanged, this, [this]() {
        const QString p = deploymentConfig();
        const QString n = toLocalPath(p);
        if (n != p) {
            QSignalBlocker b(this);
            setDeploymentConfig(n);
        }
        QSettings("Logos", "BlockchainUI")
            .setValue("deploymentConfigPath", deploymentConfig());
    });

    if (!m_logosAPI) {
        qWarning() << "BlockchainBackend: constructed without LogosAPI";
        return;
    }

    m_blockchainClient = m_logosAPI->getClient(BLOCKCHAIN_MODULE_NAME);
    if (!m_blockchainClient) {
        setError(QStringLiteral("Module not initialized"));
        qWarning() << "BlockchainBackend: failed to get blockchain module client";
        return;
    }

    LogosObject* replica =
        m_blockchainClient->requestObject(BLOCKCHAIN_MODULE_NAME);
    if (replica) {
        m_blockchainClient->onEvent(
            replica, "newBlock",
            [this](const QString&, const QVariantList& data) {
                const QString timestamp =
                    QDateTime::currentDateTime().toString("HH:mm:ss");
                QString line;
                if (!data.isEmpty())
                    line = QString("[%1] New block: %2")
                               .arg(timestamp, data.first().toString());
                else
                    line = QString("[%1] New block (no data)").arg(timestamp);
                m_logModel->append(line);
            });
    } else {
        setError(QStringLiteral("Failed to subscribe to events"));
    }

    qDebug() << "BlockchainBackend: initialized";
}

BlockchainBackend::~BlockchainBackend()
{
    if (status() == Running || status() == Starting)
        stopBlockchain();
}

QString BlockchainBackend::claimLeaderRewards()
{
    if (!m_blockchainClient)
        return QStringLiteral("Error: Module not initialized.");

    return toDisplayMessage(toLogosResult(m_blockchainClient->invokeRemoteMethod(
        BLOCKCHAIN_MODULE_NAME, "leader_claim")));
}

void BlockchainBackend::startBlockchain()
{
    if (!m_blockchainClient) {
        setError(QStringLiteral("Module not initialized"));
        return;
    }

    setStatus(Starting);

    const LogosResult result = toLogosResult(m_blockchainClient->invokeRemoteMethod(
        BLOCKCHAIN_MODULE_NAME, "start", userConfig(), deploymentConfig()));

    if (result.success) {
        setStatus(Running);
        QTimer::singleShot(500, this, [this]() { refreshAccounts(); });
    } else {
        setError(result.error.toString());
    }
}

void BlockchainBackend::stopBlockchain()
{
    if (status() != Running && status() != Starting)
        return;

    if (!m_blockchainClient) {
        setError(QStringLiteral("Module not initialized"));
        return;
    }

    setStatus(Stopping);

    const LogosResult result = toLogosResult(m_blockchainClient->invokeRemoteMethod(
        BLOCKCHAIN_MODULE_NAME, "stop"));

    if (result.success) {
        setStatus(Stopped);
    } else {
        setError(result.error.toString());
    }
}

void BlockchainBackend::refreshAccounts()
{
    if (!m_blockchainClient) return;

    const LogosResult result = toLogosResult(m_blockchainClient->invokeRemoteMethod(
        BLOCKCHAIN_MODULE_NAME, "wallet_get_known_addresses"));

    if (!result.success) {
        qWarning() << "refreshAccounts: failed:" << result.error.toString();
        return;
    }

    // The SDK marshals the JSON array into a QVariantList; rely on toList()
    // rather than canConvert<QStringList>() (which is unreliable for a
    // QVariantList under Qt6), and fall back to toStringList() for the rare
    // case where the value already arrives as a QStringList.
    QStringList list;
    const QVariantList items = result.value.toList();
    if (!items.isEmpty()) {
        for (const QVariant& item : items) {
            const QString addr = item.toString();
            if (!addr.isEmpty())
                list << addr;
        }
    } else {
        list = result.value.toStringList();
    }

    qDebug() << "refreshAccounts: loaded" << list.size() << "addresses";

    m_accountsModel->setAddresses(list);

    QTimer::singleShot(0, this,
                       [this, list]() { fetchBalancesForAccounts(list); });
}

void BlockchainBackend::fetchBalancesForAccounts(const QStringList& list)
{
    if (!m_blockchainClient) return;
    for (const QString& address : list) {
        if (address.isEmpty()) continue;
        getBalance(address);
    }
}

QString BlockchainBackend::getBalance(QString addressHex)
{
    QString result;
    if (!m_blockchainClient) {
        result = QStringLiteral("Error: Module not initialized.");
    } else {
        result = toDisplayMessage(toLogosResult(m_blockchainClient->invokeRemoteMethod(
            BLOCKCHAIN_MODULE_NAME, "wallet_get_balance", addressHex)));
    }

    m_accountsModel->setBalanceForAddress(addressHex, result);
    return result;
}

QString BlockchainBackend::transferFunds(
    QString fromKeyHex, QString toKeyHex, QString amountStr)
{
    if (!m_blockchainClient)
        return QStringLiteral("Error: Module not initialized.");

    QStringList senders{fromKeyHex};
    return toDisplayMessage(toLogosResult(m_blockchainClient->invokeRemoteMethod(
        BLOCKCHAIN_MODULE_NAME, "wallet_transfer_funds",
        fromKeyHex, senders, toKeyHex, amountStr, QString())));
}

int BlockchainBackend::generateConfig(
    QString outputPath, QStringList initialPeers, int netPort, int blendPort,
    QString httpAddr, QString externalAddress, bool noPublicIpCheck,
    int deploymentMode, QString deploymentConfigPath, QString statePath)
{
    if (!m_blockchainClient)
        return -1;

    QVariantMap normalized;

    QString out = outputPath.trimmed();
    if (out.isEmpty())
        out = generatedUserConfigPath();
    else
        out = toLocalPath(out);
    normalized.insert("output", out);

    if (!initialPeers.isEmpty()) {
        QVariantList peersList;
        for (const QString& p : initialPeers) {
            if (!p.trimmed().isEmpty())
                peersList.append(p.trimmed());
        }
        if (!peersList.isEmpty())
            normalized.insert("initial_peers", peersList);
    }
    if (netPort > 0)
        normalized.insert("net_port", netPort);
    if (blendPort > 0)
        normalized.insert("blend_port", blendPort);
    if (!httpAddr.trimmed().isEmpty())
        normalized.insert("http_addr", httpAddr.trimmed());
    if (!externalAddress.trimmed().isEmpty())
        normalized.insert("external_address", externalAddress.trimmed());
    if (noPublicIpCheck)
        normalized.insert("no_public_ip_check", true);
    if (deploymentMode == 0) {
        QVariantMap deployment;
        deployment.insert("well_known_deployment", "devnet");
        normalized.insert("deployment", deployment);
    } else if (deploymentMode == 1
               && !deploymentConfigPath.trimmed().isEmpty()) {
        QVariantMap deployment;
        deployment.insert("config_path",
                          toLocalPath(deploymentConfigPath.trimmed()));
        normalized.insert("deployment", deployment);
    }
    if (!statePath.trimmed().isEmpty())
        normalized.insert("state_path", toLocalPath(statePath.trimmed()));

    const QJsonDocument doc = QJsonDocument::fromVariant(normalized);
    const QString jsonToSend =
        QString::fromUtf8(doc.toJson(QJsonDocument::Compact));

    const LogosResult result = toLogosResult(m_blockchainClient->invokeRemoteMethod(
        BLOCKCHAIN_MODULE_NAME, "generate_user_config", jsonToSend));

    return result.success ? 0 : -1;
}

QString BlockchainBackend::getNotes(QString walletAddressHex, QString optionalTipHex)
{
    if (!m_blockchainClient)
        return QStringLiteral("Error: Module not initialized.");

    return toDisplayMessage(toLogosResult(m_blockchainClient->invokeRemoteMethod(
        BLOCKCHAIN_MODULE_NAME, "wallet_get_notes",
        walletAddressHex, optionalTipHex)));
}

QString BlockchainBackend::channelDepositWithNotes(
    QString channelIdHex, QStringList inputNoteIdHexes, QString metadataBase58,
    QString changePublicKeyHex, QStringList fundingPublicKeyHexes,
    QString maxTxFee, QString optionalTipHex)
{
    if (!m_blockchainClient)
        return QStringLiteral("Error: Module not initialized.");

    // The metadata arrives base58-encoded; the module expects metadata_hex, so
    // decode to bytes and hex-encode. Empty stays empty (metadata is optional).
    QString metadataHex;
    if (!metadataBase58.trimmed().isEmpty()) {
        bool ok = false;
        const QByteArray bytes = decodeBase58(metadataBase58, &ok);
        if (!ok)
            return QStringLiteral("Error: Invalid base58 metadata.");
        metadataHex = QString::fromLatin1(bytes.toHex());
    }

    // 7 positional args exceed the variadic invokeRemoteMethod overloads
    // (max 5), so pass them through the QVariantList form.
    QVariantList args;
    args << channelIdHex << inputNoteIdHexes << metadataHex << changePublicKeyHex
         << fundingPublicKeyHexes << maxTxFee << optionalTipHex;

    return toDisplayMessage(toLogosResult(m_blockchainClient->invokeRemoteMethod(
        BLOCKCHAIN_MODULE_NAME, QStringLiteral("channel_deposit_with_notes"),
        args)));
}

void BlockchainBackend::clearLogs()
{
    m_logModel->clear();
}

void BlockchainBackend::copyToClipboard(QString text)
{
    // The backend runs in a non-GUI ViewModuleHost subprocess, where there is
    // no QGuiApplication and accessing the clipboard segfaults. Clipboard is
    // handled QML-side (see BlockchainView.copyText); guard here so any stray
    // call is a no-op rather than a crash.
    if (!qobject_cast<QGuiApplication*>(QCoreApplication::instance())) {
        qWarning() << "copyToClipboard: no GUI application; ignoring";
        return;
    }
    if (QClipboard* clipboard = QGuiApplication::clipboard())
        clipboard->setText(text);
}