#include "LocalStateHelper.h"
#include "ConfigHelper.h"
#include <QDir>
#include <QFile>
#include <QJsonDocument>

LocalStateHelper::LocalStateHelper(const QString& baseDir)
    : m_baseDir(baseDir)
    , m_filePath(ConfigHelper::instance().localStatePath())
{
}

bool LocalStateHelper::loadState(const QString& relativePath)
{
    const QString defaultState = QStringLiteral("config/local_state.json");
    if (relativePath == defaultState)
        m_filePath = ConfigHelper::instance().localStatePath();
    else if (QDir::isAbsolutePath(relativePath))
        m_filePath = relativePath;
    else
        m_filePath = m_baseDir + "/" + relativePath;
    QFile file(m_filePath);
    if (!file.exists())
    {
        m_state = QJsonObject{
            {"max_policy_seq", 0},
            {"last_success_run_at", QString()},
            {"last_online_verified_at", QString()},
            {"last_success_version", QString()}
        };
        m_loaded = true;
        if (!saveState())
        {
            m_error = QString("Cannot write new state file: %1").arg(m_filePath);
            return false;
        }
        return true;
    }

    if (!file.open(QIODevice::ReadOnly))
    {
        m_error = QString("Cannot open state file: %1").arg(m_filePath);
        return false;
    }

    QByteArray raw = file.readAll();
    file.close();

    QJsonParseError parseError;
    QJsonDocument doc = QJsonDocument::fromJson(raw, &parseError);
    if (parseError.error != QJsonParseError::NoError || !doc.isObject())
    {
        m_error = QString("Invalid state JSON: %1").arg(parseError.errorString());
        return false;
    }

    m_state = doc.object();
    m_loaded = true;
    return true;
}

bool LocalStateHelper::saveState() const
{
    if (!m_loaded)
    {
        m_error = "State is not loaded";
        return false;
    }

    QJsonDocument doc(m_state);
    QString writeError;
    if (!ConfigHelper::writeFileWithElevationIfNeeded(m_filePath, doc.toJson(QJsonDocument::Indented), &writeError))
    {
        m_error = QString("Cannot save state file: %1").arg(writeError);
        return false;
    }
    m_error.clear();
    return true;
}

bool LocalStateHelper::isLoaded() const
{
    return m_loaded;
}

QString LocalStateHelper::errorString() const
{
    return m_error;
}

qint64 LocalStateHelper::maxPolicySeq() const
{
    return m_state.value("max_policy_seq").toVariant().toLongLong();
}

QDateTime LocalStateHelper::lastSuccessRunAt() const
{
    return QDateTime::fromString(m_state.value("last_success_run_at").toString(), Qt::ISODate);
}

QDateTime LocalStateHelper::lastOnlineVerifiedAt() const
{
    return QDateTime::fromString(m_state.value("last_online_verified_at").toString(), Qt::ISODate);
}

QString LocalStateHelper::lastSuccessVersion() const
{
    return m_state.value("last_success_version").toString();
}

bool LocalStateHelper::isPolicySeqRolledBack(qint64 policySeq) const
{
    if (!m_loaded)
        return false;
    return policySeq < maxPolicySeq();
}

bool LocalStateHelper::isSystemTimeRewound() const
{
    if (!m_loaded)
        return false;
    const QDateTime now = QDateTime::currentDateTimeUtc();
    const QDateTime lastRun = lastSuccessRunAt();
    const QDateTime lastOnline = lastOnlineVerifiedAt();
    return (lastRun.isValid() && now < lastRun)
        || (lastOnline.isValid() && now < lastOnline);
}

void LocalStateHelper::updateAfterSuccessfulRun(const QString& currentVersion, qint64 policySeq)
{
    if (!m_loaded)
        m_loaded = true;

    m_state["last_success_run_at"] = QDateTime::currentDateTimeUtc().toString(Qt::ISODate);
    m_state["last_success_version"] = currentVersion;
    if (policySeq > maxPolicySeq())
        m_state["max_policy_seq"] = policySeq;
}

void LocalStateHelper::updateOnlineVerified(qint64 policySeq)
{
    if (!m_loaded)
        m_loaded = true;

    m_state["last_online_verified_at"] = QDateTime::currentDateTimeUtc().toString(Qt::ISODate);
    if (policySeq > maxPolicySeq())
        m_state["max_policy_seq"] = policySeq;
}