#include "PerformanceLogger.h"

PerformanceLogger &PerformanceLogger::instance()
{
    static PerformanceLogger logger;
    return logger;
}

void PerformanceLogger::beginSession(const QString &sessionName)
{
    QMutexLocker locker(&m_mutex);
    m_sessionName = sessionName;
    m_sessionActive = true;
}

void PerformanceLogger::endSession()
{
    QMutexLocker locker(&m_mutex);
    m_sessionActive = false;
}

void PerformanceLogger::log(const QString &category, const QString &name, qint64 elapsedMs)
{
    QMutexLocker locker(&m_mutex);
    Record rec;
    rec.category = category;
    rec.name = name;
    rec.elapsedMs = elapsedMs;
    rec.timestamp = QDateTime::currentDateTime();
    m_records.append(rec);
}

QVector<PerformanceLogger::Record> PerformanceLogger::records() const
{
    QMutexLocker locker(&m_mutex);
    return m_records;
}

void PerformanceLogger::clear()
{
    QMutexLocker locker(&m_mutex);
    m_records.clear();
}

QString PerformanceLogger::reportString() const
{
    QMutexLocker locker(&m_mutex);
    QString report;
    QTextStream ts(&report);

    ts << "==================================================\n";
    ts << "Performance Report";
    if (!m_sessionName.isEmpty())
        ts << " - " << m_sessionName;
    ts << "\n";
    ts << "Generated: " << QDateTime::currentDateTime().toString("yyyy-MM-dd hh:mm:ss") << "\n";
    ts << "==================================================\n";

    if (m_records.isEmpty()) {
        ts << "No records.\n";
        return report;
    }

    // Group by category
    QString currentCategory;
    qint64 categoryTotal = 0;
    for (const auto &rec : m_records) {
        if (rec.category != currentCategory) {
            if (!currentCategory.isEmpty()) {
                ts << "  [Category Total: " << categoryTotal << " ms]\n\n";
            }
            currentCategory = rec.category;
            categoryTotal = 0;
            ts << "[" << currentCategory << "]\n";
        }
        ts << "  " << rec.name << ": " << rec.elapsedMs << " ms\n";
        categoryTotal += rec.elapsedMs;
    }
    if (!currentCategory.isEmpty()) {
        ts << "  [Category Total: " << categoryTotal << " ms]\n";
    }

    ts << "\n==================================================\n";
    ts << "Grand Total: ";
    qint64 grandTotal = 0;
    for (const auto &rec : m_records)
        grandTotal += rec.elapsedMs;
    ts << grandTotal << " ms\n";
    ts << "==================================================\n";

    return report;
}

void PerformanceLogger::printReport() const
{
    const QString report = reportString();
    qDebug().noquote() << report;
}

void PerformanceLogger::saveToFile(const QString &filePath) const
{
    QFile file(filePath);
    if (!file.open(QIODevice::WriteOnly | QIODevice::Text | QIODevice::Append)) {
        qDebug() << "PerformanceLogger: failed to open" << filePath;
        return;
    }
    QTextStream ts(&file);
    ts << reportString();
    file.close();
}

ScopedPerfTimer::ScopedPerfTimer(const QString &category, const QString &name)
    : m_category(category), m_name(name)
{
    m_timer.start();
}

ScopedPerfTimer::~ScopedPerfTimer()
{
    const qint64 elapsed = m_timer.elapsed();
    PerformanceLogger::instance().log(m_category, m_name, elapsed);
}