#include "qlogmanager.h"
#include <QTextStream>
#include <QCoreApplication>
QBasicAtomicPointer<QLogManager> QLogManager::s_instance = Q_BASIC_ATOMIC_INITIALIZER(0);
QMutex QLogManager::s_mutex;
QLogManager::QLogManager(QObject* parent)
	: QObject(parent),
	m_minLevel(SQ_INFO),
	m_workerThread(nullptr),
	m_running(true)
{
	m_logDirectory = QDir(QCoreApplication::applicationDirPath() + "/logs/");
	if (!m_logDirectory.exists()) {
		if (!m_logDirectory.mkpath(".")) {
			emit newLog(SQ_ERROR, QString("Failed to create log directory: %1").arg(m_logDirectory.path()));
		}
	}
	cleanOldLogs();
	m_workerThread = new QThread();
	QObject::connect(m_workerThread, &QThread::started, [this]() {
		this->processLogs();
	});
	m_workerThread->start();
}
QLogManager::~QLogManager()
{
	m_running = false;
	m_queueSemaphore.release(); 
	if (m_workerThread) {
		m_workerThread->quit();
		if (!m_workerThread->wait(3000)) { 
			m_workerThread->terminate();
			m_workerThread->wait();
		}
		delete m_workerThread;
	}
	LogEntry entry;
	while (m_logQueue.dequeue(entry)) {
		writeToFile(entry.level, entry.message);
	}
	for (auto& file : m_openFiles) {
		if (!file.isNull()) {
			file->close();
		}
	}
}
QLogManager* QLogManager::Instance()
{
	if (!s_instance.load()) {
		QMutexLocker locker(&s_mutex);
		if (!s_instance.load()) {
			QLogManager* instance = new QLogManager();
			s_instance.store(instance);
			qAddPostRoutine(QLogManager::destroyInstance);
		}
	}
	return s_instance.load();
}
void QLogManager::destroyInstance()
{
	QMutexLocker locker(&s_mutex);
	QLogManager* instance = s_instance.load();
	if (instance) {
		delete instance;
		s_instance.store(nullptr);
	}
}
void QLogManager::setLogLevel(LogLevel level)
{
	QMutexLocker locker(&s_mutex);
	m_minLevel = level;
}
void QLogManager::log(LogLevel level, const QString& message, const QString& module)
{
	if (level < m_minLevel) {
		return;
	}
	static thread_local QString lastTimeStr;
	static thread_local qint64 lastTimeMs = 0;
	qint64 now = QDateTime::currentMSecsSinceEpoch();
	if (now - lastTimeMs > TIMESTAMP_CACHE_DURATION_MS) {
		lastTimeStr = QDateTime::currentDateTime().toString("yyyy-MM-dd hh:mm:ss.zzz");
		lastTimeMs = now;
	}
	QString levelStr;
	switch (level) {
	case SQ_DEBUG:    levelStr = "DEBUG";    break;
	case SQ_INFO:     levelStr = "INFO";     break;
	case SQ_WARNING:  levelStr = "WARNING";  break;
	case SQ_ERROR:    levelStr = "ERROR";    break;
	case SQ_FATAL:    levelStr = "FATAL";    break;
	}
	QString logLine = QString("[%1][%2][%3] %4")
		.arg(lastTimeStr, levelStr, module, message);
	emit newLog(level, logLine);
	LogEntry entry;
	entry.level = level;
	entry.message = logLine;
	entry.timestamp = now;
	m_logQueue.enqueue(entry);
	m_queueSemaphore.release(); 
}
void QLogManager::processLogs()
{
	while (m_running) {
		m_queueSemaphore.acquire();
		LogEntry entry;
		while (m_logQueue.dequeue(entry)) {
			writeToFile(entry.level, entry.message);
			if (!m_running) {
				break;
			}
		}
	}
}
QString QLogManager::getLogFileName(LogLevel level)
{
	QString levelStr;
	switch (level) {
	case SQ_DEBUG:    levelStr = "debug";    break;
	case SQ_INFO:     levelStr = "info";     break;
	case SQ_WARNING:  levelStr = "warning";  break;
	case SQ_ERROR:    levelStr = "error";    break;
	case SQ_FATAL:    levelStr = "fatal";    break;
	default:          levelStr = "system";   break;
	}
	return QString("%1_%2.log")
		.arg(levelStr)
		.arg(QDateTime::currentDateTime().toString("yyyyMMdd"));
}
void QLogManager::writeToFile(LogLevel level, const QString& logLine)
{
	try {
		if (!m_openFiles.contains(level)) {
			QString fileName = m_logDirectory.filePath(getLogFileName(level));
			QSharedPointer<QFile> file(new QFile(fileName));
			if (!file->open(QIODevice::WriteOnly | QIODevice::Append)) {
				emit newLog(SQ_ERROR, QString("[LogSystem] Failed to open log file: %1").arg(fileName));
				return;
			}
			m_openFiles[level] = file;
		}
		if (!m_openFiles[level].isNull()) {
			QTextStream stream(m_openFiles[level].data());
			stream << logLine << "\n";
			stream.flush();
			if (m_openFiles[level]->size() > MAX_FILE_SIZE) {
				rotateLogFile(level);
			}
		}
	}
	catch (...) {
		emit newLog(SQ_ERROR, "[LogSystem] Exception occurred while writing log");
	}
}
void QLogManager::rotateLogFile(LogLevel level)
{
	if (!m_openFiles.contains(level)) {
		return;
	}
	try {
		m_openFiles[level]->close();
		QString oldName = m_logDirectory.filePath(getLogFileName(level));
		QString newName = oldName + "." + QDateTime::currentDateTime().toString("hhmmsszzz");
		if (!QFile::rename(oldName, newName)) {
			emit newLog(SQ_ERROR, QString("[LogSystem] Failed to rotate log file from %1 to %2")
				.arg(oldName, newName));
		}
		m_openFiles.remove(level);
	}
	catch (...) {
		emit newLog(SQ_ERROR, "[LogSystem] Exception occurred while rotating log file");
	}
}
void QLogManager::cleanOldLogs()
{
	try {
		QStringList logFiles = m_logDirectory.entryList(QStringList() << "*.log" << "*.log.*", QDir::Files);
		QDateTime now = QDateTime::currentDateTime();
		for (const QString& fileName : logFiles) {
			QFileInfo fileInfo(m_logDirectory.filePath(fileName));
			if (fileInfo.lastModified().daysTo(now) > MAX_LOG_DAYS) {
				if (!QFile::remove(fileInfo.absoluteFilePath())) {
					emit newLog(SQ_WARNING, QString("Failed to remove old log file: %1")
						.arg(fileInfo.absoluteFilePath()));
				}
			}
		}
	}
	catch (...) {
		emit newLog(SQ_ERROR, "[LogSystem] Exception occurred while cleaning old logs");
	}
}
void QLogManager::flush()
{
	QMutexLocker locker(&s_mutex);
	for (auto& file : m_openFiles) {
		if (!file.isNull()) {
			file->flush();
		}
	}
}