/*
 * scribiu -- read notebooks and voice memos from Livescribe pens
 * Copyright (C) 2015 Javier S. Pedro <javier@javispedro.com>
 *
 * 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 <QtCore/QBuffer>
#include <QtCore/QScopedArrayPointer>
#include <QtCore/QThread>
#include <QtCore/QDebug>
#include <quazipfile.h>
#include <cstdio>
#include "paperreplay.h"
#include "notebookmodel.h"
#include "smartpensyncer.h"

#define BUFFER_SIZE 128 * 1024

namespace {
class LockFile
{
public:
	LockFile(const QString &path);
	~LockFile();

	bool lock();

private:
	QString _path;
	FILE * _file;
	bool _locked;
};

class TimestampFile
{
public:
	TimestampFile(const QString &path);

	Smartpen::PenTime get();
	void set(Smartpen::PenTime time);

private:
	QFile _f;
};

LockFile::LockFile(const QString &path)
    : _path(path), _file(0), _locked(false)
{

}

LockFile::~LockFile()
{
	if (_file) {
		fclose(_file);
	}
	if (_locked) {
		if (!QFile::remove(_path)) {
			qWarning() << "Cannot remove lock file:" << _path;
		}
	}
}

bool LockFile::lock()
{
	Q_ASSERT(!_locked);

	QFileInfo info(_path);
	if (info.exists()) {
		if (info.lastModified().secsTo(QDateTime::currentDateTime()) > 10 * 60) {
			if (QFile::remove(info.filePath())) {
				qDebug() << "Removing stale lock file:" << info.absoluteFilePath();
			}
		} else {
			return false;
		}
	}

	_file = ::fopen(info.absoluteFilePath().toLocal8Bit().data(), "wx");
	if (_file) {
		_locked = true;
		return true;
	} else {
		return false;
	}
}

TimestampFile::TimestampFile(const QString &path)
    : _f(path)
{
}

Smartpen::PenTime TimestampFile::get()
{
	if (_f.exists()) {
		if (_f.open(QIODevice::ReadOnly | QIODevice::Text)) {
			QString data = QString::fromUtf8(_f.readLine(32));
			_f.close();
			return data.toULongLong();
		} else {
			qWarning() << "Could not read timestamp file:" << _f.fileName();
		}
	}

	return 0;
}

void TimestampFile::set(Smartpen::PenTime time)
{
	if (_f.open(QIODevice::WriteOnly | QIODevice::Truncate)) {
		_f.write(QString::number(time).toUtf8());
		_f.close();
	} else {
		qWarning() << "Could not set timestamp file:" << _f.fileName();
		return;
	}
}
} /* anonymous namespace */

SmartpenSyncer::SmartpenSyncer(const Smartpen::Address &addr, QObject *parent) :
    QThread(parent),
    _addr(addr), _errored(false), _aborted(false),
    _pen(new Smartpen(this))
{
	connect(_pen, SIGNAL(linkError(QString)), SLOT(handleLinkError(QString)));
}

SmartpenSyncer::~SmartpenSyncer()
{
	if (isRunning()) {
		_aborted = true;
		wait();
	}
}

Smartpen::Address SmartpenSyncer::penAddress() const
{
	return _addr;
}

bool SmartpenSyncer::hasErrors() const
{
	return _errored;
}

void SmartpenSyncer::abort()
{
	_aborted = true;
}

void SmartpenSyncer::reset()
{
	_aborted = false;
	_errored = false;
}

void SmartpenSyncer::run()
{
	if (!_pen->connectToPen(_addr)) {
		qWarning() << "Could not connect to pen with USB address: " << _addr;
		_errored = true;
		return;
	}

	if (_aborted) {
		_pen->disconnectFromPen();
		return;
	}

	_penName = _pen->getPenName();
	qDebug() << "got pen name:" << _penName;

	if (_penName.isEmpty()) {
		_penName = _pen->getPenSerial();
		qDebug() << "pen with no name, using pen serial instead:" << _penName;
	}

	emit gotPenName(_penName);

	QVariantMap penInfo = _pen->getPenInfo();
	if (penInfo.isEmpty()) {
		qWarning() << "Could not get pen info";
		_errored = true;
		_pen->disconnectFromPen();
		return;
	}

	_penDataDir.setPath(NotebookModel::userDataDirectory() + "/" + _penName + ".pen");
	if (!_penDataDir.exists()) {
		if (!_penDataDir.mkpath(".")) {
			qWarning() << "Cannot create pen data directory:" << _penDataDir.absolutePath();
		}
	}

	if (!syncPen()) {
		_errored = true;
	}

	if (_errored) {
		qDebug() << "Sync finished with errors";
	} else {
		qDebug() << "Sync finished";
	}

	_pen->disconnectFromPen();
}

bool SmartpenSyncer::syncPen()
{
	LockFile lock(_penDataDir.filePath(".sync.lck"));
	if (!lock.lock()) {
		qWarning() << "Pen is already being synchronized; delete this file if it is not:" << _penDataDir.absoluteFilePath(".sync.lck");
		return false;
	}

	// Get the current user time offset from the pen
	// and store it so that we have it even when the pen is offline
	TimestampFile userTimeFile(_penDataDir.filePath(PEN_USER_TIME_FILE));
	Smartpen::PenTime userTime = _pen->getPenTime(Smartpen::Parameter::UserTime);
	userTimeFile.set(userTime);
	qDebug() << "pen time base:" << userTime << Smartpen::fromPenTime(userTime, 0);

	Smartpen::PenTime penTime = _pen->getPenTime(Smartpen::Parameter::RtcTime);
	qDebug() << "pen current time:" << penTime << Smartpen::fromPenTime(userTime, penTime);

	// Read when is the last time we synchronized with this pen (in PenTime, not user time)
	TimestampFile lastSyncFile(_penDataDir.filePath(PEN_LAST_SYNC_FILE));
	Smartpen::PenTime lastSync = lastSyncFile.get();
	if (lastSync != 0) lastSync += 1; // We want the changes _from_ the last sync

	// Ask the pen for all the changes which happened since the last sync time
	QList<Smartpen::ChangeReport> changes = _pen->getChangeList(lastSync);

	Smartpen::PenTime changesEndTime = 0;

	foreach(const Smartpen::ChangeReport &change, changes) {
		if (!change.guid.isEmpty()) {
			qDebug() << "Synchronizing guid: " << change.guid << change.title;
			if (!syncNotebook(lastSync, change)) {
				return false;
			}
		} else if (change.className == "com.livescribe.paperreplay.PaperReplay") {
			qDebug() << "Synchronizing paper replay";
			if (!syncPaperReplay(lastSync, change)) {
				return false;
			}
		} else {
			qWarning() << "Unknown change report";
			return false;
		}

		if (_aborted) {
			qWarning() << "Aborting sync";
			return false;
		}

		if (change.endTime > changesEndTime) {
			changesEndTime = change.endTime;
		}
	}

	if (changesEndTime > 0) {
		lastSyncFile.set(changesEndTime);
	}

	return true;
}

bool SmartpenSyncer::syncNotebook(Smartpen::PenTime lastSync, const Smartpen::ChangeReport &change)
{
	QDir notebookDir(_penDataDir.filePath(change.title + "." AFD_NOTEBOOK_EXTENSION));
	if (!notebookDir.exists()) {
		if (!notebookDir.mkpath(".")) {
			qWarning() << "Cannot create notebook data directory:" << notebookDir.absolutePath();
		}
	}

	LockFile lock(notebookDir.filePath(PEN_SYNC_LOCK_FILE));
	if (!lock.lock()) {
		qWarning() << "Notebook is already being synchronized; delete this file if it is not:" << notebookDir.absoluteFilePath(PEN_SYNC_LOCK_FILE);
		return false;
	}

	QByteArray lspData = _pen->getLspData(change.guid, lastSync);

	if (!extractZip(lspData, notebookDir)) {
		return false;
	}

	return true;
}

bool SmartpenSyncer::syncPaperReplay(Smartpen::PenTime lastSync, const Smartpen::ChangeReport &)
{
	QDir replayDir(_penDataDir.filePath(PAPER_REPLAY));
	if (!replayDir.exists()) {
		if (!replayDir.mkpath(".")) {
			qWarning() << "Cannot create PaperReplay data directory:" << replayDir.absolutePath();
		}
	}

	LockFile lock(replayDir.filePath(PEN_SYNC_LOCK_FILE));
	if (!lock.lock()) {
		qWarning() << "Paper replay is already being synchronized; delete this file if it is not:" << replayDir.absoluteFilePath(PEN_SYNC_LOCK_FILE);
		return false;
	}

	QByteArray replayData = _pen->getPaperReplay(lastSync);

	if (!extractZip(replayData, replayDir)) {
		return false;
	}

	return true;
}

bool SmartpenSyncer::extractZip(QByteArray &zipData, QDir &dir)
{
	QBuffer zipBuffer(&zipData);
	QuaZip zip(&zipBuffer);
	QuaZipFile zipFile(&zip);

	if (!zip.open(QuaZip::mdUnzip)) {
		qWarning() << "Could not open zip file";
		return false;
	}

	QByteArray buffer(BUFFER_SIZE, Qt::Uninitialized);

	for (bool more=zip.goToFirstFile(); more; more=zip.goToNextFile()) {
		QString zipName = zip.getCurrentFileName();
		if (!dir.absoluteFilePath(zipName).startsWith(dir.absolutePath())) {
			qWarning() << "broken zip filename:" << zipName;
			continue;
		}
		QFileInfo finfo(dir.filePath(zipName));
		if (!dir.mkpath(finfo.path())) {
			qWarning() << "cannot mkpath for:" << finfo.absoluteFilePath();
		}

		if (zipName.endsWith('/')) {
			// Nothing to do
			continue;
		}

		if (!zipFile.open(QIODevice::ReadOnly)) {
			qWarning() << "cannot open zip file for reading:" << zipName;
			continue;
		}

		QFile file(finfo.filePath());
		if (!file.open(QIODevice::WriteOnly | QIODevice::Truncate)) {
			qWarning() << "cannot open for writing:" << finfo.absoluteFilePath();
			zipFile.close();
			continue;
		}

		while (!zipFile.atEnd()) {
			qint64 read = zipFile.read(buffer.data(), buffer.size());
			if (read <= 0) {
				qWarning() << "short read on:" << zipName;
				zipFile.close();
				continue;
			}
			qint64 written = file.write(buffer.data(), read);
			if (written != read) {
				qWarning() << "short write on:" << file.fileName();
				zipFile.close();
				continue;
			}
		}

		file.close();
		zipFile.close();
	}

	if (zip.getZipError() == UNZ_OK) {
		return true;
	} else {
		qWarning() << "Error while decompressing";
		return false;
	}
}

void SmartpenSyncer::handleLinkError(const QString &msg)
{
	qWarning() << "link error:" << msg;
	_errored = true;
}