/*
 * 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/QDateTime>
#include <QtCore/QDebug>
#include <QtCore/QStringList>
#include <QtCore/QtEndian>
#include <usb.h>
#include "xmlutils.h"
#include "smartpen.h"

#define PEN_EPOCH (1289335960000LL) // This is probably not correct
#define PEN_MTU 900
#define PEN_TIMEOUT_SECONDS 30

#define INVALID_CID 0xFFFFFFFFU

static const char pen_serial_chars[] = "ABCDEFGHJKMNPQRSTUWXYZ23456789";
static const unsigned int pen_serial_num_chars = sizeof(pen_serial_chars) - 1;

/* Terrible hack comes now: */
struct obex_usb_intf_transport_t {
	struct obex_usb_intf_transport_t *prev, *next;	/* Next and previous interfaces in the list */
	struct usb_device *device;		/* USB device that has the interface */
};

Smartpen::Smartpen(QObject *parent) :
    QObject(parent), _obex(0), _connId(INVALID_CID)
{
}

Smartpen::~Smartpen()
{
	if (_connId != INVALID_CID || _obex) {
		disconnectFromPen();
	}
}

bool Smartpen::isConnected() const
{
	return _obex && _connId != INVALID_CID;
}

QByteArray Smartpen::getObject(const QString &name)
{
	obex_object_t *obj = OBEX_ObjectNew(_obex, OBEX_CMD_GET);
	Q_ASSERT(obj);

	addConnHeader(obj);

	obex_headerdata_t hd;
	QByteArray encodedName = encodeUtf16(name);
	hd.bs = reinterpret_cast<const uint8_t*>(encodedName.constData());
	if (OBEX_ObjectAddHeader(_obex, obj, OBEX_HDR_NAME, hd, encodedName.size(), 0) < 0) {
		qCritical("Could not add name header");
		OBEX_ObjectDelete(_obex, obj);
		return QByteArray();
	}

	qDebug() << "Getting object" << name;

	if (OBEX_Request(_obex, obj) < 0) {
		qWarning() << "Get object request failed";
		return QByteArray();
	}

	QDateTime start = QDateTime::currentDateTimeUtc();
	QDateTime now;
	do {
		OBEX_HandleInput(_obex, PEN_TIMEOUT_SECONDS);
		now = QDateTime::currentDateTimeUtc();
	} while (_inBuf.isEmpty() && start.secsTo(now) < PEN_TIMEOUT_SECONDS);

	if (_inBuf.isEmpty()) {
		qWarning() << "Did not receive any data in" << start.secsTo(now) << "seconds";
	}

	QByteArray result;
	qSwap(_inBuf, result);

	return result;
}

QString Smartpen::getParameter(Parameters parameter)
{
	QString objectName = QString("ppdata?key=pp%1").arg(int(parameter), 4);
	QByteArray data = getObject(objectName);
	QXmlStreamReader r(data);

	advanceToFirstChildElement(r, "xml");
	advanceToFirstChildElement(r, "parameter");

	if (!r.atEnd()) {
		QXmlStreamAttributes attrs = r.attributes();
		return attrs.value("value").toString();
	}

	return QString();
}

QString Smartpen::getPenName()
{
	QString name = getParameter(PenName);
	if (name.isEmpty()) {
		return name;
	}

	QByteArray hex = QByteArray::fromHex(name.mid(2).toLatin1());
	return QString::fromUtf8(hex);
}

QVariantMap Smartpen::getPenInfo()
{
	QVariantMap result;
	QByteArray data = getObject("peninfo");
	QXmlStreamReader r(data);

	advanceToFirstChildElement(r, "xml");
	advanceToFirstChildElement(r, "peninfo");

	if (!r.atEnd()) {
		Q_ASSERT(r.isStartElement() && r.name() == "peninfo");
		QString penId = r.attributes().value("penid").toString();
		result["penid"] = penId;
		result["penserial"] = toPenSerial(penId.mid(2).toULongLong(0, 16));

		while (r.readNextStartElement()) {
			if (r.name() == "battery") {
				result["battery"] = r.attributes().value("level").toString();
				r.skipCurrentElement();
			} else if (r.name() == "time") {
				result["time"] = r.attributes().value("absolute").toString();
				r.skipCurrentElement();
			} else {
				r.skipCurrentElement();
			}
		}
	} else {
		qWarning() << "Could not parse peninfo XML";
	}

	return result;
}

QList<Smartpen::ChangeReport> Smartpen::getChangeList(PenTime from)
{
	QList<ChangeReport> result;
	QByteArray data = getObject(QString("changelist?start_time=%1").arg(from));
	QXmlStreamReader r(data);

	qDebug() << QString::fromAscii(data);

	advanceToFirstChildElement(r, "xml");
	advanceToFirstChildElement(r, "changelist");

	if (!r.atEnd()) {
		Q_ASSERT(r.isStartElement() && r.name() == "changelist");

		while (r.readNextStartElement()) {
			if (r.name() == "lsp") {
				QXmlStreamAttributes attrs = r.attributes();
				ChangeReport report;
				if (attrs.hasAttribute("guid")) {
					report.guid = attrs.value("guid").toString();
					report.title = attrs.value("title").toString();

					// Figure out the change record endtime to enumerating the
					// endtime of all the record's changed pages
					report.endTime = 0;
					while (r.readNextStartElement()) {
						if (r.name() == "page") {
							QXmlStreamAttributes attrs = r.attributes();
							PenTime endTime = attrs.value("end_time").toString().toLongLong();
							if (endTime > report.endTime) report.endTime = endTime;
						}
						r.skipCurrentElement();
					}

					result.append(report);
				} else if (attrs.hasAttribute("classname")) {
					report.className = attrs.value("classname").toString();
					report.title = attrs.value("title").toString();
					report.endTime = attrs.value("end_time").toString().toLongLong();
					result.append(report);
					r.skipCurrentElement();
				} else {
					qWarning() << "Unknown change report format";
					r.skipCurrentElement();
				}
			} else {
				r.skipCurrentElement();
			}
		}

	} else {
		qWarning() << "Could not parse changelist XML";
	}

	return result;
}

QByteArray Smartpen::getLspData(const QString &name, PenTime from)
{
	return getObject(QString("lspdata?name=%1&start_time=%2").arg(name).arg(from));
}

QByteArray Smartpen::getPaperReplay(PenTime from)
{
	return getObject(QString("lspdata?name=com.livescribe.paperreplay.PaperReplay&start_time=%1&returnVersion=0.3&remoteCaller=WIN_LD_200").arg(from));
}

qint64 Smartpen::toPenTime(const QDateTime &dt)
{
	if (dt.isValid()) {
		return dt.toMSecsSinceEpoch() - PEN_EPOCH;
	} else {
		return 0;
	}
}

QDateTime Smartpen::fromPenTime(qint64 t)
{
	if (t) {
		return QDateTime::fromMSecsSinceEpoch(t + PEN_EPOCH).toLocalTime();
	} else {
		return QDateTime();
	}
}

QString Smartpen::toPenSerial(quint64 id)
{
	QString serial;
	serial.reserve(3 + 1 + 3 + 1 + 3 + 1 + 2 + 1);

	serial.append(toPenSerialSegment(id >> 32, 3));
	serial.append('-');
	serial.append(toPenSerialSegment(id, 6).mid(0, 3));
	serial.append('-');
	serial.append(toPenSerialSegment(id, 6).mid(3, 3));
	serial.append('-');
	serial.append(toPenSerialSegment(id % 0x36D, 2));

	return serial;
}

quint64 Smartpen::toPenId(const QString &serial)
{
	QStringList segments = serial.split('-');
	if (segments.size() != 4) {
		return 0;
	}

	quint64 id = quint64(fromPenSerialSegment(segments[0])) << 32;
	id |= fromPenSerialSegment(segments[1] + segments[2]) * 0x36D;
	id |= fromPenSerialSegment(segments[3]);
	return id;
}

bool Smartpen::connectToPen(const Address &addr)
{
	if (_obex) {
		qWarning() << "Already connected";
		return false;
	}

	_obex = OBEX_Init(OBEX_TRANS_USB, obexEventCb, 0);
	Q_ASSERT(_obex);

	OBEX_SetUserData(_obex, this);
	OBEX_SetTransportMTU(_obex, PEN_MTU, PEN_MTU);

	obex_interface_t *interfaces, *ls_interface = 0;
	int count = OBEX_FindInterfaces(_obex, &interfaces);
	for (int i = 0; i < count; i++) {
		if (interfaces[i].usb.intf->device->bus->location == addr.first &&
		        interfaces[i].usb.intf->device->devnum == addr.second) {
			ls_interface = &interfaces[i];
		}
	}

	if (!ls_interface) {
		qWarning() << "Could not find Lightscribe interface on device:" << addr;
		return false;
	}

	usb_dev_handle *handle = usb_open(ls_interface->usb.intf->device);
	if (handle) {
		qDebug() << "resetting usb device";
		usb_reset(handle);
		usb_close(handle);
	} else {
		qWarning() << "could not open usb device for resetting";
	}

	qDebug() << "connecting to" << ls_interface->usb.product;

	if (OBEX_InterfaceConnect(_obex, ls_interface) < 0) {
		qWarning() << "Could not connect to Livescribe interface";
		return false;
	}

	static const char * livescribe_service = "LivescribeService";
	obex_object_t *object = OBEX_ObjectNew(_obex, OBEX_CMD_CONNECT);
	obex_headerdata_t hd;
	int hd_len;

	Q_ASSERT(object);

	hd.bs = reinterpret_cast<const quint8*>(livescribe_service);
	hd_len = strlen(livescribe_service) + 1;
	if (OBEX_ObjectAddHeader(_obex, object, OBEX_HDR_TARGET, hd, hd_len, 0) < 0) {
		qWarning() << "Failed to add Target header";
		OBEX_ObjectDelete(_obex, object);
		return false;
	}

	if (OBEX_Request(_obex, object) < 0) {
		qWarning() << "Failed to make connection request";
		OBEX_ObjectDelete(_obex, object);
		return false;
	}

	qDebug() << "Connection in progress";

	OBEX_HandleInput(_obex, PEN_TIMEOUT_SECONDS);

	return _connId != INVALID_CID;
}

void Smartpen::disconnectFromPen()
{
	if (_connId != INVALID_CID) {
		if (_obex) {
			obex_object_t *object = OBEX_ObjectNew(_obex, OBEX_CMD_DISCONNECT);
			Q_ASSERT(object);
			addConnHeader(object);
			OBEX_Request(_obex, object);
			OBEX_HandleInput(_obex, PEN_TIMEOUT_SECONDS);
		}
		_connId = INVALID_CID;
	}
	if (_obex) {
		OBEX_Cleanup(_obex);
		_obex = 0;
	}
	_inBuf.clear();
}

void Smartpen::obexEventCb(obex_t *handle, obex_object_t *obj,
                           int mode, int event, int obex_cmd, int obex_rsp)
{
	Smartpen *smartpen = static_cast<Smartpen*>(OBEX_GetUserData(handle));
	Q_UNUSED(mode);
	smartpen->handleObexEvent(obj, event, obex_cmd, obex_rsp);
}

void Smartpen::handleObexEvent(obex_object_t *object,
                               int event, int obex_cmd, int obex_rsp)
{

	switch (event) {
	case OBEX_EV_PROGRESS:
		if (obex_cmd == OBEX_CMD_GET) {
			// It seems that the pen wants us to add this header on every continue response
			addConnHeader(object);
		}
		break;
	case OBEX_EV_REQDONE:
		qDebug() << "event reqdone cmd=" << obex_cmd << " rsp=" << OBEX_ResponseToString(obex_rsp);
		handleObexRequestDone(object, obex_cmd, obex_rsp);
		break;
	case OBEX_EV_LINKERR:
		qWarning() << "link error cmd=" << obex_cmd;
		emit error();
		break;
	default:
		qDebug() << "event" << event << obex_cmd << obex_rsp;
		break;
	}
}

void Smartpen::handleObexRequestDone(obex_object_t *object, int obex_cmd, int obex_rsp)
{
	quint8 header_id;
	obex_headerdata_t hdata;
	quint32 hlen;

	switch (obex_cmd & ~OBEX_FINAL) {
	case OBEX_CMD_CONNECT:
		switch (obex_rsp) {
		case OBEX_RSP_SUCCESS:
			while (OBEX_ObjectGetNextHeader(_obex, object, &header_id, &hdata, &hlen)) {
				if (header_id == OBEX_HDR_CONNECTION) {
					Q_ASSERT(_connId == INVALID_CID);
					_connId = hdata.bq4;
					qDebug() << "Connection established, id:" << _connId;
				}
			}
			break;
		default:
			qWarning() << "Failed connection request:" << OBEX_ResponseToString(obex_rsp);
			emit error();
			break;
		}
		break;
	case OBEX_CMD_DISCONNECT:
		switch (obex_rsp) {
		case OBEX_RSP_SUCCESS:
			qDebug() << "Disconnected succesfully";
			_connId = INVALID_CID;
			break;
		default:
			qWarning() << "Failed disconnection request:" << OBEX_ResponseToString(obex_rsp);
			_connId = INVALID_CID;
			break;
		}

		break;
	case OBEX_CMD_GET:
		switch (obex_rsp) {
		case OBEX_RSP_SUCCESS:
			qDebug() << "GET request succesful";
			while (OBEX_ObjectGetNextHeader(_obex, object, &header_id, &hdata, &hlen)) {
				if (header_id == OBEX_HDR_BODY || header_id == OBEX_HDR_BODY_END) {
					_inBuf = QByteArray(reinterpret_cast<const char*>(hdata.bs), hlen);
				}
			}
			break;
		default:
			qWarning() << "Failed GET request:" << OBEX_ResponseToString(obex_rsp);
			break;
		}

		break;
	}
}

QString Smartpen::toPenSerialSegment(quint32 id, int len)
{

	QString segment(len, Qt::Uninitialized);

	for (int i = 0; i < len; i++) {
		segment[len - (i + 1)] = pen_serial_chars[id % pen_serial_num_chars];
		id /= pen_serial_num_chars;
	}

	return segment;
}

quint32 Smartpen::fromPenSerialSegment(const QString &s)
{
	const int len = s.length();
	quint32 id = 0;

	for (int i = 0; i < len; i++) {
		uint val = qFind(&pen_serial_chars[0], &pen_serial_chars[pen_serial_num_chars], s[i]) - &pen_serial_chars[0];
		if (val >= pen_serial_num_chars) return 0;
		id = val + id * pen_serial_num_chars;
	}

	return id;
}

QByteArray Smartpen::encodeUtf16(const QString &s)
{
	const int size = s.size();
	QByteArray data((size + 1) * sizeof(quint16), Qt::Uninitialized);
	quint16 *p = reinterpret_cast<quint16*>(data.data());
	for (int i = 0; i < size; i++) {
		p[i] = qToBigEndian(s.at(i).unicode());
	}
	p[size] = 0;
	return data;
}

void Smartpen::addConnHeader(obex_object_t *obj) const
{
	obex_headerdata_t hd;
	hd.bq4 = _connId;
	if (OBEX_ObjectAddHeader(_obex, obj, OBEX_HDR_CONNECTION, hd, sizeof(hd.bq4), 0) < 0) {
		qCritical() << "Could not add connection header";
	}
}