// SPDX-License-Identifier: GPL-2.0
#include <errno.h>

#include <QtBluetooth/QBluetoothAddress>
#include <QtBluetooth/QBluetoothSocket>
#include <QEventLoop>
#include <QTimer>
#include <QDebug>

#include <libdivecomputer/version.h>
#include <libdivecomputer/context.h>

#if defined(SSRF_CUSTOM_IO)

#if defined(Q_OS_WIN)
	#include <winsock2.h>
	#include <windows.h>
	#include <ws2bth.h>
#endif

#include <libdivecomputer/custom_io.h>

#ifdef BLE_SUPPORT
# include "qt-ble.h"
#endif

QList<QBluetoothUuid> registeredUuids;

void addBtUuid(QBluetoothUuid uuid)
{
	registeredUuids << uuid;
}

extern "C" {
typedef struct qt_serial_t {
	/*
	 * RFCOMM socket used for Bluetooth Serial communication.
	 */
#if defined(Q_OS_WIN)
	SOCKET socket;
#else
	QBluetoothSocket *socket;
#endif
	long timeout;
} qt_serial_t;

#ifdef BLE_SUPPORT

static dc_status_t ble_serial_open(dc_custom_io_t *io, dc_context_t *, const char* devaddr);
static dc_status_t ble_serial_close(dc_custom_io_t *io);
static dc_status_t ble_serial_read(dc_custom_io_t *io, void* data, size_t size, size_t *actual);
static dc_status_t ble_serial_write(dc_custom_io_t *io, const void* data, size_t size, size_t *actual);
static dc_status_t ble_serial_purge(dc_custom_io_t *io, dc_direction_t queue);
static dc_status_t ble_serial_get_available(dc_custom_io_t *io, size_t *available);
static dc_status_t ble_serial_set_timeout(dc_custom_io_t *io, long timeout);

static dc_custom_io_t ble_serial_ops = {
	.userdata = NULL,
	.user_device = NULL,

	.serial_open = ble_serial_open,
	.serial_close = ble_serial_close,
	.serial_read = ble_serial_read,
	.serial_write = ble_serial_write,
	.serial_purge = ble_serial_purge,
	.serial_get_available = ble_serial_get_available,
	.serial_set_timeout = ble_serial_set_timeout,
// These doesn't make sense over bluetooth
// NULL means NOP
	.serial_configure = NULL,
	.serial_set_dtr = NULL,
	.serial_set_rts = NULL,
	.serial_set_break = NULL,

	.packet_size  = 20,
	.packet_open  = qt_ble_open,
	.packet_close = qt_ble_close,
	.packet_read  = qt_ble_read,
	.packet_write = qt_ble_write,
};


static dc_status_t ble_serial_open(dc_custom_io_t *io, dc_context_t *context, const char* devaddr)
{
	dc_context_set_custom_io(context, &ble_serial_ops, io->user_device);
	return qt_ble_open(&ble_serial_ops, context, devaddr);
}

#define BT_BLE_BUFSIZE 4096
static struct {
	unsigned int out_bytes, in_bytes, in_pos;
	unsigned char in[BT_BLE_BUFSIZE];
	unsigned char out[BT_BLE_BUFSIZE];
} buffer;

static dc_status_t ble_serial_flush_write(void)
{
	int bytes = buffer.out_bytes;

	if (!bytes)
		return DC_STATUS_SUCCESS;
	buffer.out_bytes = 0;
	return ble_serial_ops.packet_write(&ble_serial_ops, buffer.out, bytes, NULL);
}

static dc_status_t ble_serial_flush_read(void)
{
	buffer.in_bytes = buffer.in_pos = 0;
	return DC_STATUS_SUCCESS;
}

static dc_status_t ble_serial_close(dc_custom_io_t *io)
{
	ble_serial_flush_write();
	io->userdata = NULL;
	return qt_ble_close(&ble_serial_ops);
}

static dc_status_t ble_serial_read(dc_custom_io_t *io, void* data, size_t size, size_t *actual)
{
	Q_UNUSED(io)
	size_t len;
	size_t received = 0;

	if (buffer.in_pos >= buffer.in_bytes) {
		ble_serial_flush_write();
	}

	/* There is still unused/unread data in the input steam.
	 * So preseve it at the start of a new read.
	 */
	if (buffer.in_pos > 0) {
		len = buffer.in_bytes - buffer.in_pos;
		memcpy(buffer.in, buffer.in + buffer.in_pos, len);
		buffer.in_pos = 0;
		buffer.in_bytes = len;
	}

	/* Read a long as requested in the size parameter */
	while ((buffer.in_bytes - buffer.in_pos) < size) {
		dc_status_t rc;

		rc = ble_serial_ops.packet_read(&ble_serial_ops, buffer.in + buffer.in_bytes,
						sizeof(buffer.in) - buffer.in_bytes, &received);
		if (rc != DC_STATUS_SUCCESS)
			return rc;
		if (!received)
			return DC_STATUS_IO;

		buffer.in_bytes += received;
	}

	len = buffer.in_bytes - buffer.in_pos;
	if (len > size)
		len = size;

	memcpy(data, buffer.in + buffer.in_pos, len);
	buffer.in_pos += len;
	if (actual)
		*actual = len;
	return DC_STATUS_SUCCESS;
}

static dc_status_t ble_serial_write(dc_custom_io_t *io, const void* data, size_t size, size_t *actual)
{
	Q_UNUSED(io)
	dc_status_t rc = DC_STATUS_SUCCESS;
	size_t transferred = 0;

	ble_serial_flush_read();

	/*
	 * Most writes to a connected DC are small, typically some command bytes to get
	 * DC in download mode, or to set some parameter. All this just worked over BLE,
	 * however, sending a full firmware update (on an OSTC device) failed, as the
	 * underlying BLE interface can only handle small 20 byte BLE packets at once.
	 *
	 * So, send max ble->packet_size chuncks at once.
	 */
	while (size) {
		size_t len = sizeof(buffer.out) - transferred;

		if ((int)len > io->packet_size)
			len = io->packet_size;
		if (len > size)
			len = size;
		memcpy(buffer.out + buffer.out_bytes, data, len);
		buffer.out_bytes += len;

		if ((int)buffer.out_bytes <= io->packet_size || buffer.out_bytes == size) {
			rc = ble_serial_flush_write();
			if (rc != DC_STATUS_SUCCESS)
				break;
		}
		transferred += len;
		data = (const void *) (len + (const char *)data);
		size -= len;
	}
	if (actual)
		*actual = transferred;
	return DC_STATUS_SUCCESS;
}

static dc_status_t ble_serial_purge(dc_custom_io_t *io, dc_direction_t queue)
{
	Q_UNUSED(io)
	Q_UNUSED(queue)
	/* Do we care? */
	return DC_STATUS_SUCCESS;
}

static dc_status_t ble_serial_get_available(dc_custom_io_t *io, size_t *available)
{
	Q_UNUSED(io)
	*available = buffer.in_bytes - buffer.in_pos;
	return DC_STATUS_SUCCESS;
}

static dc_status_t ble_serial_set_timeout(dc_custom_io_t *io, long timeout)
{
	Q_UNUSED(io)
	Q_UNUSED(timeout)
	/* Do we care? */
	return DC_STATUS_SUCCESS;
}

#endif



static dc_status_t qt_serial_open(dc_custom_io_t *io, dc_context_t *context, const char* devaddr)
{
#ifdef BLE_SUPPORT
	if (!strncmp(devaddr, "LE:", 3))
		return ble_serial_open(io, context, devaddr);
#endif

	// Allocate memory.
	qt_serial_t *serial_port = (qt_serial_t *) malloc (sizeof (qt_serial_t));
	if (serial_port == NULL) {
		return DC_STATUS_NOMEMORY;
	}

	// Default to blocking reads.
	serial_port->timeout = -1;

#if defined(Q_OS_WIN)
	// Create a RFCOMM socket
	serial_port->socket = ::socket(AF_BTH, SOCK_STREAM, BTHPROTO_RFCOMM);

	if (serial_port->socket == INVALID_SOCKET) {
		free(serial_port);
		return DC_STATUS_IO;
	}

	SOCKADDR_BTH socketBthAddress;
	int socketBthAddressBth = sizeof (socketBthAddress);
	char *address = strdup(devaddr);

	ZeroMemory(&socketBthAddress, socketBthAddressBth);
	qDebug() << "Trying to connect to address " << devaddr;

	if (WSAStringToAddressA(address,
				AF_BTH,
				NULL,
				(LPSOCKADDR) &socketBthAddress,
				&socketBthAddressBth
				) != 0) {
		qDebug() << "Failed to convert the address " << address;
		free(address);

		return DC_STATUS_IO;
	}

	free(address);

	socketBthAddress.addressFamily = AF_BTH;
	socketBthAddress.port = BT_PORT_ANY;
	memset(&socketBthAddress.serviceClassId, 0, sizeof(socketBthAddress.serviceClassId));
	socketBthAddress.serviceClassId = SerialPortServiceClass_UUID;

	// Try to connect to the device
	if (::connect(serial_port->socket,
		      (struct sockaddr *) &socketBthAddress,
		      socketBthAddressBth
		      ) != 0) {
		qDebug() << "Failed to connect to device";

		return DC_STATUS_NODEVICE;
	}

	qDebug() << "Successfully connected to device";
#else
	// Create a RFCOMM socket
	serial_port->socket = new QBluetoothSocket(QBluetoothServiceInfo::RfcommProtocol);

	// Wait until the connection succeeds or until an error occurs
	QEventLoop loop;
	loop.connect(serial_port->socket, SIGNAL(connected()), SLOT(quit()));
	loop.connect(serial_port->socket, SIGNAL(error(QBluetoothSocket::SocketError)), SLOT(quit()));

	// Create a timer. If the connection doesn't succeed after five seconds or no error occurs then stop the opening step
	QTimer timer;
	int msec = 5000;
	timer.setSingleShot(true);
	loop.connect(&timer, SIGNAL(timeout()), SLOT(quit()));

#if defined(Q_OS_LINUX) && !defined(Q_OS_ANDROID)
	// First try to connect on RFCOMM channel 1. This is the default channel for most devices
	QBluetoothAddress remoteDeviceAddress(devaddr);
	serial_port->socket->connectToService(remoteDeviceAddress, 1, QIODevice::ReadWrite | QIODevice::Unbuffered);
	timer.start(msec);
	loop.exec();

	if (serial_port->socket->state() == QBluetoothSocket::ConnectingState) {
		// It seems that the connection on channel 1 took more than expected. Wait another 15 seconds
		qDebug() << "The connection on RFCOMM channel number 1 took more than expected. Wait another 15 seconds.";
		timer.start(3 * msec);
		loop.exec();
	} else if (serial_port->socket->state() == QBluetoothSocket::UnconnectedState) {
		// Try to connect on channel number 5. Maybe this is a Shearwater Petrel2 device.
		qDebug() << "Connection on channel 1 failed. Trying on channel number 5.";
		serial_port->socket->connectToService(remoteDeviceAddress, 5, QIODevice::ReadWrite | QIODevice::Unbuffered);
		timer.start(msec);
		loop.exec();

		if (serial_port->socket->state() == QBluetoothSocket::ConnectingState) {
			// It seems that the connection on channel 5 took more than expected. Wait another 15 seconds
			qDebug() << "The connection on RFCOMM channel number 5 took more than expected. Wait another 15 seconds.";
			timer.start(3 * msec);
			loop.exec();
		}
	}
#elif defined(Q_OS_ANDROID) || (QT_VERSION >= 0x050500 && defined(Q_OS_MAC))
	// Try to connect to the device using the uuid of the Serial Port Profile service
	QBluetoothAddress remoteDeviceAddress(devaddr);
#if defined(Q_OS_ANDROID)
	QBluetoothUuid uuid = QBluetoothUuid(QUuid("{00001101-0000-1000-8000-00805f9b34fb}"));
	qDebug() << "connecting to Uuid" << uuid;
	serial_port->socket->setPreferredSecurityFlags(QBluetooth::NoSecurity);
	serial_port->socket->connectToService(remoteDeviceAddress, uuid, QIODevice::ReadWrite | QIODevice::Unbuffered);
#else
	serial_port->socket->connectToService(remoteDeviceAddress, 1, QIODevice::ReadWrite | QIODevice::Unbuffered);
#endif
	timer.start(msec);
	loop.exec();

	if (serial_port->socket->state() == QBluetoothSocket::ConnectingState ||
	    serial_port->socket->state() == QBluetoothSocket::ServiceLookupState) {
		// It seems that the connection step took more than expected. Wait another 20 seconds.
		qDebug() << "The connection step took more than expected. Wait another 20 seconds";
		timer.start(4 * msec);
		loop.exec();
	}
#endif
	if (serial_port->socket->state() != QBluetoothSocket::ConnectedState) {

		// Get the latest error and try to match it with one from libdivecomputer
		QBluetoothSocket::SocketError err = serial_port->socket->error();
		qDebug() << "Failed to connect to device " << devaddr << ". Device state " << serial_port->socket->state() << ". Error: " << err;

		free (serial_port);
		switch(err) {
		case QBluetoothSocket::HostNotFoundError:
		case QBluetoothSocket::ServiceNotFoundError:
			return DC_STATUS_NODEVICE;
		case QBluetoothSocket::UnsupportedProtocolError:
			return DC_STATUS_PROTOCOL;
#if QT_VERSION >= 0x050400
		case QBluetoothSocket::OperationError:
			return DC_STATUS_UNSUPPORTED;
#endif
		case QBluetoothSocket::NetworkError:
			return DC_STATUS_IO;
		default:
			return DC_STATUS_IO;
		}
	}
#endif
	io->userdata = serial_port;

	return DC_STATUS_SUCCESS;
}

static dc_status_t qt_serial_close(dc_custom_io_t *io)
{
	qt_serial_t *device = (qt_serial_t*) io->userdata;

	if (device == NULL)
		return DC_STATUS_SUCCESS;

#if defined(Q_OS_WIN)
	// Cleanup
	closesocket(device->socket);
	free(device);
#else
	if (device->socket == NULL) {
		free(device);
		return DC_STATUS_SUCCESS;
	}

	device->socket->close();

	delete device->socket;
	free(device);
#endif

	io->userdata = NULL;

	return DC_STATUS_SUCCESS;
}

static dc_status_t qt_serial_read(dc_custom_io_t *io, void* data, size_t size, size_t *actual)
{
	qt_serial_t *device = (qt_serial_t*) io->userdata;

#if defined(Q_OS_WIN)
	if (device == NULL)
		return DC_STATUS_INVALIDARGS;

	size_t nbytes = 0;
	int rc;

	while (nbytes < size) {
		rc = recv (device->socket, (char *) data + nbytes, size - nbytes, 0);

		if (rc < 0) {
			return DC_STATUS_IO; // Error during recv call.
		} else if (rc == 0) {
			break; // EOF reached.
		}

		nbytes += rc;
	}
#else
	if (device == NULL || device->socket == NULL)
		return DC_STATUS_INVALIDARGS;

	size_t nbytes = 0;
	int rc;

	while(nbytes < size && device->socket->state() == QBluetoothSocket::ConnectedState)
	{
		rc = device->socket->read((char *) data + nbytes, size - nbytes);

		if (rc < 0) {
			if (errno == EINTR || errno == EAGAIN)
			    continue; // Retry.

			return DC_STATUS_IO; // Something really bad happened :-(
		} else if (rc == 0) {
			// Wait until the device is available for read operations
			QEventLoop loop;
			QTimer timer;
			timer.setSingleShot(true);
			loop.connect(&timer, SIGNAL(timeout()), SLOT(quit()));
			loop.connect(device->socket, SIGNAL(readyRead()), SLOT(quit()));
			timer.start(device->timeout);
			loop.exec();

			if (!timer.isActive())
				break;
		}

		nbytes += rc;
	}
#endif
	if (actual)
		*actual = nbytes;

	return DC_STATUS_SUCCESS;
}

static dc_status_t qt_serial_write(dc_custom_io_t *io, const void* data, size_t size, size_t *actual)
{
	qt_serial_t *device = (qt_serial_t*) io->userdata;

#if defined(Q_OS_WIN)
	if (device == NULL)
		return DC_STATUS_INVALIDARGS;

	size_t nbytes = 0;
	int rc;

	while (nbytes < size) {
	    rc = send(device->socket, (char *) data + nbytes, size - nbytes, 0);

	    if (rc < 0) {
	       return DC_STATUS_IO; // Error during send call.
	    }

	    nbytes += rc;
	}
#else
	if (device == NULL || device->socket == NULL)
		return DC_STATUS_INVALIDARGS;

	size_t nbytes = 0;
	int rc;

	while(nbytes < size && device->socket->state() == QBluetoothSocket::ConnectedState)
	{
		rc = device->socket->write((char *) data + nbytes, size - nbytes);

		if (rc < 0) {
			if (errno == EINTR || errno == EAGAIN)
			    continue; // Retry.

			return DC_STATUS_IO; // Something really bad happened :-(
		} else if (rc == 0) {
			break;
		}

		nbytes += rc;
	}
#endif
	if (actual)
		*actual = nbytes;

	return DC_STATUS_SUCCESS;
}

static dc_status_t qt_serial_purge(dc_custom_io_t *io, dc_direction_t queue)
{
	qt_serial_t *device = (qt_serial_t*) io->userdata;

	(void)queue;
	if (device == NULL)
		return DC_STATUS_INVALIDARGS;
#if !defined(Q_OS_WIN)
	if (device->socket == NULL)
		return DC_STATUS_INVALIDARGS;
#endif
	// TODO: add implementation

	return DC_STATUS_SUCCESS;
}

static dc_status_t qt_serial_get_available(dc_custom_io_t *io, size_t *available)
{
	qt_serial_t *device = (qt_serial_t*) io->userdata;

#if defined(Q_OS_WIN)
	if (device == NULL)
		return DC_STATUS_INVALIDARGS;

	// TODO use WSAIoctl to get the information

	*available = 0;
#else
	if (device == NULL || device->socket == NULL)
		return DC_STATUS_INVALIDARGS;

	*available = device->socket->bytesAvailable();
#endif

	return DC_STATUS_SUCCESS;
}

/* UNUSED! */
static int qt_serial_get_transmitted(qt_serial_t *device) __attribute__ ((unused));

static int qt_serial_get_transmitted(qt_serial_t *device)
{
#if defined(Q_OS_WIN)
	if (device == NULL)
		return DC_STATUS_INVALIDARGS;

	// TODO add implementation

	return 0;
#else
	if (device == NULL || device->socket == NULL)
		return DC_STATUS_INVALIDARGS;

	return device->socket->bytesToWrite();
#endif
}

static dc_status_t qt_serial_set_timeout(dc_custom_io_t *io, long timeout)
{
	qt_serial_t *device = (qt_serial_t*) io->userdata;

	if (device == NULL)
		return DC_STATUS_INVALIDARGS;

	device->timeout = timeout;

	return DC_STATUS_SUCCESS;
}

dc_custom_io_t qt_serial_ops = {
	.userdata = NULL,
	.user_device = NULL,
	.serial_open = qt_serial_open,
	.serial_close = qt_serial_close,
	.serial_read = qt_serial_read,
	.serial_write = qt_serial_write,
	.serial_purge = qt_serial_purge,
	.serial_get_available = qt_serial_get_available,
	.serial_set_timeout = qt_serial_set_timeout,
// These doesn't make sense over bluetooth
// NULL means NOP
	.serial_configure = NULL,
	.serial_set_dtr = NULL,
	.serial_set_rts = NULL,
	.serial_set_break = NULL,

#ifdef BLE_SUPPORT
	.packet_size  = 20,
	.packet_open  = qt_ble_open,
	.packet_close = qt_ble_close,
	.packet_read  = qt_ble_read,
	.packet_write = qt_ble_write,
#endif
};

dc_custom_io_t* get_qt_serial_ops() {
	return (dc_custom_io_t*) &qt_serial_ops;
}

}
#endif