// -*- tab-width: 4; Mode: C++; c-basic-offset: 4; indent-tabs-mode: t -*-
//
//  SiRF Binary GPS driver for ArduPilot and ArduPilotMega.
//	Code by Michael Smith.
//
//	This library is free software; you can redistribute it and / or
//	modify it under the terms of the GNU Lesser General Public
//	License as published by the Free Software Foundation; either
//	version 2.1 of the License, or (at your option) any later version.
//
#ifndef AP_GPS_SIRF_h
#define AP_GPS_SIRF_h

#include <GPS.h>

#define SIRF_SET_BINARY	"$PSRF100,0,38400,8,1,0*3C"

class AP_GPS_SIRF : public GPS {
public:
	AP_GPS_SIRF(Stream *s);

	virtual void   	init();
	virtual void	read();

private:
#pragma pack(1)
	struct sirf_geonav {
		uint16_t	fix_invalid;
		uint16_t	fix_type;
		uint16_t	week;
		uint32_t	time;
		uint16_t	year;
		uint8_t		month;
		uint8_t		day;
		uint8_t		hour;
		uint8_t		minute;
		uint16_t	second;
		uint32_t	satellites_used;
		int32_t		latitude;
		int32_t		longitude;
		int32_t		altitude_ellipsoid;
		int32_t		altitude_msl;
		int8_t		map_datum;
		int16_t		ground_speed;
		int16_t		ground_course;
		int16_t		res1;
		int16_t		climb_rate;
		uint16_t	heading_rate;
		uint32_t	horizontal_position_error;
		uint32_t	vertical_position_error;
		uint32_t	time_error;
		int16_t		horizontal_velocity_error;
		int32_t		clock_bias;
		uint32_t	clock_bias_error;
		int32_t		clock_drift;
		uint32_t	clock_drift_error;
		uint32_t	distance;
		uint16_t	distance_error;
		uint16_t	heading_error;
		uint8_t		satellites;
		uint8_t		hdop;
		uint8_t		mode_info;
	};
#pragma pack(pop)
	enum sirf_protocol_bytes {
		PREAMBLE1 = 0xa0,
		PREAMBLE2 = 0xa2,
		POSTAMBLE1 = 0xb0,
		POSTAMBLE2 = 0xb3,
		MSG_GEONAV = 0x29
	};
	enum sirf_fix_type {
		FIX_3D = 0x6,
		FIX_MASK = 0x7
	};


	// State machine state
	uint8_t			_step;
	uint16_t		_checksum;
	bool			_gather;
	uint16_t		_payload_length;
	uint16_t		_payload_counter;
	uint8_t			_msg_id;

	// Message buffer
	union {
		sirf_geonav		nav;
		uint8_t			bytes[];
	} _buffer;

	void			_parse_gps(void);
	void			_accumulate(uint8_t val);
};

#endif // AP_GPS_SIRF_h