// -*- tab-width: 4; Mode: C++; c-basic-offset: 4; indent-tabs-mode: nil -*-
/*
   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/>.
 */

#ifndef __AP_GPS_H__
#define __AP_GPS_H__

#include <AP_HAL.h>
#include <inttypes.h>
#include <AP_Progmem.h>
#include <AP_Common.h>
#include <AP_Param.h>
#include <AP_Math.h>
#include "GPS_detect_state.h"

/**
   maximum number of GPS instances available on this platform. If more
   than 1 then redundent sensors may be available
 */
#if HAL_CPU_CLASS > HAL_CPU_CLASS_16
#define GPS_MAX_INSTANCES 2
#else
#define GPS_MAX_INSTANCES 1
#endif

class DataFlash_Class;
class AP_GPS_Backend;

/// @class AP_GPS
/// GPS driver main class
class AP_GPS
{
public:
    // constructor
	AP_GPS() {
		AP_Param::setup_object_defaults(this, var_info);
    }

    /// Startup initialisation.
    void init(DataFlash_Class *dataflash);

    /// Update GPS state based on possible bytes received from the module.
    /// This routine must be called periodically (typically at 10Hz or
    /// more) to process incoming data.
    void update(void);

    // GPS driver types
    enum GPS_Type {
        GPS_TYPE_NONE  = 0,
        GPS_TYPE_AUTO  = 1,
        GPS_TYPE_UBLOX = 2,
        GPS_TYPE_MTK   = 3,
        GPS_TYPE_MTK19 = 4,
        GPS_TYPE_NMEA  = 5,
        GPS_TYPE_SIRF  = 6
    };

    /// GPS status codes
    enum GPS_Status {
        NO_GPS = 0,             ///< No GPS connected/detected
        NO_FIX = 1,             ///< Receiving valid GPS messages but no lock
        GPS_OK_FIX_2D = 2,      ///< Receiving valid messages and 2D lock
        GPS_OK_FIX_3D = 3       ///< Receiving valid messages and 3D lock
    };

    // GPS navigation engine settings. Not all GPS receivers support
    // this
    enum GPS_Engine_Setting {
        GPS_ENGINE_NONE        = -1,
        GPS_ENGINE_PORTABLE    = 0,
        GPS_ENGINE_STATIONARY  = 2,
        GPS_ENGINE_PEDESTRIAN  = 3,
        GPS_ENGINE_AUTOMOTIVE  = 4,
        GPS_ENGINE_SEA         = 5,
        GPS_ENGINE_AIRBORNE_1G = 6,
        GPS_ENGINE_AIRBORNE_2G = 7,
        GPS_ENGINE_AIRBORNE_4G = 8
    };

    struct GPS_State {
        uint8_t instance; // the instance number of this GPS

        // all the following fields must all be filled by the backend driver
        GPS_Status status;                  ///< driver fix status
        uint32_t time_week_ms;              ///< GPS time (milliseconds from start of GPS week)
        uint16_t time_week;                 ///< GPS week number
        Location location;                  ///< last fix location
        float ground_speed;                 ///< ground speed in m/sec
        int32_t ground_course_cd;           ///< ground course in 100ths of a degree
        int16_t hdop;                       ///< horizontal dilution of precision in cm
        uint8_t num_sats;                   ///< Number of visible satelites        
        Vector3f velocity;                  ///< 3D velocitiy in m/s, in NED format
        bool have_vertical_velocity:1;      ///< does this GPS give vertical velocity?
        uint32_t last_gps_time_ms;          ///< the system time we got the last GPS timestamp, milliseconds
    };

    // Accessor functions

    // return number of active GPS sensors
    uint8_t num_sensors(void) const {
        uint8_t count = 0;
        for (uint8_t i=0; i<GPS_MAX_INSTANCES; i++) {
            if (drivers[i] != NULL) count++;
        }
        return count;
    }

    /// Query GPS status
    GPS_Status status(uint8_t instance) const {
        return state[instance].status;
    }
    GPS_Status status(void) const {
        return status(primary_instance());
    }

    // location of last fix
    const Location &location(uint8_t instance) const {
        return state[instance].location;
    }
    const Location &location() const {
        return location(primary_instance());
    }

    // 3D velocity in NED format
    const Vector3f &velocity(uint8_t instance) const {
        return state[instance].velocity;
    }
    const Vector3f &velocity() const {
        return velocity(primary_instance());
    }

    // ground speed in m/s
    float ground_speed(uint8_t instance) const {
        return state[instance].ground_speed;
    }
    float ground_speed() const {
        return ground_speed(primary_instance());
    }

    // ground speed in cm/s
    uint32_t ground_speed_cm(void) {
        return ground_speed() * 100;
    }

    // ground course in centidegrees
    int32_t ground_course_cd(uint8_t instance) const {
        return state[instance].ground_course_cd;
    }
    int32_t ground_course_cd() const {
        return ground_course_cd(primary_instance());
    }

    // number of locked satellites
    uint8_t num_sats(uint8_t instance) const {
        return state[instance].num_sats;
    }
    uint8_t num_sats() const {
        return num_sats(primary_instance());
    }

    // GPS time of week in milliseconds
    uint32_t time_week_ms(uint8_t instance) const {
        return state[instance].time_week_ms;
    }
    uint32_t time_week_ms() const {
        return time_week_ms(primary_instance());
    }

    // GPS week
    uint16_t time_week(uint8_t instance) const {
        return state[instance].time_week;
    }
    uint16_t time_week() const {
        return time_week(primary_instance());
    }

    // horizontal dilution of precision
    int16_t get_hdop(uint8_t instance) const {
        return state[instance].hdop;
    }
    int16_t get_hdop() const {
        return get_hdop(primary_instance());
    }

    // the time we got our last fix in system milliseconds. This is
    // used when calculating how far we might have moved since that fix
    uint32_t last_fix_time_ms(uint8_t instance) const {
        return timing[instance].last_fix_time_ms;
    }
    uint32_t last_fix_time_ms(void) const {
        return last_fix_time_ms(primary_instance());
    }

	// the time we last processed a message in milliseconds. This is
	// used to indicate that we have new GPS data to process
	uint32_t last_message_time_ms(uint8_t instance) const { 
        return timing[instance].last_message_time_ms;        
    }
    uint32_t last_message_time_ms(void) const {
        return last_message_time_ms(primary_instance());
    }

    // return last fix time since the 1/1/1970 in microseconds
    uint64_t time_epoch_usec(uint8_t instance);
    uint64_t time_epoch_usec(void) { 
        return time_epoch_usec(primary_instance()); 
    }

	// return true if the GPS supports vertical velocity values
    bool have_vertical_velocity(uint8_t instance) const { 
        return state[instance].have_vertical_velocity; 
    }
    bool have_vertical_velocity(void) const { 
        return have_vertical_velocity(primary_instance());
    }

    // the expected lag (in seconds) in the position and velocity readings from the gps
    float get_lag() const { return 0.2f; }

    // set position for HIL
    void setHIL(GPS_Status status, uint64_t time_epoch_ms, 
                Location &location, Vector3f &velocity, uint8_t num_sats);

    static const struct AP_Param::GroupInfo var_info[];

    // dataflash for logging, if available
    DataFlash_Class *_DataFlash;

    // configuration parameters
    AP_Int8 _type[GPS_MAX_INSTANCES];
    AP_Int8 _navfilter;

private:
    struct GPS_timing {
        // the time we got our last fix in system milliseconds
        uint32_t last_fix_time_ms;

        // the time we got our last fix in system milliseconds
        uint32_t last_message_time_ms;
    };
    GPS_timing timing[GPS_MAX_INSTANCES];
    GPS_State state[GPS_MAX_INSTANCES];
    AP_GPS_Backend *drivers[GPS_MAX_INSTANCES];

    /// return primary GPS instance
    uint8_t primary_instance(void) const { return 0; }

    // state of auto-detection process, per instance
    struct detect_state {
        uint32_t detect_started_ms;
        uint32_t last_baud_change_ms;
        uint8_t last_baud;
        uint8_t init_blob_offset;
        struct UBLOX_detect_state ublox_detect_state;
        struct MTK_detect_state mtk_detect_state;
        struct MTK19_detect_state mtk19_detect_state;
        struct SIRF_detect_state sirf_detect_state;
        struct NMEA_detect_state nmea_detect_state;
    } detect_state[GPS_MAX_INSTANCES];

    static const uint16_t  _baudrates[];
    static const prog_char _initialisation_blob[];

    void detect_instance(uint8_t instance);
    void update_instance(uint8_t instance);
};

#include <GPS_Backend.h>
#include <AP_GPS_UBLOX.h>
#include <AP_GPS_MTK.h>
#include <AP_GPS_MTK19.h>
#include <AP_GPS_NMEA.h>
#include <AP_GPS_SIRF.h>

#endif // __AP_GPS_H__