/*
   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/>.
 */
/*
  support for serial connected AHRS systems
 */

#pragma once

#include "AP_ExternalAHRS_config.h"

#if AP_EXTERNAL_AHRS_VECTORNAV_ENABLED

#include "AP_ExternalAHRS_backend.h"

class AP_ExternalAHRS_VectorNav : public AP_ExternalAHRS_backend {

public:
    AP_ExternalAHRS_VectorNav(AP_ExternalAHRS *frontend, AP_ExternalAHRS::state_t &state);

    // get serial port number, -1 for not enabled
    int8_t get_port(void) const override;

    // accessors for AP_AHRS
    bool healthy(void) const override;
    bool initialised(void) const override;
    bool pre_arm_check(char *failure_msg, uint8_t failure_msg_len) const override;
    void get_filter_status(nav_filter_status &status) const override;
    void send_status_report(class GCS_MAVLINK &link) const override;

    // check for new data
    void update() override {
        check_uart();
    }

    // Get model/type name
    const char* get_name() const override;

protected:

    uint8_t num_gps_sensors(void) const override {
        return 1;
    }
private:
    AP_HAL::UARTDriver *uart;
    int8_t port_num;
    bool setup_complete;
    uint32_t baudrate;

    void update_thread();
    bool check_uart();

    void initialize();

    void run_command(const char *fmt, ...);
    void process_imu_packet(const uint8_t *b);
    void process_ahrs_ekf_packet(const uint8_t *b);
    void process_ins_ekf_packet(const uint8_t *b);
    void process_ins_gnss_packet(const uint8_t *b);

    uint8_t *pktbuf;
    uint16_t pktoffset;
    uint16_t bufsize;

    struct VN_imu_packet const *latest_imu_packet = nullptr;
    struct VN_INS_ekf_packet const *latest_ins_ekf_packet = nullptr;
    struct VN_INS_gnss_packet const *latest_ins_gnss_packet = nullptr;

    uint32_t last_pkt1_ms = UINT32_MAX;
    uint32_t last_pkt2_ms = UINT32_MAX;
    uint32_t last_pkt3_ms = UINT32_MAX;

    enum class TYPE {
        VN_INS,  // Full INS mode, requiring GNSS. Used by VN-2X0 and VN-3X0
        VN_AHRS,  // IMU-only mode, used by VN-1X0
    } type;

    bool has_dual_gnss = false;

    char model_name[20];

    char message_to_send[50];
    // NMEA parsing for setup
    bool decode(char c);
    bool decode_latest_term();
    struct NMEA_parser {
        char term[20];            // buffer for the current term within the current sentence
        uint8_t term_offset;      // offset within the _term buffer where the next character should be placed
        uint8_t term_number;      // term index within the current sentence
        uint8_t checksum;         // checksum accumulator
        bool term_is_checksum;    // current term is the checksum
        bool sentence_valid;      // is current sentence valid so far
        bool sentence_done;       // true if this sentence has already been decoded
        bool error_response;      // true if received a VNERR response
    } nmea;
};

#endif  // AP_EXTERNAL_AHRS_VECTORNAV_ENABLED