#ifndef AIRMAP_TELEMETRY_H_
#define AIRMAP_TELEMETRY_H_

#include <airmap/do_not_copy_or_move.h>
#include <airmap/error.h>

#include <cstdint>
#include <string>
#include <type_traits>

namespace airmap {

struct Flight;

/// Telemetry provides functionality to submit telemetry updates to the
/// AirMap services during flight.
class Telemetry : DoNotCopyOrMove {
 public:
  /// Position describes a timestamped geographical position.
  struct Position {
    std::uint64_t timestamp;     ///< Ingestion timestamp of the update.
    double latitude;             ///< The latitude of the position [°].
    double longitude;            ///< The longitude of the position in [°].
    double altitude_msl;         ///< The altitude above mean sea level of the position in [m].
    double altitude_gl;          ///< The altitude above ground level of the position in [m].
    double horizontal_accuracy;  ///< The horizontal accuracy of the position in [m].
  };

  /// Speed describes the timestamped 3-dim velocity of a vehicle.
  struct Speed {
    std::uint64_t timestamp;  ///< Ingestion timestamp of the update.
    float velocity_x;         ///< The velocity of the vehicle in direction of the x axis in [m/s].
    float velocity_y;         ///< The velocity of the vehicle in direction of the y axis in [m/s].
    float velocity_z;         ///< The velocity of the vehicle in direction of the z axis in [m/s].
  };

  /// Attitude describes the timestamped 3-dim orientation of a vehicle.
  struct Attitude {
    std::uint64_t timestamp;  ///< Ingestion timestamp of the update.
    float yaw;                ///< The yaw of the vehicle in [°/s].
    float pitch;              ///< The pitch of the vehicle in [°/s].
    float roll;               ///< The roll of the vehicle in [°/s].
  };

  /// Barometer describes the timestamped atmospheric pressurce conditions.
  struct Barometer {
    std::uint64_t timestamp;  ///< Ingestion timestamp of the update.
    float pressure;           ///< The atmospheric pressure measurement in [Pa].
  };

  /// @cond
  static_assert(std::is_pod<Position>::value, "Position must be a POD");
  static_assert(std::is_pod<Speed>::value, "Speed must be a POD");
  static_assert(std::is_pod<Attitude>::value, "Attitude must be a POD");
  static_assert(std::is_pod<Barometer>::value, "Barometer must be a POD");
  /// @endcond

  /// Update models an update of the current position, speed, attitude or atmospheric pressure
  /// measurement/estimate.
  class Update {
   public:
    /// Type enumerates all known update types.
    enum class Type : std::uint8_t {
      position  = 1,  ///< The update contains a Position instance.
      speed     = 2,  ///< The update contains a Speed instance.
      attitude  = 3,  ///< The update contains an Attitude instance.
      barometer = 4   ///< The update contains a Barometer instance.
    };

    /// Update initializes a new instance with 'position'.
    explicit Update(const Position& position);
    /// Update initializes a new instance with 'speed'.
    explicit Update(const Speed& speed);
    /// Update initializes a new instance with 'attitude'.
    explicit Update(const Attitude& attitude);
    /// Update initializes a new instance with 'barometer'.
    explicit Update(const Barometer& barometer);

    /// type returns the Type of the update contained within this instance.
    Type type() const;
    /// position returns the position update contained within this instance.
    /// The behavior is undefined if type() != Type::position.
    const Position& position() const;
    /// speed returns the speed update contained within this instance.
    /// The behavior is undefined if type() != Type::speed.
    const Speed& speed() const;
    /// attitude returns the attitde update contained within this instance.
    /// The behavior is undefined if type() != Type::attitude.
    const Attitude& attitude() const;
    /// barometer returns the barometer update contained within this instance.
    /// The behavior is undefined if type() != Type::barometer.
    const Barometer& barometer() const;

   private:
    Type type_;
    union {
      Position position;
      Speed speed;
      Attitude attitude;
      Barometer barometer;
    } data_;
  };

  /// submit_updates sends the telemetry data in 'updates' associated to 'flight' to the AirMap
  /// services.
  virtual void submit_updates(const Flight& flight, const std::string& key,
                              const std::initializer_list<Update>& updates) = 0;

 protected:
  /// @cond
  Telemetry() = default;
  /// @endcond
};

}  // namespace airmap

#endif  // AIRMAP_TELEMETRY_H_