syntax = "proto2";

package c_its_io;

// ------------------------------
// Data Types
// ------------------------------

message Position {
  required  float     latitude_deg              =  1;
  required  float     longitude_deg             =  2;
}

enum TrafficDir {
  // for all directions of traffic
  ALL_DIRECTIONS                                =  0;
  // for the direction of traffic according to the reference direction, and the portion of traffic upstream of the reference position
  UPSTREAM                                      =  1;
  // for the direction of traffic according to the reference direction, and the portion of traffic downstream of the reference position
  DOWNSTREAM                                    =  2;
  // for the direction of traffic opposite to the reference direction
  OPPOSITE                                      =  3;
}

message VehicleContainer {
  optional  uint32        heading_deg           =  1; // vehicle heading in degrees, if not "unavailable"
  optional  uint32        speed                 =  2; // vehicle speed in 1/100 m/s, if not "unavailable"
  optional  uint32        vehicle_length_dm     =  3; // vehicle length in 1/10 m, if not "unavailable"
  optional  uint32        vehicle_width_dm      =  4; // vehicle width in 1/10 m, if not "unavailable"
}


// GeoNetworking Destination Area Shape
enum GNAreaShape {
  ETSI_AREASHAPE_CIRCLE                         =  0;
  ETSI_AREASHAPE_RECTANGLE                      =  1;
  ETSI_AREASHAPE_ELLIPSIS                       =  2;
}

// GeoNetworking Destination Area/ Source Position
message ITSPosition {
  required  int32         latitude              =  1; // Latitude in 1/10th of micro degrees
  required  int32         longitude             =  2; // Longitude in 1/10th of micro degrees
}

// GeoNetworking Destination Area
message GNArea {
  optional  GNAreaShape   area                  =  1;
  optional  ITSPosition   position              =  2;
  optional  int32         distA                 =  3; // Distance A of the geometric shape in meters
  optional  int32         distB                 =  4; // Distance B of the geometric shape in meters, mandatory for rectangle and ellipsis
  optional  int32         angle                 =  5; // Angle of the geometric shape in degrees, mandatory for rectangle and ellipsis
}

// GeoNetworking Transport
enum GNTransport {
  GN_TRANSPORT_GAC                              =  3; // Geographically-Scoped Anycast
  GN_TRANSPORT_GBC                              =  4; // Geographically-Scoped broadcast
  GN_TRANSPORT_TSB                              =  5; // Topologically-scoped broadcast
  GN_TRANSPORT_SHB                              =  7; // Single hop broadcast
}

message RawMsgTx {
  required bytes          payload               =  1; // as UPER
  required uint32         message_type          =  2; // ITS `MessageId` integer value

  required GNTransport    gnTransport           =  3;
  required GNArea         gnArea                =  4;
  required uint32         hopLimit              =  5;

  optional uint32         stationType           =  6; // for source position vector
}

// ------------------------------
// Messages
// ------------------------------

message PositionState {
  required  sfixed64      timestamp_ms          =  1; // current UNIX time in milliseconds
  required  Position      position              =  2;
  optional  uint32        heading               =  3; // heading in 1/10 deg
  optional  uint32        speed                 =  4; // speed in 1/100 m/s
}

message DenmEvent {
  required  fixed64       timestamp             =  1; // DENM reference time as UNIX time (in seconds)
  required  fixed64       validity_end_ts       =  2; // UNIX time when event validity ends (from denm.management.validityDuration)
  required  fixed32       station_id            =  3; // unique ID of the event when combined with `seq_num`
  required  uint32        seq_num               =  4; // unique ID of the event when combined with `station_id`
  optional  Position      event_position        =  5; // event location (from denm.management.eventPosition)
  optional  uint32        event_heading_deg     =  6; // event heading (from denm.location.eventPositionHeading)
  optional  TrafficDir    direction             =  7; // relevance traffic direction (from denm.management.trafficDirection)
  optional  uint32        cause_code            =  8;
  optional  uint32        sub_cause_code        =  9;
}

message CamEvent {
  required  fixed32       station_id            =  1; // Station ID of the vehicle
  required  uint32        station_type          =  2; // ITS `StationType`
  required  Position      position              =  3; // vehicle position
  optional  uint32        vehicle_role          =  4; // ITS `VehicleRole`
  optional  VehicleContainer  vehicle_data      =  5; // speed, etc unless CAM contains an RSU container
}

message RawMsgRx {
  required  uint32        msg_type              =  1; // ITS message type (`MessageId` from PDU header)
  required  bytes         payload               =  2; // UPER message with Geonetworking and BTP headers
}

message SerialOutputMsg {
  oneof                   payload {
    DenmEvent             denm                  =  1;
    RawMsgRx              rx_msg                =  2;
  }
}

message SerialInputMsg {
  oneof                   payload {
    PositionState         position              =  1;
    RawMsgTx              tx_msg                =  2;
  }
}