syntax = "proto3";

package livefeed.v1;

// C# namespace
option csharp_namespace = "Grote.Grpc.LiveFeed";

// Java package name
option java_package = "com.grote.grpc.livefeed";
option java_multiple_files = true;

import "google/protobuf/timestamp.proto";

// ---------------------------------------------------------
// LiveFeed Service
// ---------------------------------------------------------
// The LiveFeed service provides real-time updates about fleets,
// trailers, and telemetry data. Clients subscribe once and
// receive a continuous stream of LiveUpdateResponse messages as new
// information becomes available or to keep the stream alive.
service LiveFeed {
  // Opens a live data stream. The server will continuously
  // send LiveUpdateResponse messages until the client disconnects.
  rpc Subscribe(SubscribeRequest) returns (stream LiveUpdateResponse);
}

// ---------------------------------------------------------
// Request & Response Messages
// ---------------------------------------------------------

// Subscription request (currently empty).
// In the future, filters such as FleetID may be added.
message SubscribeRequest {}

// Wrapper for stream messages. This allows the server to send either
// a real LiveUpdate or a lightweight heartbeat to keep the stream alive.
message LiveUpdateResponse {
  bool is_heartbeat = 1;                 // True if this message is a heartbeat/ping
  optional LiveUpdate live_update = 2;   // Optional actual update payload
}

// A single update in the live feed stream.
// Each LiveUpdate contains fleet-level metadata and trailer data.
message LiveUpdate {
  int32 fleet_id = 1;                      // Fleet identifier
  optional string fleet_name = 2;          // Human-friendly fleet name
  google.protobuf.Timestamp ts = 3;        // Time the update was created (UTC)
  Trailer trailer = 4;                     // Trailer data included in this update
}

// ---------------------------------------------------------
// Trailer Details
// ---------------------------------------------------------
// Represents the trailer included in the update. Each trailer
// may include its latest status, telemetry, and diagnostic info.
message Trailer {
  string id = 1;                           // Trailer identifier
  optional string unit_id = 2;             // Unit or asset tag, if available
  optional string vin = 3;                 // Vehicle Identification Number (VIN)
  optional Status status = 4;              // Current operational status
  optional google.protobuf.Timestamp status_date = 5; // When the status changed
  int32 faulted_devices = 6;               // Number of devices currently faulted
  int32 warning_devices = 7;               // Number of devices reporting warnings
  optional Telemetry telemetry = 8;        // Latest GPS and motion information
}

// ---------------------------------------------------------
// Telemetry Data
// ---------------------------------------------------------
// Real-time telemetry readings reported by the trailer.
message Telemetry {
  optional google.protobuf.Timestamp timestamp = 1;   // When telemetry was recorded
  optional double lat = 2;                            // Latitude (decimal degrees)
  optional double long = 3;                           // Longitude (decimal degrees)
  optional double speed = 4;                          // Speed in mph
  optional string heading = 5;                        // Direction of travel (cardinal)
}

// ---------------------------------------------------------
// Status
// ---------------------------------------------------------
// Represents the trailer’s current operational status, if any.
message Status {
  optional string name = 1;            // Status label (e.g., "OK", "Warning", "Faulted")
  optional bool is_warning = 2;        // True if this is a warning condition
  optional bool is_fault = 3;          // True if this is a fault condition
}