/// Pure conversion and serialization logic, free of Flutter and platform types.
///
/// Ported from `com.rippr.Telemetry`. The Kotlin original also held process-wide
/// recording state; that was already deleted in v2 (state lives in the database, because
/// it must survive process death) and is not resurrected here.
library;

import 'dart:convert';

import '../domain/models.dart';

const double msToKmhFactor = 3.6;

double msToKmh(double metersPerSecond) => metersPerSecond * msToKmhFactor;

/// A parked bike still emits jittering fixes. Anything under this is reported as zero so
/// "max speed" is not set by GPS noise while the phone sits in a pocket.
const double speedNoiseFloorKmh = 1.5;

double sanitizeSpeedKmh(double raw) {
  if (!raw.isFinite || raw < speedNoiseFloorKmh) return 0.0;
  return raw;
}

/// Drop fixes too imprecise to be worth storing. 0 means "accuracy unknown".
bool isUsableFix(double accuracyMeters, {double maxAccuracyMeters = 50.0}) =>
    accuracyMeters <= 0.0 || accuracyMeters <= maxAccuracyMeters;

String formatDuration(int millis) {
  if (millis <= 0) return '00:00:00';
  final totalSeconds = millis ~/ 1000;
  final h = (totalSeconds ~/ 3600).toString().padLeft(2, '0');
  final m = ((totalSeconds % 3600) ~/ 60).toString().padLeft(2, '0');
  final s = (totalSeconds % 60).toString().padLeft(2, '0');
  return '$h:$m:$s';
}

/// Encode a batch of points for the upload endpoint.
///
/// The trip and segment ids are written **per point, not per batch**: the unsynced-point
/// query draws by id and can straddle a segment or, after a discard-and-restart, a trip
/// boundary. Hoisting them to batch level would silently mislabel points.
String encodeBatch(String deviceId, List<TrackPoint> points) {
  final array = points
      .map((p) => <String, Object?>{
            'id': p.id,
            'trip_id': p.tripId,
            'segment_id': p.segmentId,
            'ts': p.timestamp,
            'lat': p.latitude,
            'lon': p.longitude,
            'speed_kmh': p.speedKmh,
            'alt_m': p.altitudeM,
            'acc_m': p.accuracyM,
            'bearing': p.bearingDeg,
          })
      .toList(growable: false);

  return jsonEncode(<String, Object?>{
    'device_id': deviceId,
    'points': array,
  });
}