import 'dart:async';
import 'dart:convert';
import 'dart:io';

import '../pb_auth.dart';
import 'flight_record.dart';

/// The API Server's logbook (`/api/drones/auto`, `/api/flights`) as the
/// recorded-flight upload needs it. [ApiLogbookRemote] is the real one.
abstract class LogbookRemote {
  /// Signed in, so uploads can run.
  bool get available;

  /// The logbook's drone for this aircraft, created on first sight (keyed by
  /// the flight controller's serial, like the Web App's fleet auto-fill).
  Future<String> ensureDrone({required String flightControllerSerial, String? model, String? firmware});

  /// Creates the logbook entry; answers its id.
  Future<String> createFlight(Map<String, Object?> entry);
}

class LogbookException implements Exception {
  const LogbookException(this.message);
  final String message;

  @override
  String toString() => message;
}

/// `2026-10-20`, in local time like the Web App's date field.
String logbookDate(DateTime t) =>
    '${t.year.toString().padLeft(4, '0')}-${t.month.toString().padLeft(2, '0')}-${t.day.toString().padLeft(2, '0')}';

/// `14:05`, the logbook's `HH:MM`.
String logbookTime(DateTime t) => '${t.hour.toString().padLeft(2, '0')}:${t.minute.toString().padLeft(2, '0')}';

/// The track as a GeoJSON LineString, thinned evenly to at most [maxPoints]
/// (the `route_geojson` field caps at 200 kB). Null with fewer than two points.
Map<String, Object?>? routeGeoJson(List<TrackPoint> track, {int maxPoints = 500}) {
  if (track.length < 2) return null;
  final List<TrackPoint> pts;
  if (track.length <= maxPoints) {
    pts = track;
  } else {
    final double step = (track.length - 1) / (maxPoints - 1);
    pts = <TrackPoint>[for (int i = 0; i < maxPoints; i++) track[(i * step).round()]];
  }
  return <String, Object?>{
    'type': 'LineString',
    // GeoJSON is lon, lat (, alt).
    'coordinates': <List<double>>[
      for (final TrackPoint p in pts)
        <double>[
          double.parse(p.longitude.toStringAsFixed(6)),
          double.parse(p.latitude.toStringAsFixed(6)),
          double.parse(p.altitude.toStringAsFixed(1)),
        ],
    ],
  };
}

/// Where the flight took place, for the logbook's "area or route flown":
/// the take-off point, as coordinates.
String areaLabel(FlightRecord r) {
  double? lat = r.homeLatitude, lon = r.homeLongitude;
  if (!validFix(lat, lon) && r.track.isNotEmpty) {
    lat = r.track.first.latitude;
    lon = r.track.first.longitude;
  }
  if (!validFix(lat, lon)) return 'Position not recorded';
  String deg(double v, String pos, String neg) => '${v.abs().toStringAsFixed(5)}° ${v >= 0 ? pos : neg}';
  return 'Take-off ${deg(lat!, 'N', 'S')}, ${deg(lon!, 'E', 'W')}';
}

/// The `/api/flights` body for [r] flown with logbook drone [droneId]: the
/// app-recorded ("automatic") path, the §5 times and maximum height, the track
/// as GeoJSON, and the flight's numbers in the notes.
Map<String, Object?> logbookEntry(FlightRecord r, {required String droneId}) {
  final String notes = <String>[
    'Recorded by PilotVault Fly',
    r.durationLabel,
    '${(r.distanceFlown / 1000).toStringAsFixed(2)} km flown',
    'max ${r.maxDistance.round()} m from home',
    'max ${r.maxSpeed.toStringAsFixed(1)} m/s',
    if (r.batteryStart != null && r.batteryEnd != null) 'battery ${r.batteryStart}% → ${r.batteryEnd}%',
  ].join(' · ');
  final Map<String, Object?>? route = routeGeoJson(r.track);
  return <String, Object?>{
    'operationDate': logbookDate(r.start),
    'startTime': logbookTime(r.start),
    'endTime': logbookTime(r.end),
    'drone': droneId,
    'areaRoute': areaLabel(r),
    if (route != null) 'routeGeojson': route,
    // Height above take-off: the closest the aircraft's barometer gets to AGL.
    'maxAltitudeAgl': double.parse(r.maxAltitude.toStringAsFixed(1)),
    'loggingPath': 'automatic',
    'notes': notes,
  };
}

/// Uploads one recorded flight to the logbook. Returns the record with
/// [FlightRecord.logbookId] set, or [FlightRecord.uploadError] on failure.
/// Simulator flights and flights without a serial are refused up front.
Future<FlightRecord> uploadFlightRecord(FlightRecord r, LogbookRemote remote) async {
  if (r.uploaded) return r;
  try {
    if (r.simulated) throw const LogbookException('Simulator flights are not logbook flights');
    if (!remote.available) throw const LogbookException('Sign in to upload flights');
    final String serial = (r.flightControllerSerial ?? '').trim();
    if (serial.isEmpty) throw const LogbookException('The aircraft\'s serial was not read during this flight');
    final String drone = await remote.ensureDrone(flightControllerSerial: serial, model: r.aircraftModel, firmware: r.firmware);
    r.logbookId = await remote.createFlight(logbookEntry(r, droneId: drone));
    r.uploadError = null;
  } on LogbookException catch (e) {
    r.uploadError = e.message;
  } catch (e) {
    r.uploadError = e is SocketException || e is TimeoutException ? 'The API Server could not be reached' : e.toString();
  }
  return r;
}

/// [LogbookRemote] over the API Server, as the signed-in pilot ([auth]).
class ApiLogbookRemote implements LogbookRemote {
  ApiLogbookRemote({PbAuth? auth}) : _auth = auth;

  final PbAuth? _auth;
  PbAuth get _a => _auth ?? auth;

  static const Duration _timeout = Duration(seconds: 15);

  @override
  bool get available => _a.isAuthed;

  @override
  Future<String> ensureDrone({required String flightControllerSerial, String? model, String? firmware}) async {
    final (int status, Map<String, dynamic> body) = await _send('POST', '/api/drones/auto', <String, Object?>{
      'flightControllerSerial': flightControllerSerial,
      if (model != null) 'model': model,
      if (firmware != null) 'firmware': firmware,
    });
    final Object? drone = body['drone'];
    final Object? id = drone is Map ? drone['id'] : null;
    if ((status == 200 || status == 201) && id is String && id.isNotEmpty) return id;
    throw LogbookException(_error(body, 'Could not add the aircraft to the fleet ($status)'));
  }

  @override
  Future<String> createFlight(Map<String, Object?> entry) async {
    final (int status, Map<String, dynamic> body) = await _send('POST', '/api/flights', entry);
    final Object? flight = body['flight'];
    final Object? id = flight is Map ? flight['id'] : null;
    if ((status == 200 || status == 201) && id is String && id.isNotEmpty) return id;
    throw LogbookException(_error(body, 'The logbook refused the flight ($status)'));
  }

  static String _error(Map<String, dynamic> body, String fallback) {
    final Object? e = body['error'] ?? body['message'];
    return e is String && e.isNotEmpty ? e : fallback;
  }

  Future<(int, Map<String, dynamic>)> _send(String method, String path, Object body) async {
    final HttpClient http = HttpClient()..connectionTimeout = _timeout;
    try {
      final HttpClientRequest req = await http.openUrl(method, Uri.parse('${_a.serverUrl}$path'));
      req.headers.set(HttpHeaders.authorizationHeader, _a.token);
      req.headers.contentType = ContentType.json;
      req.add(utf8.encode(jsonEncode(body)));
      final HttpClientResponse resp = await req.close().timeout(_timeout);
      final String text = await resp.transform(utf8.decoder).join().timeout(_timeout);
      Map<String, dynamic> json = <String, dynamic>{};
      try {
        final Object? decoded = text.isEmpty ? null : jsonDecode(text);
        if (decoded is Map) json = Map<String, dynamic>.from(decoded);
      } catch (_) {}
      if (resp.statusCode == 401) throw const LogbookException('Your session expired: sign in again');
      return (resp.statusCode, json);
    } finally {
      http.close(force: true);
    }
  }
}