import 'package:flutter_test/flutter_test.dart';
import 'package:shared_preferences/shared_preferences.dart';

import 'package:miler/data/api_config.dart';
import 'package:miler/data/route_order.dart';
import 'package:miler/data/service_profile.dart';
import 'package:miler/views/Dashboard/home/trip.dart';

/// ─────────────────────────────────────────────────────────────────────────
/// THE ADMIN'S ROUTE IS THE ROUTE
///
/// ── The regression ──
///
/// The pickup leg followed the hub's solved `step`. The delivery leg did not,
/// and could not: `step` reached the app only through `GET /miler/assignments`,
/// which is deliberately the *active* queue (`Assigned`/`Accepted`), and a
/// booking leaves those two states the moment it is collected — which is
/// exactly when the delivery leg begins. So every delivery arrived unsequenced
/// and the tab re-sorted it **nearest-first from the rider's GPS fix**, while
/// the hub believed its route was being followed.
///
/// Two systems, two orders, and neither side had any way to notice. That is
/// not a cosmetic difference: the sequence is what the customer's arrival
/// window was quoted from.
///
/// These pin the rule end to end — that an assigned order survives the whole
/// pipeline, that nothing replaces it, and that the fallback is a fallback and
/// says so.
/// ─────────────────────────────────────────────────────────────────────────
void main() {
  TestWidgetsFlutterBinding.ensureInitialized();

  setUp(() {
    SharedPreferences.setMockInitialValues({'userid': 38});
    ServiceProfile.setActive(ServiceProfile.milkMan);
  });
  tearDown(() => ServiceProfile.setActive(ServiceProfile.parcel));

  /// A stop as the Deliveries tab holds it, with a position and a place.
  Map<String, dynamic> stop(
    String id, {
    int step = 0,
    double lat = 11.0,
    double lng = 76.9,
    String? due,
    String status = 'outfordelivery',
  }) => {
    'orderid': id,
    'pickupid': int.tryParse(id) ?? id.hashCode.abs(),
    'orderstatus': status,
    'step': step,
    'pickuplat': lat,
    'pickuplon': lng,
    'droplat': lat,
    'droplon': lng,
    if (due != null) 'expected_pickup_time': due,
  };

  /// Straight-line-ish stand-in for the rider's distance to a stop, so the
  /// proximity branch is exercised without a GPS.
  double fromRider(Map<String, dynamic> s) =>
      ((s['droplat'] as double) - 11.0).abs() * 1000;

  List<String> idsOf(List<Map<String, dynamic>> stops) => [
    for (final s in stops) (s['orderid'] as String),
  ];

  group('an assigned sequence is used, exactly', () {
    test('stops come back in the hub\'s order, not the list\'s', () {
      final (ordered, source) = RouteOrder.sort([
        stop('3', step: 3),
        stop('1', step: 1),
        stop('2', step: 2),
      ]);
      expect(idsOf(ordered), ['1', '2', '3']);
      expect(source, RouteOrderSource.adminSequence);
    });

    test('nearest-first never replaces an assigned order', () {
      // Stop 3 is on the rider's doorstep and stop 1 is furthest away. The old
      // Deliveries sort would have put 3 first. The hub said 1.
      final (ordered, source) = RouteOrder.sort([
        stop('1', step: 1, lat: 11.9),
        stop('2', step: 2, lat: 11.5),
        stop('3', step: 3, lat: 11.0),
      ], distanceTo: fromRider);

      expect(idsOf(ordered), ['1', '2', '3']);
      expect(
        source,
        RouteOrderSource.adminSequence,
        reason:
            'offering a distance function must not tempt the sort into '
            'using it while a route exists',
      );
    });

    test('a booked time never replaces an assigned order either', () {
      final (ordered, _) = RouteOrder.sort(
        [
          stop('1', step: 1, due: '2026-08-21T18:00:00'),
          stop('2', step: 2, due: '2026-08-21T09:00:00'),
        ],
        bookedTimeOf: (s) => DateTime.tryParse('${s['expected_pickup_time']}'),
      );
      expect(idsOf(ordered), ['1', '2']);
    });

    test('one sequenced stop makes the whole set admin-ordered', () {
      // The old sort split the list — sequenced stops by step, the rest by
      // distance — and produced a list that was neither order.
      final (ordered, source) = RouteOrder.sort([
        stop('far', lat: 11.9),
        stop('near', lat: 11.0),
        stop('assigned', step: 1, lat: 11.5),
      ], distanceTo: fromRider);

      expect(source, RouteOrderSource.adminSequence);
      expect(
        idsOf(ordered).first,
        'assigned',
        reason: 'sequenced work leads the route the hub planned',
      );
      expect(
        idsOf(ordered).sublist(1),
        ['far', 'near'],
        reason:
            'the unplanned tail keeps the order it arrived in — it is not '
            're-sorted by distance behind a solved route',
      );
    });

    test('step 0 is "not sequenced", never "first"', () {
      expect(RouteOrder.sequenceOf(stop('a')), 0);
      expect(RouteOrder.sequenceOf(stop('a', step: 1)), 1);
      expect(RouteOrder.hasAdminSequence([stop('a'), stop('b')]), isFalse);
      expect(
        RouteOrder.hasAdminSequence([stop('a'), stop('b', step: 4)]),
        isTrue,
      );
    });

    test('the delivery leg\'s own spelling is read too', () {
      expect(RouteOrder.sequenceOf({'deliverystep': 2}), 2);
      expect(RouteOrder.sequenceOf({'routestep': 5}), 5);
      expect(RouteOrder.sequenceOf({'sequence': '7'}), 7);
    });
  });

  group('the fallback is a fallback', () {
    test('nearest-first is used only with no assigned sequence at all', () {
      final (ordered, source) = RouteOrder.sort([
        stop('far', lat: 11.9),
        stop('near', lat: 11.0),
        stop('mid', lat: 11.5),
      ], distanceTo: fromRider);

      expect(idsOf(ordered), ['near', 'mid', 'far']);
      expect(source, RouteOrderSource.proximity);
      expect(
        source.isAdmin,
        isFalse,
        reason:
            'the screen must be able to tell the rider this is the app\'s '
            'guess and not his route',
      );
    });

    test('booked time is preferred over the rider\'s position', () {
      final (ordered, source) = RouteOrder.sort(
        [
          stop('later', lat: 11.0, due: '2026-08-21T18:00:00'),
          stop('sooner', lat: 11.9, due: '2026-08-21T09:00:00'),
        ],
        distanceTo: fromRider,
        bookedTimeOf: (s) => DateTime.tryParse('${s['expected_pickup_time']}'),
      );
      expect(idsOf(ordered), ['sooner', 'later']);
      expect(source, RouteOrderSource.bookedTime);
    });

    test('with nothing to go on, the backend order is kept', () {
      final (ordered, source) = RouteOrder.sort([stop('b'), stop('a')]);
      expect(idsOf(ordered), [
        'b',
        'a',
      ], reason: 'unordered means unchanged, not shuffled');
      expect(source, RouteOrderSource.backendOrder);
    });

    test('no GPS is not a reason to invent an order', () {
      final (ordered, source) = RouteOrder.sort([
        stop('b', lat: 11.9),
        stop('a', lat: 11.0),
      ]);
      expect(idsOf(ordered), ['b', 'a']);
      expect(source, RouteOrderSource.backendOrder);
    });

    test('each source says out loud what it is', () {
      expect(RouteOrderSource.adminSequence.label, 'Hub route');
      expect(RouteOrderSource.proximity.label, 'Nearest first');
      expect(
        RouteOrderSource.proximity.explanation,
        contains('No route assigned'),
      );
      expect(RouteOrderSource.adminSequence.explanation, contains('assigned'));
    });
  });

  group('API → repository → screen', () {
    test('the sequence survives the booking adapter', () {
      // The adapter builds a FIXED map: a field it does not name is a field no
      // screen can ever see. `step` was not named, so the hub's order was
      // dropped in translation — before any sort had a chance to honour it.
      final stop = ApiConfig.pickupFromBooking({
        'bookingid': 75,
        'bookingreference': 'DM-BK-1',
        'status': 'Converted_To_Consignment',
        'consignmentid': 46,
        'consignmentstatus': 'Out_for_Delivery',
        'step': 4,
        'stoptype': 'delivery',
      });

      expect(RouteOrder.sequenceOf(stop), 4);
      expect(
        stop['type'],
        'delivery',
        reason: 'the leg was hardcoded to "pickup" for every row',
      );
    });

    test('an unsequenced booking maps to 0, not to null or first', () {
      final stop = ApiConfig.pickupFromBooking({
        'bookingid': 82,
        'status': 'Miler_Assigned',
        'step': 0,
      });
      expect(RouteOrder.sequenceOf(stop), 0);
    });

    test('both legs order the same day identically', () {
      // Home orders through Trip.sortStops, Deliveries through RouteOrder.
      // They were two implementations; a stop third on one was second on the
      // other. One rule now, and this is the assertion that keeps it one.
      final day = [
        stop('c', step: 3, lat: 11.0),
        stop('a', step: 1, lat: 11.9),
        stop('b', step: 2, lat: 11.5),
      ];
      final home = Trip.sortStops([...day]);
      final (deliveries, source) = RouteOrder.sort([
        ...day,
      ], distanceTo: fromRider);
      expect(idsOf(home), idsOf(deliveries));
      expect(idsOf(home), ['a', 'b', 'c']);
      expect(source, RouteOrderSource.adminSequence);
    });
  });

  group('the order holds as the day progresses', () {
    test('a partly collected run keeps the assigned sequence', () {
      // Collection changes a stop's status, not its place in the route.
      final (ordered, source) = RouteOrder.sort([
        stop('1', step: 1, status: 'picked'),
        stop('2', step: 2, status: 'accepted'),
        stop('3', step: 3, status: 'outfordelivery'),
      ], distanceTo: fromRider);
      expect(idsOf(ordered), ['1', '2', '3']);
      expect(source, RouteOrderSource.adminSequence);
    });

    test('a fully collected run keeps it too', () {
      final (ordered, _) = RouteOrder.sort([
        stop('1', step: 1, status: 'outfordelivery', lat: 11.9),
        stop('2', step: 2, status: 'outfordelivery', lat: 11.0),
      ], distanceTo: fromRider);
      expect(
        idsOf(ordered),
        ['1', '2'],
        reason:
            'this is precisely where the old code switched to nearest-first',
      );
    });
  });

  group('trips group the route without re-ordering it', () {
    Map<String, dynamic> at(String id, int step, DateTime due) => {
      ...stop(id, step: step),
      'expected_pickup_time': due.toIso8601String(),
    };

    test('grouping into day parts never reorders within a trip', () {
      final trips = Trip.groupIntoTrips([
        at('m3', 3, DateTime(2026, 8, 21, 10)),
        at('m1', 1, DateTime(2026, 8, 21, 8)),
        at('m2', 2, DateTime(2026, 8, 21, 9)),
      ]);
      expect(trips.single.tripNumber, 1);
      expect(idsOf(trips.single.stops), ['m1', 'm2', 'm3']);
    });

    test('the sequence is not re-based per trip', () {
      // Steps 4,5 are the hub's numbers for the afternoon leg of one solved
      // route. Grouping must not renumber them, or reverse them because they
      // are "later" in a list that starts at 1.
      final trips = Trip.groupIntoTrips([
        at('a5', 5, DateTime(2026, 8, 21, 15)),
        at('a4', 4, DateTime(2026, 8, 21, 14)),
        at('m1', 1, DateTime(2026, 8, 21, 9)),
      ]);
      expect(trips.length, 2);
      expect(idsOf(trips.first.stops), ['m1']);
      expect(idsOf(trips.last.stops), ['a4', 'a5']);
      expect(RouteOrder.sequenceOf(trips.last.stops.first), 4);
    });

    test('a backend trip id overrides the day-part grouping', () {
      // The hub's own grouping wins over the app's clock rule, and the stops
      // inside it stay in the hub's order.
      final trips = Trip.groupIntoTrips([
        {...at('b', 2, DateTime(2026, 8, 21, 20)), 'tripid': 'T1'},
        {...at('a', 1, DateTime(2026, 8, 21, 9)), 'tripid': 'T1'},
      ]);
      expect(trips.length, 1, reason: 'morning and evening, one hub trip');
      expect(idsOf(trips.single.stops), ['a', 'b']);
    });

    test('a slot id overrides it as well', () {
      final trips = Trip.groupIntoTrips([
        {...at('a', 1, DateTime(2026, 8, 21, 9)), 'slotid': 'S9'},
        {...at('b', 2, DateTime(2026, 8, 21, 19)), 'slotid': 'S9'},
      ]);
      expect(trips.length, 1);
      expect(idsOf(trips.single.stops), ['a', 'b']);
    });

    test('day parts split the day but not the route', () {
      final trips = Trip.groupIntoTrips([
        at('m', 1, DateTime(2026, 8, 21, 9)),
        at('a', 2, DateTime(2026, 8, 21, 14)),
        at('e', 3, DateTime(2026, 8, 21, 19)),
      ]);
      expect(trips.map((t) => t.tripNumber), [1, 2, 3]);
      expect(
        [for (final t in trips) ...idsOf(t.stops)],
        ['m', 'a', 'e'],
        reason: 'flattening the trips must give back the hub\'s sequence',
      );
    });
  });
}