import 'dart:convert';

import 'package:flutter_test/flutter_test.dart';
import 'package:http/http.dart' as http;
import 'package:http/testing.dart';
import 'package:shared_preferences/shared_preferences.dart';

import 'package:miler/data/api_config.dart';
import 'package:miler/data/api_status.dart';
import 'package:miler/data/consignment_state.dart';
import 'package:miler/data/miler_api.dart';
import 'package:miler/data/mock_backend.dart';

/// ─────────────────────────────────────────────────────────────────────────
/// THE RUNG BETWEEN THE COUNTER AND THE ROAD
///
/// Backend contract change, 21 Aug 2026. Until then `pickup-complete` pushed a
/// hyperlocal booking straight to `Out_for_Delivery`, so the hub's board said
/// *actively delivering* for food still on the kitchen counter, and the app
/// had nowhere honest to put the one fact only the rider knows — that he has
/// set off. **Start round** could therefore only ever be a note to self.
///
/// The pivot now stops at `Collected_By_Miler` and
/// `POST /miler/consignments/:id/start-delivery` makes the release, so the
/// press is a real write again. These pin the four pieces that has to hold:
/// the state exists and is not mistaken for a hub hold, the gate routes it to
/// the rider rather than blaming the warehouse, the release is asked of the
/// server before anything local is written, and a list row's consignment
/// status outranks the booking status that stopped being informative at
/// conversion.
/// ─────────────────────────────────────────────────────────────────────────
void main() {
  TestWidgetsFlutterBinding.ensureInitialized();

  late List<http.Request> sent;

  /// Answers every request with [body], and records what was asked.
  void stub({
    Map<String, dynamic> body = const {'success': true},
    int code = 200,
  }) {
    sent = <http.Request>[];
    MilerApi.client = MockClient((req) async {
      sent.add(req);
      return http.Response(
        json.encode(body),
        code,
        headers: const {'content-type': 'application/json'},
      );
    });
  }

  /// Answers each path from [routes], falling back to a bare success.
  void stubRoutes(Map<String, http.Response> routes) {
    sent = <http.Request>[];
    MilerApi.client = MockClient((req) async {
      sent.add(req);
      for (final entry in routes.entries) {
        if (req.url.path.endsWith(entry.key)) return entry.value;
      }
      return http.Response(
        json.encode({'success': true}),
        200,
        headers: const {'content-type': 'application/json'},
      );
    });
  }

  http.Response jsonRes(Object body, [int code = 200]) => http.Response(
    json.encode(body),
    code,
    headers: const {'content-type': 'application/json'},
  );

  setUp(() async {
    MockBackend.enabled = false;
    SharedPreferences.setMockInitialValues({'authtoken': 'test-token'});
    await ApiConfig.setToken('test-token');
    stub();
  });

  tearDown(() {
    MilerApi.client = http.Client();
    MockBackend.enabled = kMockBackend;
  });

  group('the state itself', () {
    test('Collected_By_Miler parses, however it is spelled', () {
      for (final raw in [
        'Collected_By_Miler',
        'collected_by_miler',
        'COLLECTED BY MILER',
      ]) {
        expect(
          consignmentStateFromRaw(raw),
          ConsignmentState.collectedByMiler,
          reason:
              '$raw must not fall through to unknown — an unrecognised '
              'state blocks the door',
        );
      }
    });

    test('it is the rider holding the parcel, not the hub', () {
      const state = ConsignmentState.collectedByMiler;
      expect(
        state.awaitsHub,
        isFalse,
        reason:
            'telling a rider the hub has the parcel in his own box is the '
            'exact error this state exists to prevent',
      );
      expect(state.needsRelease, isTrue);
      expect(
        state.isDeliverable,
        isFalse,
        reason: 'deliver is refused until start-delivery has run',
      );
      expect(state.isClosed, isFalse);
    });

    test('a skip is reportable the moment the parcel is collected', () {
      // Widened server-side on 21 Aug 2026: a customer who is not home is not
      // home whether or not the rider remembered to press Start round.
      expect(ConsignmentState.collectedByMiler.canSkip, isTrue);
      expect(ConsignmentState.outForDelivery.canSkip, isTrue);
      expect(ConsignmentState.delivered.canSkip, isFalse);
      expect(ConsignmentState.inwardedAtHub.canSkip, isFalse);
    });

    test('the gate sends the rider to Start round, not to the hub', () {
      expect(
        ConsignmentGate.gateFor(ConsignmentState.collectedByMiler),
        DeliverGate.needsRelease,
      );
      expect(
        ConsignmentGate.gateFor(ConsignmentState.inwardedAtHub),
        DeliverGate.awaitingHub,
        reason: 'the genuine hub guard must survive this change',
      );
      expect(
        ConsignmentGate.gateFor(ConsignmentState.delivered),
        DeliverGate.alreadyDelivered,
      );
      expect(
        ConsignmentGate.gateFor(ConsignmentState.outForDelivery),
        DeliverGate.deliverable,
      );
    });
  });

  group('reading the state', () {
    test('one call answers it, where it used to take a history', () async {
      stubRoutes({
        '/miler/consignments/34': jsonRes({
          'success': true,
          'data': {'consignmentid': 34, 'status': 'Collected_By_Miler'},
        }),
      });

      expect(
        await ConsignmentGate.stateOf(34),
        ConsignmentState.collectedByMiler,
      );
      expect(sent.single.method, 'GET');
      expect(
        sent.single.url.path.endsWith('/miler/consignments/34'),
        isTrue,
        reason: 'the logs walk was one round trip and a sort per stop',
      );
    });

    test(
      'the flags answer it when the word is one this build cannot read',
      () async {
        stubRoutes({
          '/miler/consignments/34': jsonRes({
            'success': true,
            'data': {
              'status': 'Handed_To_Locker_Bank',
              'collected': false,
              'out_for_delivery': false,
              'delivered': true,
            },
          }),
        });

        expect(
          await ConsignmentGate.stateOf(34),
          ConsignmentState.delivered,
          reason:
              'delivered is read first: mistaking a finished delivery for an '
              'open one makes a rider post work he has already done',
        );
      },
    );

    test('an old deployment still answers, through the history', () async {
      // A rider mid-round on this build meeting a server that has not shipped
      // the route yet must not be stranded at a door.
      stubRoutes({
        '/miler/consignments/logs/34': jsonRes([
          {'historyid': 2, 'eventstatus': 'Out_for_Delivery'},
          {'historyid': 1, 'eventstatus': 'Created'},
        ]),
        '/miler/consignments/34': jsonRes({
          'success': false,
          'message': 'not found',
        }, 404),
      });

      expect(
        await ConsignmentGate.stateOf(34),
        ConsignmentState.outForDelivery,
      );
      expect(
        sent.map((r) => r.url.path.endsWith('/miler/consignments/logs/34')),
        contains(true),
      );
    });

    test('a read that fails is not evidence of anything', () async {
      stub(body: const {'success': false, 'message': 'gateway'}, code: 502);
      expect(await ConsignmentGate.stateOf(34), ConsignmentState.unknown);
      expect(
        ConsignmentGate.gateFor(ConsignmentState.unknown),
        DeliverGate.unknown,
        reason: 'blocking on a timed-out GET strands a rider at a door',
      );
    });

    test('nothing is asked about a consignment that does not exist', () async {
      expect(await ConsignmentGate.stateOf(''), ConsignmentState.unknown);
      expect(await ConsignmentGate.stateOf('0'), ConsignmentState.unknown);
      expect(sent, isEmpty);
    });
  });

  group('the release', () {
    test('start-delivery posts against the consignment', () async {
      await MilerApi.startDelivery(34);
      expect(sent.single.method, 'POST');
      expect(
        sent.single.url.path.endsWith('/miler/consignments/34/start-delivery'),
        isTrue,
      );
    });

    test('it carries an idempotency key, stable across a retry', () async {
      await MilerApi.startDelivery(34);
      final first = sent.single.headers['Idempotency-Key'];
      stub();
      await MilerApi.startDelivery(34);
      expect(first, isNotNull);
      expect(
        sent.single.headers['Idempotency-Key'],
        first,
        reason:
            'a key that changes per press is not idempotency — a dropped '
            'response would release the round twice',
      );
    });

    test('a different consignment gets a different key', () async {
      await MilerApi.startDelivery(34);
      final first = sent.single.headers['Idempotency-Key'];
      stub();
      await MilerApi.startDelivery(35);
      expect(sent.single.headers['Idempotency-Key'], isNot(first));
    });

    test(
      'the write that is already running is waited out, not reported',
      () async {
        var calls = 0;
        sent = <http.Request>[];
        MilerApi.client = MockClient((req) async {
          sent.add(req);
          calls++;
          // The first attempt's response was lost; the server is running it.
          if (calls == 1) {
            return jsonRes({
              'success': false,
              'code': 'IDEMPOTENCY_IN_PROGRESS',
              'message': 'in progress',
            }, 409);
          }
          return jsonRes({
            'success': true,
            'data': {'status': 'Out_for_Delivery'},
          });
        });

        final res = await MilerApi.startDelivery(34);
        expect(
          res.ok,
          isTrue,
          reason:
              'telling a rider his round failed while it is in the act of '
              'succeeding sends him to press the same refusal again',
        );
        expect(calls, 2);
      },
    );

    test('a failure names the code, not just the prose', () async {
      stub(
        body: const {
          'success': false,
          'code': 'INVALID_STATE',
          'message': 'consignment is not collected',
        },
        code: 400,
      );
      final res = await MilerApi.startDelivery(34);
      expect(res.ok, isFalse);
      expect(
        res.isInvalidState,
        isTrue,
        reason: 'branching on message text breaks the day it is reworded',
      );
    });
  });

  group('the list row carries the delivery half', () {
    Map<String, dynamic> booking(String status, {String? consignment}) => {
      'bookingid': 59,
      'bookingreference': 'DM-BK-501CB551-45130',
      'status': status,
      if (consignment != null) 'consignmentstatus': consignment,
      'consignmentid': 34,
    };

    test('the consignment id arrives on the row, so nothing has to hunt', () {
      // The 17-of-29 blocker: bookings carried no consignment id and
      // /miler/assignments listed only 12 of them, so for 17 collected stops
      // the delivery reference was unobtainable by any route.
      final stop = ApiConfig.pickupFromBooking(
        booking('Converted_To_Consignment', consignment: 'Collected_By_Miler'),
      );
      expect(stop['consignmentid'], '34');
    });

    test('a delivered consignment is not an open delivery stop', () {
      final stop = ApiConfig.pickupFromBooking(
        booking('Converted_To_Consignment', consignment: 'Delivered'),
      );
      expect(
        stop['orderstatus'],
        'delivered',
        reason:
            'the booking word is terminal at conversion and says the same '
            'thing for a parcel in the box and one handed over an hour ago',
      );
    });

    test('collected and on-the-road are told apart on the list', () {
      expect(
        ApiConfig.pickupFromBooking(
          booking(
            'Converted_To_Consignment',
            consignment: 'Collected_By_Miler',
          ),
        )['orderstatus'],
        'picked',
      );
      expect(
        ApiConfig.pickupFromBooking(
          booking('Converted_To_Consignment', consignment: 'Out_for_Delivery'),
        )['orderstatus'],
        'outfordelivery',
      );
    });

    test('a hub-side consignment keeps the booking’s own word', () {
      // Not this rider's parcel to act on, and it has no rung on his card —
      // inventing one would draw somebody else's warehouse on his screen.
      final stop = ApiConfig.pickupFromBooking(
        booking('Converted_To_Consignment', consignment: 'Inwarded_at_Hub'),
      );
      expect(stop['orderstatus'], 'picked');
    });

    test('a row with no consignment status behaves exactly as before', () {
      expect(
        ApiConfig.pickupFromBooking(booking('Pickup_Scheduled'))['orderstatus'],
        'accepted',
      );
      expect(
        ApiConfig.pickupFromBooking(
          booking('Converted_To_Consignment'),
        )['orderstatus'],
        'picked',
      );
    });
  });

  group('arrival is a rung the hub can see', () {
    test('Arrived_At_Pickup is the status reached writes', () {
      expect(
        BookingStatus.parse('Arrived_At_Pickup'),
        BookingStatus.arrivedAtPickup,
      );
      expect(ApiConfig.legacyStatusFromNew('Arrived_At_Pickup'), 'arrived');
    });

    test('the older At_Customer spelling means the same thing', () {
      expect(BookingStatus.parse('At_Customer'), BookingStatus.arrivedAtPickup);
      expect(ApiConfig.legacyStatusFromNew('At_Customer'), 'arrived');
    });

    test('arriving is not collecting', () {
      expect(
        BookingStatus.arrivedAtPickup.isCollected,
        isFalse,
        reason:
            'the work boundary must not move a bag the rider has not '
            'picked up yet onto the delivery tab',
      );
      expect(BookingStatus.arrivedAtPickup.isOpen, isTrue);
      expect(BookingStatus.arrivedAtPickup.canCancel, isTrue);
    });
  });
}