import 'dart:convert';

import 'package:doormile_cx/data/api_client.dart';
import 'package:doormile_cx/data/api_exception.dart';
import 'package:doormile_cx/data/live_doormile_api.dart';
import 'package:doormile_cx/data/models.dart';
import 'package:doormile_cx/data/session_store.dart';
import 'package:flutter_test/flutter_test.dart';
import 'package:http/http.dart' as http;
import 'package:http/testing.dart';

/// What [LiveDoormileApi] actually puts on the wire, checked field by field
/// against the customer API document.
///
/// These are not parser tests. Every one of them exists because a plausible,
/// readable, wrong spelling — `otp` for `code`, `latitude` for `lat`, `min` for
/// `minRupees` — costs a whole feature at runtime and nothing at compile time.
///
/// Where the written contract and the running server disagree, these tests
/// follow the server. The `otp`/`code` case below is why.

class _Sent {
  http.Request? last;
  Map<String, dynamic> get body =>
      jsonDecode(last!.body) as Map<String, dynamic>;
}

({LiveDoormileApi api, _Sent sent}) _api(Object responseData) {
  final sent = _Sent();
  final http.Client transport = MockClient((request) async {
    sent.last = request;
    return http.Response(
      jsonEncode({'success': true, 'data': responseData}),
      200,
      headers: {'content-type': 'application/json'},
    );
  });
  return (
    api: LiveDoormileApi(
      client: ApiClient(httpClient: transport, sessions: MemorySessionStore()),
    ),
    sent: sent,
  );
}

void main() {
  // ── This test used to assert the opposite, and that is why the bug shipped ──
  //
  // The written contract names this field `otp`. The server does not:
  // CxVerifyOtp reads `json:"code"` and treats a body without it as an empty
  // code, answering 400 "Enter the code we sent you" to every sign-in — with
  // any code, correct or not. Verified against production: `otp` gets that 400,
  // `code` gets 401 "That code did not match" for a wrong code, and a session
  // for a right one.
  //
  // The document was wrong and this test agreed with it, so nothing failed
  // until a human tried to log in. The assertion is inverted deliberately —
  // the server is the contract.
  test('OTP verification sends `code` — the field the server actually reads', () async {
    final t = _api({
      'accessToken': 'a',
      'refreshToken': 'r',
      'expiresIn': 3600,
      'customer': {'id': 1042, 'name': 'Alex Kumar', 'phone': '+919876543210'},
    });

    final customer = await t.api.verifyOtp('9876543210', '1234');

    expect(t.sent.last!.url.path, endsWith('/customer/auth/otp/verify'));
    expect(t.sent.body['code'], '1234');
    expect(t.sent.body['identifier'], '+919876543210');
    expect(
      t.sent.body.containsKey('otp'),
      isFalse,
      reason: 'the server ignores `otp` and reads the body as an empty code',
    );
    expect(t.sent.last!.headers['Idempotency-Key'], isNotNull);
    expect(customer.name, 'Alex Kumar');
  });

  test('a fare estimate prices packages, and reads the rupee band back', () async {
    final t = _api({
      'minRupees': 240,
      'maxRupees': 310,
      'routeKm': 348.5,
      'breakdown': {'baseFare': 180, 'additionalStopsUplift': 60},
    });

    final fare = await t.api.estimateFare(
      pickup: const Place(title: 'Home', sub: '', lat: 13.0827, lng: 80.2707),
      destinations: [
        DestinationGroup(
          destination: Destination(stateCode: 'TN', districtCode: 'CHN'),
          packageCount: 2,
        ),
      ],
    );

    // ── `lat`/`lng`, not `latitude`/`longitude` ──
    //
    // The written contract says the long spelling and this app sent it. The
    // server reads the short one, so it saw a pickup with no coordinates, could
    // not place it in a serviceable area, and answered every booking with
    // 422 `unserviceable`. Verified against production on 2026-09-23 one
    // request apart — same pickup, same slot: long spelling 422, short
    // spelling 201 and booking DM-252803.
    final pickup = t.sent.body['pickup'] as Map<String, dynamic>;
    expect(pickup['lat'], 13.0827);
    expect(pickup['lng'], 80.2707);
    expect(pickup.containsKey('latitude'), isFalse);

    final destination =
        (t.sent.body['destinations'] as List).single as Map<String, dynamic>;
    expect(destination['stateCode'], 'TN');
    // One entry per package, and no weight on any of them — the customer is
    // never asked what a parcel weighs.
    expect((destination['packages'] as List).length, 2);

    expect(fare.min, 240);
    expect(fare.max, 310);
    expect(fare.routeKm, 348.5);
  });

  test('a booking nests its destination details', () async {
    final t = _api({
      'reference': 'DM-482913',
      'stage': 'booked',
      'status': 'active',
      'cancellable': true,
      'createdAt': 1788775499000,
      'slotId': 'slot_20260908_t2',
      'pickup': {
        'title': 'Home',
        'sub': 'Flat 4B, Green Towers',
        'latitude': 13.0827,
        'longitude': 80.2707,
      },
      'destinations': [
        {
          'index': 0,
          'stateName': 'Tamil Nadu',
          'districtName': 'Chennai',
          'packageCount': 1,
          'codAmount': 450,
          'trackingId': null,
          'stage': null,
        },
      ],
    });

    await t.api.client.adoptSession(
      Session(
        accessToken: 'a',
        refreshToken: 'r',
        expiresAt: DateTime.now().add(const Duration(hours: 1)),
        customer: const Customer(
          id: '1042',
          name: 'Alex Kumar',
          phone: '+919876543210',
          email: '',
        ),
      ),
    );

    final group = DestinationGroup(
      destination: Destination(stateCode: 'TN', districtCode: 'CHN'),
    );
    group.details.update(
      recipientName: 'Priya S',
      building: '12/A',
      street: 'MG Road',
      instructions: 'Handle with care',
    );

    final booking = await t.api.createBooking(
      pickup: const Place(
        title: 'Home',
        sub: 'Flat 4B, Green Towers',
        lat: 13.0827,
        lng: 80.2707,
      ),
      destinations: [group],
      slotId: 'slot_20260908_t2',
    );

    final body = t.sent.body;
    final pickup = body['pickup'] as Map<String, dynamic>;
    expect(pickup['lat'], 13.0827);

    // ── The pickup carries no contact ──
    //
    // It used to send `contactName` and `contactPhone` here and this test
    // asserted them. The create contract's pickup is `{title, sub, lat, lng}`;
    // extra keys are dropped without an error, and the rider's number is
    // derived by the backend from the account. Two fields written on every
    // booking and read by nobody.
    expect(pickup.containsKey('contactName'), isFalse);
    expect(pickup.containsKey('contactPhone'), isFalse);

    final destination =
        (body['destinations'] as List).single as Map<String, dynamic>;

    // ── Nested, not flat ──
    //
    // The previous shape spread these across the destination and this test
    // asserted `details` was absent. The contract nests them, and a
    // destination's extra keys are dropped silently — so the whole
    // full-address path was being accepted with a 201 and thrown away.
    //
    // NOT yet confirmed against the running server. The `lat`/`lng` fix was
    // proven with two identical requests one apart; this deserves the same
    // before it is trusted in production.
    final details = destination['details'] as Map<String, dynamic>;
    expect(details['recipientName'], 'Priya S');
    expect(details['building'], '12/A');
    expect(details['street'], 'MG Road');
    // The note has its own field per destination; it is not the visit's line.
    expect(details['instructions'], 'Handle with care');
    expect(destination.containsKey('recipientName'), isFalse);

    // `remarks` is now only the handover person, and there is none here.
    expect(body.containsKey('remarks'), isFalse);

    // And the response — which names the state and district but sends no
    // codes — must still render as a destination.
    expect(booking.reference, 'DM-482913');
    expect(booking.pickup.lat, 13.0827);
    final read = booking.destinations.single;
    expect(read.destination.label, 'Chennai, Tamil Nadu');
    expect(read.index, 0);
    expect(read.codAmount, 450);
    expect(read.trackingId, isNull);
  });

  test('the cancel window closes when the Miler arrives', () {
    final t = _api(const {});
    expect(t.api.isCancellable(JourneyStage.onTheWay), isTrue);
    expect(t.api.isCancellable(JourneyStage.arrived), isFalse);
    expect(t.api.isCancellable(JourneyStage.pickedUp), isFalse);
  });

  test('booking limits carry the COD cap', () {
    const limits = BookingLimits();
    expect(limits.allowsCod, isFalse);
    expect(
      BookingLimits.fromJson(const {
        'maxDestinations': 1,
        'maxPackages': 20,
        'maxCodAmount': 5000,
      }).maxCodAmount,
      5000,
    );
  });

  group('error codes', () {
    /// Drives a real failure through [ApiClient], because the translation that
    /// matters happens while the response is being decoded.
    Future<ApiException> failing(int status, String code) async {
      final client = ApiClient(
        httpClient: MockClient(
          (_) async => http.Response(
            jsonEncode({
              'success': false,
              'error': {'code': code, 'message': 'Something the server said'},
            }),
            status,
            headers: {'content-type': 'application/json'},
          ),
        ),
        sessions: MemorySessionStore(),
      );
      try {
        await client.get('/bookings', authenticated: false);
      } on ApiException catch (e) {
        return e;
      }
      fail('expected $code to throw');
    }

    test('the contract spells its codes in capitals; the client translates', () async {
      expect((await failing(401, 'UNAUTHORIZED')).isAuthFailure, isTrue);
      expect((await failing(409, 'SLOT_CAPACITY_FULL')).needsFreshSlots, isTrue);
      expect((await failing(400, 'SLOT_EXPIRED')).needsFreshSlots, isTrue);
      expect(
        (await failing(409, 'BOOKING_NOT_CANCELLABLE')).code,
        ApiException.notCancellable,
      );
      expect(
        (await failing(422, 'UNSERVICEABLE_PINCODE')).code,
        ApiException.unserviceable,
      );
      expect((await failing(429, 'RATE_LIMITED')).isTransient, isTrue);
      // The raw code is kept for the log line and the support report.
      expect((await failing(401, 'UNAUTHORIZED')).serverCode, 'UNAUTHORIZED');
      // An unknown code still lands somewhere useful: the HTTP status.
      expect((await failing(404, 'NO_SUCH_THING')).code, ApiException.notFound);
    });
  });

  test('a paged list is read through its wrapper as well as beside it', () async {
    final client = ApiClient(
      httpClient: MockClient(
        (_) async => http.Response(
          jsonEncode({
            'success': true,
            'data': {
              'items': [
                {'reference': 'DM-1'},
              ],
              'nextCursor': 'cur_2',
              'total': 9,
            },
          }),
          200,
          headers: {'content-type': 'application/json'},
        ),
      ),
      sessions: MemorySessionStore(),
    );

    final page = await client.get('/bookings', authenticated: false);
    expect(page.rows.single['reference'], 'DM-1');
    expect(page.nextCursor, 'cur_2');
    expect(page.total, 9);
  });
}