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

import 'package:miler/controllers/pickups_controller.dart';
import 'package:miler/data/geofence.dart';
import 'package:miler/data/miler_api.dart';

/// ─────────────────────────────────────────────────────────────────────────
/// THE PROXIMITY FENCE
///
/// This is the control that decides whether "Picked up" means the rider was
/// standing at the door or merely pressed a button, and it has been wrong in
/// four directions inside one year: compiled off by default, set to a 10 m
/// radius no consumer GPS can resolve, failing **open** on any thrown
/// exception, and crediting the phone's own error to the rider so that a vague
/// fix bought slack rather than a refusal.
///
/// So the tests below are not a spot check of the arithmetic. They pin, in
/// order:
///
///  1. the **switch** — on by default, because that default has flipped twice;
///  2. the **radius** — 100 m, inclusive at the boundary;
///  3. the **distance table** the spec asks for, 0 m to 250 m;
///  4. every way of **failing to measure**, each of which must refuse;
///  5. the one that matters most — **a blocked rung sends no HTTP request.**
///
/// (5) is the whole point. A fence that shows a message and posts the status
/// anyway is worse than no fence: the hub is told the rider was there *and*
/// the app claims to have checked.
/// ─────────────────────────────────────────────────────────────────────────

/// A stop in Coimbatore. Any point would do; a real one keeps the numbers
/// recognisable when a failure prints them.
const double kTargetLat = 11.0272;
const double kTargetLng = 76.9905;

/// Metres per degree of latitude. Constant enough for a fixture — the tests
/// assert against what [Geolocator.distanceBetween] actually measures, not
/// against this, so the approximation cannot make a test pass wrongly.
const double _metresPerDegreeLat = 111320.0;

/// A rider fix [metres] due north of the stop.
Position riderAt(
  double metres, {
  double accuracy = 8,
  Duration age = Duration.zero,
}) => Position(
  latitude: kTargetLat + (metres / _metresPerDegreeLat),
  longitude: kTargetLng,
  timestamp: DateTime.now().subtract(age),
  accuracy: accuracy,
  altitude: 0,
  altitudeAccuracy: 0,
  heading: 0,
  headingAccuracy: 0,
  speed: 0,
  speedAccuracy: 0,
);

void useFix(Position p) =>
    Geofence.positionProvider = () async => GeofenceFix(position: p);

void useFailure(GeofenceOutcome outcome) =>
    Geofence.positionProvider = () async => GeofenceFix(failure: outcome);

void main() {
  tearDown(Geofence.useDevice);

  // ───────────────────────────────────────────────────────────────────────
  group('the switch and the radius', () {
    test('enforcement is ON by default', () {
      // It was `defaultValue: false`, so every release build shipped with the
      // fence returning true on its third line. If this fails, either the
      // default was reverted — which is the release blocker this file exists to
      // prevent — or the run passed `--dart-define=ENFORCE_GEOFENCE=false`, in
      // which case the failure is correct and is telling you so.
      expect(
        kGeofenceEnforced,
        isTrue,
        reason:
            'Proximity enforcement must be ON by default. Either the default '
            'was reverted, or this run passed ENFORCE_GEOFENCE=false.',
      );
    });

    test('the radius is 100 metres, and there is only one of them', () {
      // The app once held three: a configured `pickupradius` defaulting to 100,
      // a hardcoded 500 in Home's bulk gate, and 10 in the controller. Which
      // fence a rider met depended on whether he ticked boxes or slid a sheet.
      expect(kGeofenceRadiusMetres, 100);
    });

    test('one fix may serve a batch, but only briefly', () {
      // [kGeofenceFixReuse] is what makes a twenty-order bulk action cost one
      // GPS settle instead of twenty. It is a performance change to a safety
      // control, so the two bounds that keep it honest are asserted here.
      expect(
        kGeofenceFixReuse,
        lessThanOrEqualTo(kGeofenceFixMaxAge),
        reason:
            'the reuse window must sit inside the staleness rule — a fix too '
            'old to measure with cannot become acceptable by being cached',
      );
      // At walking pace (~1.4 m/s) the window is ~20 m of possible drift
      // against a 100 m fence. Riding away covers the radius inside it, so a
      // rider who genuinely leaves is refused on the next real fix rather than
      // carried to the next door by the cached one.
      expect(
        kGeofenceFixReuse.inSeconds * 1.4,
        lessThan(kGeofenceRadiusMetres / 2),
        reason: 'drift during the window must stay well under the radius',
      );
    });

    test('resetting the cache is available to sign-out and tests', () {
      // A cached position is a fact about a rider. It must not outlive him on a
      // shared handset.
      Geofence.resetCache();
      Geofence.useDevice();
    });

    test('a cached fix has a shelf life, and a vague one is rejected', () {
      expect(kGeofenceFixMaxAge, const Duration(seconds: 30));
      expect(
        kGeofenceMaxAccuracyMetres,
        lessThan(kGeofenceRadiusMetres),
        reason:
            'a fix whose error is as large as the fence cannot resolve it, and '
            'must be refused rather than credited',
      );
    });
  });

  // ───────────────────────────────────────────────────────────────────────
  group('the distance table', () {
    // Every case the spec names. Each asserts the *rule* against what
    // Geolocator actually measured, so a fixture that drifts by a metre cannot
    // quietly invert a boundary case.
    for (final metres in const [0.0, 25.0, 50.0, 99.0, 100.0, 101.0, 125.0,
      250.0]) {
      test('${metres.round()} m', () async {
        final pos = riderAt(metres);
        useFix(pos);

        final measured = Geofence.distanceBetween(
          kTargetLat,
          kTargetLng,
          pos.latitude,
          pos.longitude,
        );
        expect(
          measured,
          closeTo(metres, 1.0),
          reason: 'fixture should sit where it claims',
        );

        final d = await Geofence.check(
          targetLat: kTargetLat,
          targetLng: kTargetLng,
          action: 'Arrived',
        );

        final shouldAllow = measured <= kGeofenceRadiusMetres;
        expect(
          d.allowed,
          shouldAllow,
          reason:
              'at ${measured.toStringAsFixed(1)} m against a '
              '${kGeofenceRadiusMetres.round()} m fence',
        );
        expect(
          d.outcome,
          shouldAllow ? GeofenceOutcome.inside : GeofenceOutcome.outside,
        );
        expect(d.distanceMetres, closeTo(measured, 0.001));
        expect(d.accuracyMetres, 8);
        expect(d.timestamp, isNotNull);
      });
    }

    test('the boundary is inclusive — 100 m is in, a hair over is out', () {
      // Stated as arithmetic rather than as a fixture, because this is the one
      // place a `<` for a `<=` changes a rider's day and no GPS fixture can be
      // placed accurately enough to catch it.
      expect(99.999 <= kGeofenceRadiusMetres, isTrue);
      expect(100.0 <= kGeofenceRadiusMetres, isTrue);
      expect(100.001 <= kGeofenceRadiusMetres, isFalse);
    });

    test('a refusal tells the rider how far, and in a unit he uses', () async {
      useFix(riderAt(240));
      final d = await Geofence.check(
        targetLat: kTargetLat,
        targetLng: kTargetLng,
        action: 'Arrived',
      );
      expect(d.allowed, isFalse);
      expect(d.reason, contains('240 m'));
      expect(d.reason, contains('100 m'));
      expect(d.reason, contains('arrived'));
      // Never a developer error, a status code or a coordinate pair.
      expect(d.reason, isNot(contains('Exception')));
      expect(d.reason, isNot(contains('null')));
    });

    test('over a kilometre reads in kilometres', () async {
      useFix(riderAt(4200));
      final d = await Geofence.check(
        targetLat: kTargetLat,
        targetLng: kTargetLng,
        action: 'Delivered',
      );
      expect(d.reason, contains('4.2 km'));
      expect(d.reason, contains('delivered'));
    });

    test('the verb follows the rung', () async {
      useFix(riderAt(500));
      for (final action in const [
        'Arrived',
        'Picked',
        'Picked up',
        'Delivery arrived',
        'Delivered',
        'Handed over',
      ]) {
        final d = await Geofence.check(
          targetLat: kTargetLat,
          targetLng: kTargetLng,
          action: action,
        );
        expect(d.allowed, isFalse, reason: action);
        expect(d.reason, contains(action.toLowerCase()), reason: action);
      }
    });
  });

  // ───────────────────────────────────────────────────────────────────────
  group('every way of failing to measure is a refusal', () {
    // The old implementation allowed on four of these six. That is what made
    // the fence decorative: switching location off opened every rung.

    test('GPS switched off', () async {
      useFailure(GeofenceOutcome.serviceDisabled);
      final d = await Geofence.check(
        targetLat: kTargetLat,
        targetLng: kTargetLng,
        action: 'Arrived',
      );
      expect(d.allowed, isFalse);
      expect(d.outcome, GeofenceOutcome.serviceDisabled);
      expect(d.reason, contains('Location is switched off'));
    });

    test('permission denied', () async {
      useFailure(GeofenceOutcome.permissionDenied);
      final d = await Geofence.check(
        targetLat: kTargetLat,
        targetLng: kTargetLng,
        action: 'Delivered',
      );
      expect(d.allowed, isFalse);
      expect(d.outcome, GeofenceOutcome.permissionDenied);
      expect(d.reason, contains('Allow location access'));
    });

    test('permission denied forever points at Settings', () async {
      useFailure(GeofenceOutcome.permissionDeniedForever);
      final d = await Geofence.check(
        targetLat: kTargetLat,
        targetLng: kTargetLng,
        action: 'Arrived',
      );
      expect(d.allowed, isFalse);
      expect(d.outcome, GeofenceOutcome.permissionDeniedForever);
      expect(d.reason, contains('Settings'));
    });

    test('a timeout waiting for the fix', () async {
      useFailure(GeofenceOutcome.timeout);
      final d = await Geofence.check(
        targetLat: kTargetLat,
        targetLng: kTargetLng,
        action: 'Arrived',
      );
      expect(d.allowed, isFalse);
      expect(d.outcome, GeofenceOutcome.timeout);
    });

    test('a stale fix is not a measurement', () async {
      // On a round, a stale position is reliably the *previous* stop — which is
      // how a rider marks a delivery arrived from the last street.
      useFailure(GeofenceOutcome.staleFix);
      final d = await Geofence.check(
        targetLat: kTargetLat,
        targetLng: kTargetLng,
        action: 'Arrived',
      );
      expect(d.allowed, isFalse);
      expect(d.outcome, GeofenceOutcome.staleFix);
    });

    test('a fix too vague to resolve the fence is refused, not credited',
        () async {
      // The inversion this replaces: the old check was
      // `distance - accuracy > radius`, so a ±250 m fix bought 250 m of slack.
      // The worse the fix, the easier it was to pass. Here the rider is 10 m
      // away — comfortably inside — and is still refused, because the phone
      // cannot show that he is.
      useFix(riderAt(10, accuracy: kGeofenceMaxAccuracyMetres + 1));
      final d = await Geofence.check(
        targetLat: kTargetLat,
        targetLng: kTargetLng,
        action: 'Arrived',
      );
      expect(d.allowed, isFalse);
      expect(d.outcome, GeofenceOutcome.poorAccuracy);
      expect(d.reason, contains('Step into the open'));
      expect(d.accuracyMetres, kGeofenceMaxAccuracyMetres + 1);
    });

    test('a vague fix cannot pass even when it is standing on the stop',
        () async {
      useFix(riderAt(0, accuracy: 500));
      final d = await Geofence.check(
        targetLat: kTargetLat,
        targetLng: kTargetLng,
        action: 'Delivered',
      );
      expect(d.allowed, isFalse, reason: 'distance 0 must not beat accuracy');
    });

    test('a fix at the accuracy ceiling is still usable', () async {
      useFix(riderAt(20, accuracy: kGeofenceMaxAccuracyMetres));
      final d = await Geofence.check(
        targetLat: kTargetLat,
        targetLng: kTargetLng,
        action: 'Arrived',
      );
      expect(d.allowed, isTrue, reason: 'the ceiling is inclusive');
    });

    test('the provider throwing is a refusal, not a pass', () async {
      // This is the `catch { return true; // fail-safe }` that used to open
      // every rung in the app on any throw from the location stack.
      Geofence.positionProvider = () async => throw Exception('platform');
      final d = await Geofence.check(
        targetLat: kTargetLat,
        targetLng: kTargetLng,
        action: 'Arrived',
      );
      expect(d.allowed, isFalse);
      expect(d.outcome, GeofenceOutcome.error);
      expect(d.reason, isNotNull);
      expect(d.reason, isNot(contains('platform')),
          reason: 'the rider must not be shown the exception');
    });

    test('a rider fix of 0,0 is absent, not the Gulf of Guinea', () async {
      useFix(
        Position(
          latitude: 0,
          longitude: 0,
          timestamp: DateTime.now(),
          accuracy: 5,
          altitude: 0,
          altitudeAccuracy: 0,
          heading: 0,
          headingAccuracy: 0,
          speed: 0,
          speedAccuracy: 0,
        ),
      );
      final d = await Geofence.check(
        targetLat: kTargetLat,
        targetLng: kTargetLng,
        action: 'Arrived',
      );
      expect(d.allowed, isFalse);
      expect(d.outcome, GeofenceOutcome.noFix);
    });
  });

  // ───────────────────────────────────────────────────────────────────────
  group('a stop with no coordinates', () {
    // This used to return true — "Missing coordinates. Proceeding with update."
    // A booking with a blank latitude therefore opened every rung on that stop,
    // which is the bypass that makes a fence decorative.
    for (final pair in const [
      (null, null, 'both null'),
      (0.0, 0.0, 'both zero'),
      (kTargetLat, 0.0, 'longitude zero'),
      (0.0, kTargetLng, 'latitude zero'),
      (95.0, kTargetLng, 'latitude out of range'),
      (kTargetLat, 200.0, 'longitude out of range'),
    ]) {
      test('is refused — ${pair.$3}', () async {
        useFix(riderAt(0));
        final d = await Geofence.check(
          targetLat: pair.$1,
          targetLng: pair.$2,
          action: 'Arrived',
        );
        expect(d.allowed, isFalse);
        expect(d.outcome, GeofenceOutcome.noTarget);
        // The rider cannot fix the hub's data from a doorstep, so the sentence
        // sends him to the people who can.
        expect(d.reason, contains('office'));
      });
    }

    test('it does not even ask the phone for a fix', () async {
      // An 8-second GPS settle to answer a question with no target is time
      // taken off a rider's round for nothing.
      var asked = false;
      Geofence.positionProvider = () async {
        asked = true;
        return GeofenceFix(position: riderAt(0));
      };
      await Geofence.check(
        targetLat: null,
        targetLng: null,
        action: 'Arrived',
      );
      expect(asked, isFalse);
    });
  });

  // ───────────────────────────────────────────────────────────────────────
  group('BLOCKED MEANS NO REQUEST IS SENT', () {
    // The rule the whole control rests on. Every one of these drives the real
    // `PickupsController` rung with an HTTP client that fails the test if it is
    // ever called — so this asserts the *call sites*, not the policy object.

    late PickupsController controller;
    late List<String> sent;

    setUp(() {
      SharedPreferences.setMockInitialValues({'userid': 38});
      sent = <String>[];
      MilerApi.client = MockClient((req) async {
        sent.add('${req.method} ${req.url.path}');
        // A realistic `reached` reply, in the shape production actually
        // returns — `success` is the envelope key (`ApiConfig.toLegacyEnvelope`
        // reads it; `status` is ignored), and the arrival stamp sits inside
        // `data`. A bare 200 is deliberately NOT read as a transition (see
        // `MilerLifecycle.reached`), so a thin fixture would fail the positive
        // case below for a reason that has nothing to do with the fence.
        return http.Response(
          '{"success":true,"data":{"bookingid":4821,'
          '"status":"Miler_Assigned","reachedat":"2026-09-16T10:14:02Z"}}',
          200,
        );
      });
      controller = PickupsController();
    });

    tearDown(() {
      MilerApi.client = http.Client();
      Geofence.useDevice();
    });

    test('Arrived, 250 m away — no request', () async {
      useFix(riderAt(250));
      final ok = await controller.updateArrivedStatus(
        pickupId: 4821,
        orderHeaderId: 4821,
        pickupLat: '$kTargetLat',
        pickupLng: '$kTargetLng',
      );
      expect(ok, isFalse);
      expect(sent, isEmpty, reason: 'the fence refused; nothing may be posted');
      expect(controller.lastBlockedReason, contains('Move within 100 m'));
    });

    test('Arrived with GPS off — no request', () async {
      useFailure(GeofenceOutcome.serviceDisabled);
      final ok = await controller.updateArrivedStatus(
        pickupId: 4821,
        orderHeaderId: 4821,
        pickupLat: '$kTargetLat',
        pickupLng: '$kTargetLng',
      );
      expect(ok, isFalse);
      expect(sent, isEmpty);
    });

    test('Arrived with permission denied forever — no request', () async {
      useFailure(GeofenceOutcome.permissionDeniedForever);
      final ok = await controller.updateArrivedStatus(
        pickupId: 4821,
        orderHeaderId: 4821,
        pickupLat: '$kTargetLat',
        pickupLng: '$kTargetLng',
      );
      expect(ok, isFalse);
      expect(sent, isEmpty);
    });

    test('Arrived on a stop with no pin — no request', () async {
      useFix(riderAt(0));
      final ok = await controller.updateArrivedStatus(
        pickupId: 4821,
        orderHeaderId: 4821,
        pickupLat: '0',
        pickupLng: '0',
      );
      expect(ok, isFalse);
      expect(
        sent,
        isEmpty,
        reason:
            'a booking with no coordinates used to be waved through — that is '
            'the bypass that made the fence decorative',
      );
    });

    test('Delivery arrived, 250 m away — no request', () async {
      useFix(riderAt(250));
      final ok = await controller.updateDeliveryArrived(
        pickupId: 4821,
        dropLat: '$kTargetLat',
        dropLng: '$kTargetLng',
      );
      expect(ok, isFalse);
      expect(sent, isEmpty);
    });

    test('Delivery arrived with NO drop pin — no request', () async {
      // The conditional that used to wrap this call site —
      // `if (dLat != 0 && dLng != 0)` — skipped the fence silently for exactly
      // the stops where nobody could say afterwards where the rider was.
      useFix(riderAt(0));
      final ok = await controller.updateDeliveryArrived(
        pickupId: 4821,
        dropLat: '0',
        dropLng: '0',
      );
      expect(ok, isFalse);
      expect(sent, isEmpty);
    });

    test('Delivered, 250 m away — no request', () async {
      useFix(riderAt(250));
      final ok = await controller.updateDeliveredStatus(
        pickupId: 4821,
        consignmentId: '77',
        deliveredToName: 'Anitha R',
        dropLat: '$kTargetLat',
        dropLng: '$kTargetLng',
      );
      expect(ok, isFalse);
      expect(sent, isEmpty);
    });

    test('Delivered with NO drop pin — no request', () async {
      useFix(riderAt(0));
      final ok = await controller.updateDeliveredStatus(
        pickupId: 4821,
        consignmentId: '77',
        deliveredToName: 'Anitha R',
        dropLat: '0',
        dropLng: '0',
      );
      expect(ok, isFalse);
      expect(sent, isEmpty);
    });

    test('inside the fence, the request DOES go out', () async {
      // The other half of the contract, and the reason this group is not just
      // an assertion that everything is broken.
      useFix(riderAt(40));
      final ok = await controller.updateArrivedStatus(
        pickupId: 4821,
        orderHeaderId: 4821,
        pickupLat: '$kTargetLat',
        pickupLng: '$kTargetLng',
      );
      expect(ok, isTrue);
      expect(sent, isNotEmpty);
      expect(sent.single, contains('/miler/bookings/4821/reached'));
      expect(controller.lastBlockedReason, isNull);
    });
  });
}