import 'package:flutter/material.dart';
import 'package:flutter_screenutil/flutter_screenutil.dart';
import 'package:flutter_test/flutter_test.dart';

import 'package:miler/views/helpers/constants/app_theme.dart';
import 'package:miler/views/introscreens/introscreen.dart';

/// ─────────────────────────────────────────────────────────────────────────
/// THE FIRST-RUN SLIDES
///
/// These used to be miniature mock-ups of Home built out of fixed-width rows —
/// the hub rail on slide 1 was a dozen sized children in a single unflexed
/// `Row` — and the tests existed because that is exactly the shape which
/// overflows on a narrow phone.
///
/// The slides are finished posters now: headline, sub-copy, product shot and
/// the MILER lockup are all baked into the artwork, and the screen draws no
/// text of its own. A `BoxFit.cover` image cannot overflow, so the width sweep
/// is no longer about the illustrations — it is about the controls laid over
/// them, which are the only Flutter-built objects left on the screen.
///
/// What is worth pinning instead is the part a wrong asset path would break
/// silently: three specific images, in the order the rider is meant to see
/// them, with the CTA changing on the last one.
/// ─────────────────────────────────────────────────────────────────────────
void main() {
  const slides = <String>[
    'assets/images/onboard_1.png',
    'assets/images/onboard_2.png',
    'assets/images/onboard_3.png',
  ];

  Future<void> pump(WidgetTester tester, {required Size screen}) async {
    tester.view.physicalSize = Size(screen.width * 3, screen.height * 3);
    tester.view.devicePixelRatio = 3.0;
    addTearDown(tester.view.resetPhysicalSize);
    addTearDown(tester.view.resetDevicePixelRatio);

    await tester.pumpWidget(
      ScreenUtilInit(
        designSize: const Size(390, 844),
        builder: (_, _) =>
            MaterialApp(theme: AppTheme.light, home: const Introscreen()),
      ),
    );
    await tester.pumpAndSettle();
  }

  /// The asset the slide currently on screen is drawing.
  String? shownAsset(WidgetTester tester) {
    for (final image in tester.widgetList<Image>(find.byType(Image))) {
      final provider = image.image;
      if (provider is AssetImage &&
          provider.assetName.startsWith('assets/images/onboard_')) {
        return provider.assetName;
      }
    }
    return null;
  }

  for (final size in const [
    Size(320, 640), // smallest Android still in the fleet
    Size(360, 740),
    Size(390, 844),
    Size(430, 932),
  ]) {
    testWidgets('all three slides lay out at ${size.width.toInt()}pt', (
      tester,
    ) async {
      await pump(tester, screen: size);
      expect(tester.takeException(), isNull);

      expect(shownAsset(tester), slides[0]);
      expect(find.text('Next'), findsOneWidget);
      expect(find.text('Skip'), findsOneWidget);

      // A near-full-width drag, so the page always snaps to the next one. A
      // velocity fling does not reliably cross the threshold here.
      final swipe = Offset(-size.width * 0.9, 0);

      await tester.drag(find.byType(PageView), swipe);
      await tester.pumpAndSettle();
      expect(tester.takeException(), isNull);
      expect(shownAsset(tester), slides[1]);
      expect(find.text('Next'), findsOneWidget);

      await tester.drag(find.byType(PageView), swipe);
      await tester.pumpAndSettle();
      expect(tester.takeException(), isNull);
      expect(shownAsset(tester), slides[2]);

      // Last slide swaps the CTA and drops Skip — an invisible-but-present
      // control is a trap for screen readers, so it is unmounted rather than
      // faded to `opacity: 0`.
      expect(find.text('Get started'), findsOneWidget);
      expect(find.text('Next'), findsNothing);
      expect(find.text('Skip'), findsNothing);
    });
  }

  testWidgets('the three posters are in the order they were given', (
    tester,
  ) async {
    await pump(tester, screen: const Size(390, 844));

    // `PageView.builder` only builds the page on screen, so the order has to be
    // walked rather than read out of the tree in one go. Which is the honest
    // test anyway: what matters is the sequence the rider is shown, and 1-3-2
    // would pass any assertion made against a set.
    final seen = <String?>[shownAsset(tester)];
    for (var i = 1; i < slides.length; i++) {
      await tester.drag(find.byType(PageView), const Offset(-351, 0));
      await tester.pumpAndSettle();
      seen.add(shownAsset(tester));
    }

    expect(seen, slides);
  });

  testWidgets('the artwork runs edge to edge', (tester) async {
    await pump(tester, screen: const Size(390, 844));

    final image = tester.widget<Image>(
      find
          .byWidgetPredicate(
            (w) =>
                w is Image &&
                w.image is AssetImage &&
                (w.image as AssetImage).assetName == slides[0],
          )
          .first,
    );

    // `cover` is what makes a 940×1672 poster fill a phone of any aspect
    // without letterboxing. `contain` would put bars down the sides, which on
    // artwork that ends in a red wave reads as a rendering fault.
    expect(image.fit, BoxFit.cover);
  });

  testWidgets('the screen adds no captions of its own', (tester) async {
    await pump(tester, screen: const Size(390, 844));

    // Every slide's headline and sub-copy are baked into the image. A Flutter
    // caption under the picture would say the same thing twice, in a second
    // typeface, at a second size — so the only text on the screen is the two
    // controls.
    final texts = tester
        .widgetList<Text>(find.byType(Text))
        .map((t) => t.data)
        .whereType<String>()
        .toSet();

    expect(texts, <String>{'Skip', 'Next'});
  });

  testWidgets('Skip is offered on the first slide', (tester) async {
    await pump(tester, screen: const Size(390, 844));
    expect(find.text('Skip'), findsOneWidget);
  });

  // The old code-drawn copy pitched a gig marketplace — "pickups near you",
  // accepted from a feed. This product assigns routes from a hub, and
  // onboarding that teaches the wrong model is worse than none.
  //
  // NOTE: this can only speak for text the *app* draws. The posters carry their
  // own headlines as pixels, and `onboard_1.png` does print "Powered by AI" —
  // a claim the previous slides deliberately dropped because nothing in the app
  // backs it. That is a copy decision about the artwork, not something a widget
  // test can hold.
  testWidgets('the app draws no marketplace copy of its own', (tester) async {
    await pump(tester, screen: const Size(390, 844));
    for (final wrong in [
      'Find pickups near you',
      'Navigate the smart way',
      'Earn more, every shift',
      'Powered by AI',
    ]) {
      expect(find.text(wrong), findsNothing, reason: '"$wrong" is not this app');
    }
  });
}