@Tags(['snapshot'])
library;

import 'package:doormile_cx/data/dev_doormile_api.dart';
import 'package:doormile_cx/data/doormile_api.dart';
import 'package:doormile_cx/data/location_service.dart';
import 'package:doormile_cx/main.dart';
import 'package:doormile_cx/state/app_state.dart';
import 'package:doormile_cx/ui/tokens.dart';
import 'package:flutter/material.dart';
import 'package:lucide_icons_flutter/lucide_icons.dart';
import 'package:flutter/services.dart';
import 'package:flutter_test/flutter_test.dart';

/// Renders each screen at phone size and writes it to `test/snapshots/`.
///
/// This is a **design** check, not a regression check. A deliberate redesign
/// would fail every one of these, which is worthless as a test signal, so the
/// `snapshot` tag is skipped in a normal run (see `dart_test.yaml`) and the
/// pictures are rendered on demand:
///
///     flutter test test/design_snapshot_test.dart --run-skipped --update-goldens
///
/// It exists because the only honest way to review a visual rebuild is to look
/// at it, and this produces the same pictures on any machine, with the real
/// fonts, without a device attached.
///
/// The real fonts are loaded first — without that, Flutter's test harness draws
/// everything in Ahem's black boxes and the pictures are worthless.
Future<void> _loadFonts() async {
  for (final (family, asset) in const [
    ('PlusJakartaSans', 'assets/fonts/PlusJakartaSans-Variable.ttf'),
    ('Switzer', 'assets/fonts/Switzer-Variable.ttf'),
    ('GeistMono', 'assets/fonts/GeistMono-VF.ttf'),
    // The icon font too, or every glyph in the picture is a hollow box.
    ('packages/lucide_icons_flutter/Lucide',
        'packages/lucide_icons_flutter/assets/lucide.ttf'),
  ]) {
    final loader = FontLoader(family)..addFont(rootBundle.load(asset));
    await loader.load();
  }
}

/// Runs the clock forward until a screen has stopped moving.
///
/// Four pumps, not two. An entrance animation is started by a zero-delay
/// `Future.delayed` inside `flutter_animate`, and under the test binding's fake
/// clock that timer only fires on the pump *after* the widget was built — so
/// the controller begins life part-way through the first elapse and a two-pump
/// settle photographs the screen mid-fade. Everything here is under a second,
/// so the extra frames cost nothing and the pictures are of settled screens.
Future<void> _settle(WidgetTester tester, [int ms = 800]) async {
  await tester.pump();
  await tester.pump(Duration(milliseconds: ms));
  for (var i = 0; i < 4; i++) {
    await tester.pump(const Duration(milliseconds: 400));
  }
}

/// Pumps until the splash's ground has left [DmColors.splash].
///
/// Returns on the first frame of the invert, so a caller can step into the
/// middle of it by a known amount. Gives up after six seconds rather than
/// spinning forever if the splash never starts.
Future<void> _pumpToInvert(WidgetTester tester) async {
  for (var i = 0; i < 120; i++) {
    final scaffold = tester.widget<Scaffold>(find.byType(Scaffold).first);
    if (scaffold.backgroundColor != DmColors.splash) return;
    await tester.pump(const Duration(milliseconds: 50));
  }
  fail('the splash never left crimson');
}

Future<void> _shot(WidgetTester tester, String name) async {
  await expectLater(
    find.byType(MaterialApp),
    matchesGoldenFile('snapshots/$name.png'),
  );
}

void main() {
  late DevDoormileApi api;

  setUp(() {
    TestDefaultBinaryMessengerBinding.instance.defaultBinaryMessenger
        .setMockMethodCallHandler(
      const MethodChannel('plugins.flutter.io/path_provider'),
      (call) async => '/tmp',
    );
    api = DevDoormileApi();
    DoormileApi.overrideInstance(api);
    LocationService.instance = FixedLocationService();
  });

  tearDown(() => DoormileApi.overrideInstance(null));

  testWidgets('screens', (tester) async {
    await _loadFonts();

    // One phone, portrait: 390x844 at 3x, the frame the design was drawn in.
    tester.view.physicalSize = const Size(1170, 2532);
    tester.view.devicePixelRatio = 3.0;
    addTearDown(tester.view.reset);

    final state = AppState();
    await tester.pumpWidget(DoormileApp(initialState: state));

    // Image.asset resolves off the frame loop, so in a test it never paints
    // unless it is decoded first — without this the mark and the wordmark are
    // blank gaps in every picture of the entrance.
    await tester.runAsync(() async {
      for (final asset in const [
        'assets/images/doormile-mark.png',
        'assets/images/doormile-logo.png',
      ]) {
        await precacheImage(
          AssetImage(asset),
          tester.element(find.byType(MaterialApp)),
        );
      }
    });

    // All three beats, with raw pumps: `_settle` always runs four extra 400ms
    // frames at the end, which is 2.5s — past the moment the splash hands
    // over, so it would photograph the login screen instead of any of them.
    // The clock does not start until the engine says it has rasterized a
    // frame and the composition has parsed, which under the test binding is
    // about 1.2s. Every shot is taken relative to that, not to pumpWidget.
    await tester.pump();
    await tester.pump(const Duration(milliseconds: 2000));
    await _shot(tester, '00-splash-truck');

    // ── The next two are found, not counted to ──
    //
    // The splash's clock does not start at `pumpWidget`: it waits for the
    // composition to parse and for the engine to report a rasterized frame,
    // and how long that takes depends on what else is in the tree. Two
    // attempts at counting milliseconds from here photographed the invert
    // 25ms in, and then the login screen. So this watches for the beat
    // instead — the ground leaving crimson is unambiguous and needs no
    // estimate of anything.
    await _pumpToInvert(tester);
    await tester.pump(const Duration(milliseconds: 160));
    await _shot(tester, '00b-splash-invert');

    // Past the invert, and far enough into the mark's entrance to photograph
    // the mark rather than its fade. `_markHold` is what leaves room for this.
    await tester.pump(const Duration(milliseconds: 320));
    await tester.pump(const Duration(milliseconds: 620));
    await _shot(tester, '00c-splash-mark');

    // The splash holds for its own minimum — and the waits in front of it — before handing over.
    await _settle(tester, 4400);
    await _shot(tester, '01-sign-in');

    // ── Sign-in is a phone number and a PIN now ──
    //
    // The "Create account" link and its screen are gone: a new number is
    // recognised by `POST /auth/login` and the PIN screen asks for the name
    // and the PIN in one step. An unknown number therefore photographs the
    // create-account state of that screen, and the known one photographs the
    // returning-customer state.
    await tester.enterText(find.byType(TextField).first, '9111122223');
    await _settle(tester, 200);
    await tester.tap(find.text('Continue'));
    await _settle(tester);
    await _shot(tester, '01b-create-account');
    await tester.tap(find.byIcon(LucideIcons.arrowLeft).first);
    await _settle(tester);

    await tester.enterText(find.byType(TextField).first, '9876543210');
    await _settle(tester, 200);
    await tester.tap(find.text('Continue'));
    await _settle(tester);
    await _shot(tester, '02-pin');

    // A PIN is submitted, not auto-verified: it is a credential the customer
    // keeps, so the screen waits for them to say they are done.
    await tester.enterText(find.byType(TextField).first, '1234');
    await _settle(tester, 200);
    await tester.tap(find.text('Sign in'));
    await _settle(tester);
    await _shot(tester, '03-home');

    // The pickup address is a live value in the header, so the search that
    // changes it is reachable from Home rather than only from the booking.
    await tester.tap(find.text('38 Mettupalayam Road'));
    await _settle(tester);
    await _shot(tester, '03b-pickup-search');
    await tester.tapAt(const Offset(200, 40)); // through the scrim
    await _settle(tester);

    await tester.tap(find.bySemanticsLabel('Orders'));
    await _settle(tester);
    await _shot(tester, '04-orders');

    await tester.tap(find.bySemanticsLabel('Account'));
    await _settle(tester);
    await _shot(tester, '05-account');

    await tester.tap(find.bySemanticsLabel('Home'));
    await _settle(tester);
    // The live card, by its reference. Home's quick-dispatch chips are
    // named after cities too, so a bare 'Chennai' finder now hits a
    // shortcut that starts a new booking instead.
    await tester.tap(find.text('DM-482913'));
    await _settle(tester);
    await _shot(tester, '06-tracking');

    // `ensureVisible`, not `dragUntilVisible`.
    //
    // `IndexedStack` keeps all three tab roots alive under the pushed route,
    // so a positional `Scrollable` finder picks Home's list — which the
    // tracking screen is covering. `ensureVisible` finds the target's own
    // scrollable ancestor and needs no finder at all.
    await tester.ensureVisible(find.text('Cancel this pickup'));
    await tester.pump();
    await tester.tap(find.text('Cancel this pickup'));
    await _settle(tester);
    await _shot(tester, '06b-cancel-sheet');
    await tester.tapAt(const Offset(200, 40));
    await _settle(tester);

    await tester.tap(find.byIcon(LucideIcons.arrowLeft).first);
    await _settle(tester);

    // ── Booking: one sheet, two questions, then the review ──
    //
    // It was two sheets, and the shots followed them: states, then the
    // districts inside a state, then a separate window sheet. There are no
    // states to open now — the list is flat and the state is a heading — and
    // the window is the same sheet's second step.
    await tester.tap(find.text('BOOK NOW'));
    await _settle(tester);
    await _shot(tester, '07-pickup-where');

    await tester.tap(
      find
          .descendant(
            of: find.byType(BottomSheet),
            matching: find.text('Chennai'),
          )
          .first,
    );
    await _settle(tester);
    // The dev backend allows several destinations, so the row ticked rather
    // than advancing — the choice is confirmed.
    await tester.tap(find.textContaining('Send to ').first);
    await _settle(tester);
    // Same surface, second question. The customer chooses their slot; it is
    // never chosen for them.
    await _shot(tester, '07b-pickup-when');
    await tester.tap(find.text('Confirm pickup'));
    await _settle(tester);
    await _shot(tester, '08-send');

    // The map editor behind the FROM row: the one screen in the flow whose
    // subject is a picture.
    await tester.tap(find.text('PICKUP'));
    await _settle(tester);
    await _shot(tester, '10-pickup-map');
    await tester.tap(find.byIcon(LucideIcons.arrowLeft).first);
    await _settle(tester);

    await tester.tap(find.text('Confirm Booking'));
    await _settle(tester);
    await _shot(tester, '11-booked');

    // A finished order, for the receipt treatment.
    await tester.tap(find.text('Back to home'));
    await _settle(tester);
    await tester.tap(find.bySemanticsLabel('Orders'));
    await _settle(tester);
    await tester.tap(find.textContaining('Past'));
    await _settle(tester);
    await _shot(tester, '04b-orders-completed');
    await tester.tap(find.text('Salem'));
    await _settle(tester);
    await _shot(tester, '12-receipt');

    await tester.pump(const Duration(seconds: 3));
  });
}