import 'dart:io' show File;

import 'package:actors/actors.dart';
import 'package:drift/native.dart';
import 'package:flutter/material.dart';
import 'package:flutter_test/flutter_test.dart';

import 'package:mews/application/actors/fetch_actor.dart';
import 'package:mews/application/controllers/browser_controller.dart'
    show BrokenPage, LoadFailed;
import 'package:mews/application/controllers/reader_settings_controller.dart'
    show ReaderSettingsController;
import 'package:mews/database/database.dart';
import 'package:mews/l10n/strings.dart';
import 'package:mews/mews/document.dart';
import 'package:mews/mews/parser.dart';
import 'package:mews/presentation/app.dart';
import 'package:mews/presentation/reader/address_bar.dart';
import 'package:mews/presentation/reader/fob.dart';
import 'package:mews/presentation/reader/reader_screen.dart';
import 'package:mews/presentation/reader/settings_sheet.dart';
import 'package:mews/presentation/reader/swipe_navigator.dart';

const pageSource = '''
<?xml version="1.0" encoding="UTF-8"?>
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
  <head>
    <title>Signal Bars</title>
    <meta name="mews-profile" content="0.1" />
  </head>
  <body class="mews-green">
    <h1>Signal Bars</h1>
    <p>Notes on old phones.</p>
    <ul>
      <li><a href="2026-10-08-retro.html">2026-10-08 Collecting retro phones</a></li>
      <li><a href="2026-09-21-first.html">2026-09-21 First post</a></li>
    </ul>
    <form action="/sign" method="post">
      <label for="name">Your name</label>
      <input type="text" id="name" name="name" />
      <input type="submit" value="Sign guestbook" />
    </form>
  </body>
</html>
''';

/// Serves pages from an in-memory map without network or isolates, so
/// navigation tests are deterministic. Cached pages parse back from their
/// cached source, like the real actor does for revalidation.
class _FakeFetch implements Actor<FetchCommand, FetchResult> {
  _FakeFetch(this.sources);

  final Map<String, String> sources;

  @override
  Future<FetchResult> send(FetchCommand message) async {
    return switch (message) {
      ParseSource(:final url, :final source) => _parse(url, source),
      FetchPage(:final url, :final cachedSource) => cachedSource != null
          ? _parse(url, cachedSource)
          : sources[url] != null
              ? _parse(url, sources[url]!)
              : const FetchNetworkError(),
      _ => const FetchNetworkError(),
    };
  }

  FetchResult _parse(String url, String source) {
    try {
      return FetchPageOk(page: parseMewsPage(source: source, url: url), source: source);
    } on MewsParseException catch (e) {
      return FetchParseError(e.message, source);
    }
  }

  @override
  Future<void> close() async {}

  @override
  dynamic noSuchMethod(Invocation invocation) => super.noSuchMethod(invocation);
}

String _page(String title, String body) => '''
<?xml version="1.0" encoding="UTF-8"?>
<html xmlns="http://www.w3.org/1999/xhtml">
  <head><title>$title</title><meta name="mews-profile" content="0.1" /></head>
  <body>$body</body>
</html>
''';

void main() {
  late MewsDatabase db;
  late AppDependencies deps;

  setUp(() async {
    db = MewsDatabase.test(NativeDatabase.memory());
    deps = AppDependencies(database: db);
  });

  tearDown(() async {
    await db.close();
  });

  Future<void> pumpApp(WidgetTester tester) async {
    final strings = Strings();
    strings.loadSource(File('locales/en-US/main.ftl').readAsStringSync());
    await tester.pumpWidget(MewsApp(deps: deps, strings: strings));
    await tester.pumpAndSettle();
  }

  testWidgets('renders a page through the full app', (tester) async {
    await pumpApp(tester);

    final page = parseSource(pageSource, 'https://example.com/index.html');
    deps.browser.currentPage.value = page;
    await tester.pumpAndSettle();

    expect(find.text('Signal Bars'), findsWidgets);
    expect(find.textContaining('Collecting retro phones'), findsOneWidget);
    expect(find.textContaining('Sign guestbook'), findsOneWidget);
  });

  testWidgets('shows the broken-page error and its text view', (tester) async {
    await pumpApp(tester);
    deps.browser.currentPage.value = null;
    deps.browser.error.value = const BrokenPage('<p>Half a page &amp; more');
    await tester.pumpAndSettle();

    expect(find.textContaining('markup error'), findsOneWidget);
    await tester.tap(find.textContaining('Show page text'));
    await tester.pumpAndSettle();
    expect(find.textContaining('Half a page & more'), findsOneWidget);
  });

  testWidgets('shows the load-failed error page', (tester) async {
    await pumpApp(tester);
    deps.browser.error.value = const LoadFailed();
    await tester.pumpAndSettle();

    expect(find.textContaining('could not be loaded'), findsOneWidget);
    expect(find.textContaining('Try again'), findsOneWidget);
  });

  testWidgets('settings sheet changes presentation and toggles library',
      (tester) async {
    await pumpApp(tester);

    final page = parseSource(pageSource, 'https://example.com/index.html');
    deps.browser.currentPage.value = page;
    await tester.pumpAndSettle();

    showReaderSettingsSheet(tester.element(find.byType(ReaderScreen)));
    await tester.pumpAndSettle();

    // Typeface, size, theme, colors.
    await tester.tap(find.text('Atkinson Hyperlegible'));
    await tester.pumpAndSettle();
    await tester.tap(find.byIcon(Icons.add));
    await tester.pumpAndSettle();
    await tester.tap(find.text('Dark'));
    await tester.pumpAndSettle();
    await tester.tap(find.text('Warm'));
    await tester.pumpAndSettle();

    expect(deps.settings.fontScale.value, 1.125);
    expect(deps.settings.themeMode.value, 'dark');
    expect(deps.settings.variant.value, 'warm');

    // Bookmark and subscribe the current page; both tiles sit at the bottom
    // of the sheet, so scroll the sheet down to the end first.
    final sheet = find.byType(Scrollable).last;
    await tester.drag(sheet, const Offset(0, -1000));
    await tester.pumpAndSettle();
    await tester.tap(find.text('Add bookmark'));
    await tester.pumpAndSettle();
    expect(deps.library.isBookmarked('https://example.com/index.html'), isTrue);

    await tester.tap(find.text('Subscribe to this site'));
    await tester.pumpAndSettle();
    expect(deps.library.isSubscribed('https://example.com/index.html'), isTrue);

    // Settings survive a reload of the controller.
    final reloaded = ReaderSettingsController(db);
    await reloaded.load();
    expect(reloaded.themeMode.value, 'dark');
  });

  testWidgets('the FOB hides on scroll down and returns on scroll up',
      (tester) async {
    await pumpApp(tester);

    // A page long enough to scroll.
    final tall = pageSource.replaceFirst(
        '</body>',
        '<p>Padding paragraph to make the page scroll.</p>' * 80 + '</body>');
    final page = parseSource(tall, 'https://example.com/index.html');
    deps.browser.currentPage.value = page;
    await tester.pumpAndSettle();

    Fob fob() => tester.widget<Fob>(find.byType(Fob));
    expect(fob().visible, isTrue);

    // Scrolling down hides the address bar and the FOB.
    await tester.drag(find.byType(ListView), const Offset(0, -300));
    await tester.pumpAndSettle();
    expect(fob().visible, isFalse);
    expect(find.byType(AddressBar), findsNothing);

    // Scrolling up brings both back.
    await tester.drag(find.byType(ListView), const Offset(0, 300));
    await tester.pumpAndSettle();
    expect(fob().visible, isTrue);
    expect(find.byType(AddressBar), findsOneWidget);
  });

  testWidgets('swiping back shows the previous page during the drag',
      (tester) async {
    final sources = {
      'https://example.com/a.html':
          _page('Page A', '<h1>Page A</h1><p>The first pages content.</p>'),
      'https://example.com/b.html':
          _page('Page B', '<h1>Page B</h1><p>The second pages content.</p>'),
    };
    final stubDeps = AppDependencies(
      database: MewsDatabase.test(NativeDatabase.memory()),
      fetch: _FakeFetch(sources),
    );
    final strings = Strings();
    strings.loadSource(File('locales/en-US/main.ftl').readAsStringSync());
    await tester.pumpWidget(MewsApp(deps: stubDeps, strings: strings));
    await tester.pumpAndSettle();

    await stubDeps.browser.open('https://example.com/a.html');
    await stubDeps.browser.open('https://example.com/b.html');
    // The swipe neighbor is parsed in the background.
    await _pumpUntil(tester, () => stubDeps.browser.backPage.value != null);

    final center = tester.getCenter(find.byType(SwipeNavigator));
    final gesture = await tester.startGesture(center);
    await gesture.moveBy(const Offset(400, 0));
    await tester.pump();

    // The real previous page is on screen mid-swipe, not a placeholder.
    expect(find.text('Page A'), findsOneWidget);
    expect(find.textContaining('The first pages content'), findsOneWidget);

    await gesture.up();
    await tester.pumpAndSettle();

    expect(stubDeps.browser.currentPage.value?.url, 'https://example.com/a.html');
    // Settled on the page itself; the address bar follows.
    expect(find.textContaining('The first pages content'), findsOneWidget);
    expect(find.text('https://example.com/a.html'), findsOneWidget);
  });

  testWidgets('reports new posts once per page', (tester) async {
    await pumpApp(tester);

    final page = parseSource(pageSource, 'https://example.com/index.html');
    deps.library.subscribedUrls.value = {'https://example.com/index.html'};
    deps.library.newEntries.value = {
      'https://example.com/index.html': [
        MewsEntry(
            url: 'https://example.com/2026-10-08-retro.html',
            date: DateTime(2026, 10, 8),
            title: 'Collecting retro phones'),
      ],
    };
    deps.browser.currentPage.value = page;
    await tester.pumpAndSettle();

    expect(find.textContaining('1 new post'), findsOneWidget);
  });
}

MewsPage parseSource(String source, String url) =>
    parseMewsPage(source: source, url: url);

/// Pumps in short bursts until [condition] holds; fails the test on timeout.
Future<void> _pumpUntil(WidgetTester tester, bool Function() condition,
    {Duration timeout = const Duration(seconds: 5)}) async {
  final end = DateTime.now().add(timeout);
  while (!condition()) {
    if (DateTime.now().isAfter(end)) {
      fail('condition not met within timeout');
    }
    await tester.pump(const Duration(milliseconds: 20));
  }
  await tester.pumpAndSettle();
}