import 'dart:io' show File;

import 'package:actors/actors.dart';
import 'package:flutter/foundation.dart' show TargetPlatform, debugDefaultTargetPlatformOverride;
import 'package:drift/native.dart';
import 'package:flutter/material.dart';
import 'package:flutter/rendering.dart' show RenderParagraph;
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/database/database.dart';
import 'package:mews/l10n/strings.dart';
import 'package:mews/mews/document.dart';
import 'package:mews/mews/parser.dart';
import 'package:mews/application/pages/mews_urls.dart';
import 'package:mews/presentation/app.dart';
import 'package:mews/presentation/reader/address_bar.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;
  late Strings strings;

  setUp(() async {
    db = MewsDatabase.test(NativeDatabase.memory());
    strings = Strings();
    strings.loadSource(File('locales/en-US/main.ftl').readAsStringSync());
    deps = AppDependencies(database: db, strings: strings);
  });

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

  /// Pumps the full app for [deps]; library pages get real strings.
  Future<void> pumpApp(WidgetTester tester) async {
    await tester.pumpWidget(MewsApp(deps: deps, strings: strings));
    await tester.pumpAndSettle();
  }

  /// Taps the run reading [label] inside a rendered paragraph. Internal pages
  /// put several links in one paragraph, so tapping the widget's center would
  /// hit whichever run happens to sit in the middle.
  Future<void> tapRun(WidgetTester tester, String label) async {
    final paragraph = tester.renderObject<RenderParagraph>(
      find
          .descendant(
            of: find.byWidgetPredicate((widget) =>
                widget is Text &&
                (widget.textSpan?.toPlainText() ?? widget.data ?? '')
                    .contains(label)),
            matching: find.byType(RichText),
          )
          .first,
    );
    final plain = paragraph.text.toPlainText();
    final start = plain.indexOf(label);
    final box = paragraph
        .getBoxesForSelection(TextSelection(
            baseOffset: start, extentOffset: start + label.length))
        .first;
    await tester.tapAt(paragraph.localToGlobal(
        Offset(box.left + 2, (box.top + box.bottom) / 2)));
    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('the hub opens the settings page, which applies a choice in place',
      (tester) async {
    await pumpApp(tester);

    // The hub opens from the left address bar icon.
    await tester.tap(find.byIcon(Icons.menu));
    await tester.pumpAndSettle();
    expect(deps.browser.currentPage.value?.url, MewsUrls.hub);
    expect(find.text('Mews'), findsOneWidget);
    expect(find.textContaining('No bookmarks yet'), findsOneWidget);

    // Its menu reaches settings, which carries the strip of our own pages.
    await tapRun(tester, 'Settings');
    expect(deps.browser.currentPage.value?.url, MewsUrls.settings);
    expect(find.text('Settings'), findsOneWidget);
    expect(find.text('Typeface'), findsOneWidget);
    expect(find.text('Theme'), findsOneWidget);
    expect(find.text('Colors'), findsOneWidget);
    // The buried Library section is gone; the strip replaced it.
    expect(find.text('Library'), findsNothing);

    Future<void> scrollTo(Finder target) async {
      // Search down the page, then back up for targets above.
      for (var i = 0; i < 20 && target.evaluate().isEmpty; i++) {
        await tester.drag(find.byType(ListView), const Offset(0, -200));
        await tester.pumpAndSettle();
      }
      for (var i = 0; i < 40 && target.evaluate().isEmpty; i++) {
        await tester.drag(find.byType(ListView), const Offset(0, 200));
        await tester.pumpAndSettle();
      }
      await tester.ensureVisible(target);
      await tester.pumpAndSettle();
    }

    // Choosing a value applies it and stays put: no new walk history entry.
    await scrollTo(find.text('Dark'));
    await tapRun(tester, 'Dark');
    expect(deps.settings.themeMode.value, 'dark');
    expect(deps.browser.currentPage.value?.url, MewsUrls.settings);
    expect(deps.browser.canGoBack, isTrue);
    final beforeSize = deps.browser.currentPage.value;

    await scrollTo(find.text('Warm'));
    await tapRun(tester, 'Warm');
    expect(deps.settings.variant.value, 'warm');

    await scrollTo(find.text('Larger text'));
    await tapRun(tester, 'Larger text');
    expect(deps.settings.fontScale.value, 1.125);
    expect(deps.browser.currentPage.value, isNot(same(beforeSize)));

    // The strip navigates and joins the walk history.
    await scrollTo(find.textContaining('Bookmarks'));
    await tapRun(tester, 'History');
    expect(deps.browser.currentPage.value?.url, MewsUrls.history);

    await deps.browser.back();
    await tester.pumpAndSettle();
    expect(deps.browser.currentPage.value?.url, MewsUrls.settings);
  });

  testWidgets('a fetched page cannot run an action link', (tester) async {
    final stubDeps = AppDependencies(
      database: MewsDatabase.test(NativeDatabase.memory()),
      fetch: _FakeFetch({
        'https://example.com/evil.html': _page('Evil',
            '<h1>Evil</h1><p><a href="mews:do/set-theme?value=dark">Go</a></p>'),
      }),
      strings: strings,
    );
    await tester.pumpWidget(MewsApp(deps: stubDeps, strings: strings));
    await tester.pumpAndSettle();

    await stubDeps.browser.open('https://example.com/evil.html');
    await tester.pumpAndSettle();
    expect(stubDeps.settings.themeMode.value, 'system');

    // Following the link from a fetched page changes nothing and goes nowhere
    // (spec 8.1: page content must not act for the reader).
    await tapRun(tester, 'Go');
    expect(stubDeps.settings.themeMode.value, 'system');
    expect(stubDeps.browser.currentPage.value?.url,
        'https://example.com/evil.html');

    // The same link works from one of our own pages.
    await stubDeps.browser.open(MewsUrls.settings);
    await stubDeps.browser.open('mews:do/set-theme?value=dark');
    expect(stubDeps.settings.themeMode.value, 'dark');
    expect(stubDeps.browser.currentPage.value?.url, MewsUrls.settings);
  });

  testWidgets('a form on one of our pages navigates instead of fetching',
      (tester) async {
    await pumpApp(tester);

    // The fetch client cannot speak the mews scheme, so a form on an internal
    // page must be routed before it ever reaches the actor.
    await deps.browser.open(MewsUrls.bookmarks);
    await deps.browser.submitForm(MewsUrls.bookmarks, 'get', {'q': 'retro'});
    await tester.pumpAndSettle();
    expect(deps.browser.currentPage.value?.url, 'mews:bookmarks?q=retro');
    expect(deps.browser.error.value, isNull);

    // A form whose action is an action link applies it in place.
    await deps.browser.open(MewsUrls.settings);
    await deps.browser.submitForm('mews:do/set-theme', 'get', {'value': 'dark'});
    await tester.pumpAndSettle();
    expect(deps.settings.themeMode.value, 'dark');
    expect(deps.browser.currentPage.value?.url, MewsUrls.settings);
    expect(deps.browser.error.value, isNull);
  });

  testWidgets('bare mews: and an unknown name resolve predictably',
      (tester) async {
    await pumpApp(tester);

    await deps.browser.open('mews:');
    await tester.pumpAndSettle();
    expect(deps.browser.currentPage.value?.url, MewsUrls.hub);

    await deps.browser.open('mews:nonsense');
    await tester.pumpAndSettle();
    expect(deps.browser.currentPage.value, isNull);
    expect(deps.browser.error.value, isA<LoadFailed>());
  });

  testWidgets('a session with no history starts at the hub', (tester) async {
    await pumpApp(tester);
    await deps.browser.restoreLastSession();
    await tester.pumpAndSettle();
    expect(deps.browser.currentPage.value?.url, MewsUrls.hub);
  });

  testWidgets('bookmark and subscribe live on the address bar', (tester) async {
    await pumpApp(tester);

    // A page with dated entries can be subscribed to.
    final page = parseSource(pageSource, 'https://example.com/index.html');
    deps.browser.currentPage.value = page;
    await tester.pumpAndSettle();

    expect(find.byIcon(Icons.notifications_outlined), findsOneWidget);
    await tester.tap(find.byIcon(Icons.notifications_outlined));
    await tester.pumpAndSettle();
    expect(deps.library.isSubscribed('https://example.com/index.html'), isTrue);
    expect(find.byIcon(Icons.notifications_active), findsOneWidget);

    expect(find.byIcon(Icons.star_border), findsOneWidget);
    await tester.tap(find.byIcon(Icons.star_border));
    await tester.pumpAndSettle();
    expect(deps.library.isBookmarked('https://example.com/index.html'), isTrue);
    expect(find.byIcon(Icons.star), findsOneWidget);

    // Pages with neither Atom feed nor dated links offer no subscription.
    final plain = parseSource(
        _page('Plain', '<h1>Plain</h1><p>No entries here.</p>'),
        'https://example.com/plain.html');
    deps.browser.currentPage.value = plain;
    await tester.pumpAndSettle();
    expect(find.byIcon(Icons.notifications_outlined), findsNothing);
  });

  testWidgets('the address bar 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();

    expect(find.byType(AddressBar), findsOneWidget);

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

    // Scrolling up brings it back.
    await tester.drag(find.byType(ListView), const Offset(0, 300));
    await tester.pumpAndSettle();
    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),
      strings: strings,
    );
    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);

    // Swipes begin at the screen edge; mid-page drags select text. Small
    // steps keep the drag recognizer's update pacing in the test environment.
    final center = tester.getCenter(find.byType(SwipeNavigator));
    final gesture = await tester.startGesture(Offset(10, center.dy));
    for (var i = 0; i < 6; i++) {
      await gesture.moveBy(const Offset(70, 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('falls back to the wap subdomain before showing an error',
      (tester) async {
    final stubDeps = AppDependencies(
      database: MewsDatabase.test(NativeDatabase.memory()),
      fetch: _FakeFetch({
        'https://wap.example.com/':
            _page('Wap site', '<h1>Wap site</h1><p>Content lives here.</p>'),
      }),
      strings: strings,
    );
    await tester.pumpWidget(MewsApp(deps: stubDeps, strings: strings));
    await tester.pumpAndSettle();

    // The address as typed has no page; the wap. equivalent does.
    await stubDeps.browser.open('https://example.com/');
    expect(stubDeps.browser.currentPage.value?.url, 'https://wap.example.com/');
    await tester.pumpAndSettle();
    expect(find.textContaining('Content lives here'), findsOneWidget);

    // Addresses that work nowhere keep showing the error.
    await stubDeps.browser.open('https://missing.example.org/');
    expect(stubDeps.browser.currentPage.value, isNull);
    expect(stubDeps.browser.error.value, isA<LoadFailed>());
  });

  testWidgets('library pages render as Mews pages and join the walk history',
      (tester) async {
    final stubDeps = AppDependencies(
      database: MewsDatabase.test(NativeDatabase.memory()),
      fetch: _FakeFetch({
        'https://example.com/a.html':
            _page('Page A', '<h1>Page A</h1><p>The first page.</p>'),
        'https://example.com/b.html':
            _page('Page B', '<h1>Page B</h1><p>The second page.</p>'),
      }),
      strings: strings,
    );
    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');
    await stubDeps.browser.open('mews:history');
    await tester.pumpAndSettle();

    // Rendered like any Mews page, with dated links to both visits.
    expect(stubDeps.browser.currentPage.value?.url, 'mews:history');
    expect(find.text('History'), findsOneWidget);
    expect(find.textContaining('Page A'), findsOneWidget);
    expect(find.textContaining('Page B'), findsOneWidget);

    // Part of the walk: back returns to page B, forward to history again.
    await stubDeps.browser.back();
    await tester.pumpAndSettle();
    expect(stubDeps.browser.currentPage.value?.url, 'https://example.com/b.html');

    await stubDeps.browser.forward();
    await tester.pumpAndSettle();
    expect(stubDeps.browser.currentPage.value?.url, 'mews:history');

    // A history link navigates like any other link.
    await tester.tap(find.textContaining('Page A'));
    await tester.pumpAndSettle();
    expect(stubDeps.browser.currentPage.value?.url, 'https://example.com/a.html');

    // Bookmarks and subscriptions get the same treatment.
    await stubDeps.library.load();
    await stubDeps.library.toggleBookmark('https://example.com/b.html', 'Page B');
    await stubDeps.library.toggleSubscription(
        'https://example.com/a.html', 'Page A', const []);
    await stubDeps.browser.open('mews:bookmarks');
    await tester.pumpAndSettle();
    expect(find.text('Bookmarks'), findsOneWidget);
    expect(find.textContaining('Page B'), findsOneWidget);

    await stubDeps.browser.open('mews:subscriptions');
    await tester.pumpAndSettle();
    expect(find.text('Subscriptions'), findsOneWidget);
    expect(find.textContaining('Page A'), findsOneWidget);
  });

  testWidgets('prev and next buttons navigate on pointer platforms',
      (tester) async {
    final stubDeps = AppDependencies(
      database: MewsDatabase.test(NativeDatabase.memory()),
      fetch: _FakeFetch({
        '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>'),
      }),
      strings: strings,
    );
    // Test bindings default to android; a Linux host shows the buttons.
    debugDefaultTargetPlatformOverride = TargetPlatform.linux;

    await tester.pumpWidget(MewsApp(deps: stubDeps, strings: strings));
    await tester.pumpAndSettle();

    final back = find.byIcon(Icons.arrow_back);
    final forward = find.byIcon(Icons.arrow_forward);
    expect(back, findsOneWidget);
    expect(forward, findsOneWidget);

    await stubDeps.browser.open('https://example.com/a.html');
    await stubDeps.browser.open('https://example.com/b.html');
    await tester.pumpAndSettle();

    await tester.tap(back);
    await tester.pumpAndSettle();
    expect(stubDeps.browser.currentPage.value?.url, 'https://example.com/a.html');

    await tester.tap(forward);
    await tester.pumpAndSettle();
    expect(stubDeps.browser.currentPage.value?.url, 'https://example.com/b.html');

    // The invariant check runs before test tear-downs, so reset by hand.
    debugDefaultTargetPlatformOverride = null;
  });

  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();
}