import 'package:drift/drift.dart' show Value;
import 'package:drift/native.dart';
import 'package:flutter_test/flutter_test.dart';

import 'package:mews/application/controllers/bookmarks_controller.dart';
import 'package:mews/application/controllers/reader_settings_controller.dart';
import 'package:mews/application/controllers/subscriptions_controller.dart';
import 'package:mews/database/database.dart';
import 'package:mews/mews/document.dart';
import 'package:mews/mews/parser.dart';

import 'fake_fetch.dart';

void main() {
  late MewsDatabase db;

  setUp(() {
    db = MewsDatabase.test(NativeDatabase.memory());
  });

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

  test('settings round-trip through the database', () async {
    final settings = ReaderSettingsController(db);
    await settings.setFont('Atkinson Hyperlegible');
    await settings.increaseSize();
    await settings.setThemeMode('dark');
    await settings.setVariant('warm');

    final reloaded = ReaderSettingsController(db);
    await reloaded.load();
    expect(reloaded.font.value, 'Atkinson Hyperlegible');
    expect(reloaded.fontScale.value, 1.125);
    expect(reloaded.themeMode.value, 'dark');
    expect(reloaded.variant.value, 'warm');
  });

  test('text size stays within its limits', () async {
    final settings = ReaderSettingsController(db);
    for (var i = 0; i < 30; i++) {
      await settings.increaseSize();
    }
    expect(settings.fontScale.value, ReaderSettingsController.maxScale);
    for (var i = 0; i < 40; i++) {
      await settings.decreaseSize();
    }
    expect(settings.fontScale.value, ReaderSettingsController.minScale);
  });

  test('bookmarks toggle and persist', () async {
    final bookmarks = BookmarksController(db);
    await bookmarks.load();
    await bookmarks.toggle('https://example.com/', 'Example');
    expect(bookmarks.isBookmarked('https://example.com/'), isTrue);

    final reloaded = BookmarksController(db);
    await reloaded.load();
    expect(reloaded.isBookmarked('https://example.com/'), isTrue);

    await reloaded.toggle('https://example.com/', 'Example');
    expect(reloaded.isBookmarked('https://example.com/'), isFalse);
  });

  test('subscribing takes on the back catalogue without flagging it', () async {
    final subscriptions = SubscriptionsController(db: db, fetch: FakeFetch(const {}));
    await subscriptions.load();

    final firstPost = MewsEntry(
        url: 'https://example.com/a.html',
        date: DateTime(2026, 9, 21),
        title: 'First post');
    await subscriptions.toggle(_page('https://example.com/', [firstPost]));
    expect(subscriptions.isSubscribed('https://example.com/'), isTrue);

    // The post was stored, but read, so nothing is waiting for the reader.
    expect(await db.unreadCount(), 0);

    // Opening the page again finds nothing new.
    expect(await subscriptions.refreshSite(_page('https://example.com/', [firstPost])),
        isEmpty);

    // A later post is new, and stays unread until the reader opens it.
    final newPost = MewsEntry(
        url: 'https://example.com/b.html',
        date: DateTime(2026, 10, 8),
        title: 'Second post');
    final fresh = await subscriptions
        .refreshSite(_page('https://example.com/', [newPost, firstPost]));
    expect(fresh.map((e) => e.url), ['https://example.com/b.html']);
    expect(await db.unreadCount(siteUrl: 'https://example.com/'), 1);

    // Finding it a second time does not report it again.
    expect(
        await subscriptions
            .refreshSite(_page('https://example.com/', [newPost, firstPost])),
        isEmpty);
    expect(await db.unreadCount(), 1);
  });

  test('unread posts survive a restart', () async {
    final subscriptions = SubscriptionsController(db: db, fetch: FakeFetch(const {}));
    await subscriptions.load();
    await subscriptions.toggle(_page('https://example.com/', const []));
    await subscriptions.refreshSite(_page('https://example.com/', [
      MewsEntry(
          url: 'https://example.com/a.html',
          date: DateTime(2026, 9, 21),
          title: 'First post'),
    ]));

    // A fresh controller over the same database sees the same unread post,
    // which the old in-memory count could not do.
    final restarted = SubscriptionsController(db: db, fetch: FakeFetch(const {}));
    await restarted.load();
    expect(restarted.isSubscribed('https://example.com/'), isTrue);
    expect(await db.unreadCount(), 1);
  });

  test('leaving a site takes its posts with it', () async {
    final subscriptions = SubscriptionsController(db: db, fetch: FakeFetch(const {}));
    await subscriptions.load();
    await subscriptions.toggle(_page('https://example.com/', const []));
    await subscriptions.refreshSite(_page('https://example.com/', [
      MewsEntry(
          url: 'https://example.com/a.html',
          date: DateTime(2026, 9, 21),
          title: 'First post'),
    ]));
    expect(await db.unreadCount(), 1);

    await subscriptions.remove('https://example.com/');
    expect(subscriptions.isSubscribed('https://example.com/'), isFalse);
    expect(await db.unreadCount(), 0);
  });

  test('a check finds new posts on every subscribed site', () async {
    const siteA = 'https://a.example/';
    const siteB = 'https://b.example/';
    final sources = {
      siteA: _entriesPage('Site A', const []),
      siteB: _entriesPage('Site B', const []),
    };
    final subscriptions =
        SubscriptionsController(db: db, fetch: FakeFetch(sources));
    await subscriptions.load();
    await subscriptions.toggle(_page(siteA, const []));
    await subscriptions.toggle(_page(siteB, const []));

    // Both sites publish something after the reader subscribed.
    sources[siteA] = _entriesPage('Site A', const [
      ('2026-10-09', 'a-one.html', 'A newer post'),
    ]);
    sources[siteB] = _entriesPage('Site B', const [
      ('2026-10-10', 'b-one.html', 'Another post'),
      ('2026-10-09', 'b-two.html', 'And one more'),
    ]);

    await subscriptions.refreshAll();
    expect(await db.unreadCount(), 3);
    expect(await db.unreadCount(siteUrl: siteA), 1);
    expect(subscriptions.refreshing.value, isFalse);

    // Every site was recorded as checked.
    for (final site in await db.allSubscriptions()) {
      expect(site.lastCheckedAt, isNotNull);
    }
  });

  test('one unreachable site does not stop the rest of the check', () async {
    const reachable = 'https://a.example/';
    const unreachable = 'https://down.example/';
    final subscriptions = SubscriptionsController(
      db: db,
      // Only the first site answers; the other has no source at all.
      fetch: FakeFetch({
        reachable: _entriesPage('Site A', const [
          ('2026-10-09', 'a-one.html', 'A newer post'),
        ]),
      }),
    );
    await subscriptions.load();
    await subscriptions.toggle(_page(unreachable, const []));
    await subscriptions.toggle(_page(reachable, const []));

    await subscriptions.refreshAll();
    expect(await db.unreadCount(siteUrl: reachable), 1);
    expect(subscriptions.refreshing.value, isFalse);
    // The site that could not be reached is still marked as checked.
    final down = (await db.allSubscriptions())
        .firstWhere((s) => s.url == unreachable);
    expect(down.lastCheckedAt, isNotNull);
  });

  test('a check already running is not started again', () async {
    final subscriptions = SubscriptionsController(
      db: db,
      fetch: FakeFetch({'https://a.example/': _entriesPage('Site A', const [])}),
    );
    await subscriptions.load();
    await subscriptions.toggle(_page('https://a.example/', const []));

    var redraws = 0;
    subscriptions.onChanged = () => redraws++;
    await Future.wait([subscriptions.refreshAll(), subscriptions.refreshAll()]);
    // One pass: it starts and finishes once, so two redraws, not four.
    expect(redraws, 2);
  });

  test('a site publishing only through a feed still reports posts', () async {
    const site = 'https://feedonly.example/';
    const feed = 'https://feedonly.example/feed.xml';
    // A page with no dated links, but it declares a feed (spec 6.2).
    const page = '''
<?xml version="1.0" encoding="UTF-8"?>
<html xmlns="http://www.w3.org/1999/xhtml">
  <head>
    <title>Feed Only</title>
    <meta name="mews-profile" content="0.1" />
    <link rel="alternate" type="application/atom+xml" href="feed.xml" />
  </head>
  <body><h1>Feed Only</h1><p>Nothing listed here.</p></body>
</html>
''';
    String feedWith(List<(String, String)> entries) => '''
<feed xmlns="http://www.w3.org/2005/Atom">
${entries.map((e) => '<entry><title>${e.$2}</title><link rel="alternate" href="${e.$1}" /><updated>2026-10-08T09:30:00Z</updated></entry>').join()}
</feed>
''';

    final feeds = {feed: feedWith(const [('old.html', 'An older post')])};
    final subscriptions = SubscriptionsController(
      db: db,
      fetch: FakeFetch({site: page}, feeds: feeds),
    );
    await subscriptions.load();
    await subscriptions.toggle(parseMewsPage(source: page, url: site));

    // What the feed already listed is the back catalogue, not news.
    expect(await db.unreadCount(), 0);
    expect((await db.allSubscriptions()).single.atomHref, feed);

    // A post added to the feed later is new.
    feeds[feed] = feedWith(const [
      ('new.html', 'A newer post'),
      ('old.html', 'An older post'),
    ]);
    await subscriptions.refreshAll();
    expect(await db.unreadCount(), 1);
    final entries = await db.riverEntries(unreadOnly: true);
    expect(entries.single.title, 'A newer post');

    // Checking again reports nothing, because an address identifies a post.
    await subscriptions.refreshAll();
    expect(await db.unreadCount(), 1);
  });

  test('a page listing dated links is not fetched twice', () async {
    const site = 'https://both.example/';
    const page = '''
<?xml version="1.0" encoding="UTF-8"?>
<html xmlns="http://www.w3.org/1999/xhtml">
  <head>
    <title>Both</title>
    <meta name="mews-profile" content="0.1" />
    <link rel="alternate" type="application/atom+xml" href="feed.xml" />
  </head>
  <body><h1>Both</h1><ul>
    <li><a href="one.html">2026-10-08 The only post</a></li>
  </ul></body>
</html>
''';
    // The feed would answer, but a page that lists its own posts is enough,
    // so nothing asks for it.
    final subscriptions = SubscriptionsController(
      db: db,
      fetch: FakeFetch({site: page}, feeds: const {
        'https://both.example/feed.xml':
            '<feed xmlns="http://www.w3.org/2005/Atom"><entry><title>Duplicate</title>'
                '<link rel="alternate" href="one.html" /><updated>2026-10-08T09:30:00Z</updated>'
                '</entry></feed>',
      }),
    );
    await subscriptions.load();
    await subscriptions.toggle(parseMewsPage(source: page, url: site));
    await subscriptions.refreshAll();

    // One post, under the title the page gave it.
    final entries = await db.riverEntries();
    expect(entries, hasLength(1));
    expect(entries.single.title, 'The only post');
  });

  test('caches pages for offline reopening', () async {
    await db.saveCachedPage(CachedPagesCompanion.insert(
      url: 'https://example.com/page.html',
      source: 'html',
      title: const Value('Page'),
      etag: const Value('"v1"'),
    ));
    final cached = await db.cachedPage('https://example.com/page.html');
    expect(cached!.source, 'html');
    expect(cached.etag, '"v1"');
    expect(cached.title, 'Page');
  });

  test('records history and returns the last visited page', () async {
    await db.recordVisit('https://a.example/', 'A');
    await db.recordVisit('https://b.example/', 'B');
    expect(await db.lastVisitedUrl(), 'https://b.example/');
  });
}

MewsPage _page(String url, List<MewsEntry> entries) => MewsPage(
      url: url,
      body: const [],
      lang: 'en',
      direction: TextDirection.ltr,
      variant: MewsVariant.plain,
      entries: entries,
      specVersion: '0.1',
    );

/// A Mews page whose list holds dated links (spec 6.1), one per entry given as
/// (date, file name, title).
String _entriesPage(
        String title, List<(String, String, String)> entries) =>
    '''
<?xml version="1.0" encoding="UTF-8"?>
<html xmlns="http://www.w3.org/1999/xhtml">
  <head><title>$title</title><meta name="mews-profile" content="0.1" /></head>
  <body>
    <h1>$title</h1>
    <ul>
${entries.map((e) => '      <li><a href="${e.$2}">${e.$1} ${e.$3}</a></li>').join('\n')}
    </ul>
  </body>
</html>
''';