import 'dart:convert';
import 'dart:ui' as ui;

import 'package:flutter/foundation.dart';
import 'package:flutter/services.dart';
import 'package:flutter_test/flutter_test.dart';
import 'package:halkyon_ui/halkyon_ui.dart';
import 'package:halkyon_ui_example/main.dart';
import 'package:material_ui/material_ui.dart';

/// How many pixels [text] inks in [family] at [weight]: heavier strokes ink
/// more.
Future<int> ink(String text, String family, FontWeight weight) async {
  final painter = TextPainter(
    text: TextSpan(
      text: text,
      style: TextStyle(
        fontFamily: family,
        fontSize: 40,
        fontWeight: weight,
        color: const Color(0xFF000000),
      ),
    ),
    textDirection: TextDirection.ltr,
  )..layout();
  final recorder = ui.PictureRecorder();
  painter.paint(Canvas(recorder), Offset.zero);
  final image = await recorder.endRecording().toImage(
    painter.width.ceil(),
    painter.height.ceil(),
  );
  final pixels = (await image.toByteData())!;
  var inked = 0;
  for (var alpha = 3; alpha < pixels.lengthInBytes; alpha += 4) {
    if (pixels.getUint8(alpha) > 128) {
      inked++;
    }
  }
  return inked;
}

void main() {
  TestWidgetsFlutterBinding.ensureInitialized();

  test("an app finds the package's Noto Sans under the theme's name, and "
      'draws every weight with it', () async {
    final manifest = jsonDecode(
      await rootBundle.loadString('FontManifest.json'),
    ) as List<Object?>;
    final noto = manifest.cast<Map<String, Object?>>().singleWhere(
      (font) => font['family'] == appFontFamily,
    );
    final assets = [
      for (final font
          in (noto['fonts']! as List<Object?>).cast<Map<String, Object?>>())
        font['asset']! as String,
    ];
    expect(
      assets,
      contains('packages/halkyon_ui/assets/fonts/NotoSans-Variable.ttf'),
    );

    // Loaded as the engine loads an app's fonts as it starts: by the
    // manifest's family and files.
    final loader = FontLoader(appFontFamily);
    for (final asset in assets) {
      loader.addFont(rootBundle.load(asset));
    }
    await loader.load();
    const text = 'Ἀθῆναι Halkyon';
    final regular = await ink(text, appFontFamily, FontWeight.w400);
    final bold = await ink(text, appFontFamily, FontWeight.w700);
    expect(bold, greaterThan(regular * 1.2));
  });

  test("Noto Sans's licence joins the app's licence list", () async {
    registerFontLicenses();

    final notices = [
      await for (final entry in LicenseRegistry.licenses)
        if (entry.packages.contains('Noto Sans')) entry,
    ];
    expect(notices, hasLength(1));
    expect(
      notices.single.paragraphs.map((paragraph) => paragraph.text).join(),
      contains('SIL OPEN FONT LICENSE'),
    );
  });

  testWidgets("the app speaks German with the package's texts", (tester) async {
    await tester.pumpWidget(const ExampleApp(locale: Locale('de')));

    expect(find.text('Halkyon'), findsOneWidget);
    expect(find.text('Example'), findsOneWidget);
    await tester.tap(find.text('Delete'));
    await tester.pumpAndSettle();
    expect(find.text('Abbrechen'), findsOneWidget);
  });
}