import 'dart:convert';
import 'dart:io';
import 'dart:math' as math;

import 'package:flutter/material.dart';

import 'package:flutter_test/flutter_test.dart';

import 'package:sxchnge_theme/sxchnge_theme.dart';

double contrast(Color a, Color b) {
  final x = a.computeLuminance();
  final y = b.computeLuminance();
  return (math.max(x, y) + 0.05) / (math.min(x, y) + 0.05);
}

void main() {
  test('website core colors stay aligned with the package snapshot', () {
    final source = File('../../../website/design/tokens.json');
    if (!source.existsSync())
      return; // Also allow testing outside this monorepo.
    final colors =
        (jsonDecode(source.readAsStringSync()) as Map)['colors'] as Map;
    for (final entry in {
      'ink': SxchngeBrand.ink,
      'mint': SxchngeBrand.mint,
      'lime': SxchngeBrand.lime,
      'paper': SxchngeBrand.paper,
      'forest': SxchngeBrand.forest,
    }.entries) {
      expect(
        entry.value.toARGB32(),
        int.parse('ff${(colors[entry.key] as String).substring(1)}', radix: 16),
      );
    }
  });

  for (final dark in [false, true]) {
    final theme = dark ? SxchngeTheme.dark() : SxchngeTheme.light();
    test(
      '${dark ? "dark" : "light"} foreground pairs meet normal text contrast',
      () {
        final c = theme.colorScheme;
        for (final pair in [
          (c.primary, c.onPrimary),
          (c.primaryContainer, c.onPrimaryContainer),
          (c.secondary, c.onSecondary),
          (c.secondaryContainer, c.onSecondaryContainer),
          (c.tertiary, c.onTertiary),
          (c.tertiaryContainer, c.onTertiaryContainer),
          (c.surface, c.onSurface),
          (c.surface, c.onSurfaceVariant),
          (c.error, c.onError),
          (c.errorContainer, c.onErrorContainer),
        ]) {
          expect(contrast(pair.$1, pair.$2), greaterThanOrEqualTo(4.5));
        }
        expect(
          theme.textTheme.bodyMedium!.fontFamily,
          'packages/sxchnge_theme/Onest',
        );
      },
    );
  }
}