import 'package:flutter_test/flutter_test.dart';
import 'package:mews/mews/document.dart';
import 'package:mews/presentation/reader/oklch.dart';
import 'package:mews/presentation/reader/palettes.dart';
import 'package:mews/presentation/reader/site_palette.dart';

/// A wide sample of what the generator can produce: enough hosts to cover all
/// 24 hues, 3 background tints and both foregrounds.
Iterable<MewsPalette> _allPalettes(bool dark) => [
      for (var i = 0; i < 2000; i++) sitePalette('gemini://h$i.example/', dark: dark)!,
    ];

void main() {
  group('seed', () {
    test('comes from the host', () {
      expect(siteSeed('gemini://example.org/page'), 'example.org');
      expect(siteSeed('gemini://Example.ORG/page'), 'example.org');
    });

    test('names the user on a personal page', () {
      expect(siteSeed('gemini://example.org/~alice/'), 'alice@example.org');
      expect(siteSeed('gemini://example.org/users/alice/x.gmi'), 'alice@example.org');
      expect(siteSeed('gemini://example.org/Users/Alice'), 'alice@example.org');
    });

    test('is empty without a host', () {
      expect(siteSeed('mews:settings'), '');
      expect(siteSeed('not a url'), '');
    });
  });

  group('palette', () {
    test('is the same every time for one address', () {
      expect(sitePalette('gemini://example.org/a', dark: false),
          same(sitePalette('gemini://example.org/b', dark: false)));
    });

    test('differs between two users on one host', () {
      final alice = sitePalette('gemini://example.org/~alice/', dark: false)!;
      final bob = sitePalette('gemini://example.org/~bob/', dark: false)!;
      expect(alice.link, isNot(bob.link));
    });

    test('is null for an address with no host', () {
      expect(sitePalette('mews:settings', dark: false), isNull);
    });

    test('falls back to plain when the reader asks for host colors', () {
      expect(
        paletteFor(
            pageVariant: MewsVariant.plain,
            readerVariant: 'host',
            dark: false,
            url: 'mews:settings'),
        paletteFor(pageVariant: MewsVariant.plain, readerVariant: 'plain', dark: false),
      );
    });

    // Spec 5.1: every text and link color meets 7:1 against its background.
    for (final dark in [false, true]) {
      test('meets 7:1 contrast in ${dark ? 'dark' : 'light'} mode', () {
        for (final palette in _allPalettes(dark)) {
          expect(contrastRatio(palette.background, palette.foreground),
              greaterThanOrEqualTo(7.0));
          expect(contrastRatio(palette.background, palette.link),
              greaterThanOrEqualTo(7.0));
          expect(contrastRatio(palette.background, palette.visited),
              greaterThanOrEqualTo(7.0));
        }
      });

      test('stays no louder than the fixed palettes in ${dark ? 'dark' : 'light'} mode', () {
        // Cool holds the most saturated link of the fixed palettes, so no
        // generated color may pass it.
        final cool = paletteFor(
            pageVariant: MewsVariant.cool, readerVariant: 'cool', dark: dark);
        final limit = chromaOf(cool.link);
        for (final palette in _allPalettes(dark)) {
          expect(chromaOf(palette.link), lessThanOrEqualTo(limit));
          expect(chromaOf(palette.background), lessThanOrEqualTo(0.03));
        }
      });
    }
  });
}