ente/auth/lib/ui/utils/icon_utils.dart

import 'dart:convert';

import 'package:ente_auth/ente_theme_data.dart';
import 'package:ente_auth/theme/ente_theme.dart';
import 'package:flutter/material.dart';
import 'package:flutter/services.dart';
import 'package:flutter_svg/svg.dart';
import 'package:logging/logging.dart';

class IconUtils {
  IconUtils._privateConstructor();

  static final IconUtils instance = IconUtils._privateConstructor();

  // Map of icon-title to the color code in HEX
  final Map<String, String> _simpleIcons = {};
  final Map<String, CustomIconData> _customIcons = {};
  // Map of icon-color to its luminance
  final Map<Color, double> _colorLuminance = {};

  Future<void> init() async {
    await _loadJson();
  }

  Widget getIcon(
    BuildContext context,
    String provider, {
    double width = 24,
  }) {
    final title = _getProviderTitle(provider);
    if (_customIcons.containsKey(title)) {
      return _getSVGIcon(
        "assets/custom-icons/icons/${_customIcons[title]!.slug ?? title}.svg",
        title,
        _customIcons[title]!.color,
        width,
        context,
      );
    } else if (_simpleIcons.containsKey(title)) {
      return _getSVGIcon(
        "assets/simple-icons/icons/$title.svg",
        title,
        _simpleIcons[title],
        width,
        context,
      );
    } else if (title.isNotEmpty) {
      bool showLargeIcon = width > 24;
      return CircleAvatar(
        radius: width / 2,
        backgroundColor: getEnteColorScheme(context).avatarColors[
            title.hashCode % getEnteColorScheme(context).avatarColors.length],
        child: Text(
          title.toUpperCase()[0],
          // fixed color
          style: showLargeIcon
              ? getEnteTextTheme(context).h3Bold.copyWith(color: Colors.white)
              : getEnteTextTheme(context).body.copyWith(color: Colors.white),
        ),
      );
    } else {
      return const SizedBox.shrink();
    }
  }

  Widget _getSVGIcon(
    String path,
    String title,
    String? color,
    double width,
    BuildContext context,
  ) {
    final iconColor = _getAdaptiveColor(color, context);
    return SvgPicture.asset(
      path,
      width: width,
      semanticsLabel: title,
      colorFilter: iconColor != null
          ? ColorFilter.mode(
              iconColor,
              BlendMode.srcIn,
            )
          : null,
    );
  }

  Color? _getAdaptiveColor(String? hexColor, BuildContext context) {
    if (hexColor == null) return null;
    final theme = Theme.of(context).brightness;
    final color = Color(int.parse("0xFF$hexColor"));
    // Color is close to neutral-grey and it's too light or dark for theme
    if (_isCloseToNeutralGrey(color) &&
        ((theme == Brightness.light && _getColorLuminance(color) > 0.70) ||
            (theme == Brightness.dark && _getColorLuminance(color) < 0.05))) {
      return Theme.of(context).colorScheme.iconColor;
    }
    return color;
  }

  double _getColorLuminance(Color color) {
    return _colorLuminance.putIfAbsent(color, () => color.computeLuminance());
  }

  bool _isCloseToNeutralGrey(Color color, {double tolerance = 3}) {
    return (color.red - color.green).abs() <= tolerance &&
        (color.green - color.blue).abs() <= tolerance &&
        (color.blue - color.red).abs() <= tolerance;
  }

  Future<void> _loadJson() async {
    try {
      final simpleIconData = await rootBundle
          .loadString('assets/simple-icons/_data/simple-icons.json');
      final simpleIcons = json.decode(simpleIconData);
      for (final icon in simpleIcons["icons"]) {
        _simpleIcons[icon["title"]
            .toString()
            .replaceAll(' ', '')
            .toLowerCase()] = icon["hex"];
      }
      final customIconData = await rootBundle
          .loadString('assets/custom-icons/_data/custom-icons.json');
      final customIcons = json.decode(customIconData);
      for (final icon in customIcons["icons"]) {
        _customIcons[icon["title"]
            .toString()
            .replaceAll(' ', '')
            .toLowerCase()] = CustomIconData(
          icon["slug"],
          icon["hex"],
        );
        if (icon["altNames"] != null) {
          for (final name in icon["altNames"]) {
            _customIcons[name] = CustomIconData(
              icon["slug"],
              icon["hex"],
            );
          }
        }
      }
    } catch (e) {
      Logger("IconUtils").severe("Error loading icons", e);
    }
  }

  String _getProviderTitle(String provider) {
    return provider.split(RegExp(r'[.(]'))[0].replaceAll(' ', '').toLowerCase();
  }
}

class CustomIconData {
  final String? slug;
  final String? color;

  CustomIconData(this.slug, this.color);
}