import 'dart:math';

import 'package:animated_theme_switcher/animated_theme_switcher.dart';
import 'package:flutter/material.dart';
import 'package:flutter_bloc/flutter_bloc.dart';
import 'package:flutter_translate/flutter_translate.dart';

import '../../../settings/settings.dart';
import '../../models/models.dart';
import '../views.dart';

const _scales = [
  1 / (1 + 1 / 2),
  1 / (1 + 1 / 3),
  1 / (1 + 1 / 4),
  1,
  1 + (1 / 4),
  1 + (1 / 2),
  1 + (1 / 1),
];
const _scaleNames = [
  '-3',
  '-2',
  '-1',
  '0',
  '1',
  '2',
  '3',
];

const _scaleNumMult = <double>[
  1,
  1,
  1,
  1,
  1 + 1 / 4,
  1 + 1 / 2,
  1 + 1 / 1,
];

int displayScaleToIndex(double displayScale) {
  final idx = _scales.indexWhere((elem) => elem > displayScale);
  final currentScaleIdx = idx == -1 ? _scales.length - 1 : max(0, idx - 1);
  return currentScaleIdx;
}

double indexToDisplayScale(int scaleIdx) {
  final displayScale =
      _scales[max(min(scaleIdx, _scales.length - 1), 0)].toDouble();
  return displayScale;
}

String indexToDisplayScaleName(int scaleIdx) =>
    _scaleNames[max(min(scaleIdx, _scales.length - 1), 0)];

final maxDisplayScaleIndex = _scales.length - 1;

Widget buildSettingsPageDisplayScalePreferences(
    {required BuildContext context, required ThemeSwitcherState switcher}) {
  final preferencesRepository = PreferencesRepository.instance;
  final themePreferences = preferencesRepository.value.themePreference;

  final currentScaleIdx = displayScaleToIndex(themePreferences.displayScale);
  final currentScaleName = indexToDisplayScaleName(currentScaleIdx);

  return StyledSlider(
      value: currentScaleIdx.toDouble(),
      label: currentScaleName,
      decoratorLabel: translate('settings_page.display_scale'),
      max: _scales.length - 1.toDouble(),
      divisions: _scales.length - 1,
      leftWidget: const Icon(Icons.text_decrease),
      rightWidget: const Icon(Icons.text_increase),
      onChanged: (value) async {
        final scaleIdx = value.toInt();
        final displayScale = indexToDisplayScale(scaleIdx);
        final newThemePrefs =
            themePreferences.copyWith(displayScale: displayScale);
        final newPrefs = preferencesRepository.value
            .copyWith(themePreference: newThemePrefs);

        await preferencesRepository.set(newPrefs);
        switcher.changeTheme(theme: newThemePrefs.themeData());
      });
}

extension DisplayScaledNum on num {
  double scaled(BuildContext context) {
    final prefs = context.watch<PreferencesCubit>().state.asData?.value ??
        PreferencesRepository.instance.value;
    final currentScaleIdx =
        displayScaleToIndex(prefs.themePreference.displayScale);
    return this * _scaleNumMult[currentScaleIdx];
  }
}

extension DisplayScaledEdgeInsets on EdgeInsets {
  EdgeInsets scaled(BuildContext context) {
    final prefs = context.watch<PreferencesCubit>().state.asData?.value ??
        PreferencesRepository.instance.value;
    final currentScaleIdx =
        displayScaleToIndex(prefs.themePreference.displayScale);
    return EdgeInsets.fromLTRB(
        left * _scaleNumMult[currentScaleIdx],
        top * _scaleNumMult[currentScaleIdx],
        right * _scaleNumMult[currentScaleIdx],
        bottom * _scaleNumMult[currentScaleIdx]);
  }
}