import 'dart:convert';
import 'package:flutter/foundation.dart';
import 'package:flutter/material.dart';
import 'package:shared_preferences/shared_preferences.dart';

/// Décrit un onglet du menu principal (bottom nav).
class AppScreen {
  final String id;
  final String label;
  final IconData icon;
  bool visible;

  AppScreen({
    required this.id,
    required this.label,
    required this.icon,
    this.visible = true,
  });

  AppScreen copyWith({bool? visible}) => AppScreen(
        id: id, label: label, icon: icon,
        visible: visible ?? this.visible,
      );

  Map<String, dynamic> toJson() => {'id': id, 'visible': visible};
}

/// Gère les préférences d'apparence et les écrans visibles.
class AppSettingsProvider extends ChangeNotifier {
  static const _themeKey        = 'app_theme_mode';
  static const _accentKey       = 'app_accent_color';
  static const _textScaleKey    = 'app_text_scale';
  static const _screensKey      = 'app_screens_config';
  static const _densityKey      = 'app_ui_density';

  ThemeMode _themeMode      = ThemeMode.system;
  int       _accentIndex    = 0;   // 0=ETM blue, 1=vert, 2=orange, 3=violet
  double    _textScale      = 1.0;
  VisualDensity _density    = VisualDensity.standard;

  // Ordre et visibilité des écrans principaux
  List<AppScreen> _screens = [
    AppScreen(id: 'dashboard',  label: 'Dashboard',          icon: Icons.home_rounded),
    AppScreen(id: 'energy',     label: 'Énergie',            icon: Icons.bar_chart_rounded),
    AppScreen(id: 'things',     label: 'Things',             icon: Icons.device_hub_rounded),
    AppScreen(id: 'favorites',  label: 'Favoris',            icon: Icons.star_rounded),
    AppScreen(id: 'groups',     label: 'Groupes',            icon: Icons.group_work_rounded, visible: false),
    AppScreen(id: 'scenes',     label: 'Scènes',             icon: Icons.auto_awesome_rounded, visible: false),
    AppScreen(id: 'media',      label: 'Médias',             icon: Icons.music_note_rounded, visible: false),
    AppScreen(id: 'garages',    label: 'Garages',            icon: Icons.garage_rounded, visible: false),
    AppScreen(id: 'ac',         label: 'AC / Climatisation', icon: Icons.ac_unit_rounded),
  ];

  ThemeMode         get themeMode  => _themeMode;
  int               get accentIndex => _accentIndex;
  double            get textScale  => _textScale;
  VisualDensity     get density    => _density;
  List<AppScreen>   get screens    => _screens;
  List<AppScreen>   get visibleScreens =>
      _screens.where((s) => s.visible).toList();

  static const List<Color> accentColors = [
    Color(0xFF2E75B6),  // ETM blue
    Color(0xFF4CAF50),  // vert
    Color(0xFFFF7043),  // orange
    Color(0xFF7B1FA2),  // violet
  ];

  Color get accentColor => accentColors[_accentIndex.clamp(0, 3)];

  // ── Chargement depuis SharedPreferences ─────────────────────────────────────
  Future<void> load() async {
    final prefs = await SharedPreferences.getInstance();

    final themeVal = prefs.getInt(_themeKey) ?? 0;
    _themeMode = ThemeMode.values[themeVal.clamp(0, 2)];

    _accentIndex = (prefs.getInt(_accentKey) ?? 0).clamp(0, 3);
    _textScale   = (prefs.getDouble(_textScaleKey) ?? 1.0).clamp(0.8, 1.4);

    final densityVal = prefs.getInt(_densityKey) ?? 1;
    _density = _densityFromIndex(densityVal);

    // Restaure l'ordre et la visibilité des écrans
    final raw = prefs.getString(_screensKey);
    if (raw != null) {
      try {
        final List<dynamic> saved = jsonDecode(raw) as List;
        final byId = {for (final s in _screens) s.id: s};
        final restored = <AppScreen>[];
        for (final item in saved) {
          final id = item['id'] as String?;
          final visible = item['visible'] as bool? ?? true;
          if (id != null && byId.containsKey(id)) {
            restored.add(byId[id]!.copyWith(visible: visible));
            byId.remove(id);
          }
        }
        // Ajoute les écrans nouveaux non présents dans la config sauvegardée
        restored.addAll(byId.values);
        _screens = restored;
      } catch (_) {}
    }

    notifyListeners();
  }

  // ── Sauvegarde ───────────────────────────────────────────────────────────────
  Future<void> _save() async {
    final prefs = await SharedPreferences.getInstance();
    await prefs.setInt(_themeKey, _themeMode.index);
    await prefs.setInt(_accentKey, _accentIndex);
    await prefs.setDouble(_textScaleKey, _textScale);
    await prefs.setInt(_densityKey, _densityIndex(_density));
    await prefs.setString(
        _screensKey, jsonEncode(_screens.map((s) => s.toJson()).toList()));
  }

  // ── Setters ──────────────────────────────────────────────────────────────────
  void setThemeMode(ThemeMode mode) {
    _themeMode = mode; _save(); notifyListeners();
  }

  void setAccentIndex(int idx) {
    _accentIndex = idx.clamp(0, 3); _save(); notifyListeners();
  }

  void setTextScale(double v) {
    _textScale = v.clamp(0.8, 1.4); _save(); notifyListeners();
  }

  void setDensity(VisualDensity d) {
    _density = d; _save(); notifyListeners();
  }

  void setScreenVisible(String id, bool visible) {
    final idx = _screens.indexWhere((s) => s.id == id);
    if (idx >= 0) {
      _screens[idx] = _screens[idx].copyWith(visible: visible);
      _save();
      notifyListeners();
    }
  }

  void reorderScreens(int oldIdx, int newIdx) {
    final item = _screens.removeAt(oldIdx);
    _screens.insert(newIdx, item);
    _save();
    notifyListeners();
  }

  void resetAppearance() {
    _themeMode   = ThemeMode.system;
    _accentIndex = 0;
    _textScale   = 1.0;
    _density     = VisualDensity.standard;
    _save();
    notifyListeners();
  }

  // ── Helpers ──────────────────────────────────────────────────────────────────
  VisualDensity _densityFromIndex(int i) => switch (i) {
        0 => VisualDensity.compact,
        2 => const VisualDensity(horizontal: 2, vertical: 2),
        _ => VisualDensity.standard,
      };

  int _densityIndex(VisualDensity d) {
    if (d == VisualDensity.compact) return 0;
    if (d.horizontal > 0)          return 2;
    return 1;
  }
}