import 'package:flutter/material.dart';
import 'package:shared_preferences/shared_preferences.dart';
import 'login_screen.dart';
import 'desktop_login_screen.dart';
import '../core/theme_manager.dart';
import 'privacy_policy_screen.dart';
import '../core/app_decoration.dart';

class SettingsScreen extends StatefulWidget {
  const SettingsScreen({Key? key}) : super(key: key);

  @override
  State<SettingsScreen> createState() => _SettingsScreenState();
}

class _SettingsScreenState extends State<SettingsScreen> {
  bool _notifications = true;
  String _appVersion = '1.6(p)';
  int _selectedSection = 0; // 0=Preferences, 1=Account, 2=About

  @override
  void initState() {
    super.initState();
    _loadPreferences();
  }

  Future<void> _loadPreferences() async {
    final prefs = await SharedPreferences.getInstance();
    setState(() {
      _notifications = prefs.getBool('reminders_enabled') ?? true;
      // app version may come from pubspec or preferences; kept static otherwise
    });
  }

  Future<void> _saveNotifications(bool value) async {
    final prefs = await SharedPreferences.getInstance();
    await prefs.setBool('reminders_enabled', value);
    setState(() => _notifications = value);
  }

  Future<void> _confirmLogout() async {
    final should = await showDialog<bool>(
      context: context,
      builder: (ctx) {
        return AlertDialog(
          title: const Text('Logout'),
          content: const Text('Are you sure you want to logout? This will clear saved login data.'),
          actions: [
            TextButton(onPressed: () => Navigator.of(ctx).pop(false), child: const Text('Cancel')),
            ElevatedButton(onPressed: () => Navigator.of(ctx).pop(true), child: const Text('Logout')),
          ],
        );
      },
    );

    if (should == true) {
      await _performLogout();
    }
  }

  Future<void> _performLogout() async {
    final prefs = await SharedPreferences.getInstance();
    await prefs.remove('username');
    await prefs.remove('email');
    await prefs.remove('profileImage');

    // Decide which login screen to show depending on current window width
    final double width = MediaQuery.of(context).size.width;
    const double desktopBreakpoint = 820; // same breakpoint used elsewhere
    final bool isDesktop = width >= desktopBreakpoint;

    // Navigate and remove all previous routes
    Navigator.of(context).pushAndRemoveUntil(
      MaterialPageRoute(
        builder: (_) => isDesktop ? const DesktopLoginScreen() : const LoginScreen(),
      ),
      (route) => false,
    );
  }

  Widget _buildTile({required IconData icon, required String title, String? subtitle, VoidCallback? onTap}) {
    return Container(
      margin: const EdgeInsets.symmetric(vertical: 6),
      decoration: BoxDecoration(
        color: Theme.of(context).cardColor,
        borderRadius: BorderRadius.circular(12),
        boxShadow: const [BoxShadow(color: Colors.black12, blurRadius: 6, offset: Offset(0, 4))],
      ),
      child: ListTile(
        leading: Container(
          width: 44,
          height: 44,
          decoration: BoxDecoration(color: Theme.of(context).scaffoldBackgroundColor, borderRadius: BorderRadius.circular(10)),
          child: Icon(icon, color: const Color(0xFF0B63D6)),
        ),
        title: Text(title, style: const TextStyle(fontWeight: FontWeight.w600)),
        subtitle: subtitle != null ? Text(subtitle) : null,
        onTap: onTap,
        contentPadding: const EdgeInsets.symmetric(horizontal: 12, vertical: 8),
      ),
    );
  }

  // ── Settings content sections ────────────────────────────────────────────
  Widget _buildPreferencesSection() {
    const primary = Color(0xFF0B63D6);
    return SingleChildScrollView(
      physics: const BouncingScrollPhysics(),
      padding: const EdgeInsets.fromLTRB(18, 0, 18, 24),
      child: Column(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: [
          const SizedBox(height: 8),
          Container(
            margin: const EdgeInsets.symmetric(vertical: 6),
            decoration: BoxDecoration(color: Theme.of(context).cardColor, borderRadius: BorderRadius.circular(12), boxShadow: const [BoxShadow(color: Colors.black12, blurRadius: 6, offset: Offset(0, 4))]),
            child: SwitchListTile(
              tileColor: Theme.of(context).cardColor,
              contentPadding: const EdgeInsets.symmetric(horizontal: 12, vertical: 4),
              value: _notifications,
              onChanged: (v) => _saveNotifications(v),
              title: const Text('Reminders'),
              secondary: const Icon(Icons.notifications, color: primary),
            ),
          ),
          const SizedBox(height: 8),
          Container(
            margin: const EdgeInsets.symmetric(vertical: 6),
            decoration: BoxDecoration(color: Theme.of(context).cardColor, borderRadius: BorderRadius.circular(12), boxShadow: const [BoxShadow(color: Colors.black12, blurRadius: 6, offset: Offset(0, 4))]),
            child: ValueListenableBuilder<ThemeMode>(
              valueListenable: ThemeManager.themeMode,
              builder: (context, mode, _) {
                return SwitchListTile(
                  tileColor: Theme.of(context).cardColor,
                  contentPadding: const EdgeInsets.symmetric(horizontal: 12, vertical: 4),
                  value: mode == ThemeMode.dark,
                  onChanged: (v) => ThemeManager.setThemeMode(v ? ThemeMode.dark : ThemeMode.light),
                  title: const Text('Dark Mode'),
                  secondary: const Icon(Icons.dark_mode, color: primary),
                );
              },
            ),
          ),
        ],
      ),
    );
  }

  Widget _buildAccountSection() {
    return SingleChildScrollView(
      physics: const BouncingScrollPhysics(),
      padding: const EdgeInsets.fromLTRB(18, 8, 18, 24),
      child: Column(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: [
          _buildTile(
            icon: Icons.person,
            title: 'Edit Profile',
            subtitle: 'Change username, email or photo',
            onTap: () => ScaffoldMessenger.of(context).showSnackBar(const SnackBar(content: Text('Open Profile tab'))),
          ),
          const SizedBox(height: 24),
          Center(
            child: ElevatedButton(
              onPressed: _confirmLogout,
              style: ElevatedButton.styleFrom(
                backgroundColor: Colors.red.shade600,
                padding: const EdgeInsets.symmetric(horizontal: 28, vertical: 14),
                shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(24)),
              ),
              child: const Text('Logout', style: TextStyle(color: Colors.white)),
            ),
          ),
        ],
      ),
    );
  }

  Widget _buildAboutSection() {
    return SingleChildScrollView(
      physics: const BouncingScrollPhysics(),
      padding: const EdgeInsets.fromLTRB(18, 8, 18, 24),
      child: Column(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: [
          _buildTile(icon: Icons.info_outline, title: 'App Version', subtitle: _appVersion, onTap: () {}),
          const SizedBox(height: 12),
          _buildTile(
            icon: Icons.privacy_tip_outlined,
            title: 'Privacy Policy',
            onTap: () => Navigator.of(context).push(MaterialPageRoute(builder: (_) => const PrivacyPolicyScreen())),
          ),
        ],
      ),
    );
  }

  Widget _buildActiveSection() {
    switch (_selectedSection) {
      case 1: return _buildAccountSection();
      case 2: return _buildAboutSection();
      default: return _buildPreferencesSection();
    }
  }

  @override
  Widget build(BuildContext context) {
    const primary = Color(0xFF0B63D6);
    final width = MediaQuery.of(context).size.width;
    final isLandscape = width >= 820;

    // ── LANDSCAPE layout ──────────────────────────────────────────────────
    if (isLandscape) {
      const navIcons = [Icons.tune, Icons.person_outline, Icons.info_outline];
      const navLabels = ['Preferences', 'Account', 'About'];

      return Row(
        children: [
          // Left: settings nav on gradient
          Flexible(
            flex: 1,
            child: RepaintBoundary(
              child: Container(
                decoration: AppDecoration.blueGradient,
                child: SafeArea(
                  child: Column(
                    crossAxisAlignment: CrossAxisAlignment.stretch,
                    children: [
                      const Padding(
                        padding: EdgeInsets.fromLTRB(20, 24, 20, 20),
                        child: Text('Settings', style: TextStyle(color: Colors.white, fontSize: 22, fontWeight: FontWeight.w700)),
                      ),
                      ...List.generate(navLabels.length, (i) {
                        final isActive = _selectedSection == i;
                        return MouseRegion(
                          cursor: SystemMouseCursors.click,
                          child: GestureDetector(
                            onTap: () => setState(() => _selectedSection = i),
                            child: AnimatedContainer(
                              duration: const Duration(milliseconds: 200),
                              margin: const EdgeInsets.fromLTRB(16, 0, 16, 8),
                              padding: const EdgeInsets.symmetric(horizontal: 16, vertical: 14),
                              decoration: BoxDecoration(
                                color: isActive ? Colors.white : Colors.white.withOpacity(0.08),
                                borderRadius: BorderRadius.circular(12),
                              ),
                              child: Row(children: [
                                Icon(navIcons[i], size: 20, color: isActive ? primary : Colors.white70),
                                const SizedBox(width: 12),
                                Text(navLabels[i], style: TextStyle(fontWeight: FontWeight.w600, fontSize: 14, color: isActive ? primary : Colors.white)),
                              ]),
                            ),
                          ),
                        );
                      }),
                      const Spacer(),
                      Padding(
                        padding: const EdgeInsets.fromLTRB(16, 0, 16, 24),
                        child: OutlinedButton.icon(
                          onPressed: _confirmLogout,
                          icon: const Icon(Icons.logout, color: Colors.white70, size: 18),
                          label: const Text('Logout', style: TextStyle(color: Colors.white70)),
                          style: OutlinedButton.styleFrom(
                            side: const BorderSide(color: Colors.white24),
                            shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(10)),
                            padding: const EdgeInsets.symmetric(vertical: 12),
                          ),
                        ),
                      ),
                    ],
                  ),
                ),
              ),
            ),
          ),
          // Right: settings content
          Flexible(
            flex: 2,
            child: RepaintBoundary(
              child: SafeArea(
                child: Column(
                  crossAxisAlignment: CrossAxisAlignment.stretch,
                  children: [
                    Padding(
                      padding: const EdgeInsets.fromLTRB(24, 24, 24, 12),
                      child: Text(
                        navLabels[_selectedSection],
                        style: const TextStyle(fontSize: 20, fontWeight: FontWeight.bold),
                      ),
                    ),
                    Expanded(child: _buildActiveSection()),
                  ],
                ),
              ),
            ),
          ),
        ],
      );
    }

    // ── MOBILE layout ─────────────────────────────────────────────────────
    return Scaffold(
      backgroundColor: Theme.of(context).scaffoldBackgroundColor,
      body: SafeArea(
        child: Column(
          children: [
            Container(
              width: double.infinity,
              padding: const EdgeInsets.fromLTRB(20, 18, 20, 18),
              decoration: AppDecoration.blueGradient.copyWith(
                borderRadius: const BorderRadius.only(bottomLeft: Radius.circular(24), bottomRight: Radius.circular(24)),
              ),
              child: Row(
                children: [
                  const Expanded(child: Text('Settings', style: TextStyle(color: Colors.white, fontSize: 20, fontWeight: FontWeight.w600))),
                  InkWell(
                    onTap: () => ScaffoldMessenger.of(context).showSnackBar(const SnackBar(content: Text('Help tapped (demo)'))),
                    child: Container(
                      width: 40,
                      height: 40,
                      decoration: BoxDecoration(color: Colors.white24, borderRadius: BorderRadius.circular(10)),
                      child: const Icon(Icons.help_outline, color: Colors.white),
                    ),
                  ),
                ],
              ),
            ),
            const SizedBox(height: 18),
            Expanded(
              child: SingleChildScrollView(
                padding: const EdgeInsets.fromLTRB(18, 0, 18, 24),
                child: Column(
                  crossAxisAlignment: CrossAxisAlignment.start,
                  children: [
                    const Text('Account', style: TextStyle(fontSize: 16, fontWeight: FontWeight.bold)),
                    const SizedBox(height: 12),
                    _buildTile(
                      icon: Icons.person,
                      title: 'Edit Profile',
                      subtitle: 'Change username, email or photo',
                      onTap: () => ScaffoldMessenger.of(context).showSnackBar(const SnackBar(content: Text('Open Profile tab (demo)'))),
                    ),
                    const SizedBox(height: 12),
                    const Text('Preferences', style: TextStyle(fontSize: 16, fontWeight: FontWeight.bold)),
                    const SizedBox(height: 12),
                    Container(
                      margin: const EdgeInsets.symmetric(vertical: 6),
                      decoration: BoxDecoration(color: Theme.of(context).cardColor, borderRadius: BorderRadius.circular(12), boxShadow: const [BoxShadow(color: Colors.black12, blurRadius: 6, offset: Offset(0, 4))]),
                      child: SwitchListTile(
                        tileColor: Theme.of(context).cardColor,
                        contentPadding: const EdgeInsets.symmetric(horizontal: 12, vertical: 4),
                        value: _notifications,
                        onChanged: (v) => _saveNotifications(v),
                        title: const Text('Reminders'),
                        secondary: const Icon(Icons.notifications, color: primary),
                      ),
                    ),
                    const SizedBox(height: 8),
                    Container(
                      margin: const EdgeInsets.symmetric(vertical: 6),
                      decoration: BoxDecoration(color: Theme.of(context).cardColor, borderRadius: BorderRadius.circular(12), boxShadow: const [BoxShadow(color: Colors.black12, blurRadius: 6, offset: Offset(0, 4))]),
                      child: ValueListenableBuilder<ThemeMode>(
                        valueListenable: ThemeManager.themeMode,
                        builder: (context, mode, _) => SwitchListTile(
                          tileColor: Theme.of(context).cardColor,
                          contentPadding: const EdgeInsets.symmetric(horizontal: 12, vertical: 4),
                          value: mode == ThemeMode.dark,
                          onChanged: (v) => ThemeManager.setThemeMode(v ? ThemeMode.dark : ThemeMode.light),
                          title: const Text('Dark Mode'),
                          secondary: const Icon(Icons.dark_mode, color: primary),
                        ),
                      ),
                    ),
                    const SizedBox(height: 18),
                    const Text('About', style: TextStyle(fontSize: 16, fontWeight: FontWeight.bold)),
                    const SizedBox(height: 12),
                    _buildTile(icon: Icons.info_outline, title: 'App Version', subtitle: _appVersion, onTap: () {}),
                    const SizedBox(height: 12),
                    _buildTile(
                      icon: Icons.privacy_tip_outlined,
                      title: 'Privacy Policy',
                      subtitle: 'Demo app',
                      onTap: () => Navigator.of(context).push(MaterialPageRoute(builder: (_) => const PrivacyPolicyScreen())),
                    ),
                    const SizedBox(height: 24),
                    Center(
                      child: Column(
                        children: [
                          ElevatedButton(
                            onPressed: _confirmLogout,
                            style: ElevatedButton.styleFrom(
                              backgroundColor: primary,
                              padding: const EdgeInsets.symmetric(horizontal: 28, vertical: 14),
                              shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(24)),
                            ),
                            child: const Text('Logout', style: TextStyle(color: Colors.white)),
                          ),
                          const SizedBox(height: 12),
                          const Text('Logging out will return you to the login screen.', style: TextStyle(color: Colors.black54, fontSize: 12)),
                        ],
                      ),
                    ),
                    const SizedBox(height: 32),
                  ],
                ),
              ),
            ),
          ],
        ),
      ),
    );
  }
}