import 'package:flutter/material.dart';
import '../services/database_helper.dart';
import '../theme/theme_controller.dart';
import '../widgets/brand_mark.dart';
import 'analysis_screen.dart';
import 'live_analysis_screen.dart';
import 'static_capture_screen.dart';
import 'history_screen.dart';

class HomeScreen extends StatefulWidget {
  const HomeScreen({super.key});

  @override
  State<HomeScreen> createState() => _HomeScreenState();
}

class _HomeScreenState extends State<HomeScreen> {
  int? _totalScans;

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

  Future<void> _loadStats() async {
    final records = await DatabaseHelper().getAllRecords();
    if (mounted) setState(() => _totalScans = records.length);
  }

  @override
  Widget build(BuildContext context) {
    final colorScheme = Theme.of(context).colorScheme;

    return Scaffold(
      body: SafeArea(
        child: SingleChildScrollView(
          padding: const EdgeInsets.all(20),
          child: Column(
            crossAxisAlignment: CrossAxisAlignment.start,
            children: [
              Row(
                children: [
                  const BrandMark(size: 44),
                  const SizedBox(width: 12),
                  Expanded(
                    child: Text(
                      'Palm Oil Ripeness AI',
                      style: TextStyle(
                        fontSize: 20,
                        fontWeight: FontWeight.bold,
                        color: colorScheme.onSurface,
                      ),
                    ),
                  ),
                  ValueListenableBuilder<ThemeMode>(
                    valueListenable: ThemeController.themeMode,
                    builder: (context, mode, _) {
                      return IconButton(
                        icon: Icon(_themeModeIcon(mode), color: colorScheme.onSurface),
                        tooltip: 'Theme',
                        onPressed: () => _showThemePicker(context, mode),
                      );
                    },
                  ),
                ],
              ),
              const SizedBox(height: 20),
              _buildStatCard(colorScheme),
              const SizedBox(height: 24),
              GridView.count(
                shrinkWrap: true,
                physics: const NeverScrollableScrollPhysics(),
                crossAxisCount: 2,
                mainAxisSpacing: 16,
                crossAxisSpacing: 16,
                childAspectRatio: 0.95,
                children: [
                  _buildTile(
                    context,
                    title: 'Analyze Gallery',
                    subtitle: 'Detect ripeness from photos',
                    icon: Icons.photo_library,
                    background: colorScheme.primary,
                    foreground: colorScheme.onPrimary,
                    onTap: () => Navigator.push(
                      context,
                      MaterialPageRoute(builder: (context) => const AnalysisScreen()),
                    ),
                  ),
                  _buildTile(
                    context,
                    title: 'Snap & Analyze',
                    subtitle: 'Manual high-res capture',
                    icon: Icons.camera_alt,
                    background: colorScheme.secondary,
                    foreground: colorScheme.onSecondary,
                    onTap: () => Navigator.push(
                      context,
                      MaterialPageRoute(builder: (context) => const StaticCaptureScreen()),
                    ),
                  ),
                  _buildTile(
                    context,
                    title: 'Live Inference',
                    subtitle: 'Real-time "Point-and-Scan"',
                    icon: Icons.camera,
                    background: colorScheme.primaryContainer,
                    foreground: colorScheme.onPrimaryContainer,
                    onTap: () => Navigator.push(
                      context,
                      MaterialPageRoute(builder: (context) => const LiveAnalysisScreen()),
                    ),
                  ),
                  _buildTile(
                    context,
                    title: 'History Vault',
                    subtitle: 'View previous detections',
                    icon: Icons.history,
                    background: colorScheme.surfaceContainerHighest,
                    foreground: colorScheme.onSurface,
                    bordered: true,
                    onTap: () => Navigator.push(
                      context,
                      MaterialPageRoute(builder: (context) => const HistoryScreen()),
                    ),
                  ),
                ],
              ),
            ],
          ),
        ),
      ),
    );
  }

  IconData _themeModeIcon(ThemeMode mode) {
    switch (mode) {
      case ThemeMode.light:
        return Icons.light_mode;
      case ThemeMode.dark:
        return Icons.dark_mode;
      case ThemeMode.system:
        return Icons.brightness_auto;
    }
  }

  Future<void> _showThemePicker(BuildContext context, ThemeMode current) async {
    await showModalBottomSheet(
      context: context,
      shape: const RoundedRectangleBorder(
        borderRadius: BorderRadius.vertical(top: Radius.circular(20)),
      ),
      builder: (sheetContext) {
        return SafeArea(
          child: Column(
            mainAxisSize: MainAxisSize.min,
            children: [
              const Padding(
                padding: EdgeInsets.fromLTRB(20, 20, 20, 8),
                child: Align(
                  alignment: Alignment.centerLeft,
                  child: Text("Theme", style: TextStyle(fontSize: 18, fontWeight: FontWeight.bold)),
                ),
              ),
              _themeOptionTile(sheetContext, "Light", Icons.light_mode, ThemeMode.light, current),
              _themeOptionTile(sheetContext, "Dark", Icons.dark_mode, ThemeMode.dark, current),
              _themeOptionTile(sheetContext, "System", Icons.brightness_auto, ThemeMode.system, current),
              const SizedBox(height: 8),
            ],
          ),
        );
      },
    );
  }

  Widget _themeOptionTile(BuildContext context, String label, IconData icon, ThemeMode mode, ThemeMode current) {
    final selected = mode == current;
    return ListTile(
      leading: Icon(icon),
      title: Text(label),
      trailing: selected ? const Icon(Icons.check) : null,
      onTap: () {
        ThemeController.setThemeMode(mode);
        Navigator.pop(context);
      },
    );
  }

  Widget _buildStatCard(ColorScheme colorScheme) {
    return Container(
      width: double.infinity,
      padding: const EdgeInsets.all(16),
      decoration: BoxDecoration(
        color: colorScheme.surfaceContainerHighest,
        borderRadius: BorderRadius.circular(16),
        border: Border.all(color: colorScheme.primary.withOpacity(0.15)),
      ),
      child: Row(
        children: [
          Icon(Icons.analytics_outlined, color: colorScheme.primary, size: 28),
          const SizedBox(width: 12),
          Column(
            crossAxisAlignment: CrossAxisAlignment.start,
            children: [
              Text(
                _totalScans == null ? '—' : '$_totalScans',
                style: TextStyle(fontSize: 22, fontWeight: FontWeight.bold, color: colorScheme.onSurface),
              ),
              Text(
                'Total Scans',
                style: TextStyle(fontSize: 13, color: colorScheme.onSurface.withOpacity(0.6)),
              ),
            ],
          ),
        ],
      ),
    );
  }

  Widget _buildTile(
    BuildContext context, {
    required String title,
    required String subtitle,
    required IconData icon,
    required Color background,
    required Color foreground,
    required VoidCallback onTap,
    bool bordered = false,
  }) {
    return GestureDetector(
      onTap: onTap,
      child: Container(
        padding: const EdgeInsets.all(16),
        decoration: BoxDecoration(
          color: background,
          borderRadius: BorderRadius.circular(20),
          border: bordered ? Border.all(color: foreground.withOpacity(0.15)) : null,
        ),
        child: Column(
          crossAxisAlignment: CrossAxisAlignment.start,
          mainAxisAlignment: MainAxisAlignment.spaceBetween,
          children: [
            Icon(icon, color: foreground, size: 32),
            Column(
              crossAxisAlignment: CrossAxisAlignment.start,
              children: [
                Text(
                  title,
                  style: TextStyle(fontSize: 16, fontWeight: FontWeight.bold, color: foreground),
                ),
                const SizedBox(height: 4),
                Text(
                  subtitle,
                  style: TextStyle(fontSize: 12, color: foreground.withOpacity(0.85)),
                ),
              ],
            ),
          ],
        ),
      ),
    );
  }
}