import 'package:flutter/material.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';
import 'package:go_router/go_router.dart';

import '../../../../core/platform/health_gateway.dart';
import '../../../../core/utils/date_time_utils.dart';
import '../../../health_sync/presentation/controllers/biometric_controller.dart';
import '../../../health_sync/presentation/widgets/log_weight_dialog.dart';
import '../../domain/entities/food_log_entry.dart';
import '../../domain/entities/hydration_log_entry.dart';
import '../../domain/entities/meal_type.dart';
import '../controllers/nutrition_controller.dart';
import '../widgets/log_food_dialog.dart';

/// GLP-1 nutrition dashboard: daily protein and hydration progress meters,
/// quick-add water buttons, a meal-grouped food diary, and the weight
/// tracker card with native health sync / manual-entry fallback.
class NutritionScreen extends ConsumerWidget {
  const NutritionScreen({super.key});

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    final nutrition = ref.watch(nutritionControllerProvider);

    return Scaffold(
      appBar: AppBar(title: const Text('Nutrition & Hydration')),
      body: Center(
        child: ConstrainedBox(
          constraints: const BoxConstraints(maxWidth: 720),
          child: nutrition.when(
            loading: () => const Center(child: CircularProgressIndicator()),
            error: (error, _) => _ErrorView(
              error: error,
              onRetry: () =>
                  ref.read(nutritionControllerProvider.notifier).retry(),
            ),
            data: (state) => ListView(
              padding: const EdgeInsets.all(16),
              children: [
                _ProteinCard(state: state),
                const SizedBox(height: 16),
                _HydrationCard(state: state),
                const SizedBox(height: 16),
                FilledButton.icon(
                  onPressed: () => showLogFoodDialog(context),
                  icon: const Icon(Icons.add_circle_outline),
                  label: const Text('Log Food'),
                ),
                const SizedBox(height: 8),
                OutlinedButton.icon(
                  onPressed: () => context.push('/food-search'),
                  icon: const Icon(Icons.qr_code_scanner),
                  label: const Text('Search Food / Scan Barcode'),
                ),
                const SizedBox(height: 16),
                const _WeightTrackerCard(),
                const SizedBox(height: 24),
                _FoodDiary(state: state),
                const SizedBox(height: 24),
              ],
            ),
          ),
        ),
      ),
    );
  }
}

/// Interactive protein meter: today's total vs. the 100 g daily target plus
/// calorie/carb/fat roll-ups.
class _ProteinCard extends StatelessWidget {
  const _ProteinCard({required this.state});

  final NutritionState state;

  @override
  Widget build(BuildContext context) {
    final progress = state.proteinProgress.clamp(0.0, 1.0).toDouble();
    final reachedGoal = state.totalProteinGrams >= state.proteinTargetGrams;

    return Card(
      child: Padding(
        padding: const EdgeInsets.all(16),
        child: Column(
          crossAxisAlignment: CrossAxisAlignment.start,
          children: [
            Row(
              mainAxisAlignment: MainAxisAlignment.spaceBetween,
              children: [
                // Flexible keeps the title from overflowing narrow phones
                // (and wide-glyph test fonts) when the goal chip is present.
                Flexible(
                  child: Text(
                    'Daily Protein Target',
                    style: Theme.of(context)
                        .textTheme
                        .titleMedium
                        ?.copyWith(fontWeight: FontWeight.bold),
                  ),
                ),
                if (reachedGoal)
                  Chip(
                    label: const Text('Goal met'),
                    visualDensity: VisualDensity.compact,
                    backgroundColor:
                        Theme.of(context).colorScheme.secondaryContainer,
                  ),
              ],
            ),
            const SizedBox(height: 12),
            ClipRRect(
              borderRadius: BorderRadius.circular(8),
              child: LinearProgressIndicator(
                value: progress,
                minHeight: 12,
                color: reachedGoal
                    ? Colors.green
                    : Theme.of(context).colorScheme.primary,
                backgroundColor:
                    Theme.of(context).colorScheme.surfaceContainerHighest,
              ),
            ),
            const SizedBox(height: 8),
            Text(
              '${state.totalProteinGrams.toStringAsFixed(1)}g / '
              '${state.proteinTargetGrams.toStringAsFixed(0)}g goal',
              style: Theme.of(context).textTheme.bodyLarge,
            ),
            const SizedBox(height: 4),
            Text(
              _macroSummary(state),
              style: Theme.of(context)
                  .textTheme
                  .bodyMedium
                  ?.copyWith(color: Theme.of(context).colorScheme.outline),
            ),
          ],
        ),
      ),
    );
  }

  /// `1,240 kcal · Carbs 40g · Fat 20g` (macro segments only when logged).
  String _macroSummary(NutritionState state) {
    final parts = <String>['${state.totalCalories} kcal'];
    final carbs = state.totalCarbsGrams;
    final fat = state.totalFatGrams;
    if (carbs != null) parts.add('Carbs ${carbs.toStringAsFixed(0)}g');
    if (fat != null) parts.add('Fat ${fat.toStringAsFixed(0)}g');
    return parts.join('  ·  ');
  }
}

/// Interactive hydration meter with quick-add buttons (+8 / +16 / +24 oz)
/// and today's fluid log (each entry deletable).
class _HydrationCard extends ConsumerWidget {
  const _HydrationCard({required this.state});

  final NutritionState state;

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    final progress = state.hydrationProgress.clamp(0.0, 1.0).toDouble();
    final reachedGoal = state.totalWaterOz >= state.hydrationTargetOz;

    return Card(
      child: Padding(
        padding: const EdgeInsets.all(16),
        child: Column(
          crossAxisAlignment: CrossAxisAlignment.start,
          children: [
            Text(
              'Daily Hydration',
              style: Theme.of(context)
                  .textTheme
                  .titleMedium
                  ?.copyWith(fontWeight: FontWeight.bold),
            ),
            const SizedBox(height: 12),
            ClipRRect(
              borderRadius: BorderRadius.circular(8),
              child: LinearProgressIndicator(
                value: progress,
                minHeight: 12,
                color: reachedGoal ? Colors.teal : Colors.blue,
                backgroundColor:
                    Theme.of(context).colorScheme.surfaceContainerHighest,
              ),
            ),
            const SizedBox(height: 8),
            Text(
              '${state.totalWaterOz.toStringAsFixed(0)} oz / '
              '${state.hydrationTargetOz.toStringAsFixed(0)} oz goal',
              style: Theme.of(context).textTheme.bodyLarge,
            ),
            const SizedBox(height: 12),
            Wrap(
              spacing: 8,
              runSpacing: 8,
              children: [
                for (final increment in [8.0, 16.0, 24.0])
                  FilledButton.tonalIcon(
                    onPressed: () => _quickAdd(ref, increment),
                    icon: const Icon(Icons.water_drop, size: 16),
                    label: Text('+$increment oz'),
                  ),
              ],
            ),
            if (state.hydrationLogs.isNotEmpty) ...[
              const SizedBox(height: 8),
              for (final entry in state.hydrationLogs)
                _HydrationTile(
                  entry: entry,
                  onDelete: () => _confirmDelete(context, ref, entry),
                ),
            ],
          ],
        ),
      ),
    );
  }

  Future<void> _quickAdd(WidgetRef ref, double ounces) =>
      ref.read(nutritionControllerProvider.notifier).logWater(ounces);

  Future<void> _confirmDelete(
    BuildContext context,
    WidgetRef ref,
    HydrationLogEntry entry,
  ) async {
    final id = entry.id;
    if (id == null) return;

    final confirmed = await showDialog<bool>(
      context: context,
      builder: (context) => AlertDialog(
        title: const Text('Delete water entry?'),
        content: Text(
          '${entry.volumeOz.toStringAsFixed(0)} oz · '
          '${formatDateTime(entry.timestamp)}',
        ),
        actions: [
          TextButton(
            onPressed: () => Navigator.of(context).pop(false),
            child: const Text('Cancel'),
          ),
          FilledButton(
            onPressed: () => Navigator.of(context).pop(true),
            child: const Text('Delete'),
          ),
        ],
      ),
    );
    if (confirmed != true) return;

    await ref.read(nutritionControllerProvider.notifier).deleteWater(id);
  }
}

/// Single fluid-log row: volume, time, and a delete action.
class _HydrationTile extends StatelessWidget {
  const _HydrationTile({required this.entry, required this.onDelete});

  final HydrationLogEntry entry;
  final VoidCallback onDelete;

  @override
  Widget build(BuildContext context) {
    return ListTile(
      dense: true,
      contentPadding: EdgeInsets.zero,
      leading: const Icon(Icons.water_drop, color: Colors.blue),
      title: Text('${entry.volumeOz.toStringAsFixed(0)} oz'),
      subtitle: Text(formatDateTime(entry.timestamp)),
      trailing: entry.id == null
          ? null
          : IconButton(
              icon: const Icon(Icons.delete_outline),
              tooltip: 'Delete',
              onPressed: onDelete,
            ),
    );
  }
}

/// Weight tracker card: latest weight, 7/30-day trends, and the
/// "Log Weight / Sync" action.
///
/// On Android/iOS the button triggers the native [IHealthGateway] sync
/// (HealthKit / Health Connect); on Windows/macOS/Web it opens the manual
/// entry dialog instead, keeping feature parity without unsupported
/// hardware calls.
class _WeightTrackerCard extends ConsumerWidget {
  const _WeightTrackerCard();

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    final biometric = ref.watch(biometricControllerProvider);
    final gateway = ref.watch(healthGatewayProvider);
    final supported =
        gateway.supportsNativeHealth || gateway.supportsCloudSync;

    // Surface sync/manual outcomes as snackbars whenever the status changes.
    ref.listen(biometricControllerProvider, (previous, next) {
      final message = next.valueOrNull?.statusMessage;
      if (message == null || message == previous?.valueOrNull?.statusMessage) {
        return;
      }
      ScaffoldMessenger.of(context)
        ..hideCurrentSnackBar()
        ..showSnackBar(SnackBar(content: Text(message)));
    });

    return Card(
      child: Padding(
        padding: const EdgeInsets.all(16),
        child: biometric.when(
          loading: () => const SizedBox(
            height: 120,
            child: Center(child: CircularProgressIndicator()),
          ),
          error: (error, _) => Column(
            crossAxisAlignment: CrossAxisAlignment.start,
            children: [
              _cardTitle(context),
              const SizedBox(height: 8),
              Text('Could not load weight history: $error'),
              const SizedBox(height: 8),
              FilledButton(
                onPressed: () =>
                    ref.read(biometricControllerProvider.notifier).retry(),
                child: const Text('Retry'),
              ),
            ],
          ),
          data: (state) => _content(context, ref, state, supported),
        ),
      ),
    );
  }

  Widget _content(
    BuildContext context,
    WidgetRef ref,
    BiometricState state,
    bool supported,
  ) {
    final latest = state.latestWeightLbs;
    final colorScheme = Theme.of(context).colorScheme;

    return Column(
      crossAxisAlignment: CrossAxisAlignment.start,
      children: [
        _cardTitle(context),
        const SizedBox(height: 8),
        Row(
          crossAxisAlignment: CrossAxisAlignment.baseline,
          textBaseline: TextBaseline.alphabetic,
          children: [
            Text(
              latest == null ? '-- lb' : '${latest.toStringAsFixed(1)} lb',
              style: Theme.of(context)
                  .textTheme
                  .headlineSmall
                  ?.copyWith(fontWeight: FontWeight.bold),
            ),
            const SizedBox(width: 8),
            if (state.latest?.timestamp != null)
              Text(
                'as of ${formatDateTime(state.latest!.timestamp)}',
                style: Theme.of(context)
                    .textTheme
                    .bodySmall
                    ?.copyWith(color: colorScheme.outline),
              ),
          ],
        ),
        const SizedBox(height: 8),
        Wrap(
          spacing: 16,
          runSpacing: 4,
          children: [
            _trendChip(context, '7-day trend', state.weight7DayDelta),
            _trendChip(context, '30-day trend', state.weight30DayDelta),
            if (state.latestActiveCaloriesBurned != null)
              Text(
                'Active burn: '
                '${state.latestActiveCaloriesBurned!.toStringAsFixed(0)} kcal',
                style: Theme.of(context).textTheme.bodyMedium,
              ),
          ],
        ),
        const SizedBox(height: 12),
        // Wrap (instead of Row) so the action buttons stack cleanly on very
        // narrow phones instead of overflowing the card.
        Wrap(
          spacing: 8,
          runSpacing: 8,
          crossAxisAlignment: WrapCrossAlignment.center,
          children: [
            FilledButton.icon(
              onPressed: state.isSyncing
                  ? null
                  : () => _logWeightOrSync(context, ref),
              icon: state.isSyncing
                  ? const SizedBox(
                      width: 16,
                      height: 16,
                      child: CircularProgressIndicator(strokeWidth: 2),
                    )
                  : Icon(
                      supported ? Icons.sync : Icons.monitor_weight_outlined,
                      size: 18,
                    ),
              label: Text(state.isSyncing ? 'Syncing...' : 'Log Weight / Sync'),
            ),
            OutlinedButton.icon(
              onPressed: () => showLogWeightDialog(context),
              icon: const Icon(Icons.edit_outlined, size: 18),
              label: const Text('Manual'),
            ),
          ],
        ),
      ],
    );
  }

  Widget _cardTitle(BuildContext context) => Text(
        'Weight Tracker',
        style: Theme.of(context)
            .textTheme
            .titleMedium
            ?.copyWith(fontWeight: FontWeight.bold),
      );

  /// `7-day trend: ▼ 1.2 lb` — green for loss, orange for gain, neutral when
  /// the history does not reach back far enough.
  Widget _trendChip(BuildContext context, String label, double? delta) {
    final color = delta == null
        ? Theme.of(context).colorScheme.outline
        : delta < 0
            ? Colors.green
            : delta > 0
                ? Colors.orange
                : Theme.of(context).colorScheme.outline;
    final text = delta == null
        ? '—'
        : '${delta < 0 ? '▼' : delta > 0 ? '▲' : '·'} '
            '${delta.abs().toStringAsFixed(1)} lb';

    return Text.rich(
      TextSpan(
        children: [
          TextSpan(text: '$label: '),
          TextSpan(
            text: text,
            style: TextStyle(color: color, fontWeight: FontWeight.bold),
          ),
        ],
      ),
      style: Theme.of(context).textTheme.bodyMedium,
    );
  }

  /// Syncs from the first available source — HealthKit / Health Connect on
  /// mobile, a connected cloud partner (Google Health) on desktop/web — and
  /// surfaces the sync outcome as a snackbar. Falls back to the manual entry
  /// dialog when no source is available or connected (the dedicated
  /// "Manual" button always opens it regardless).
  Future<void> _logWeightOrSync(BuildContext context, WidgetRef ref) async {
    final gateway = ref.read(healthGatewayProvider);
    final canSync =
        gateway.supportsNativeHealth || await gateway.isCloudSyncReady();
    if (!context.mounted) return;
    if (!canSync) {
      await showLogWeightDialog(context);
      return;
    }
    await ref.read(biometricControllerProvider.notifier).syncFromHealth();
    if (!context.mounted) return;
    final message =
        ref.read(biometricControllerProvider).valueOrNull?.statusMessage;
    if (message != null) {
      ScaffoldMessenger.of(context)
        ..hideCurrentSnackBar()
        ..showSnackBar(SnackBar(content: Text(message)));
    }
  }
}

/// Today's food diary grouped by meal slot (breakfast → snack) with
/// per-entry delete actions.
class _FoodDiary extends ConsumerWidget {
  const _FoodDiary({required this.state});

  final NutritionState state;

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    final grouped = state.mealsByType;

    return Column(
      crossAxisAlignment: CrossAxisAlignment.start,
      children: [
        Text(
          'Food Diary',
          style: Theme.of(context)
              .textTheme
              .titleMedium
              ?.copyWith(fontWeight: FontWeight.bold),
        ),
        const SizedBox(height: 8),
        if (grouped.isEmpty)
          const Card(
            child: Padding(
              padding: EdgeInsets.all(16),
              child: Text(
                'No meals logged today yet. Tap "Log Food" to add your '
                'first entry.',
              ),
            ),
          )
        else
          for (final meal in grouped.entries) ...[
            Padding(
              padding: const EdgeInsets.only(top: 8, bottom: 4),
              child: Builder(
                builder: (context) {
                  final mealProtein = meal.value.fold<double>(
                    0,
                    (sum, entry) => sum + entry.proteinGrams,
                  );
                  return Row(
                    children: [
                      Icon(_mealIcon(meal.key), size: 18),
                      const SizedBox(width: 8),
                      Text(
                        meal.key.displayName,
                        style: Theme.of(context)
                            .textTheme
                            .titleSmall
                            ?.copyWith(fontWeight: FontWeight.bold),
                      ),
                      const SizedBox(width: 8),
                      Text(
                        '${mealProtein.toStringAsFixed(0)}g protein',
                        style: Theme.of(context).textTheme.bodySmall?.copyWith(
                              color: Theme.of(context).colorScheme.outline,
                            ),
                      ),
                    ],
                  );
                },
              ),
            ),
            for (final entry in meal.value)
              _FoodTile(entry: entry, mealType: meal.key),
          ],
      ],
    );
  }

  IconData _mealIcon(MealType type) {
    switch (type) {
      case MealType.breakfast:
        return Icons.free_breakfast;
      case MealType.lunch:
        return Icons.lunch_dining;
      case MealType.dinner:
        return Icons.dinner_dining;
      case MealType.snack:
        return Icons.cookie;
    }
  }
}

/// Single diary row: description, timestamp, macro summary, delete action.
class _FoodTile extends ConsumerWidget {
  const _FoodTile({required this.entry, required this.mealType});

  final FoodLogEntry entry;
  final MealType mealType;

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    return ListTile(
      dense: true,
      contentPadding: EdgeInsets.zero,
      title: Text(entry.description),
      subtitle: Text(_subtitle()),
      trailing: entry.id == null
          ? null
          : PopupMenuButton<String>(
              onSelected: (value) {
                if (value == 'delete') _confirmDelete(context, ref);
              },
              itemBuilder: (context) => const [
                PopupMenuItem(value: 'delete', child: Text('Delete')),
              ],
            ),
    );
  }

  /// `Oct 16, 2026 · 8:05 AM · 30g protein · 320 kcal · ...`
  String _subtitle() {
    final parts = <String>[
      formatDateTime(entry.timestamp),
      '${entry.proteinGrams.toStringAsFixed(1)}g protein',
      '${entry.calories} kcal',
    ];
    final carbs = entry.carbsGrams;
    final fat = entry.fatGrams;
    if (carbs != null) parts.add('C ${carbs.toStringAsFixed(0)}g');
    if (fat != null) parts.add('F ${fat.toStringAsFixed(0)}g');
    return parts.join('  ·  ');
  }

  Future<void> _confirmDelete(BuildContext context, WidgetRef ref) async {
    final id = entry.id;
    if (id == null) return;

    final confirmed = await showDialog<bool>(
      context: context,
      builder: (context) => AlertDialog(
        title: const Text('Delete meal entry?'),
        content: Text('${entry.description} · ${mealType.displayName}'),
        actions: [
          TextButton(
            onPressed: () => Navigator.of(context).pop(false),
            child: const Text('Cancel'),
          ),
          FilledButton(
            onPressed: () => Navigator.of(context).pop(true),
            child: const Text('Delete'),
          ),
        ],
      ),
    );
    if (confirmed != true) return;

    await ref.read(nutritionControllerProvider.notifier).deleteFood(id);
  }
}

/// Full-screen failure state shown when today's logs could not be loaded.
class _ErrorView extends StatelessWidget {
  const _ErrorView({required this.error, required this.onRetry});

  final Object error;
  final VoidCallback onRetry;

  @override
  Widget build(BuildContext context) {
    return Center(
      child: Padding(
        padding: const EdgeInsets.all(24),
        child: Column(
          mainAxisSize: MainAxisSize.min,
          children: [
            const Icon(Icons.error_outline, size: 48, color: Colors.red),
            const SizedBox(height: 12),
            Text(
              'Could not load your nutrition data.',
              style: Theme.of(context).textTheme.titleMedium,
              textAlign: TextAlign.center,
            ),
            const SizedBox(height: 4),
            Text('$error', textAlign: TextAlign.center),
            const SizedBox(height: 16),
            FilledButton.icon(
              onPressed: onRetry,
              icon: const Icon(Icons.refresh),
              label: const Text('Retry'),
            ),
          ],
        ),
      ),
    );
  }
}