import 'package:flutter/foundation.dart';
import 'package:flutter/material.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';
import 'package:supabase_flutter/supabase_flutter.dart';

import '../../../../core/network/supabase_status.dart';
import '../../../auth/presentation/controllers/auth_controller.dart';
import '../../../nutrition/presentation/controllers/nutrition_controller.dart';
import '../controllers/integrations_controller.dart';

/// Application settings hub: identity & session, daily tracking targets,
/// encrypted-storage status, and health integrations.
class SettingsScreen extends ConsumerWidget {
  const SettingsScreen({super.key});

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

    ref.listen(integrationsControllerProvider, (previous, next) {
      if (next.errorMessage != null &&
          next.errorMessage != previous?.errorMessage) {
        ScaffoldMessenger.of(context).showSnackBar(
          SnackBar(
            content: Text(next.errorMessage!),
            backgroundColor: Theme.of(context).colorScheme.error,
          ),
        );
        ref.read(integrationsControllerProvider.notifier).clearError();
      }
    });

    return Scaffold(
      appBar: AppBar(title: const Text('Settings')),
      body: ListView(
        padding: const EdgeInsets.fromLTRB(16, 16, 16, 32),
        children: [
          const _IdentitySection(),
          const SizedBox(height: 16),
          const _TargetsSection(),
          const SizedBox(height: 16),
          const _SecuritySection(),
          const SizedBox(height: 16),
          _IntegrationsSection(state: integrations),
        ],
      ),
    );
  }
}

/// Identity: signed-in email, Supabase connection status, and sign-out.
class _IdentitySection extends ConsumerWidget {
  const _IdentitySection();

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    final theme = Theme.of(context);
    final email = _currentEmail();
    final authState = ref.watch(authControllerProvider);
    final isSigningOut = authState.isLoading;

    return _SettingsCard(
      title: 'Identity',
      icon: Icons.person_outline,
      child: Column(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: [
          Row(
            children: [
              Icon(Icons.email_outlined,
                  size: 18, color: theme.colorScheme.outline),
              const SizedBox(width: 8),
              Expanded(
                child: Text(
                  email ?? 'Not signed in',
                  style: theme.textTheme.bodyMedium,
                ),
              ),
            ],
          ),
          const SizedBox(height: 8),
          Row(
            children: [
              Icon(Icons.cloud_outlined,
                  size: 18, color: theme.colorScheme.outline),
              const SizedBox(width: 8),
              Flexible(
                child: _StatusBadge(
                  label:
                      isSupabaseAvailable ? 'Supabase connected' : 'Offline',
                  ok: isSupabaseAvailable,
                ),
              ),
            ],
          ),
          const SizedBox(height: 12),
          Align(
            alignment: Alignment.centerRight,
            child: FilledButton.tonalIcon(
              onPressed:
                  email == null || isSigningOut ? null : () => _signOut(ref),
              icon: isSigningOut
                  ? const SizedBox(
                      width: 16,
                      height: 16,
                      child: CircularProgressIndicator(strokeWidth: 2),
                    )
                  : const Icon(Icons.logout),
              label: const Text('Sign Out'),
            ),
          ),
        ],
      ),
    );
  }

  /// Authenticated user's email, or `null` when the SDK is unavailable or no
  /// session exists (e.g. debug dev bypass).
  String? _currentEmail() {
    if (!isSupabaseAvailable) return null;
    return Supabase.instance.client.auth.currentUser?.email;
  }

  Future<void> _signOut(WidgetRef ref) =>
      ref.read(authControllerProvider.notifier).signOut();
}

/// Targets: editable daily protein (g) and water (oz) goals driving the
/// nutrition progress meters and meal-plan rollups.
class _TargetsSection extends ConsumerStatefulWidget {
  const _TargetsSection();

  @override
  ConsumerState<_TargetsSection> createState() => _TargetsSectionState();
}

class _TargetsSectionState extends ConsumerState<_TargetsSection> {
  late final TextEditingController _proteinController;
  late final TextEditingController _waterController;
  final GlobalKey<FormState> _formKey = GlobalKey<FormState>();

  @override
  void initState() {
    super.initState();
    final nutrition = ref.read(nutritionControllerProvider).valueOrNull;
    _proteinController = TextEditingController(
      text: _fmt(nutrition?.proteinTargetGrams ??
          NutritionController.defaultProteinTargetGrams),
    );
    _waterController = TextEditingController(
      text: _fmt(nutrition?.hydrationTargetOz ??
          NutritionController.defaultHydrationTargetOz),
    );
  }

  @override
  void dispose() {
    _proteinController.dispose();
    _waterController.dispose();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    final nutrition = ref.watch(nutritionControllerProvider);
    final loaded = nutrition.valueOrNull != null;

    return _SettingsCard(
      title: 'Targets',
      icon: Icons.flag_outlined,
      child: Form(
        key: _formKey,
        child: Column(
          crossAxisAlignment: CrossAxisAlignment.stretch,
          children: [
            TextFormField(
              controller: _proteinController,
              enabled: loaded,
              decoration: const InputDecoration(
                labelText: 'Daily protein goal (g)',
                border: OutlineInputBorder(),
                isDense: true,
                prefixIcon: Icon(Icons.fitness_center),
              ),
              keyboardType:
                  const TextInputType.numberWithOptions(decimal: true),
              validator: _positiveDouble,
            ),
            const SizedBox(height: 12),
            TextFormField(
              controller: _waterController,
              enabled: loaded,
              decoration: const InputDecoration(
                labelText: 'Daily water goal (oz)',
                border: OutlineInputBorder(),
                isDense: true,
                prefixIcon: Icon(Icons.water_drop_outlined),
              ),
              keyboardType:
                  const TextInputType.numberWithOptions(decimal: true),
              validator: _positiveDouble,
            ),
            const SizedBox(height: 12),
            Align(
              alignment: Alignment.centerRight,
              child: FilledButton.icon(
                onPressed: loaded ? _save : null,
                icon: const Icon(Icons.save_outlined),
                label: const Text('Save Targets'),
              ),
            ),
          ],
        ),
      ),
    );
  }

  String? _positiveDouble(String? value) {
    final parsed = double.tryParse((value ?? '').trim());
    if (parsed == null || parsed <= 0) return 'Must be a positive number';
    return null;
  }

  void _save() {
    if (!(_formKey.currentState?.validate() ?? false)) return;
    ref.read(nutritionControllerProvider.notifier).updateTargets(
          proteinTargetGrams: double.parse(_proteinController.text.trim()),
          hydrationTargetOz: double.parse(_waterController.text.trim()),
        );
    ScaffoldMessenger.of(context).showSnackBar(
      const SnackBar(content: Text('Targets updated.')),
    );
  }

  static String _fmt(double value) {
    final rounded = value.roundToDouble();
    return rounded == value
        ? rounded.toStringAsFixed(0)
        : value.toStringAsFixed(1);
  }
}

/// Security & Storage: SQLCipher encryption status badge.
///
/// Native builds open the drift database through SQLCipher with a
/// vault-managed AES-256 key; web builds fall back to unencrypted WASM
/// SQLite (SQLCipher cannot run in the browser).
class _SecuritySection extends StatelessWidget {
  const _SecuritySection();

  @override
  Widget build(BuildContext context) {
    final theme = Theme.of(context);
    const encrypted = !kIsWeb;

    return _SettingsCard(
      title: 'Security & Storage',
      icon: Icons.shield_outlined,
      child: Column(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: [
          Row(
            children: [
              Icon(
                encrypted ? Icons.lock_outline : Icons.lock_open_outlined,
                size: 18,
                color: encrypted ? Colors.green.shade700 : Colors.orange,
              ),
              const SizedBox(width: 8),
              const Flexible(
                child: _StatusBadge(
                  label: encrypted
                      ? 'SQLCipher AES-256 active'
                      : 'Web storage (unencrypted)',
                  ok: encrypted,
                ),
              ),
            ],
          ),
          const SizedBox(height: 8),
          Text(
            encrypted
                ? 'Health markers are persisted in a SQLCipher-encrypted '
                    'database; the master key lives in your platform keystore '
                    '(Keychain / EncryptedSharedPreferences / DPAPI).'
                : 'SQLCipher cannot run inside the browser — web builds '
                    'store data in OPFS/IndexedDB without at-rest '
                    'encryption. Use a native app for encrypted storage.',
            style: theme.textTheme.bodySmall
                ?.copyWith(color: theme.colorScheme.outline),
          ),
        ],
      ),
    );
  }
}

/// Integrations: Apple Health / Health Connect / HealthGateway toggles.
class _IntegrationsSection extends ConsumerWidget {
  const _IntegrationsSection({required this.state});

  final IntegrationsState state;

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    final theme = Theme.of(context);

    return _SettingsCard(
      title: 'Integrations',
      icon: Icons.sync_outlined,
      child: Column(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: [
          SwitchListTile(
            contentPadding: EdgeInsets.zero,
            secondary: const Icon(Icons.apple),
            title: const Text('Apple Health'),
            subtitle: const Text('Sync weight & active energy (iOS)'),
            value: state.appleHealthEnabled,
            onChanged: state.isRequestingPermissions
                ? null
                : (enabled) => ref
                    .read(integrationsControllerProvider.notifier)
                    .setAppleHealthEnabled(enabled),
          ),
          SwitchListTile(
            contentPadding: EdgeInsets.zero,
            secondary: const Icon(Icons.fingerprint),
            title: const Text('Health Connect'),
            subtitle: const Text('Sync weight & active energy (Android)'),
            value: state.healthConnectEnabled,
            onChanged: state.isRequestingPermissions
                ? null
                : (enabled) => ref
                    .read(integrationsControllerProvider.notifier)
                    .setHealthConnectEnabled(enabled),
          ),
          SwitchListTile(
            contentPadding: EdgeInsets.zero,
            secondary: const Icon(Icons.cloud_sync_outlined),
            title: const Text('HealthGateway'),
            subtitle: const Text(
              'Cloud partner sync (MyFitnessPal / Withings) with '
              'manual-entry fallback',
            ),
            value: state.healthGatewayEnabled,
            onChanged: (enabled) => ref
                .read(integrationsControllerProvider.notifier)
                .setHealthGatewayEnabled(enabled),
          ),
          if (state.isRequestingPermissions)
            Padding(
              padding: const EdgeInsets.only(top: 4),
              child: Row(
                children: [
                  const SizedBox(
                    width: 14,
                    height: 14,
                    child: CircularProgressIndicator(strokeWidth: 2),
                  ),
                  const SizedBox(width: 8),
                  Text(
                    'Requesting health permissions…',
                    style: theme.textTheme.labelSmall,
                  ),
                ],
              ),
            ),
        ],
      ),
    );
  }
}

/// Shared card chrome for a settings section.
class _SettingsCard extends StatelessWidget {
  const _SettingsCard({
    required this.title,
    required this.icon,
    required this.child,
  });

  final String title;
  final IconData icon;
  final Widget child;

  @override
  Widget build(BuildContext context) {
    final theme = Theme.of(context);
    return Card(
      child: Padding(
        padding: const EdgeInsets.all(16),
        child: Column(
          crossAxisAlignment: CrossAxisAlignment.start,
          children: [
            Row(
              children: [
                Icon(icon, size: 20, color: theme.colorScheme.primary),
                const SizedBox(width: 8),
                Text(
                  title,
                  style: theme.textTheme.titleSmall
                      ?.copyWith(fontWeight: FontWeight.bold),
                ),
              ],
            ),
            const SizedBox(height: 12),
            child,
          ],
        ),
      ),
    );
  }
}

/// Compact colored badge used for capability/status rows.
class _StatusBadge extends StatelessWidget {
  const _StatusBadge({required this.label, required this.ok});

  final String label;
  final bool ok;

  @override
  Widget build(BuildContext context) {
    final color = ok ? Colors.green.shade100 : Colors.orange.shade100;
    final textColor = ok ? Colors.green.shade800 : Colors.orange.shade900;
    return Container(
      padding: const EdgeInsets.symmetric(horizontal: 8, vertical: 3),
      decoration: BoxDecoration(
        color: color,
        borderRadius: BorderRadius.circular(8),
      ),
      child: Text(
        label,
        maxLines: 1,
        overflow: TextOverflow.ellipsis,
        style: TextStyle(
          fontSize: 12,
          fontWeight: FontWeight.bold,
          color: textColor,
        ),
      ),
    );
  }
}