import 'dart:async';
import 'dart:io';

import 'package:firebase_messaging/firebase_messaging.dart';
import 'package:flutter/foundation.dart';
import 'package:flutter/material.dart';
import 'package:flutter_bloc/flutter_bloc.dart';
import 'package:package_info_plus/package_info_plus.dart';

import '../../../api/marianumconnect/auth/device_token_name.dart';
import '../../../api/marianumconnect/auth/token_storage.dart';
import '../../../api/marianumconnect/marianumconnect_endpoint.dart';
import '../../../api/marianumconnect/queries/telemetry_heartbeat/telemetry_device_id.dart';
import '../../../background/widget_background_task.dart';
import '../../../extensions/date_time.dart';
import '../../../model/account_data.dart';
import '../../../model/endpoint_data.dart';
import '../../../push/push_registration_store.dart';
import '../../../push/push_registration_type.dart';
import '../../../state/app/modules/account/bloc/account_bloc.dart';
import '../../../state/app/modules/settings/bloc/settings_cubit.dart';
import '../../../utils/clipboard_helper.dart';
import '../../../widget/app_progress_indicator.dart';
import '../../../widget/async_action_button.dart';
import '../../../widget/centered_leading.dart';
import '../../../widget_data/widget_sync.dart';
import 'widgets/push_status_sheet.dart';

typedef _Row = ({String label, String value});
typedef _Section = ({String title, List<_Row> rows});

/// Read-only snapshot of build, endpoint, session, push and widget state for
/// bug reports. Secrets (passwords, bearer token) are never shown.
class DiagnosticsPage extends StatefulWidget {
  const DiagnosticsPage({super.key});

  @override
  State<DiagnosticsPage> createState() => _DiagnosticsPageState();
}

class _DiagnosticsPageState extends State<DiagnosticsPage> {
  late Future<List<_Section>> _sections = _collect();

  Future<List<_Section>> _collect() async {
    final settings = context.read<SettingsCubit>().val();
    final accountStatus = context.read<AccountBloc>().state.status;
    final account = AccountData();
    const tokens = MarianumConnectTokenStorage();
    final push = PushRegistrationStore();

    Future<String> safe(Future<Object?> Function() read) async {
      try {
        final value = await read().timeout(const Duration(seconds: 5));
        return switch (value) {
          null => '–',
          bool() => value ? 'ja' : 'nein',
          DateTime() => '${value.formatDateTime()} (${value.formatRelative()})',
          _ => '$value',
        };
      } on Object catch (e) {
        return 'Fehler: $e';
      }
    }

    Future<List<_Row>> rows(Map<String, Future<Object?> Function()> reads) =>
        Future.wait(
          reads.entries.map(
            (e) async => (label: e.key, value: await safe(e.value)),
          ),
        );

    final info = await PackageInfo.fromPlatform();
    return [
      (
        title: 'App',
        rows: await rows({
          'Version': () async => '${info.version} (${info.buildNumber})',
          'Paket': () async => info.packageName,
          'Build-Modus': () async => kReleaseMode
              ? 'Release'
              : kProfileMode
              ? 'Profile'
              : 'Debug',
          'Plattform': () async =>
              '${Platform.operatingSystem} ${Platform.operatingSystemVersion}',
          'Gerät': DeviceTokenName.resolve,
          'Dart': () async => Platform.version.split(' ').first,
        }),
      ),
      (
        title: 'Server',
        rows: await rows({
          'Marianum Connect': () async => MarianumConnectEndpoint.current(),
          'Nextcloud': () async =>
              'https://${EndpointData().nextcloud().full()}',
          'Notfall-Nachricht': () async =>
              settings.devToolsSettings.resolveEmergencyNoticeUrl(),
        }),
      ),
      (
        title: 'Sitzung',
        rows: await rows({
          'Status': () async => accountStatus.name,
          'Benutzer': () async =>
              account.isPopulated() ? account.getUsername() : null,
          'Demo-Modus': () async => account.isDemo,
          'Login Flow v2': () async => account.usesLoginFlow,
          'App-Passwort (Dateien)': () async => account.hasAppPassword(),
          'App-Passwort (Talk)': () async => account.hasAppPasswordTalk(),
          'Session-Epoche': () async => account.sessionEpoch,
          'MC-Token-ID': tokens.readTokenId,
          'MC-Token läuft ab': tokens.readExpiresAt,
        }),
      ),
      (
        title: 'Push',
        rows: await rows({
          'Benachrichtigungen': () async =>
              settings.notificationSettings.enabled,
          'FCM-Token': FirebaseMessaging.instance.getToken,
          for (final type in PushRegistrationType.values) ...{
            'Registriert (${type.name})': () => push.isRegistered(type),
            'Letzte Registrierung (${type.name})': () =>
                push.lastRegistrationAt(type),
            'Letzter Fehler (${type.name})': () =>
                push.lastRegistrationError(type),
          },
        }),
      ),
      (
        title: 'Sonstiges',
        rows: await rows({
          'Telemetrie-Geräte-ID': TelemetryDeviceId.resolve,
          'Widget zuletzt abgerufen': WidgetSync.getFetchedAt,
        }),
      ),
    ];
  }

  String _asText(List<_Section> sections) => [
    for (final s in sections) ...[
      '## ${s.title}',
      for (final r in s.rows) '${r.label}: ${r.value}',
      '',
    ],
  ].join('\n');

  @override
  Widget build(BuildContext context) => Scaffold(
    appBar: AppBar(
      title: const Text('Diagnose'),
      actions: [
        IconButton(
          tooltip: 'Neu laden',
          icon: const Icon(Icons.refresh),
          onPressed: () => setState(() {
            _sections = _collect();
          }),
        ),
        FutureBuilder(
          future: _sections,
          builder: (context, snapshot) => IconButton(
            tooltip: 'Alles kopieren',
            icon: const Icon(Icons.copy_all_outlined),
            onPressed: snapshot.hasData
                ? () => copyToClipboard(context, _asText(snapshot.data!))
                : null,
          ),
        ),
      ],
    ),
    body: FutureBuilder(
      future: _sections,
      builder: (context, snapshot) {
        final sections = snapshot.data;
        if (sections == null) {
          return const Center(child: AppProgressIndicator.large());
        }
        return ListView(
          children: [
            for (final section in sections) ...[
              ListTile(
                dense: true,
                title: Text(
                  section.title,
                  style: TextStyle(
                    color: Theme.of(context).colorScheme.primary,
                    fontWeight: FontWeight.bold,
                  ),
                ),
              ),
              for (final row in section.rows)
                ListTile(
                  dense: true,
                  title: Text(row.label),
                  subtitle: SelectableText(row.value),
                  onLongPress: () => copyToClipboard(context, row.value),
                ),
              if (section.title == 'Push')
                ListTile(
                  leading: const CenteredLeading(
                    Icon(Icons.notifications_active_outlined),
                  ),
                  title: const Text('Push-Status prüfen'),
                  trailing: const Icon(Icons.arrow_right),
                  onTap: () => showPushStatusSheet(context),
                ),
              if (section.title == 'Sonstiges')
                AsyncListTile(
                  leading: const CenteredLeading(Icon(Icons.widgets_outlined)),
                  title: const Text('Widget jetzt aktualisieren'),
                  closeOnSuccess: false,
                  onPressed: WidgetBackgroundTask.requestImmediateRefresh,
                ),
              const Divider(),
            ],
          ],
        );
      },
    ),
  );
}