import 'dart:async';

import 'package:dio/dio.dart';
import 'package:fintracker_api/fintracker_api.dart';
import 'package:flutter/material.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';
import 'package:intl/intl.dart';

import '../../core/api/api_client.dart';
import '../../core/auth/auth_controller.dart';
import '../../core/cache/cached.dart';
import '../../core/widgets/async_value_view.dart';
import '../../core/widgets/empty_state.dart';
import '../home/providers.dart' show dataQualityProvider;
import 'data_quality_list.dart';

final _dateFmt = DateFormat('dd.MM.yyyy HH:mm');

final syncStatusProvider = FutureProvider.autoDispose<List<SourceStatus>>((ref) async {
  final r = await ref.watch(apiProvider).getSyncApi().syncStatus();
  return r.data ?? const [];
});

final syncRunsProvider = FutureProvider.autoDispose<List<SyncRunOut>>((ref) async {
  final r = await ref.watch(apiProvider).getSyncApi().syncRuns(limit: 20);
  return r.data ?? const [];
});

const _pollInterval = Duration(seconds: 10);

/// Здоровье: the one screen that answers "is my data OK right now" — source
/// sync status with a manual trigger per source, a log of the last 20 runs,
/// and the data-quality findings, as two tabs of one page. Polls
/// `/sync/status` every 10 s while this page is mounted, regardless of which
/// tab is showing.
class HealthPage extends ConsumerStatefulWidget {
  const HealthPage({this.initialTab = 0, super.key});

  /// 0 = «Источники», 1 = «Качество данных». Lets the dashboard's data-quality
  /// chip deep-link straight to the findings tab instead of always opening on
  /// sources.
  final int initialTab;

  @override
  ConsumerState<HealthPage> createState() => _HealthPageState();
}

class _HealthPageState extends ConsumerState<HealthPage> {
  Timer? _timer;

  @override
  void initState() {
    super.initState();
    _timer = Timer.periodic(_pollInterval, (_) {
      if (!mounted) return;
      ref.invalidate(syncStatusProvider);
    });
  }

  @override
  void dispose() {
    _timer?.cancel();
    super.dispose();
  }

  Future<void> _refreshAll() async {
    ref.invalidate(syncStatusProvider);
    ref.invalidate(syncRunsProvider);
    ref.invalidate(dataQualityProvider);
  }

  Future<void> _trigger(String source) async {
    try {
      await ref.read(apiProvider).getSyncApi().syncTrigger(source_: source);
    } on DioException catch (e) {
      if (!mounted) return;
      ScaffoldMessenger.of(context).showSnackBar(SnackBar(content: Text(problemMessage(e))));
    } finally {
      ref.invalidate(syncStatusProvider);
      ref.invalidate(syncRunsProvider);
    }
  }

  @override
  Widget build(BuildContext context) {
    final dataQuality = ref.watch(dataQualityProvider);
    final issueCount = dataQuality.valueOrNull?.data.length;

    return DefaultTabController(
      length: 2,
      initialIndex: widget.initialTab,
      child: Scaffold(
        appBar: AppBar(
          title: const Text('Здоровье'),
          actions: [
            IconButton(
              tooltip: 'Обновить',
              icon: const Icon(Icons.refresh),
              onPressed: _refreshAll,
            ),
          ],
          bottom: TabBar(
            tabs: [
              const Tab(icon: Icon(Icons.cable_outlined), text: 'Источники'),
              Tab(
                icon: const Icon(Icons.fact_check_outlined),
                text: issueCount == null || issueCount == 0
                    ? 'Качество данных'
                    : 'Качество данных ($issueCount)',
              ),
            ],
          ),
        ),
        body: TabBarView(
          children: [
            _SourcesTab(onRefresh: _refreshAll, onTrigger: _trigger),
            _QualityTab(dataQuality: dataQuality, onRefresh: () async => ref.invalidate(dataQualityProvider)),
          ],
        ),
      ),
    );
  }
}

class _SourcesTab extends ConsumerWidget {
  const _SourcesTab({required this.onRefresh, required this.onTrigger});

  final Future<void> Function() onRefresh;
  final Future<void> Function(String source) onTrigger;

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    final status = ref.watch(syncStatusProvider);
    final runs = ref.watch(syncRunsProvider);

    return RefreshIndicator(
      onRefresh: onRefresh,
      child: ListView(
        padding: const EdgeInsets.all(16),
        children: [
          Text('Источники', style: Theme.of(context).textTheme.titleMedium),
          const SizedBox(height: 8),
          AsyncValueView(
            value: status,
            onRetry: () => ref.invalidate(syncStatusProvider),
            data: (rows) => rows.isEmpty
                ? const EmptyState(
                    icon: Icons.cable_outlined,
                    message: 'Источники данных ещё не подключены (фаза 1: ZenMoney, ЦБ).',
                  )
                : Column(
                    children: [for (final s in rows) _SourceCard(source: s, onTrigger: onTrigger)],
                  ),
          ),
          const SizedBox(height: 24),
          Text('Последние запуски', style: Theme.of(context).textTheme.titleMedium),
          const SizedBox(height: 8),
          AsyncValueView(
            value: runs,
            onRetry: () => ref.invalidate(syncRunsProvider),
            data: (rows) => rows.isEmpty
                ? const EmptyState(icon: Icons.history, message: 'Запусков ещё не было.')
                : Column(children: [for (final r in rows) _RunTile(run: r)]),
          ),
        ],
      ),
    );
  }
}

class _QualityTab extends StatelessWidget {
  const _QualityTab({required this.dataQuality, required this.onRefresh});

  final AsyncValue<Cached<List<DataQualityRow>>> dataQuality;
  final Future<void> Function() onRefresh;

  @override
  Widget build(BuildContext context) {
    return RefreshIndicator(
      onRefresh: onRefresh,
      child: ListView(
        padding: const EdgeInsets.all(16),
        children: [
          AsyncValueView(
            value: dataQuality,
            data: (cached) => DataQualityList(rows: cached.data),
          ),
        ],
      ),
    );
  }
}

class _SourceCard extends StatelessWidget {
  const _SourceCard({required this.source, required this.onTrigger});

  final SourceStatus source;
  final Future<void> Function(String source) onTrigger;

  @override
  Widget build(BuildContext context) {
    return Card(
      child: ListTile(
        title: Row(
          children: [
            Text(source.source_, style: Theme.of(context).textTheme.titleSmall),
            const SizedBox(width: 8),
            _statusChip(context, source.lastRunStatus),
            if (source.queued) ...[
              const SizedBox(width: 8),
              const Chip(
                visualDensity: VisualDensity.compact,
                label: Text('в очереди'),
              ),
            ],
          ],
        ),
        subtitle: Padding(
          padding: const EdgeInsets.only(top: 4),
          child: Text([
            if (source.lastRunAt != null) 'запуск ${_dateFmt.format(source.lastRunAt!.toLocal())}',
            if (source.cursor != null) 'курсор ${_shortCursor(source.cursor!)}',
          ].join(' · ')),
        ),
        trailing: IconButton(
          tooltip: 'Запустить синхронизацию',
          icon: const Icon(Icons.sync),
          onPressed: source.queued ? null : () => onTrigger(source.source_),
        ),
      ),
    );
  }
}

class _RunTile extends StatelessWidget {
  const _RunTile({required this.run});

  final SyncRunOut run;

  @override
  Widget build(BuildContext context) {
    final duration = run.finishedAt?.difference(run.startedAt);
    final subtitle = [
      _dateFmt.format(run.startedAt.toLocal()),
      duration != null ? _formatDuration(duration) : 'выполняется',
    ].join(' · ');

    final counts = run.counts;
    final content = Column(
      crossAxisAlignment: CrossAxisAlignment.start,
      children: [
        if (counts != null && counts.isNotEmpty)
          Wrap(
            spacing: 8,
            runSpacing: 4,
            children: [
              for (final e in counts.entries)
                Chip(
                  visualDensity: VisualDensity.compact,
                  label: Text('${e.key}=${e.value}'),
                ),
            ],
          ),
      ],
    );

    if (run.error != null && run.error!.isNotEmpty) {
      return Card(
        child: ExpansionTile(
          title: _runTitle(context),
          subtitle: Text(subtitle),
          children: [
            Padding(
              padding: const EdgeInsets.fromLTRB(16, 0, 16, 12),
              child: Column(
                crossAxisAlignment: CrossAxisAlignment.start,
                children: [
                  content,
                  const SizedBox(height: 8),
                  Text(run.error!, style: TextStyle(color: Theme.of(context).colorScheme.error)),
                ],
              ),
            ),
          ],
        ),
      );
    }

    return Card(
      child: Padding(
        padding: const EdgeInsets.fromLTRB(16, 8, 16, 12),
        child: Column(
          crossAxisAlignment: CrossAxisAlignment.start,
          children: [
            _runTitle(context),
            Padding(
              padding: const EdgeInsets.only(top: 2, bottom: 6),
              child: Text(subtitle, style: Theme.of(context).textTheme.bodySmall),
            ),
            content,
          ],
        ),
      ),
    );
  }

  Widget _runTitle(BuildContext context) {
    return Row(
      children: [
        Text(run.source_, style: Theme.of(context).textTheme.titleSmall),
        const SizedBox(width: 8),
        _statusChip(context, run.status),
      ],
    );
  }
}

Widget _statusChip(BuildContext context, RunStatus? status) {
  if (status == null) {
    return const Chip(visualDensity: VisualDensity.compact, label: Text('нет данных'));
  }
  final scheme = Theme.of(context).colorScheme;
  final (label, color) = switch (status) {
    RunStatus.ok => ('ok', Colors.green),
    RunStatus.error => ('error', scheme.error),
    RunStatus.running => ('running', Colors.amber.shade700),
    RunStatus.unknownDefaultOpenApi => ('неизвестно', scheme.outline),
  };
  return Chip(
    visualDensity: VisualDensity.compact,
    label: Text(label),
    backgroundColor: color.withValues(alpha: 0.15),
    labelStyle: TextStyle(color: color),
    side: BorderSide(color: color.withValues(alpha: 0.4)),
  );
}

String _shortCursor(String cursor) {
  if (cursor.length <= 20) return cursor;
  return '${cursor.substring(0, 10)}…${cursor.substring(cursor.length - 6)}';
}

String _formatDuration(Duration d) {
  if (d.inMinutes >= 1) return '${d.inMinutes} мин ${d.inSeconds % 60} с';
  return '${d.inSeconds} с';
}