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

import '../../core/utils/ru_date.dart';
import '../../core/widgets/async_value_view.dart';
import '../../core/widgets/empty_state.dart';
import '../pending/providers.dart';
import 'data/imports_api.dart';
import 'data/report_picker.dart';
import 'labels.dart';
import 'providers.dart';

/// Импорт: the list of uploaded broker reports plus the upload button.
///
/// Uploading never writes to the ledger — it parses the file and opens the preview, where
/// the numbers are checked against the ledger before anything is committed.
class ImportsPage extends ConsumerStatefulWidget {
  const ImportsPage({super.key});

  @override
  ConsumerState<ImportsPage> createState() => _ImportsPageState();
}

class _ImportsPageState extends ConsumerState<ImportsPage> {
  bool _uploading = false;

  Future<void> _upload() async {
    final picked = await ref.read(reportPickerProvider).pick();
    if (picked == null || !mounted) return;

    setState(() => _uploading = true);
    try {
      final preview = await ref.read(importsApiProvider).upload(picked);
      if (!mounted) return;
      ref.invalidate(importsListProvider);
      if (preview.duplicateOfId != null) {
        _snack(
          'Этот файл уже загружали — открыт существующий импорт №${preview.id}',
        );
      }
      context.go('/imports/${preview.id}');
    } catch (e) {
      if (!mounted) return;
      _snack(importErrorMessage(e));
    } finally {
      if (mounted) setState(() => _uploading = false);
    }
  }

  void _snack(String message) =>
      ScaffoldMessenger.of(context)
          .showSnackBar(SnackBar(content: Text(message)));

  @override
  Widget build(BuildContext context) {
    final imports = ref.watch(importsListProvider);
    final pendingCount = ref.watch(pendingCountProvider).valueOrNull ?? 0;

    return Scaffold(
      appBar: AppBar(
        title: const Text('Импорт отчётов'),
        actions: [
          IconButton(
            tooltip: 'Обновить',
            icon: const Icon(Icons.refresh),
            onPressed: () {
              ref.invalidate(importsListProvider);
              ref.invalidate(pendingCountProvider);
            },
          ),
        ],
      ),
      floatingActionButton: FloatingActionButton.extended(
        onPressed: _uploading ? null : _upload,
        icon: _uploading
            ? const SizedBox(
                width: 18,
                height: 18,
                child: CircularProgressIndicator(strokeWidth: 2),
              )
            : const Icon(Icons.upload_file),
        label: Text(_uploading ? 'Загрузка…' : 'Загрузить отчёт'),
      ),
      body: RefreshIndicator(
        onRefresh: () async {
          ref.invalidate(importsListProvider);
          ref.invalidate(pendingCountProvider);
        },
        child: ListView(
          padding: const EdgeInsets.fromLTRB(16, 16, 16, 88),
          children: [
            if (pendingCount > 0)
              Card(
                color: Theme.of(context).colorScheme.tertiaryContainer,
                child: ListTile(
                  leading: const Icon(Icons.help_outline),
                  title: Text('Нераспознанных инструментов: $pendingCount'),
                  subtitle: const Text(
                    'События по ним ждут в статусе pending и не попадают в аналитику.',
                  ),
                  trailing: const Icon(Icons.chevron_right),
                  onTap: () => context.go('/instruments/pending'),
                ),
              ),
            const _StatusFilter(),
            const SizedBox(height: 8),
            AsyncValueView(
              value: imports,
              onRetry: () => ref.invalidate(importsListProvider),
              data: (rows) => rows.isEmpty
                  ? const Padding(
                      padding: EdgeInsets.only(top: 48),
                      child: EmptyState(
                        icon: Icons.upload_file_outlined,
                        message:
                            'Отчёты ещё не загружались.\n'
                            'Поддерживаются выгрузки Сбера и ВТБ (HTML, XLSX) и CSV.',
                      ),
                    )
                  : Column(
                      children: [
                        for (final row in rows) _ImportCard(item: row),
                      ],
                    ),
            ),
          ],
        ),
      ),
    );
  }
}

class _StatusFilter extends ConsumerWidget {
  const _StatusFilter();

  static const _options = <String?, String>{
    null: 'Все',
    'uploaded': 'Загружены',
    'parsed': 'Разобраны',
    'committed': 'Импортированы',
    'failed': 'С ошибкой',
  };

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    final current = ref.watch(importsStatusFilterProvider);
    return Padding(
      padding: const EdgeInsets.symmetric(vertical: 8),
      child: Wrap(
        spacing: 8,
        children: [
          for (final e in _options.entries)
            ChoiceChip(
              label: Text(e.value),
              selected: current == e.key,
              onSelected: (_) =>
                  ref.read(importsStatusFilterProvider.notifier).state = e.key,
            ),
        ],
      ),
    );
  }
}

class _ImportCard extends StatelessWidget {
  const _ImportCard({required this.item});

  final ImportPreview item;

  @override
  Widget build(BuildContext context) {
    final theme = Theme.of(context);
    final period = item.periodFrom != null && item.periodTo != null
        ? '${ruDate(item.periodFrom!)} – ${ruDate(item.periodTo!)}'
        : 'период не определён';
    final subtitle = [
      period,
      item.accountName ??
          (item.accountId != null
              ? 'счёт #${item.accountId}'
              : 'счёт не найден'),
      if (item.uploadedAt != null)
        'загружен ${ruDate(item.uploadedAt!.toLocal())}',
      if (item.sizeBytes != null) formatBytes(item.sizeBytes),
    ].join(' · ');

    return Card(
      child: ListTile(
        onTap: () => context.go('/imports/${item.id}'),
        title: Row(
          children: [
            Flexible(
              child: Text(item.filename, overflow: TextOverflow.ellipsis),
            ),
            const SizedBox(width: 8),
            parseStatusChip(context, item.parseStatus),
          ],
        ),
        subtitle: Padding(
          padding: const EdgeInsets.only(top: 4),
          child: Column(
            crossAxisAlignment: CrossAxisAlignment.start,
            children: [
              Text('${brokerLabel(item.broker)} · $subtitle'),
              if (item.counts.eventsTotal > 0)
                Padding(
                  padding: const EdgeInsets.only(top: 4),
                  child: Text(
                    'событий ${item.counts.eventsTotal}'
                    ' · новых ${item.counts.eventsNew}'
                    ' · дубликатов ${item.counts.eventsDuplicate}',
                    style: theme.textTheme.bodySmall,
                  ),
                ),
              if (item.isFailed && item.error != null)
                Padding(
                  padding: const EdgeInsets.only(top: 4),
                  child: Text(
                    item.error!,
                    style: theme.textTheme.bodySmall?.copyWith(
                      color: theme.colorScheme.error,
                    ),
                  ),
                ),
            ],
          ),
        ),
        trailing: const Icon(Icons.chevron_right),
      ),
    );
  }
}