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

import '../../core/cache/cached.dart';
import '../../core/widgets/stale_banner.dart';
import 'data/tax_api.dart';
import 'lots_tab.dart';
import 'providers.dart';
import 'summary_tab.dart';

/// Налоги: the year summary and the open-lot list with ЛДВ dates.
///
/// The word «оценка» is on the screen itself, not in a tooltip: the tax agent is the
/// broker, and these numbers exist so that the broker's statement can be checked against
/// something — not to replace it.
class TaxPage extends ConsumerWidget {
  const TaxPage({super.key});

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    final stale = oldestFetch([
      ref.watch(taxSummaryProvider).valueOrNull?.fetchedAt,
      ref.watch(taxLotsProvider).valueOrNull?.fetchedAt,
    ]);

    return DefaultTabController(
      length: 2,
      child: Scaffold(
        appBar: AppBar(
          title: const Text('Налоги (оценка)'),
          actions: [
            const _YearSelector(),
            IconButton(
              tooltip: 'Обновить',
              icon: const Icon(Icons.refresh),
              onPressed: () => invalidateTaxProviders(ref),
            ),
          ],
          bottom: const TabBar(
            tabs: [
              Tab(text: 'Сводка за год'),
              Tab(text: 'Лоты и ЛДВ'),
            ],
          ),
        ),
        body: Column(
          children: [
            const EstimateBanner(),
            if (stale != null)
              Padding(
                padding: const EdgeInsets.fromLTRB(16, 0, 16, 12),
                child: StaleBanner(fetchedAt: stale),
              ),
            const Expanded(
              child: TabBarView(children: [TaxSummaryTab(), TaxLotsTab()]),
            ),
          ],
        ),
      ),
    );
  }
}

/// The disclaimer, always visible above both tabs.
class EstimateBanner extends ConsumerWidget {
  const EstimateBanner({super.key});

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    final summary = ref.watch(taxSummaryProvider).valueOrNull?.data;
    final scheme = Theme.of(context).colorScheme;
    final text = summary?.disclaimer ?? TaxSummary.defaultDisclaimer;

    return Material(
      color: scheme.tertiaryContainer,
      child: Padding(
        padding: const EdgeInsets.symmetric(horizontal: 16, vertical: 10),
        child: Row(
          children: [
            const Icon(Icons.info_outline, size: 18),
            const SizedBox(width: 8),
            Expanded(
              child: Text(text, style: Theme.of(context).textTheme.bodySmall),
            ),
          ],
        ),
      ),
    );
  }
}

class _YearSelector extends ConsumerWidget {
  const _YearSelector();

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    final year = ref.watch(taxYearProvider);
    final now = DateTime.now().year;
    return DropdownButtonHideUnderline(
      child: DropdownButton<int>(
        value: year,
        borderRadius: BorderRadius.circular(8),
        items: [
          for (var y = now; y >= now - 6; y--)
            DropdownMenuItem(value: y, child: Text('$y')),
        ],
        onChanged: (v) {
          if (v != null) ref.read(taxYearProvider.notifier).state = v;
        },
      ),
    );
  }
}