import 'dart:convert';

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

import '../../api/cache_store.dart';
import '../../extensions/date_time.dart';
import '../../routing/app_routes.dart';
import '../app_progress_indicator.dart';
import '../confirm_dialog.dart';
import '../placeholder_view.dart';

/// Lists the [CacheStore] entries (one file per request key), newest first.
class CacheView extends StatefulWidget {
  const CacheView({super.key});

  @override
  State<CacheView> createState() => _CacheViewState();
}

class _CacheViewState extends State<CacheView> {
  late Future<List<MapEntry<String, CacheEntry>>> _entries = _read();

  Future<List<MapEntry<String, CacheEntry>>> _read() async =>
      (await CacheStore.instance.readAll()).entries.toList()
        ..sort((a, b) => b.value.lastUpdate.compareTo(a.value.lastUpdate));

  void _reload() => setState(() {
    _entries = _read();
  });

  void _confirmDelete(String key) {
    ConfirmDialog(
      title: 'Eintrag löschen',
      content: '„$key“ wird gelöscht und bei Bedarf neu geladen.',
      confirmButton: 'Löschen',
      errorBuilder: (e) => '$e',
      onConfirmAsync: () async {
        await CacheStore.instance.delete(key);
        if (mounted) _reload();
      },
    ).asDialog(context);
  }

  void _confirmClear() {
    ConfirmDialog(
      title: 'Request-Cache leeren',
      content:
          'Alle Einträge werden gelöscht. Der Cache baut sich bei Nutzung der '
          'App automatisch wieder auf.',
      confirmButton: 'Alles löschen',
      errorBuilder: (e) => '$e',
      onConfirmAsync: () async {
        await CacheStore.instance.clear();
        if (mounted) _reload();
      },
    ).asDialog(context);
  }

  @override
  Widget build(BuildContext context) => Scaffold(
    appBar: AppBar(
      title: const Text('Request-Cache'),
      actions: [
        IconButton(
          tooltip: 'Neu laden',
          icon: const Icon(Icons.refresh),
          onPressed: _reload,
        ),
        IconButton(
          tooltip: 'Alles löschen',
          icon: const Icon(Icons.delete_sweep_outlined),
          onPressed: _confirmClear,
        ),
      ],
    ),
    body: FutureBuilder(
      future: _entries,
      builder: (context, snapshot) {
        if (snapshot.connectionState != ConnectionState.done) {
          return const Center(child: AppProgressIndicator.large());
        }
        final entries = snapshot.data ?? const [];
        if (entries.isEmpty) {
          return const PlaceholderView(
            icon: Icons.hourglass_empty,
            text: 'Keine Daten',
          );
        }
        return ListView.builder(
          itemCount: entries.length,
          itemBuilder: (context, index) {
            final MapEntry(:key, :value) = entries[index];
            return ListTile(
              leading: const Icon(Icons.text_snippet_outlined),
              title: Text(key),
              subtitle: Text(
                '${filesize(utf8.encode(value.json).length)} · '
                '${DateTime.fromMillisecondsSinceEpoch(value.lastUpdate).formatRelative()}',
              ),
              onTap: () => AppRoutes.openJsonViewer(
                context,
                jsonDecode(value.json),
                title: key,
              ),
              trailing: IconButton(
                tooltip: 'Löschen',
                icon: const Icon(Icons.delete_outline),
                onPressed: () => _confirmDelete(key),
              ),
            );
          },
        );
      },
    ),
  );
}