import 'package:flutter/material.dart';

import '../../core/theme/tokens.dart';
import 'station_data.dart';
import 'station_suggest_screen.dart';
import '../../core/i18n/app_locale.dart';

/// STATION 탭 루트 — S-S-HUB.
///
/// **Figma 에 이 화면의 시안이 없다.** 근거는 견적서 v2.1 의 5탭 구성과
/// Firestore 설계서의 `stationLinks` · `stationSuggestions` 다. 그래서 데이터가
/// 정의한 것까지만 그렸고, 시안이 확정되면 그때 맞춘다.
class StationScreen extends StatefulWidget {
  const StationScreen({
    super.key,
    this.repository = const SampleStationRepository(),
  });

  final StationRepository repository;

  @override
  State<StationScreen> createState() => _StationScreenState();
}

class _StationScreenState extends State<StationScreen> {
  StationSnapshot? _snapshot;
  bool _loading = true;
  String? _error;
  StationCategory? _filter;

  @override
  void initState() {
    super.initState();
    _load();
  }

  Future<void> _load() async {
    setState(() {
      _loading = true;
      _error = null;
    });
    try {
      final snap = await widget.repository.load();
      if (!mounted) return;
      setState(() {
        _snapshot = snap;
        _loading = false;
      });
    } on Object {
      if (!mounted) return;
      setState(() {
        _loading = false;
        _error = context.l10n.stationLoadFailed;
      });
    }
  }

  List<StationLink> get _visible {
    final links = _snapshot?.links ?? const <StationLink>[];
    final filter = _filter;
    if (filter == null) return links;
    return links.where((l) => l.category == filter).toList();
  }

  @override
  Widget build(BuildContext context) {
    final t = Theme.of(context).textTheme;
    final snapshot = _snapshot;
    return Scaffold(
      appBar: AppBar(
        title: const Text('STATION'),
        bottom: PreferredSize(
          preferredSize: const Size.fromHeight(48),
          child: SingleChildScrollView(
            scrollDirection: Axis.horizontal,
            padding: const EdgeInsets.symmetric(horizontal: AppSpace.s4),
            child: Row(
              children: [
                ChoiceChip(
                  label: Text(context.l10n.commonAll),
                  selected: _filter == null,
                  onSelected: (_) => setState(() => _filter = null),
                ),
                const SizedBox(width: AppSpace.s2),
                for (final c in StationCategory.values) ...[
                  ChoiceChip(
                    label: Text(c.label),
                    selected: _filter == c,
                    onSelected: (_) => setState(() => _filter = c),
                  ),
                  const SizedBox(width: AppSpace.s2),
                ],
              ],
            ),
          ),
        ),
      ),
      floatingActionButton: (snapshot?.canSuggest ?? false)
          ? FloatingActionButton.extended(
              onPressed: () => Navigator.of(context, rootNavigator: true).push<void>(
                MaterialPageRoute(builder: (_) => const StationSuggestScreen()),
              ),
              icon: const Icon(Icons.add_link),
              label: Text(context.l10n.stationSuggest),
            )
          : null,
      body: switch ((_loading, _error, _visible.isEmpty)) {
        (true, _, _) => const Center(child: CircularProgressIndicator()),
        (_, final String message, _) => Center(
          child: Column(
            mainAxisSize: MainAxisSize.min,
            children: [
              Text(message, style: t.titleMedium),
              const SizedBox(height: AppSpace.s4),
              FilledButton(onPressed: _load, child: Text(context.l10n.commonRetry)),
            ],
          ),
        ),
        (_, _, true) => Center(
          child: Padding(
            padding: const EdgeInsets.all(AppSpace.s5),
            child: Text(
              snapshot == null || snapshot.links.isEmpty
                  ? context.l10n.stationEmpty
                  : context.l10n.stationCategoryEmpty,
              style: t.bodyMedium,
              textAlign: TextAlign.center,
            ),
          ),
        ),
        _ => RefreshIndicator(
          onRefresh: _load,
          child: ListView.separated(
            padding: const EdgeInsets.fromLTRB(
              AppSpace.s4,
              AppSpace.s4,
              AppSpace.s4,
              AppSpace.s8,
            ),
            itemCount: _visible.length,
            separatorBuilder: (_, _) => const SizedBox(height: AppSpace.s3),
            itemBuilder: (context, i) => StationLinkTile(link: _visible[i]),
          ),
        ),
      },
    );
  }
}

/// 링크 한 줄.
class StationLinkTile extends StatelessWidget {
  const StationLinkTile({super.key, required this.link, this.onTap});

  final StationLink link;
  final VoidCallback? onTap;

  @override
  Widget build(BuildContext context) {
    final t = Theme.of(context).textTheme;
    return Material(
      color: AppColors.cosmicSurfaceContainer,
      borderRadius: BorderRadius.circular(AppRadius.md),
      child: InkWell(
        onTap: onTap,
        borderRadius: BorderRadius.circular(AppRadius.md),
        child: Padding(
          padding: const EdgeInsets.all(AppSpace.s4),
          child: Row(
            crossAxisAlignment: CrossAxisAlignment.start,
            children: [
              Expanded(
                child: Column(
                  crossAxisAlignment: CrossAxisAlignment.start,
                  children: [
                    Row(
                      children: [
                        Text(link.category.label, style: t.labelSmall),
                        if (link.verified) ...[
                          const SizedBox(width: AppSpace.s2),
                          Icon(
                            Icons.verified_outlined,
                            size: 14,
                            color: AppColors.neonCyan,
                          ),
                        ],
                      ],
                    ),
                    const SizedBox(height: AppSpace.s2),
                    Text(link.title, style: t.titleMedium),
                    if (link.description.isNotEmpty) ...[
                      const SizedBox(height: AppSpace.s1),
                      Text(link.description, style: t.bodySmall),
                    ],
                  ],
                ),
              ),
              const SizedBox(width: AppSpace.s3),
              Icon(Icons.open_in_new, size: 18, color: t.labelSmall?.color),
            ],
          ),
        ),
      ),
    );
  }
}