import 'dart:async';
import 'package:flutter/material.dart';
import 'package:flutter/services.dart';
import 'package:sensors_plus/sensors_plus.dart';
import '../../core/data/planet_visual_state.dart';
import '../../core/data/backend.dart';
import '../../core/ui/live_stream.dart';
import 'planet_data.dart';
import '../../core/i18n/app_locale.dart';
import '../quest/quest_evidence.dart' show ShakeDetector;

/// 수량·상한·중복 여부는 서버가 결정한다. 단말은 참여 의사와 결과만 전달한다.
class HeroParticipationSheet extends StatefulWidget {
  const HeroParticipationSheet({
    super.key,
    required this.fandomId,
    required this.watch,
    required this.repository,
    this.accelerometer,
  });
  final String fandomId;
  final PlanetWatch watch;
  final PlanetRepository repository;
  final Stream<AccelerometerEvent>? accelerometer;
  @override
  State<HeroParticipationSheet> createState() => _HeroParticipationSheetState();
}

class _HeroParticipationSheetState extends State<HeroParticipationSheet>
    with WidgetsBindingObserver {
  StreamSubscription<AccelerometerEvent>? _sensor;
  PlanetVisualState? _state;
  final _received = <String, HeroDropReceipt>{};
  final _unavailable = <String>{};
  String? _notice;
  bool _accessDenied = false;
  String? _pendingId;
  bool _sending = false;
  bool _failed = false;
  bool _foreground = true;

  @override
  void initState() {
    super.initState();
    WidgetsBinding.instance.addObserver(this);
    final shakes = ShakeDetector();
    _sensor = (widget.accelerometer ??
            accelerometerEventStream(samplingPeriod: ShakeDetector.sampling))
        .listen((event) {
      if (!shakes.add(event.x, event.y, event.z, DateTime.now())) return;
      if (!_failed) _claim();
    }, onError: (_) {}); // 센서가 없어도 동일한 서버 경로의 참여 버튼을 제공한다.
  }

  @override
  void didChangeAppLifecycleState(AppLifecycleState state) {
    _foreground = state == AppLifecycleState.resumed;
  }

  @override
  void dispose() {
    WidgetsBinding.instance.removeObserver(this);
    _sensor?.cancel();
    super.dispose();
  }

  String? get _next {
    final state = _state;
    if (_accessDenied ||
        state?.isHeroTime != true ||
        state?.heroEndsAt?.isAfter(DateTime.now()) != true)
      return null;
    final ids =
        (state?.heroEventIds ?? {})
            .where(
              (id) => !_received.containsKey(id) && !_unavailable.contains(id),
            )
            .toList()
          ..sort();
    return ids.firstOrNull;
  }

  Future<void> _claim() async {
    if (_sending || !_foreground || ModalRoute.of(context)?.isCurrent != true)
      return;
    // 응답 유실 재확인은 이벤트 종료 뒤에도 같은 멱등키로 요청한다.
    final id = _pendingId ?? _next;
    if (id == null) return;
    setState(() {
      _sending = true;
      _failed = false;
      _notice = null;
      _pendingId = id;
    });
    try {
      final receipt = await widget.repository.claimHeroDrop(id);
      if (!mounted) return;
      setState(() {
        _received[id] = receipt;
        _pendingId = null;
      });
      if (_foreground) HapticFeedback.lightImpact();
    } catch (error) {
      if (!mounted) return;
      final code = error is BackendException ? error.code : null;
      setState(() {
        _notice = switch (code) {
          'E-POP-02' => context.l10n.heroGiftUnavailable,
          'E-POP-03' => context.l10n.heroGiftAlready,
          'E-AUTH-03' => context.l10n.heroGiftRelogin,
          'E-PERM-01' => context.l10n.heroGiftNoPermission,
          _ => null,
        };
        _failed = _notice == null;
        if (!_failed) {
          _pendingId = null;
          _unavailable.add(id);
          _accessDenied = code == 'E-AUTH-03' || code == 'E-PERM-01';
        }
      });
    } finally {
      if (mounted) setState(() => _sending = false);
    }
  }

  @override
  Widget build(BuildContext context) => LiveStreamBuilder<PlanetVisualState>(
    key: ValueKey(widget.fandomId),
    create: () => widget.watch(widget.fandomId),
    builder: (context, state) {
      _state = state;
      final available = _next != null;
      final total = _received.values.fold<int>(0, (sum, r) => sum + r.amount);
      return SafeArea(
        child: Padding(
          padding: const EdgeInsets.all(24),
          child: Column(
            mainAxisSize: MainAxisSize.min,
            crossAxisAlignment: CrossAxisAlignment.start,
            children: [
              Text(
                'HERO TIME · ZAP+',
                style: Theme.of(context).textTheme.titleLarge,
              ),
              const SizedBox(height: 12),
              Text(context.l10n.heroGiftHowTo),
              Text(context.l10n.heroGiftPopNote),
              const SizedBox(height: 16),
              if (_received.isNotEmpty)
                Semantics(
                  liveRegion: true,
                  child: Text(
                    context.l10n.heroGiftReceived('$total'),
                    style: Theme.of(context).textTheme.titleMedium,
                  ),
                ),
              if (_notice case final notice?)
                Semantics(liveRegion: true, child: Text(notice)),
              if (_failed) Text(context.l10n.heroGiftUnknown),
              if (!available && !_sending && !_failed && _notice == null)
                Text(
                  _received.isEmpty
                      ? context.l10n.heroGiftNone
                      : context.l10n.heroGiftConfirmed,
                ),
              const SizedBox(height: 12),
              FilledButton.icon(
                onPressed: _sending || (!available && !_failed) ? null : _claim,
                icon: const Icon(Icons.auto_awesome),
                label: Text(
                  _sending
                      ? context.l10n.heroGiftChecking
                      : _failed
                      ? context.l10n.heroGiftRetry
                      : context.l10n.heroGiftTap,
                ),
              ),
            ],
          ),
        ),
      );
    },
  );
}