import 'package:flutter/material.dart';
import 'package:patbond_flutter/analytics/analytics_page_name.dart';
import 'package:patbond_flutter/core/navigation/fade_route.dart';
import 'package:patbond_flutter/core/network/api_exception.dart';
import 'package:patbond_flutter/core/theme/app_theme.dart';
import 'package:patbond_flutter/core/widgets/empty_state_illustration.dart';
import 'package:patbond_flutter/core/widgets/inline_error_banner.dart';
import 'package:patbond_flutter/core/widgets/record_type_dot.dart';
import 'package:patbond_flutter/features/pets/health_event_edit_page.dart';
import 'package:patbond_flutter/features/pets/health_event_form_page.dart';
import 'package:patbond_flutter/features/pets/health_record_analytics.dart';
import 'package:patbond_flutter/features/pets/health_record_display.dart';
import 'package:patbond_flutter/features/pets/money.dart';
import 'package:patbond_flutter/features/pets/pet_display.dart';
import 'package:patbond_flutter/features/pets/pet_models.dart';
import 'package:patbond_flutter/features/pets/pets_repository.dart';
import 'package:patbond_flutter/widgets/common.dart';

enum _ListPhase { loading, ready, error }

/// 健康事件时间线页（T2-14）：cursor 分页（occurred_at DESC，
/// 「加载更多」追加，末页收起），按月分组（05 §4.2 组头），四态齐备。
///
/// - 六类事件经 [recordTypeForHealthEvent] 映射 RecordTypeDot，
///   类型标签 TagPill 双通道呈现；金额以元展示（传输为整数分）。
/// - 录入经 [HealthEventFormPage]；成功后重拉首页（排序与月分组以
///   服务端为准，不本地猜位置）。
/// - 编辑经 [HealthEventEditPage]（canWrite 点条目进入）；成功就地替换。
/// - 曝光埋点：每次进入首个成功加载上报一次
///   `health_record_viewed(recordType=health_event, source=pet_detail)`。
class HealthEventsPage extends StatefulWidget {
  const HealthEventsPage({
    required this.repository,
    required this.petId,
    required this.canWrite,
    super.key,
    this.analytics,
    this.pageSize,
  });

  final PetsRepository repository;
  final String petId;

  /// owner/caregiver 可写；viewer 隐藏录入/编辑入口（40300 语义前置）。
  final bool canWrite;

  final HealthRecordAnalytics? analytics;

  /// 每页条数（测试注入小页验证分页；缺省走服务端默认 20）。
  final int? pageSize;

  @override
  State<HealthEventsPage> createState() => _HealthEventsPageState();
}

class _HealthEventsPageState extends State<HealthEventsPage> {
  _ListPhase _phase = _ListPhase.loading;
  List<HealthEvent> _events = const [];
  String? _nextCursor;
  bool _hasMore = false;
  bool _loadingMore = false;
  ApiException? _error;
  bool _viewedFired = false;

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

  Future<void> _loadFirstPage() async {
    setState(() {
      _phase = _ListPhase.loading;
      _error = null;
    });
    try {
      final page = await widget.repository.listHealthEvents(
        widget.petId,
        limit: widget.pageSize,
      );
      if (!mounted) return;
      setState(() {
        _events = page.items;
        _nextCursor = page.nextCursor;
        _hasMore = page.hasMore;
        _phase = _ListPhase.ready;
      });
      if (!_viewedFired) {
        _viewedFired = true;
        widget.analytics?.viewed(
          recordType: HealthRecordType.healthEvent,
          source: HealthRecordViewSource.petDetail,
        );
      }
    } on ApiException catch (error) {
      if (!mounted) return;
      setState(() {
        _error = error;
        _phase = _ListPhase.error;
      });
    }
  }

  Future<void> _loadMore() async {
    if (_loadingMore || !_hasMore) return;
    setState(() => _loadingMore = true);
    try {
      final page = await widget.repository.listHealthEvents(
        widget.petId,
        limit: widget.pageSize,
        cursor: _nextCursor,
      );
      if (!mounted) return;
      setState(() {
        _events = [..._events, ...page.items];
        _nextCursor = page.nextCursor;
        _hasMore = page.hasMore;
      });
    } on ApiException catch (error) {
      if (!mounted) return;
      ScaffoldMessenger.of(
        context,
      ).showSnackBar(SnackBar(content: Text(petLoadErrorMessage(error))));
    } finally {
      if (mounted) setState(() => _loadingMore = false);
    }
  }

  Future<void> _openCreate() async {
    final created = await Navigator.of(context).push<HealthEvent>(
      fadePageRoute(
        HealthEventFormPage(
          repository: widget.repository,
          petId: widget.petId,
          analytics: widget.analytics,
        ),
        // record_form：健康记录漏斗到达段页名（06 §1.6 / §2.2）。
        settings: RouteSettings(name: AnalyticsPageName.recordForm.pageName),
      ),
    );
    if (created != null && mounted) {
      ScaffoldMessenger.of(
        context,
      ).showSnackBar(const SnackBar(content: Text('已记录健康事件')));
      // occurred_at DESC + 月分组：补录历史日期的位置由服务端定，
      // 重拉首页而非本地猜位置。
      await _loadFirstPage();
    }
  }

  Future<void> _openEdit(HealthEvent event) async {
    final updated = await Navigator.of(context).push<HealthEvent>(
      // 编辑页不带路由名：record_form 专属创建漏斗到达段（T2-12 先例）。
      fadePageRoute(
        HealthEventEditPage(
          repository: widget.repository,
          event: event,
          analytics: widget.analytics,
        ),
      ),
    );
    if (updated != null && mounted) {
      setState(() {
        // occurredAt 不可编辑 → 排序/分组位置不变，就地替换安全。
        _events = [
          for (final item in _events)
            if (item.id == updated.id) updated else item,
        ];
      });
      ScaffoldMessenger.of(
        context,
      ).showSnackBar(const SnackBar(content: Text('已保存修改')));
    }
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        backgroundColor: Colors.transparent,
        elevation: 0,
        foregroundColor: AppColors.ink,
        title: const Text('健康时间线'),
        centerTitle: true,
        titleTextStyle: const TextStyle(
          color: AppColors.ink,
          fontSize: 16,
          fontWeight: FontWeight.w800,
        ),
        actions: [
          if (widget.canWrite && _phase == _ListPhase.ready)
            IconButton(
              tooltip: '记录健康事件',
              onPressed: _openCreate,
              icon: const Icon(Icons.add),
            ),
        ],
      ),
      body: switch (_phase) {
        _ListPhase.loading => const Center(child: CircularProgressIndicator()),
        _ListPhase.error => Center(
          child: Padding(
            padding: const EdgeInsets.all(24),
            child: Column(
              mainAxisAlignment: MainAxisAlignment.center,
              children: [
                InlineErrorBanner(message: petLoadErrorMessage(_error)),
                const SizedBox(height: 16),
                FilledButton(
                  onPressed: _loadFirstPage,
                  child: const Text('重试'),
                ),
              ],
            ),
          ),
        ),
        _ListPhase.ready when _events.isEmpty => Center(
          child: SingleChildScrollView(
            child: EmptyStateIllustration(
              icon: Icons.event_note_outlined,
              title: '还没有健康记录',
              description: '就医、驱虫、洗护……随手记下毛孩子的健康点滴',
              ctaLabel: widget.canWrite ? '记录第一条' : null,
              onCtaPressed: widget.canWrite ? _openCreate : null,
            ),
          ),
        ),
        _ListPhase.ready => _list(),
      },
    );
  }

  /// 按月分组渲染：服务端 occurred_at DESC 保证同月相邻，
  /// 月份变化处插组头（05 §4.2「2026 年 9 月」）。
  Widget _list() {
    final children = <Widget>[];
    String? currentMonth;
    for (final event in _events) {
      final month = healthEventMonthHeader(event.occurredAt);
      if (month != currentMonth) {
        currentMonth = month;
        children.add(
          Padding(
            padding: EdgeInsets.only(top: children.isEmpty ? 0 : 14, bottom: 8),
            child: Text(
              month,
              style: const TextStyle(
                color: AppColors.inkSoft,
                fontSize: 12,
                fontWeight: FontWeight.w700,
              ),
            ),
          ),
        );
      }
      children
        ..add(
          _HealthEventTile(
            event: event,
            onTap: widget.canWrite ? () => _openEdit(event) : null,
          ),
        )
        ..add(const SizedBox(height: 10));
    }
    if (_hasMore) {
      children.add(
        Center(
          child: _loadingMore
              ? const Padding(
                  padding: EdgeInsets.all(12),
                  child: SizedBox(
                    width: 22,
                    height: 22,
                    child: CircularProgressIndicator(strokeWidth: 2),
                  ),
                )
              : TextButton(onPressed: _loadMore, child: const Text('加载更多')),
        ),
      );
    }
    return RefreshIndicator(
      onRefresh: _loadFirstPage,
      child: ListView(
        padding: const EdgeInsets.fromLTRB(16, 8, 16, 30),
        children: children,
      ),
    );
  }
}

/// 时间线条目（05 §3.3 形态）：RecordTypeDot(六类映射) + 标题 +
/// 日期/备注副行；尾部类型 TagPill（双通道）与金额（元展示，
/// 15/w800 类型文字色）。
class _HealthEventTile extends StatelessWidget {
  const _HealthEventTile({required this.event, this.onTap});

  final HealthEvent event;
  final VoidCallback? onTap;

  @override
  Widget build(BuildContext context) {
    final recordType = recordTypeForHealthEvent(event.eventType);
    final style = recordTypeStyles[recordType]!;
    final meta = StringBuffer(formatOccurredAt(event.occurredAt));
    if (event.notes != null && event.notes!.isNotEmpty) {
      meta.write(' · ${event.notes}');
    }
    return Card(
      child: InkWell(
        onTap: onTap,
        borderRadius: BorderRadius.circular(AppRadius.xl),
        child: Padding(
          padding: const EdgeInsets.all(14),
          child: Row(
            children: [
              RecordTypeDot(type: recordType, size: RecordTypeDotSize.md),
              const SizedBox(width: 12),
              Expanded(
                child: Column(
                  crossAxisAlignment: CrossAxisAlignment.start,
                  children: [
                    Text(
                      event.title,
                      maxLines: 1,
                      overflow: TextOverflow.ellipsis,
                      style: Theme.of(context).textTheme.titleMedium,
                    ),
                    const SizedBox(height: 4),
                    Text(
                      meta.toString(),
                      maxLines: 1,
                      overflow: TextOverflow.ellipsis,
                      style: const TextStyle(
                        color: AppColors.inkSoft,
                        fontSize: 12,
                      ),
                    ),
                  ],
                ),
              ),
              const SizedBox(width: 8),
              Column(
                crossAxisAlignment: CrossAxisAlignment.end,
                children: [
                  TagPill(
                    healthEventTypeLabel(event.eventType),
                    color: style.baseColor,
                  ),
                  if (event.amountCents != null) ...[
                    const SizedBox(height: 4),
                    Text(
                      '¥${formatCentsAsYuan(event.amountCents!)}',
                      style: TextStyle(
                        color: style.inkColor,
                        fontSize: 15,
                        fontWeight: FontWeight.w800,
                      ),
                    ),
                  ],
                ],
              ),
            ],
          ),
        ),
      ),
    );
  }
}