import 'package:flutter/material.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/pet_avatar.dart';
import 'package:patbond_flutter/features/pets/pet_analytics.dart';
import 'package:patbond_flutter/features/pets/pet_display.dart';
import 'package:patbond_flutter/features/pets/pet_exceptions.dart';
import 'package:patbond_flutter/features/pets/pet_form_page.dart';
import 'package:patbond_flutter/features/pets/pet_models.dart';
import 'package:patbond_flutter/features/pets/pets_controller.dart';
import 'package:patbond_flutter/widgets/common.dart';

enum _DetailPhase { loading, ready, error, notFound }

/// 宠物详情页（T2-12 / 05 号规范 §4.2 P2 的档案信息部分）。
///
/// 打开即用控制器内存副本首屏渲染，同时经 [PetsController.getPet]
/// 拉取最新详情（同步列表副本）。四态：loading / ready / error+重试 /
/// notFound（40401 防枚举三态同响应 → 提示后返回列表并刷新）。
///
/// 体重、疫苗进度、健康时间线与提醒区块随 T2-13/14 接入摘要与
/// 记录接口后补充，本单不渲染 demo 占位。
class PetDetailPage extends StatefulWidget {
  const PetDetailPage({
    required this.controller,
    required this.petId,
    super.key,
    this.analytics,
  });

  final PetsController controller;
  final String petId;
  final PetAnalytics? analytics;

  @override
  State<PetDetailPage> createState() => _PetDetailPageState();
}

class _PetDetailPageState extends State<PetDetailPage> {
  _DetailPhase _phase = _DetailPhase.loading;
  Pet? _pet;
  ApiException? _error;

  @override
  void initState() {
    super.initState();
    _pet = _fromController();
    if (_pet != null) _phase = _DetailPhase.ready;
    _load();
  }

  Pet? _fromController() {
    for (final pet in widget.controller.pets) {
      if (pet.id == widget.petId) return pet;
    }
    return null;
  }

  Future<void> _load() async {
    if (_pet == null) {
      setState(() => _phase = _DetailPhase.loading);
    }
    try {
      final pet = await widget.controller.getPet(widget.petId);
      if (!mounted) return;
      setState(() {
        _pet = pet;
        _phase = _DetailPhase.ready;
      });
    } on PetNotFoundException {
      if (!mounted) return;
      setState(() => _phase = _DetailPhase.notFound);
    } on ApiException catch (error) {
      if (!mounted) return;
      if (_pet == null) {
        setState(() {
          _error = error;
          _phase = _DetailPhase.error;
        });
      } else {
        // 已有内存副本：刷新失败降级为瞬态提示，不打断阅读。
        ScaffoldMessenger.of(
          context,
        ).showSnackBar(SnackBar(content: Text(petLoadErrorMessage(error))));
      }
    }
  }

  Future<void> _openEdit() async {
    final pet = _pet;
    if (pet == null) return;
    final updated = await Navigator.of(context).push<Pet>(
      // 编辑态不带路由名：pet_form 专属建宠漏斗到达段（06 §1.6），
      // 编辑曝光不计入，避免「到达→动笔」分母虚高。
      fadePageRoute(
        PetFormPage.edit(
          controller: widget.controller,
          pet: pet,
          analytics: widget.analytics,
        ),
      ),
    );
    if (updated != null && mounted) {
      setState(() {
        _pet = updated;
        _phase = _DetailPhase.ready;
      });
      ScaffoldMessenger.of(
        context,
      ).showSnackBar(const SnackBar(content: Text('已保存修改')));
    }
  }

  /// 仅 owner 可改档案（40300：caregiver/viewer 改档案被拒 → 隐藏写入口）。
  bool get _canEdit =>
      _phase == _DetailPhase.ready && _pet?.myRole == PetRole.owner;

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        backgroundColor: Colors.transparent,
        elevation: 0,
        foregroundColor: AppColors.ink,
        actions: [
          if (_canEdit)
            IconButton(
              tooltip: '编辑资料',
              onPressed: _openEdit,
              icon: const Icon(Icons.edit_outlined),
            ),
        ],
      ),
      body: switch (_phase) {
        _DetailPhase.loading => const Center(
          child: CircularProgressIndicator(),
        ),
        _DetailPhase.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: _load, child: const Text('重试')),
              ],
            ),
          ),
        ),
        _DetailPhase.notFound => Center(
          child: SingleChildScrollView(
            child: EmptyStateIllustration(
              icon: Icons.search_off_rounded,
              title: '宠物不存在或已被删除',
              description: '档案可能已被移除，返回列表查看最新档案',
              ctaLabel: '返回列表',
              onCtaPressed: () {
                widget.controller.refresh();
                Navigator.of(context).pop();
              },
            ),
          ),
        ),
        _DetailPhase.ready => _content(_pet!),
      },
    );
  }

  Widget _content(Pet pet) {
    return ListView(
      padding: const EdgeInsets.fromLTRB(16, 0, 16, 30),
      children: [
        Column(
          children: [
            PetAvatar(
              size: PetAvatarSize.xl,
              showEditBadge: _canEdit,
              onTap: _canEdit ? _openEdit : null,
              semanticLabel: _canEdit ? '编辑宠物资料' : null,
            ),
            const SizedBox(height: 12),
            Text(pet.name, style: Theme.of(context).textTheme.headlineSmall),
            const SizedBox(height: 4),
            Text(
              petMetaLine(pet),
              style: const TextStyle(color: AppColors.inkSoft, fontSize: 12),
            ),
            if (pet.status != PetStatus.active) ...[
              const SizedBox(height: 8),
              TagPill(
                petStatusLabel(pet.status),
                color: pet.status == PetStatus.lost
                    ? AppColors.error
                    : AppColors.muted,
              ),
            ],
          ],
        ),
        const SizedBox(height: 24),
        Text('基本资料', style: Theme.of(context).textTheme.titleLarge),
        const SizedBox(height: 10),
        SectionCard(
          child: Column(
            children: [
              _InfoRow(label: '物种', value: petSpeciesLabel(pet.species)),
              const _RowDivider(),
              _InfoRow(label: '品种', value: petBreedLabel(pet)),
              const _RowDivider(),
              _InfoRow(label: '性别', value: petSexLabel(pet.sex)),
              const _RowDivider(),
              _InfoRow(
                label: '生日',
                value: pet.birthDate == null
                    ? '未填写'
                    : dateToJson(pet.birthDate!) +
                          (pet.birthDateEstimated ? '（估算）' : ''),
              ),
              const _RowDivider(),
              _InfoRow(label: '芯片号', value: pet.microchipNo ?? '未填写'),
              const _RowDivider(),
              _InfoRow(label: '性格', value: pet.personality ?? '未填写'),
              const _RowDivider(),
              _InfoRow(
                label: '绝育日期',
                value: pet.sterilizedOn == null
                    ? '未填写'
                    : dateToJson(pet.sterilizedOn!),
              ),
            ],
          ),
        ),
        if (_canEdit) ...[
          const SizedBox(height: 16),
          OutlinedButton.icon(
            onPressed: _openEdit,
            icon: const Icon(Icons.edit_outlined, size: 17),
            label: const Text('编辑资料'),
          ),
        ],
      ],
    );
  }
}

/// 键值行（05 §4.3 P3 风格：字段名 12 inkSoft / 值 bodyMedium ink）。
class _InfoRow extends StatelessWidget {
  const _InfoRow({required this.label, required this.value});

  final String label;
  final String value;

  @override
  Widget build(BuildContext context) {
    return Padding(
      padding: const EdgeInsets.symmetric(vertical: 7),
      child: Row(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: [
          SizedBox(
            width: 72,
            child: Text(
              label,
              style: const TextStyle(color: AppColors.inkSoft, fontSize: 12),
            ),
          ),
          Expanded(
            child: Text(value, style: Theme.of(context).textTheme.bodyMedium),
          ),
        ],
      ),
    );
  }
}

class _RowDivider extends StatelessWidget {
  const _RowDivider();

  @override
  Widget build(BuildContext context) {
    return const Divider(height: 1, thickness: 1, color: AppColors.border);
  }
}