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/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/health_record_analytics.dart';
import 'package:patbond_flutter/features/pets/pet_analytics.dart';
import 'package:patbond_flutter/features/pets/pet_detail_page.dart';
import 'package:patbond_flutter/features/pets/pet_display.dart';
import 'package:patbond_flutter/features/pets/pet_form_page.dart';
import 'package:patbond_flutter/features/pets/pets_controller.dart';
import 'package:patbond_flutter/features/pets/pet_models.dart';
import 'package:patbond_flutter/widgets/common.dart';

/// 档案 Tab 落地页：宠物列表（T2-12 / 05 号规范 §4.1 P1）。
///
/// 真实数据经 [PetsController] 四态驱动：loading（居中转圈）、
/// empty（空态插画 + 建档 CTA）、error（横幅 + 重试）、ready（列表）。
/// 页面不直连 ApiClient，不读写 AppState demo 数据。
class PetsPage extends StatefulWidget {
  const PetsPage({
    required this.controller,
    super.key,
    this.analytics,
    this.healthAnalytics,
  });

  final PetsController controller;
  final PetAnalytics? analytics;

  /// health_record 域埋点（T2-13，记录页面族透传）。
  final HealthRecordAnalytics? healthAnalytics;

  @override
  State<PetsPage> createState() => _PetsPageState();
}

class _PetsPageState extends State<PetsPage> {
  @override
  void initState() {
    super.initState();
    // 主壳挂载即预取（IndexedStack 各 Tab 同时构建）；重登后控制器
    // 已被 reset 回 initial，会重新拉取。
    if (widget.controller.phase == PetsLoadPhase.initial) {
      widget.controller.refresh();
    }
  }

  Future<void> _openCreate(PetCreateEntryPoint entryPoint) async {
    final created = await Navigator.of(context).push<Pet>(
      fadePageRoute(
        PetFormPage.create(
          controller: widget.controller,
          analytics: widget.analytics,
          entryPoint: entryPoint,
        ),
        // 建宠表单曝光由既有 RouteObserver 采集（06 §1.6 pet_form）。
        settings: RouteSettings(name: AnalyticsPageName.petForm.pageName),
      ),
    );
    if (created != null && mounted) {
      ScaffoldMessenger.of(
        context,
      ).showSnackBar(SnackBar(content: Text('已为「${created.name}」建立档案 🐾')));
    }
  }

  void _openDetail(Pet pet) {
    Navigator.of(context).push(
      fadePageRoute(
        PetDetailPage(
          controller: widget.controller,
          petId: pet.id,
          analytics: widget.analytics,
          healthAnalytics: widget.healthAnalytics,
        ),
        settings: RouteSettings(name: AnalyticsPageName.petDetail.pageName),
      ),
    );
  }

  @override
  Widget build(BuildContext context) {
    return ListenableBuilder(
      listenable: widget.controller,
      builder: (context, _) {
        final controller = widget.controller;
        switch (controller.phase) {
          case PetsLoadPhase.initial:
          case PetsLoadPhase.loading:
            return const Center(child: CircularProgressIndicator());
          case PetsLoadPhase.error:
            return _LoadErrorView(
              message: petLoadErrorMessage(controller.lastError),
              onRetry: controller.refresh,
            );
          case PetsLoadPhase.ready:
            if (controller.isEmpty) {
              return Center(
                child: SingleChildScrollView(
                  child: EmptyStateIllustration(
                    icon: Icons.pets,
                    title: '还没有宠物档案',
                    description: '添加毛孩子，开始记录 TA 的健康点滴',
                    ctaLabel: '添加宠物',
                    onCtaPressed: () =>
                        _openCreate(PetCreateEntryPoint.profileEmptyState),
                  ),
                ),
              );
            }
            return _petList(controller.pets);
        }
      },
    );
  }

  Widget _petList(List<Pet> pets) {
    return RefreshIndicator(
      onRefresh: widget.controller.refresh,
      child: ListView(
        padding: const EdgeInsets.fromLTRB(16, 16, 16, 30),
        children: [
          Row(
            children: [
              Text('我的宠物', style: Theme.of(context).textTheme.titleLarge),
              const Spacer(),
              TextButton.icon(
                onPressed: () => _openCreate(PetCreateEntryPoint.petList),
                icon: const Icon(Icons.add, size: 18),
                label: const Text('添加'),
              ),
            ],
          ),
          const SizedBox(height: 12),
          for (final pet in pets) ...[
            _PetCard(pet: pet, onTap: () => _openDetail(pet)),
            const SizedBox(height: 10),
          ],
          _AddPetCard(onTap: () => _openCreate(PetCreateEntryPoint.petList)),
        ],
      ),
    );
  }
}

/// 加载失败态：InlineErrorBanner + 重试按钮（05 §4.2 错误三层模型）。
class _LoadErrorView extends StatelessWidget {
  const _LoadErrorView({required this.message, required this.onRetry});

  final String message;
  final Future<void> Function() onRetry;

  @override
  Widget build(BuildContext context) {
    return Center(
      child: Padding(
        padding: const EdgeInsets.all(24),
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: [
            InlineErrorBanner(message: message),
            const SizedBox(height: 16),
            FilledButton(onPressed: onRetry, child: const Text('重试')),
          ],
        ),
      ),
    );
  }
}

/// 宠物卡（05 §4.1）：头像 lg + 名字 + 元信息 + chevron；非 active
/// 状态以 TagPill 标示（图文双通道由状态文案承担）。
class _PetCard extends StatelessWidget {
  const _PetCard({required this.pet, required this.onTap});

  final Pet pet;
  final VoidCallback onTap;

  @override
  Widget build(BuildContext context) {
    return Card(
      child: InkWell(
        onTap: onTap,
        borderRadius: BorderRadius.circular(AppRadius.xl),
        child: Padding(
          padding: const EdgeInsets.all(14),
          child: Row(
            children: [
              const PetAvatar(size: PetAvatarSize.lg),
              const SizedBox(width: 12),
              Expanded(
                child: Column(
                  crossAxisAlignment: CrossAxisAlignment.start,
                  children: [
                    Text(
                      pet.name,
                      style: Theme.of(context).textTheme.titleMedium,
                    ),
                    const SizedBox(height: 4),
                    Text(
                      petMetaLine(pet),
                      style: const TextStyle(
                        color: AppColors.inkSoft,
                        fontSize: 12,
                      ),
                    ),
                  ],
                ),
              ),
              if (pet.status != PetStatus.active)
                TagPill(
                  petStatusLabel(pet.status),
                  color: pet.status == PetStatus.lost
                      ? AppColors.error
                      : AppColors.muted,
                )
              else
                const Icon(Icons.chevron_right, color: AppColors.muted),
            ],
          ),
        ),
      ),
    );
  }
}

/// 虚线「添加宠物」卡（05 §4.1：border 色 1.5px dashed，radius 24，高 64）。
class _AddPetCard extends StatelessWidget {
  const _AddPetCard({required this.onTap});

  final VoidCallback onTap;

  @override
  Widget build(BuildContext context) {
    return CustomPaint(
      painter: _DashedBorderPainter(
        color: AppColors.border,
        strokeWidth: 1.5,
        radius: AppRadius.xl,
      ),
      child: SizedBox(
        height: 64,
        child: Material(
          color: Colors.transparent,
          child: InkWell(
            onTap: onTap,
            borderRadius: BorderRadius.circular(AppRadius.xl),
            child: const Center(
              child: Text(
                '＋ 添加宠物',
                style: TextStyle(
                  color: AppColors.primaryStrong,
                  fontSize: 14,
                  fontWeight: FontWeight.w600,
                ),
              ),
            ),
          ),
        ),
      ),
    );
  }
}

class _DashedBorderPainter extends CustomPainter {
  const _DashedBorderPainter({
    required this.color,
    required this.strokeWidth,
    required this.radius,
  });

  final Color color;
  final double strokeWidth;
  final double radius;

  @override
  void paint(Canvas canvas, Size size) {
    final paint = Paint()
      ..color = color
      ..strokeWidth = strokeWidth
      ..style = PaintingStyle.stroke;
    final path = Path()
      ..addRRect(
        RRect.fromRectAndRadius(Offset.zero & size, Radius.circular(radius)),
      );
    const dashWidth = 6.0;
    const dashGap = 4.0;
    for (final metric in path.computeMetrics()) {
      var distance = 0.0;
      while (distance < metric.length) {
        canvas.drawPath(
          metric.extractPath(distance, distance + dashWidth),
          paint,
        );
        distance += dashWidth + dashGap;
      }
    }
  }

  @override
  bool shouldRepaint(_DashedBorderPainter oldDelegate) =>
      color != oldDelegate.color ||
      strokeWidth != oldDelegate.strokeWidth ||
      radius != oldDelegate.radius;
}