import 'package:flutter/material.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';

import '../../domain/catalog/catalog_item.dart';
import '../../state/catalog_providers.dart';
import '../widgets/reference_expand_card.dart';

class ProtocolPreviewScreen extends ConsumerWidget {
  const ProtocolPreviewScreen({super.key, required this.item});

  final CatalogItem item;

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    return Scaffold(
      appBar: AppBar(
        title: Text(item.title, maxLines: 1, overflow: TextOverflow.ellipsis),
      ),
      body: ListView(
        padding: const EdgeInsets.fromLTRB(16, 16, 16, 96),
        children: [
          _Header(item: item),
          const SizedBox(height: 16),
          ..._buildBody(context),
          const SizedBox(height: 24),
          _References(referenceIds: item.referenceIds),
        ],
      ),
      bottomNavigationBar: const _ImportFooter(),
    );
  }

  List<Widget> _buildBody(BuildContext context) {
    return switch (item) {
      ProtocolCatalogItem p => [
          _section(context, '무엇 (What)', p.what),
          _section(context, '언제 (When)', p.whenText),
          _section(context, '도즈 (Dose)', p.dose),
          _section(context, '왜 (Why)', p.why),
          if (p.how.isNotEmpty) _howSection(context, p.how),
          _section(context, '체크 (Check)', p.checkText),
          if (p.caution != null) _section(context, '주의 (Caution)', p.caution!),
          if (p.defaultAnchor != null)
            _section(context, '기본 앵커', _anchorText(p.defaultAnchor!)),
          if (p.minDoseForStart != null)
            _section(context, '최소 도즈 (시작용)', p.minDoseForStart!),
          if (p.sourceDoc != null)
            _section(context, '출처 문서', p.sourceDoc!),
        ],
      BreakCatalogItem b => [
          _section(context, '요약 (Huberman)', b.hubermanSummary),
          _section(context, '구분', b.breakCategory),
          if (b.phases.isNotEmpty)
            _section(context, '단계', b.phases.join(' / ')),
          if (b.defaultCommonFrames.isNotEmpty)
            _section(context, '기본 공통 프레임',
                b.defaultCommonFrames.join(', ')),
          if (b.tools.isNotEmpty)
            _section(context, '도구', b.tools.join(', ')),
          if (b.medicalWarning != null)
            _section(context, '의료 경고', b.medicalWarning!),
        ],
      DietCatalogItem d => [
          _section(context, '핵심', d.core),
          if (d.strengths.isNotEmpty)
            _section(context, '강점', d.strengths.join('\n• ')),
          if (d.weaknesses.isNotEmpty)
            _section(context, '약점', d.weaknesses.join('\n• ')),
          if (d.koreanContextFit != null)
            _section(context, '한국 컨텍스트 적합도', d.koreanContextFit!),
          if (d.starterLevers.isNotEmpty)
            _section(context, '시작 레버', d.starterLevers.join(', ')),
          if (d.medicalWarning != null)
            _section(context, '의료 경고', d.medicalWarning!),
          if (d.linkedProtocolIds.isNotEmpty)
            _section(context, '연결 프로토콜', d.linkedProtocolIds.join(', ')),
        ],
    };
  }

  String _anchorText(Map<String, dynamic> m) {
    final when = m['when'] ?? '';
    final after = m['after_what'] ?? '';
    if (when == '' && after == '') return m.toString();
    return [if (when != '') 'when: $when', if (after != '') 'after: $after']
        .join(' · ');
  }

  Widget _section(BuildContext context, String label, String body) {
    return Padding(
      padding: const EdgeInsets.only(bottom: 12),
      child: Column(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: [
          Text(label, style: Theme.of(context).textTheme.labelLarge),
          const SizedBox(height: 4),
          Text(body, style: Theme.of(context).textTheme.bodyMedium),
        ],
      ),
    );
  }

  Widget _howSection(BuildContext context, List<String> steps) {
    return Padding(
      padding: const EdgeInsets.only(bottom: 12),
      child: Column(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: [
          Text('어떻게 (How)', style: Theme.of(context).textTheme.labelLarge),
          const SizedBox(height: 4),
          for (var i = 0; i < steps.length; i++)
            Padding(
              padding: const EdgeInsets.only(bottom: 2),
              child: Text('${i + 1}. ${steps[i]}',
                  style: Theme.of(context).textTheme.bodyMedium),
            ),
        ],
      ),
    );
  }
}

class _Header extends StatelessWidget {
  const _Header({required this.item});
  final CatalogItem item;

  @override
  Widget build(BuildContext context) {
    final dc = item.displayCategory;
    return Row(
      children: [
        Icon(dc.icon, size: 20),
        const SizedBox(width: 8),
        Expanded(
          child: Column(
            crossAxisAlignment: CrossAxisAlignment.start,
            children: [
              Text(dc.label,
                  style: Theme.of(context).textTheme.labelMedium?.copyWith(
                        color: Colors.grey,
                      )),
              if (item.titleEn != null)
                Text(item.titleEn!,
                    style: Theme.of(context).textTheme.bodySmall?.copyWith(
                          color: Colors.grey,
                        )),
            ],
          ),
        ),
        if (item.evidenceStrength != null)
          Padding(
            padding: const EdgeInsets.only(left: 8),
            child: Text('근거: ${item.evidenceStrength!}',
                style: Theme.of(context).textTheme.bodySmall),
          ),
      ],
    );
  }
}

class _References extends ConsumerWidget {
  const _References({required this.referenceIds});
  final List<String> referenceIds;

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    if (referenceIds.isEmpty) return const SizedBox.shrink();
    final refsAsync = ref.watch(referencesByIdsProvider(referenceIds));
    return refsAsync.when(
      loading: () => const SizedBox.shrink(),
      error: (_, _) => const SizedBox.shrink(),
      data: (refs) {
        if (refs.isEmpty) return const SizedBox.shrink();
        return Column(
          crossAxisAlignment: CrossAxisAlignment.start,
          children: [
            Text('참고 (${refs.length})',
                style: Theme.of(context).textTheme.titleSmall),
            const SizedBox(height: 8),
            for (final r in refs) ReferenceExpandCard(reference: r),
          ],
        );
      },
    );
  }
}

class _ImportFooter extends StatelessWidget {
  const _ImportFooter();

  @override
  Widget build(BuildContext context) {
    return SafeArea(
      child: Padding(
        padding: const EdgeInsets.all(16),
        child: Tooltip(
          message: '다음 업데이트 예정',
          child: FilledButton.icon(
            onPressed: null,
            icon: const Icon(Icons.add_task),
            label: const Text('내 습관으로 (다음 업데이트 예정)'),
          ),
        ),
      ),
    );
  }
}