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

import '../../core/contracts/auth.dart';
import '../../core/contracts/library.dart';
import '../../providers/emby_headers_provider.dart';
import '../../providers/person_items_provider.dart';
import '../../providers/session_provider.dart';
import '../../shared/constants/layout_constants.dart';
import '../../shared/mappers/media_image_url.dart';
import '../../shared/utils/media_nav.dart';
import '../../shared/widgets/app_error_state.dart';
import '../../shared/widgets/app_loading_ring.dart';
import '../../shared/widgets/app_sliver_header.dart';
import '../../shared/widgets/empty_state.dart';
import '../../shared/widgets/media_poster_card.dart';


class PersonDetailPage extends ConsumerWidget {
  final String embyPersonId;

  const PersonDetailPage({super.key, required this.embyPersonId});

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    final session = ref.watch(activeSessionProvider);
    if (session == null) {
      return Scaffold(
        extendBodyBehindAppBar: true,
        body: CustomScrollView(
          slivers: [
            AppSliverHeader(title: '演员', leading: _buildBackButton(context)),
            const SliverFillRemaining(
              hasScrollBody: false,
              child: _EmptyState(message: '请先登录服务器'),
            ),
          ],
        ),
      );
    }

    final asyncDetail = ref.watch(personItemDetailProvider(embyPersonId));
    final asyncItems = ref.watch(personItemsProvider(embyPersonId));
    final imageHeaders = ref.watch(embyImageHeadersProvider).value;

    final personName = asyncDetail.value?.Name;
    final title = (personName != null && personName.isNotEmpty)
        ? '演员 $personName 的全部作品'
        : '演员';

    final leadingAvatar = _personAvatar(
      context: context,
      session: session,
      person: asyncDetail.value,
      headers: imageHeaders,
    );

    final Widget titleWidget = Row(
      children: [
        if (leadingAvatar != null) ...[
          leadingAvatar,
          const SizedBox(width: 12),
        ],
        Expanded(
          child: Text(
            title,
            maxLines: 1,
            overflow: TextOverflow.ellipsis,
            style: Theme.of(context).textTheme.titleMedium,
          ),
        ),
      ],
    );

    final Widget contentSliver = asyncItems.when(
      loading: () => const SliverFillRemaining(
        hasScrollBody: false,
        child: Center(child: AppLoadingRing()),
      ),
      error: (_, _) => SliverFillRemaining(
        hasScrollBody: false,
        child: AppErrorState(
          title: '查询失败',
          onRetry: () => ref.invalidate(personItemsProvider(embyPersonId)),
        ),
      ),
      data: (items) {
        if (items.isEmpty) {
          return const SliverFillRemaining(
            hasScrollBody: false,
            child: EmptyState(icon: Icons.movie_filter_outlined, title: '暂无作品'),
          );
        }
        return SliverPadding(
          padding: const EdgeInsets.fromLTRB(16, 0, 16, 16),
          sliver: SliverGrid(
            gridDelegate: mediaGridDelegate,
            delegate: SliverChildBuilderDelegate((_, i) {
              final item = items[i];
              return MediaPosterCard(
                item: item,
                width: double.infinity,
                imageUrl: EmbyImageUrl.primary(
                  baseUrl: session.serverUrl,
                  token: session.token,
                  item: item,
                  maxHeight: 360,
                ),
                preloadImageUrl: EmbyImageUrl.detailBanner(
                  baseUrl: session.serverUrl,
                  token: session.token,
                  item: item,
                ),
                imageHeaders: imageHeaders,
                onTap: () => goMediaDetail(context, item, ref: ref),
              );
            }, childCount: items.length),
          ),
        );
      },
    );

    return Scaffold(
      extendBodyBehindAppBar: true,
      body: CustomScrollView(
        slivers: [
          AppSliverHeader(
            titleWidget: titleWidget,
            leading: _buildBackButton(context),
          ),
          contentSliver,
        ],
      ),
    );
  }

  Widget _buildBackButton(BuildContext context) {
    return IconButton(
      icon: const Icon(Icons.arrow_back),
      onPressed: () {
        if (context.canPop()) {
          context.pop();
        } else {
          context.go('/');
        }
      },
    );
  }

  Widget? _personAvatar({
    required BuildContext context,
    required AuthedSession session,
    required EmbyRawItem? person,
    required Map<String, String>? headers,
  }) {
    if (person == null) return null;
    final hasImage =
        (person.PrimaryImageTag != null) ||
        (person.ImageTags?['Primary'] != null);
    if (!hasImage) return null;
    final url = EmbyImageUrl.primaryById(
      baseUrl: session.serverUrl,
      token: session.token,
      itemId: person.Id,
      maxHeight: 80,
    );
    return CircleAvatar(
      radius: 16,
      backgroundColor: Theme.of(context).colorScheme.surfaceContainerHighest,
      backgroundImage: ResizeImage.resizeIfNeeded(
        96,
        null,
        CachedNetworkImageProvider(url, headers: headers),
      ),
    );
  }
}

class _EmptyState extends StatelessWidget {
  final String message;
  const _EmptyState({required this.message});

  @override
  Widget build(BuildContext context) {
    return Center(
      child: Text(
        message,
        style: TextStyle(
          color: Theme.of(context).colorScheme.onSurfaceVariant,
          fontSize: 14,
        ),
      ),
    );
  }
}