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

import '../../core/contracts/auth.dart';
import '../../core/contracts/server.dart';
import '../../providers/di_providers.dart';
import '../../providers/item_counts_provider.dart'
    show serverItemCountsProvider;
import '../../providers/server_connectivity_provider.dart';
import '../../providers/server_provider.dart';
import '../../providers/session_provider.dart';
import '../../shared/constants/breakpoints.dart';
import '../../shared/layout/adaptive_card_grid.dart';
import '../../shared/theme/app_theme.dart';
import '../../shared/widgets/add_server_modal.dart';
import '../../shared/widgets/app_card.dart';
import '../../shared/widgets/auto_dismiss_menu.dart';
import '../../shared/widgets/app_error_state.dart';
import '../../shared/widgets/app_skeleton.dart';
import '../../shared/widgets/app_sliver_header.dart';
import '../../shared/widgets/empty_state.dart';
import '../../shared/widgets/metadata_chip.dart';
import '../../shared/widgets/page_background.dart';
import '../../shared/widgets/server_action_menu.dart';
import '../../shared/widgets/server_avatar.dart';
import '../../shared/widgets/status_dot.dart';
import '../../shared/utils/user_error_formatter.dart';
import '../modules/modules_home_page.dart';

class ServersPage extends ConsumerWidget {
  const ServersPage({super.key});

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    final servers = ref.watch(serverListProvider);
    final sessions = ref.watch(sessionProvider);
    final enabledScriptWidgets =
        (ref.watch(installedScriptWidgetsProvider).value ?? const [])
            .where((installedWidget) => installedWidget.enabled)
            .toList(growable: false);
    final isCompact = MediaQuery.sizeOf(context).width < Breakpoints.compact;

    final headerActions = <Widget>[
      if (isCompact) ...[
        IconButton(
          icon: const Icon(Icons.refresh_outlined, size: 20),
          onPressed: () => Future.wait([
            ref.read(serverListProvider.notifier).refresh(),
            ref.read(sessionProvider.notifier).refresh(),
          ]),
          tooltip: '刷新',
        ),
        IconButton(
          icon: const Icon(Icons.add, size: 20),
          onPressed: () => showAddServerModal(context),
          tooltip: '添加服务器',
        ),
      ] else ...[
        FButton(
          variant: FButtonVariant.outline,
          onPress: () => showAddServerModal(context),
          prefix: const Icon(Icons.add, size: 16),
          child: const Text('添加服务器'),
        ),
      ],
    ];

    Widget withBackground(List<Widget> slivers) {
      return Stack(
        children: [
          const Positioned.fill(child: PageBackground()),
          RefreshIndicator(
            onRefresh: () => Future.wait([
              ref.read(serverListProvider.notifier).refresh(),
              ref.read(sessionProvider.notifier).refresh(),
            ]),
            child: CustomScrollView(
              physics: const AlwaysScrollableScrollPhysics(
                parent: BouncingScrollPhysics(),
              ),
              slivers: slivers,
            ),
          ),
        ],
      );
    }

    List<Widget> buildModuleSlivers() {
      if (enabledScriptWidgets.isEmpty) return const [];

      final horizontalPadding = isCompact ? 16.0 : 24.0;
      return [
        SliverToBoxAdapter(
          child: Padding(
            padding: EdgeInsets.fromLTRB(horizontalPadding, 16, 12, 8),
            child: Row(
              children: [
                Expanded(
                  child: Text(
                    '模块',
                    style: Theme.of(context).textTheme.titleLarge?.copyWith(
                      fontWeight: FontWeight.w700,
                    ),
                  ),
                ),
                TextButton.icon(
                  onPressed: () => showModuleCenterSheet(context),
                  icon: const Icon(Icons.settings_outlined, size: 16),
                  label: const Text('模块中心'),
                ),
              ],
            ),
          ),
        ),
        SliverPadding(
          padding: EdgeInsets.fromLTRB(
            horizontalPadding,
            0,
            horizontalPadding,
            isCompact ? 100 : 24,
          ),
          sliver: SliverGrid(
            gridDelegate: isCompact
                ? const SliverGridDelegateWithFixedCrossAxisCount(
                    crossAxisCount: 2,
                    childAspectRatio: 1.05,
                    crossAxisSpacing: 12,
                    mainAxisSpacing: 12,
                  )
                : const SliverGridDelegateWithMaxCrossAxisExtent(
                    maxCrossAxisExtent: kRichCardMinWidth,
                    childAspectRatio: 1.55,
                    crossAxisSpacing: kCardGap,
                    mainAxisSpacing: kCardGap,
                  ),
            delegate: SliverChildBuilderDelegate((context, moduleIndex) {
              final installedWidget = enabledScriptWidgets[moduleIndex];
              final manifest = installedWidget.manifest;
              return _ModuleCard(
                title: manifest.title,
                description: manifest.description,
                onTap: () =>
                    context.go('/modules/${Uri.encodeComponent(manifest.id)}'),
              );
            }, childCount: enabledScriptWidgets.length),
          ),
        ),
      ];
    }

    return Scaffold(
      backgroundColor: Colors.transparent,
      extendBodyBehindAppBar: true,
      body: servers.when(
        data: (serverList) {
          if (serverList.isEmpty) {
            return withBackground([
              AppSliverHeader(title: '服务器', actions: headerActions),
              SliverFillRemaining(
                hasScrollBody: false,
                child: EmptyState(
                  icon: Icons.cloud_outlined,
                  title: '尚未添加 Emby 服务器',
                  message: '点击下方按钮添加第一个服务器，开始构建你的沉浸式影库。',
                  action: FButton(
                    variant: FButtonVariant.primary,
                    onPress: () => showAddServerModal(context),
                    child: const Row(
                      mainAxisSize: MainAxisSize.min,
                      children: [
                        Icon(Icons.add, size: 16),
                        SizedBox(width: 6),
                        Text('添加服务器'),
                      ],
                    ),
                  ),
                ),
              ),
              ...buildModuleSlivers(),
            ]);
          }

          final sessionList = sessions.value?.sessions ?? [];
          final sessionMap = {for (final s in sessionList) s.serverId: s};

          return withBackground([
            AppSliverHeader(
              title: isCompact ? '媒体服务器' : '服务器',
              actions: headerActions,
            ),
            SliverPadding(
              padding: EdgeInsets.fromLTRB(
                isCompact ? 16 : 24,
                8,
                isCompact ? 16 : 24,
                enabledScriptWidgets.isEmpty ? (isCompact ? 100 : 24) : 8,
              ),
              sliver: SliverReorderableGrid(
                gridDelegate: isCompact
                    ? const SliverGridDelegateWithFixedCrossAxisCount(
                        crossAxisCount: 2,
                        childAspectRatio: 1.05,
                        crossAxisSpacing: 12,
                        mainAxisSpacing: 12,
                      )
                    : const SliverGridDelegateWithMaxCrossAxisExtent(
                        maxCrossAxisExtent: kRichCardMinWidth,
                        childAspectRatio: 1.55,
                        crossAxisSpacing: kCardGap,
                        mainAxisSpacing: kCardGap,
                      ),
                itemCount: serverList.length,
                onReorder: (oldIndex, newIndex) => ref
                    .read(serverListProvider.notifier)
                    .reorder(oldIndex, newIndex),
                itemBuilder: (context, serverIndex) {
                  final server = serverList[serverIndex];
                  final session = sessionMap[server.id];
                  final actions = buildServerActionCallbacks(
                    context: context,
                    ref: ref,
                    server: server,
                    session: session,
                  );
                  return _ServerCardReorderListener(
                    key: ValueKey(server.id),
                    index: serverIndex,
                    child: _ServerCard(
                      server: server,
                      session: session,
                      onTap: () async {
                        if (session != null) {
                          await ref
                              .read(sessionProvider.notifier)
                              .switchSession(server.id);
                          if (!context.mounted) return;
                          context.go('/');
                        }
                      },
                      onRefresh: actions.onRefresh!,
                      onChangeIcon: actions.onChangeIcon!,
                      onEdit: actions.onEdit!,
                      onTogglePause: actions.onTogglePause!,
                      onDelete: actions.onDelete!,
                      onChangePassword: actions.onChangePassword,
                    ),
                  );
                },
              ),
            ),
            ...buildModuleSlivers(),
          ]);
        },
        loading: () => withBackground([
          AppSliverHeader(title: '服务器', actions: headerActions),
          const SliverToBoxAdapter(
            child: SkeletonGrid(
              itemCount: 6,
              itemHeight: 194,
              minCardWidth: kRichCardMinWidth,
              padding: EdgeInsets.fromLTRB(24, 8, 24, 0),
            ),
          ),
        ]),
        error: (e, _) => withBackground([
          AppSliverHeader(title: '服务器', actions: headerActions),
          SliverFillRemaining(
            hasScrollBody: false,
            child: AppErrorState(
              message: formatUserError(e, fallback: '服务器加载失败'),
              onRetry: () => ref.invalidate(serverListProvider),
            ),
          ),
        ]),
      ),
    );
  }
}

class _ModuleCard extends StatelessWidget {
  final String title;
  final String description;
  final VoidCallback onTap;

  const _ModuleCard({
    required this.title,
    required this.description,
    required this.onTap,
  });

  @override
  Widget build(BuildContext context) {
    final theme = Theme.of(context);
    final normalizedDescription = description.trim();

    return AppCard(
      onTap: onTap,
      padding: const EdgeInsets.all(16),
      child: Column(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: [
          Icon(
            Icons.extension_rounded,
            size: 28,
            color: theme.colorScheme.primary,
          ),
          const Spacer(),
          Text(
            title,
            maxLines: 1,
            overflow: TextOverflow.ellipsis,
            style: theme.textTheme.titleMedium?.copyWith(
              fontWeight: FontWeight.w700,
            ),
          ),
          if (normalizedDescription.isNotEmpty) ...[
            const SizedBox(height: 4),
            Text(
              normalizedDescription,
              maxLines: 2,
              overflow: TextOverflow.ellipsis,
              style: theme.textTheme.bodySmall?.copyWith(
                color: theme.colorScheme.onSurfaceVariant,
              ),
            ),
          ],
        ],
      ),
    );
  }
}

class _ServerCardReorderListener extends StatelessWidget {
  final int index;
  final Widget child;

  const _ServerCardReorderListener({
    super.key,
    required this.index,
    required this.child,
  });

  @override
  Widget build(BuildContext context) {
    const desktop = {
      TargetPlatform.linux,
      TargetPlatform.macOS,
      TargetPlatform.windows,
    };

    if (desktop.contains(Theme.of(context).platform)) {
      return ReorderableGridDragStartListener(index: index, child: child);
    }

    return ReorderableGridDelayedDragStartListener(index: index, child: child);
  }
}

class _ServerCard extends ConsumerStatefulWidget {
  final EmbyServer server;
  final AuthedSession? session;
  final VoidCallback onTap;
  final VoidCallback onRefresh;
  final VoidCallback onChangeIcon;
  final VoidCallback onEdit;
  final VoidCallback onDelete;
  final VoidCallback onTogglePause;
  final VoidCallback? onChangePassword;

  const _ServerCard({
    required this.server,
    required this.session,
    required this.onTap,
    required this.onRefresh,
    required this.onChangeIcon,
    required this.onEdit,
    required this.onDelete,
    required this.onTogglePause,
    this.onChangePassword,
  });

  @override
  ConsumerState<_ServerCard> createState() => _ServerCardState();
}

class _ServerCardState extends ConsumerState<_ServerCard> {
  String _relativeTime() {
    final dateStr = widget.server.lastConnectedAt ?? widget.server.updatedAt;
    final dt = DateTime.tryParse(dateStr);
    if (dt == null) return '未观看';
    final diff = DateTime.now().difference(dt);
    if (diff.inDays >= 1) return '${diff.inDays}天前';
    if (diff.inHours >= 1) return '${diff.inHours}小时前';
    if (diff.inMinutes >= 1) return '${diff.inMinutes}分钟前';
    return '刚刚';
  }

  ConnectivityStatus _mapStatus(AsyncValue<ServerConnectivity> conn) =>
      conn.when(
        data: (c) => c.reachable
            ? ConnectivityStatus.online
            : ConnectivityStatus.offline,
        loading: () => ConnectivityStatus.unknown,
        error: (_, _) => ConnectivityStatus.offline,
      );

  List<FItem> _cardMenuItems() => buildServerActionMenuItems(
    onRefresh: widget.onRefresh,
    onChangeIcon: widget.onChangeIcon,
    onEdit: widget.onEdit,
    onChangePassword: widget.session == null ? null : widget.onChangePassword,
    paused: widget.server.paused,
    onTogglePause: widget.onTogglePause,
    onDelete: widget.onDelete,
  );

  @override
  Widget build(BuildContext context) {
    final isPaused = widget.server.paused;
    final counts = widget.session != null && !isPaused
        ? ref.watch(serverItemCountsProvider(widget.server.id)).value
        : null;
    final connectivity = isPaused
        ? null
        : ref.watch(serverConnectivityProvider(widget.server.baseUrl));
    final theme = Theme.of(context);
    final tokens = context.appTokens;
    final hasSession = widget.session != null;
    final seedColor = ServerAvatar.seedColorFor(widget.server.name);

    final Widget latencyWidget = isPaused
        ? MetadataChip(
            icon: Icons.pause_circle_outline,
            label: '已暂停',
            foreground: theme.colorScheme.onSurfaceVariant,
          )
        : connectivity!.when(
            data: (c) {
              if (c.reachable && c.latencyMs != null) {
                final Color color;
                if (c.latencyMs! < 100) {
                  color = tokens.statusOnline;
                } else if (c.latencyMs! < 300) {
                  color = tokens.statusWarn;
                } else {
                  color = tokens.statusOffline;
                }
                return MetadataChip(
                  label: '${c.latencyMs}ms',
                  foreground: color,
                );
              }
              return MetadataChip(
                label: '不可达',
                foreground: tokens.statusOffline,
              );
            },
            loading: () => MetadataChip(
              label: '检测中...',
              foreground: theme.colorScheme.onSurfaceVariant,
            ),
            error: (_, _) =>
                MetadataChip(label: '检测失败', foreground: tokens.statusOffline),
          );

    return Opacity(
      opacity: isPaused ? 0.5 : 1.0,
      child: AppCard(
        onTap: hasSession && !isPaused ? widget.onTap : null,
        contextMenuItems: _cardMenuItems(),
        enableLongPressMenu: false,
        child: DecoratedBox(
          decoration: BoxDecoration(
            gradient: LinearGradient(
              begin: Alignment.topLeft,
              end: Alignment.bottomRight,
              colors: [seedColor.withValues(alpha: 0.06), Colors.transparent],
            ),
          ),
          child: Padding(
            padding: const EdgeInsets.all(12),
            child: Column(
              crossAxisAlignment: CrossAxisAlignment.start,
              children: [
                Row(
                  crossAxisAlignment: CrossAxisAlignment.start,
                  children: [
                    ServerAvatar(
                      name: widget.server.name,
                      iconUrl: widget.server.iconUrl,
                      size: 34,
                    ),
                    const SizedBox(width: 8),
                    Expanded(
                      child: SizedBox(
                        height: 34,
                        child: Row(
                          children: [
                            Flexible(
                              child: Text(
                                widget.server.name,
                                style: theme.textTheme.titleSmall?.copyWith(
                                  fontWeight: FontWeight.w600,
                                  fontSize: 13,
                                ),
                                maxLines: 1,
                                overflow: TextOverflow.ellipsis,
                              ),
                            ),
                            if (hasSession && !isPaused) ...[
                              const SizedBox(width: 4),
                              StatusDot(
                                status: _mapStatus(connectivity!),
                                size: 7,
                              ),
                            ],
                          ],
                        ),
                      ),
                    ),
                    const SizedBox(width: 4),
                    SizedBox(
                      width: 24,
                      height: 24,
                      child: FPopoverMenu(
                        menuBuilder: autoDismissMenuBuilder,
                        menuAnchor: Alignment.topRight,
                        childAnchor: Alignment.bottomRight,
                        menu: [FItemGroup(children: _cardMenuItems())],
                        builder: (context, controller, child) =>
                            GestureDetector(
                              onTap: controller.toggle,
                              child: child,
                            ),
                        child: MouseRegion(
                          cursor: SystemMouseCursors.click,
                          child: Icon(
                            Icons.more_vert,
                            size: 16,
                            color: theme.colorScheme.onSurfaceVariant,
                          ),
                        ),
                      ),
                    ),
                  ],
                ),

                const Spacer(),

                Row(
                  children: [
                    MetadataChip(
                      icon: Icons.photo_library_outlined,
                      label: counts?.movieCount != null
                          ? '${counts!.movieCount}'
                          : '—',
                    ),
                    const SizedBox(width: 8),
                    MetadataChip(
                      icon: Icons.play_circle_outline,
                      label: counts?.episodeCount != null
                          ? '${counts!.episodeCount}'
                          : '—',
                    ),
                  ],
                ),

                const SizedBox(height: 6),

                Row(
                  children: [
                    latencyWidget,
                    if (!isPaused) ...[
                      Text(
                        ' · ',
                        style: theme.textTheme.labelSmall?.copyWith(
                          color: theme.colorScheme.onSurfaceVariant,
                          fontSize: 11,
                        ),
                      ),
                      Flexible(
                        child: Text(
                          _relativeTime(),
                          style: theme.textTheme.labelSmall?.copyWith(
                            color: theme.colorScheme.onSurfaceVariant,
                            fontSize: 11,
                          ),
                          maxLines: 1,
                          overflow: TextOverflow.ellipsis,
                        ),
                      ),
                    ],
                  ],
                ),
              ],
            ),
          ),
        ),
      ),
    );
  }
}