import 'dart:async';

import 'package:flutter/material.dart';
import 'package:flutter/services.dart';
import 'package:flutter_hooks/flutter_hooks.dart';
import 'package:hooks_riverpod/hooks_riverpod.dart';
import 'package:lucide_icons_flutter/lucide_icons.dart';

import '../../shared/mentions/agent_identity_provider.dart';
import '../../shared/l10n/l10n.dart';
import '../../shared/theme/theme.dart';
import '../../shared/widgets/avatar_image.dart';
import '../../shared/widgets/buzz_loading_indicator.dart';
import '../../shared/widgets/frosted_app_bar.dart';
import '../../shared/widgets/frosted_scaffold.dart';
import '../../shared/widgets/modal_presentation.dart';
import '../channels/compose_bar.dart';
import '../channels/message_content.dart';
import '../profile/user_cache_provider.dart';
import '../profile/user_profile.dart';
import '../profile/user_profile_sheet.dart';
import 'forum_models.dart';
import 'forum_provider.dart';

/// Full-screen page showing a forum post and its replies.
class ForumThreadPage extends HookConsumerWidget {
  final String channelId;
  final String postEventId;
  final String? currentPubkey;
  final bool isMember;
  final bool isArchived;

  const ForumThreadPage({
    super.key,
    required this.channelId,
    required this.postEventId,
    required this.currentPubkey,
    required this.isMember,
    required this.isArchived,
  });

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    final threadAsync = ref.watch(
      forumThreadProvider((channelId: channelId, eventId: postEventId)),
    );

    // Periodic refresh (every 10s, matching desktop).
    useEffect(() {
      final timer = Stream.periodic(const Duration(seconds: 10)).listen((_) {
        ref.invalidate(
          forumThreadProvider((channelId: channelId, eventId: postEventId)),
        );
      });
      return timer.cancel;
    }, [channelId, postEventId]);

    final isOwnPost =
        threadAsync
            .whenData(
              (t) =>
                  currentPubkey != null &&
                  t.post.pubkey.toLowerCase() == currentPubkey!.toLowerCase(),
            )
            .value ??
        false;

    return FrostedScaffold(
      appBar: FrostedAppBar(
        title: Text(context.l10n.threadTitle),
        actions: [
          if (isOwnPost)
            IconButton(
              onPressed: () =>
                  _showPostActions(context, ref, threadAsync.value!),
              tooltip: context.l10n.postActions,
              icon: const Icon(LucideIcons.ellipsis),
            ),
        ],
      ),
      body: threadAsync.when(
        loading: () => Padding(
          padding: EdgeInsets.only(top: frostedAppBarHeight(context)),
          child: Center(
            child: BuzzLoadingIndicator(
              size: 44,
              semanticLabel: context.l10n.loadingThread,
            ),
          ),
        ),
        error: (e, _) => Padding(
          padding: EdgeInsets.only(top: frostedAppBarHeight(context)),
          child: Center(
            child: Text(
              context.l10n.failedLoadThread,
              style: context.textTheme.bodyMedium?.copyWith(
                color: context.colors.error,
              ),
            ),
          ),
        ),
        data: (thread) => _ThreadContent(
          thread: thread,
          channelId: channelId,
          currentPubkey: currentPubkey,
          isMember: isMember,
          isArchived: isArchived,
        ),
      ),
    );
  }

  void _showPostActions(
    BuildContext context,
    WidgetRef ref,
    ForumThreadResponse thread,
  ) {
    showBuzzModalBottomSheet<void>(
      context: context,
      showDragHandle: true,
      builder: (sheetContext) => SafeArea(
        child: IconTheme.merge(
          data: const IconThemeData(size: 22),
          child: Padding(
            padding: const EdgeInsets.fromLTRB(
              Grid.gutter,
              0,
              Grid.gutter,
              Grid.xs,
            ),
            child: Column(
              mainAxisSize: MainAxisSize.min,
              children: [
                ListTile(
                  leading: const Icon(LucideIcons.copy),
                  title: Text(context.l10n.copyText),
                  onTap: () {
                    Navigator.of(sheetContext).pop();
                    Clipboard.setData(ClipboardData(text: thread.post.content));
                  },
                ),
                ListTile(
                  leading: Icon(
                    LucideIcons.trash2,
                    color: sheetContext.colors.error,
                  ),
                  title: Text(
                    context.l10n.deletePost,
                    style: TextStyle(color: sheetContext.colors.error),
                  ),
                  onTap: () {
                    Navigator.of(sheetContext).pop();
                    _confirmDeletePost(context, ref, thread.post.eventId);
                  },
                ),
              ],
            ),
          ),
        ),
      ),
    );
  }

  void _confirmDeletePost(BuildContext context, WidgetRef ref, String eventId) {
    showBuzzDialog<void>(
      context: context,
      builder: (dialogContext) => AlertDialog(
        title: Text(context.l10n.deletePost),
        content: Text(context.l10n.cannotUndo),
        actions: [
          TextButton(
            onPressed: () => Navigator.of(dialogContext).pop(),
            child: Text(context.l10n.cancel),
          ),
          FilledButton(
            onPressed: () async {
              Navigator.of(dialogContext).pop();
              await deleteForumEvent(
                ref,
                channelId: channelId,
                eventId: eventId,
              );
              if (context.mounted) {
                Navigator.of(context).pop();
              }
            },
            style: FilledButton.styleFrom(
              backgroundColor: dialogContext.colors.error,
            ),
            child: Text(context.l10n.delete),
          ),
        ],
      ),
    );
  }
}

class _ThreadContent extends HookConsumerWidget {
  final ForumThreadResponse thread;
  final String channelId;
  final String? currentPubkey;
  final bool isMember;
  final bool isArchived;

  const _ThreadContent({
    required this.thread,
    required this.channelId,
    required this.currentPubkey,
    required this.isMember,
    required this.isArchived,
  });

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    // Background media delivery may outlive this route's WidgetRef.
    final providerContainer = ProviderScope.containerOf(context, listen: false);
    final forumDelivery = ForumEventDelivery.capture(providerContainer);
    final post = thread.post;
    final replies = thread.replies;

    // Preload profiles for all participants and tagged mentions.
    final allPubkeys = useMemoized(() {
      final pks = <String>{
        post.pubkey.toLowerCase(),
        ...post.mentionPubkeys.map((pubkey) => pubkey.toLowerCase()),
      };
      for (final reply in replies) {
        pks
          ..add(reply.pubkey.toLowerCase())
          ..addAll(reply.mentionPubkeys.map((pubkey) => pubkey.toLowerCase()));
      }
      return pks.toList()..sort();
    }, [post, replies]);
    final allPubkeysKey = allPubkeys.join('\u0000');

    useEffect(() {
      if (allPubkeys.isNotEmpty) {
        ref.read(userCacheProvider.notifier).preload(allPubkeys);
      }
      return null;
    }, [allPubkeysKey]);

    return Column(
      children: [
        Expanded(
          child: ListView(
            padding: EdgeInsets.only(
              top: frostedAppBarHeight(context),
              bottom: Grid.xs,
            ),
            children: [
              _OriginalPost(post: post),

              Padding(
                padding: const EdgeInsets.symmetric(
                  horizontal: Grid.gutter,
                  vertical: Grid.xxs,
                ),
                child: Row(
                  children: [
                    Icon(
                      LucideIcons.messageSquare,
                      size: 16,
                      color: context.colors.onSurfaceVariant,
                    ),
                    const SizedBox(width: Grid.half),
                    Text(
                      context.l10n.replyCount(replies.length),
                      style: context.textTheme.labelMedium?.copyWith(
                        color: context.colors.onSurfaceVariant,
                        fontWeight: FontWeight.w600,
                      ),
                    ),
                  ],
                ),
              ),

              // Reply list
              if (replies.isEmpty)
                Padding(
                  padding: const EdgeInsets.all(Grid.sm),
                  child: Text(
                    context.l10n.noRepliesYet,
                    style: context.textTheme.bodyMedium?.copyWith(
                      color: context.colors.onSurfaceVariant,
                    ),
                    textAlign: TextAlign.center,
                  ),
                )
              else
                for (final reply in replies)
                  _ReplyRow(
                    reply: reply,
                    currentPubkey: currentPubkey,
                    channelId: channelId,
                    rootEventId: post.eventId,
                  ),
            ],
          ),
        ),

        // Reply composer
        if (isMember && !isArchived)
          ComposeBar(
            channelId: channelId,
            hintText: context.l10n.replyToPost,
            onSend:
                (
                  content,
                  mentionPubkeys, {
                  mediaTags = const <List<String>>[],
                }) => forumDelivery.createReply(
                  channelId: channelId,
                  parentEventId: post.eventId,
                  content: content,
                  mentionPubkeys: mentionPubkeys,
                  mediaTags: mediaTags,
                ),
          ),
      ],
    );
  }
}

class _OriginalPost extends ConsumerWidget {
  final ForumPost post;

  const _OriginalPost({required this.post});

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    final pk = post.pubkey.toLowerCase();
    final profile =
        ref.watch(userCacheProvider.select((cache) => cache[pk])) ??
        ref.read(userCacheProvider.notifier).get(pk);
    final displayName = profile?.label ?? _shortPubkey(post.pubkey);

    final userCache = ref.watch(userCacheProvider);
    final agentMentionPubkeys = agentPubkeysWithProfileOwners(
      knownAgentPubkeys: ref.watch(agentMentionPubkeysProvider(post.channelId)),
      profileOwnedAgentPubkeys: [
        for (final profile in userCache.values)
          if (profile.ownerPubkey != null) profile.pubkey,
      ],
    );
    final mentionNames = mentionNamesWithDirectoryLabels(
      mentionPubkeys: post.mentionPubkeys,
      profileMentionNames: _buildMentionNames(post.mentionPubkeys, userCache),
      directoryDisplayNames: ref.watch(agentDirectoryDisplayNamesProvider),
      agentMentionPubkeys: agentMentionPubkeys,
    );

    return Padding(
      padding: const EdgeInsets.all(Grid.xs),
      child: Column(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: [
          Row(
            children: [
              GestureDetector(
                onTap: () => showUserProfileSheet(context, post.pubkey),
                child: _Avatar(
                  profile: profile,
                  pubkey: post.pubkey,
                  radius: 16,
                ),
              ),
              const SizedBox(width: Grid.xxs),
              Expanded(
                child: Row(
                  children: [
                    Expanded(
                      child: GestureDetector(
                        onTap: () => showUserProfileSheet(context, post.pubkey),
                        child: Text(
                          displayName,
                          maxLines: 1,
                          style: messageUsernameTextStyle,
                          overflow: TextOverflow.ellipsis,
                        ),
                      ),
                    ),
                    const SizedBox(width: Grid.xxs),
                    ConstrainedBox(
                      constraints: const BoxConstraints(maxWidth: Grid.xxl),
                      child: Text(
                        formatRelativeTimeLocalized(
                          context.l10n,
                          post.createdAt,
                        ),
                        maxLines: 1,
                        overflow: TextOverflow.ellipsis,
                        style: messageTimestampTextStyle.copyWith(
                          color: context.colors.onSurfaceVariant,
                        ),
                      ),
                    ),
                  ],
                ),
              ),
            ],
          ),
          const SizedBox(height: Grid.xxs),
          MessageContent(
            content: post.content,
            mentionNames: mentionNames,
            agentMentionPubkeys: agentMentionPubkeys,
            tags: post.tags,
            baseStyle: messageBodyTextStyle.copyWith(
              color: context.colors.onSurface,
            ),
            onMentionTap: (pubkey) => showUserProfileSheet(context, pubkey),
          ),
        ],
      ),
    );
  }
}

class _ReplyRow extends ConsumerWidget {
  final ThreadReply reply;
  final String? currentPubkey;
  final String channelId;
  final String rootEventId;

  const _ReplyRow({
    required this.reply,
    required this.currentPubkey,
    required this.channelId,
    required this.rootEventId,
  });

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    final pk = reply.pubkey.toLowerCase();
    final profile =
        ref.watch(userCacheProvider.select((cache) => cache[pk])) ??
        ref.read(userCacheProvider.notifier).get(pk);
    final displayName = profile?.label ?? _shortPubkey(reply.pubkey);

    final userCache = ref.watch(userCacheProvider);
    final agentMentionPubkeys = agentPubkeysWithProfileOwners(
      knownAgentPubkeys: ref.watch(agentMentionPubkeysProvider(channelId)),
      profileOwnedAgentPubkeys: [
        for (final profile in userCache.values)
          if (profile.ownerPubkey != null) profile.pubkey,
      ],
    );
    final mentionNames = mentionNamesWithDirectoryLabels(
      mentionPubkeys: reply.mentionPubkeys,
      profileMentionNames: _buildMentionNames(reply.mentionPubkeys, userCache),
      directoryDisplayNames: ref.watch(agentDirectoryDisplayNamesProvider),
      agentMentionPubkeys: agentMentionPubkeys,
    );

    return Padding(
      padding: const EdgeInsets.symmetric(
        horizontal: Grid.gutter,
        vertical: Grid.xxs,
      ),
      child: Column(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: [
          Row(
            children: [
              GestureDetector(
                onTap: () => showUserProfileSheet(context, reply.pubkey),
                child: _Avatar(
                  profile: profile,
                  pubkey: reply.pubkey,
                  radius: 12,
                ),
              ),
              const SizedBox(width: Grid.xxs),
              Expanded(
                child: Row(
                  children: [
                    Expanded(
                      child: GestureDetector(
                        onTap: () =>
                            showUserProfileSheet(context, reply.pubkey),
                        child: Text(
                          displayName,
                          maxLines: 1,
                          overflow: TextOverflow.ellipsis,
                          style: messageUsernameTextStyle,
                        ),
                      ),
                    ),
                    const SizedBox(width: Grid.xxs),
                    ConstrainedBox(
                      constraints: const BoxConstraints(maxWidth: Grid.xxl),
                      child: Text(
                        formatRelativeTimeLocalized(
                          context.l10n,
                          reply.createdAt,
                        ),
                        maxLines: 1,
                        overflow: TextOverflow.ellipsis,
                        style: messageTimestampTextStyle.copyWith(
                          color: context.colors.onSurfaceVariant,
                        ),
                      ),
                    ),
                  ],
                ),
              ),
              SizedBox(
                width: 28,
                height: 28,
                child: IconButton(
                  onPressed: () => _showActions(context, ref),
                  icon: Icon(
                    LucideIcons.ellipsis,
                    size: 16,
                    color: context.colors.onSurfaceVariant,
                  ),
                  padding: EdgeInsets.zero,
                  visualDensity: VisualDensity.compact,
                ),
              ),
            ],
          ),
          Padding(
            padding: const EdgeInsets.only(left: 32, top: Grid.half),
            child: MessageContent(
              content: reply.content,
              mentionNames: mentionNames,
              agentMentionPubkeys: agentMentionPubkeys,
              tags: reply.tags,
              baseStyle: messageBodyTextStyle.copyWith(
                color: context.colors.onSurface,
              ),
              onMentionTap: (pubkey) => showUserProfileSheet(context, pubkey),
            ),
          ),
        ],
      ),
    );
  }

  void _showActions(BuildContext context, WidgetRef ref) {
    final isOwn =
        currentPubkey != null &&
        reply.pubkey.toLowerCase() == currentPubkey!.toLowerCase();

    showBuzzModalBottomSheet<void>(
      context: context,
      showDragHandle: true,
      builder: (sheetContext) => SafeArea(
        child: IconTheme.merge(
          data: const IconThemeData(size: 22),
          child: Padding(
            padding: const EdgeInsets.fromLTRB(
              Grid.gutter,
              0,
              Grid.gutter,
              Grid.xs,
            ),
            child: Column(
              mainAxisSize: MainAxisSize.min,
              children: [
                ListTile(
                  leading: const Icon(LucideIcons.copy),
                  title: Text(context.l10n.copyText),
                  onTap: () {
                    Navigator.of(sheetContext).pop();
                    Clipboard.setData(ClipboardData(text: reply.content));
                  },
                ),
                if (isOwn)
                  ListTile(
                    leading: Icon(
                      LucideIcons.trash2,
                      color: sheetContext.colors.error,
                    ),
                    title: Text(
                      context.l10n.deleteReply,
                      style: TextStyle(color: sheetContext.colors.error),
                    ),
                    onTap: () {
                      Navigator.of(sheetContext).pop();
                      _confirmDelete(context, ref);
                    },
                  ),
              ],
            ),
          ),
        ),
      ),
    );
  }

  void _confirmDelete(BuildContext context, WidgetRef ref) {
    showBuzzDialog<void>(
      context: context,
      builder: (dialogContext) => AlertDialog(
        title: Text(context.l10n.deleteReply),
        content: Text(context.l10n.cannotUndo),
        actions: [
          TextButton(
            onPressed: () => Navigator.of(dialogContext).pop(),
            child: Text(context.l10n.cancel),
          ),
          FilledButton(
            onPressed: () async {
              Navigator.of(dialogContext).pop();
              await deleteForumEvent(
                ref,
                channelId: channelId,
                eventId: reply.eventId,
                rootEventId: rootEventId,
              );
            },
            style: FilledButton.styleFrom(
              backgroundColor: dialogContext.colors.error,
            ),
            child: Text(context.l10n.delete),
          ),
        ],
      ),
    );
  }
}

class _Avatar extends StatelessWidget {
  final UserProfile? profile;
  final String pubkey;
  final double radius;

  const _Avatar({
    required this.profile,
    required this.pubkey,
    required this.radius,
  });

  @override
  Widget build(BuildContext context) {
    final initial =
        profile?.initial ?? (pubkey.isNotEmpty ? pubkey[0].toUpperCase() : '?');
    final avatarUrl = profile?.avatarUrl;

    return AvatarImage(
      imageUrl: avatarUrl,
      radius: radius,
      backgroundColor: context.colors.primaryContainer,
      fallback: Text(
        initial,
        style: TextStyle(
          fontSize: radius * 0.75,
          fontWeight: FontWeight.w600,
          color: context.colors.onPrimaryContainer,
        ),
      ),
    );
  }
}

Map<String, String> _buildMentionNames(
  List<String> mentionPubkeys,
  Map<String, UserProfile> userCache,
) {
  final names = <String, String>{};
  for (final pk in mentionPubkeys) {
    final p = userCache[pk.toLowerCase()];
    if (p?.displayName != null) {
      names[pk.toLowerCase()] = p!.displayName!;
    }
  }
  return names;
}

String _shortPubkey(String pubkey) {
  if (pubkey.length > 12) return '${pubkey.substring(0, 8)}\u2026';
  return pubkey;
}