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

import '../../models/announcement_comment.dart';
import '../../providers/announcements_provider.dart';
import '../../providers/profile_provider.dart';
import '../../utils/app_time.dart';
import '../../utils/snackbar.dart';
import '../../widgets/profile_avatar.dart';

/// Inline, collapsible comments section for an announcement card.
class AnnouncementCommentsSection extends ConsumerStatefulWidget {
  const AnnouncementCommentsSection({
    super.key,
    required this.announcementId,
  });

  final String announcementId;

  @override
  ConsumerState<AnnouncementCommentsSection> createState() =>
      _AnnouncementCommentsSectionState();
}

class _AnnouncementCommentsSectionState
    extends ConsumerState<AnnouncementCommentsSection> {
  final _controller = TextEditingController();
  bool _sending = false;

  @override
  void dispose() {
    _controller.dispose();
    super.dispose();
  }

  Future<void> _submit() async {
    final text = _controller.text.trim();
    if (text.isEmpty || _sending) return;

    setState(() => _sending = true);
    try {
      await ref.read(announcementsControllerProvider).addComment(
            announcementId: widget.announcementId,
            body: text,
          );
      _controller.clear();
      if (mounted) showSuccessSnackBar(context, 'Comment posted.');
    } on AnnouncementNotificationException {
      // Comment was posted; only push notification delivery failed.
      _controller.clear();
      if (mounted) {
        ScaffoldMessenger.of(context).showSnackBar(
          const SnackBar(
            content: Text('Comment posted, but notifications may not have been sent.'),
          ),
        );
      }
    } catch (e) {
      if (mounted) {
        ScaffoldMessenger.of(context).showSnackBar(
          SnackBar(content: Text('Failed to post comment: $e')),
        );
      }
    } finally {
      if (mounted) setState(() => _sending = false);
    }
  }

  @override
  Widget build(BuildContext context) {
    final commentsAsync =
        ref.watch(announcementCommentsProvider(widget.announcementId));
    final profiles = ref.watch(profilesProvider).valueOrNull ?? [];
    final cs = Theme.of(context).colorScheme;
    final tt = Theme.of(context).textTheme;
    final currentUserId = ref.watch(currentUserIdProvider);

    return Column(
      mainAxisSize: MainAxisSize.min,
      crossAxisAlignment: CrossAxisAlignment.start,
      children: [
        Divider(height: 1, color: cs.outlineVariant.withValues(alpha: 0.5)),
        commentsAsync.when(
          loading: () => const Padding(
            padding: EdgeInsets.all(16),
            child: Center(child: CircularProgressIndicator(strokeWidth: 2)),
          ),
          error: (e, _) => Padding(
            padding: const EdgeInsets.all(16),
            child: Text('Error loading comments',
                style: tt.bodySmall?.copyWith(color: cs.error)),
          ),
          data: (comments) => comments.isEmpty
              ? Padding(
                  padding: const EdgeInsets.symmetric(
                      horizontal: 16, vertical: 12),
                  child: Text(
                    'No comments yet',
                    style: tt.bodySmall
                        ?.copyWith(color: cs.onSurfaceVariant),
                  ),
                )
              : ListView.separated(
                  shrinkWrap: true,
                  physics: const NeverScrollableScrollPhysics(),
                  padding:
                      const EdgeInsets.symmetric(horizontal: 16, vertical: 8),
                  itemCount: comments.length,
                  separatorBuilder: (_, _) => const SizedBox(height: 8),
                  itemBuilder: (context, index) {
                    final comment = comments[index];
                    return _CommentTile(
                      comment: comment,
                      profiles: profiles,
                      currentUserId: currentUserId,
                      onDelete: () async {
                        await ref
                            .read(announcementsControllerProvider)
                            .deleteComment(comment.id);
                      },
                    );
                  },
                ),
        ),
        // Input row
        Padding(
          padding: const EdgeInsets.fromLTRB(16, 4, 16, 12),
          child: Row(
            crossAxisAlignment: CrossAxisAlignment.end,
            children: [
              Expanded(
                child: TextField(
                  controller: _controller,
                  maxLines: null,
                  minLines: 1,
                  keyboardType: TextInputType.multiline,
                  textInputAction: TextInputAction.newline,
                  decoration: InputDecoration(
                    hintText: 'Write a comment...',
                    isDense: true,
                    contentPadding: const EdgeInsets.symmetric(
                        horizontal: 12, vertical: 10),
                    border: OutlineInputBorder(
                      borderRadius: BorderRadius.circular(12),
                      borderSide: BorderSide(color: cs.outlineVariant),
                    ),
                  ),
                  style: tt.bodyMedium,
                ),
              ),
              const SizedBox(width: 8),
              IconButton(
                onPressed: _sending ? null : _submit,
                icon: _sending
                    ? const SizedBox(
                        width: 20,
                        height: 20,
                        child:
                            CircularProgressIndicator(strokeWidth: 2),
                      )
                    : Icon(Icons.send, color: cs.primary),
                tooltip: 'Send',
              ),
            ],
          ),
        ),
      ],
    );
  }
}

class _CommentTile extends StatelessWidget {
  const _CommentTile({
    required this.comment,
    required this.profiles,
    required this.currentUserId,
    required this.onDelete,
  });

  final AnnouncementComment comment;
  final List profiles;
  final String? currentUserId;
  final VoidCallback onDelete;

  @override
  Widget build(BuildContext context) {
    final cs = Theme.of(context).colorScheme;
    final tt = Theme.of(context).textTheme;

    // Resolve author name
    String authorName = 'Unknown';
    String? avatarUrl;
    for (final p in profiles) {
      if (p.id == comment.authorId) {
        authorName = p.fullName;
        avatarUrl = p.avatarUrl;
        break;
      }
    }

    final isOwn = comment.authorId == currentUserId;

    return Row(
      crossAxisAlignment: CrossAxisAlignment.start,
      children: [
        ProfileAvatar(fullName: authorName, avatarUrl: avatarUrl, radius: 14),
        const SizedBox(width: 8),
        Expanded(
          child: Column(
            crossAxisAlignment: CrossAxisAlignment.start,
            children: [
              Row(
                children: [
                  Flexible(
                    child: Text(
                      authorName,
                      style: tt.labelMedium
                          ?.copyWith(fontWeight: FontWeight.w600),
                      overflow: TextOverflow.ellipsis,
                    ),
                  ),
                  const SizedBox(width: 8),
                  Flexible(
                    child: Text(
                      _relativeTime(comment.createdAt),
                      style: tt.labelSmall
                          ?.copyWith(color: cs.onSurfaceVariant),
                      overflow: TextOverflow.ellipsis,
                    ),
                  ),
                ],
              ),
              const SizedBox(height: 2),
              Text(comment.body, style: tt.bodySmall),
            ],
          ),
        ),
        if (isOwn)
          IconButton(
            icon: Icon(Icons.close, size: 16, color: cs.onSurfaceVariant),
            onPressed: onDelete,
            tooltip: 'Delete',
            visualDensity: VisualDensity.compact,
            padding: EdgeInsets.zero,
            constraints: const BoxConstraints(minWidth: 28, minHeight: 28),
          ),
      ],
    );
  }
}

String _relativeTime(DateTime dt) {
  final now = AppTime.now();
  final diff = now.difference(dt);
  if (diff.inMinutes < 1) return 'just now';
  if (diff.inMinutes < 60) return '${diff.inMinutes}m ago';
  if (diff.inHours < 24) return '${diff.inHours}h ago';
  if (diff.inDays < 7) return '${diff.inDays}d ago';
  return AppTime.formatDate(dt);
}