// Author: fruit.com.cn
// 评论楼中楼：展开回复、继续加载，没有下一页时给出结束提示。

import 'package:flutter/material.dart';

import '../../../core/data/models/comment.dart';
import '../../../core/data/services/comment_controller.dart';
import '../../../core/theme/app_colors.dart';
import '../../../l10n/app_localizations.dart';
import 'comment_tile.dart';

const double _replyIndent = 52;

/// 一条评论及其回复。
class CommentThread extends StatelessWidget {
  const CommentThread({
    super.key,
    required this.comment,
    required this.controller,
    required this.handlers,
  });

  final DramaComment comment;
  final CommentController controller;
  final CommentInteractionHandlers handlers;

  @override
  Widget build(BuildContext context) {
    final replies = controller.repliesFor(comment.id);
    final expanded = controller.repliesExpanded(comment.id);
    return Column(
      crossAxisAlignment: CrossAxisAlignment.start,
      children: [
        CommentTile(comment: comment, handlers: handlers),
        if (comment.replyCount > 0 || replies.isNotEmpty) _toggle(context, expanded),
        if (expanded) _replies(context, replies),
      ],
    );
  }

  Widget _toggle(BuildContext context, bool expanded) {
    final l10n = AppLocalizations.of(context)!;
    return Padding(
      padding: const EdgeInsets.only(left: _replyIndent, bottom: 4),
      child: TextButton(
        key: Key('comment-replies-${comment.id}'),
        onPressed: () => _toggleReplies(context),
        style: TextButton.styleFrom(
          foregroundColor: AppColors.muted,
          padding: EdgeInsets.zero,
          minimumSize: const Size(0, 24),
          tapTargetSize: MaterialTapTargetSize.shrinkWrap,
        ),
        child: Row(
          mainAxisSize: MainAxisSize.min,
          children: [
            Container(width: 16, height: 1, color: AppColors.border),
            const SizedBox(width: 8),
            Text(
              expanded ? l10n.hideReplies : l10n.viewReplies(comment.replyCount),
              style: const TextStyle(
                color: AppColors.muted,
                fontSize: 12,
                fontWeight: FontWeight.w400,
              ),
            ),
            const SizedBox(width: 4),
            Icon(
              expanded
                  ? Icons.keyboard_arrow_up_rounded
                  : Icons.keyboard_arrow_down_rounded,
              size: 14,
              color: AppColors.muted,
            ),
          ],
        ),
      ),
    );
  }

  Widget _replies(BuildContext context, List<DramaComment> replies) {
    final l10n = AppLocalizations.of(context)!;
    return Padding(
      padding: const EdgeInsets.only(left: _replyIndent),
      child: Column(
        children: [
          if (controller.repliesLoading(comment.id))
            const Padding(
              padding: EdgeInsets.symmetric(vertical: 8),
              child: CircularProgressIndicator(),
            ),
          for (final reply in replies)
            CommentTile(comment: reply, handlers: handlers, isReply: true),
          if (controller.repliesHasMore(comment.id))
            TextButton(
              onPressed: () => controller.loadMoreReplies(comment.id),
              child: Text(l10n.loadMore),
            )
          else if (replies.isNotEmpty)
            Padding(
              padding: const EdgeInsets.symmetric(vertical: 8),
              child: Text(
                l10n.noMoreItems,
                style: const TextStyle(color: AppColors.textHint, fontSize: 12),
              ),
            ),
        ],
      ),
    );
  }

  Future<void> _toggleReplies(BuildContext context) async {
    if (controller.repliesExpanded(comment.id)) {
      controller.hideReplies(comment.id);
      return;
    }
    await controller.loadReplies(comment.id);
  }
}