'use client';

import { useEffect, useMemo, useState } from 'react';
import { MessageSquare, Send, Trash2 } from 'lucide-react';
import { useAuthStore } from '@/stores/useAuthStore';
import { useCommentStore, commentKey } from '@/stores/useCommentStore';
import { useMemberStore } from '@/stores/useMemberStore';
import { extractMentionNames, mergeMentionMemberIds } from '@/lib/comment-mentions';
import { formatDateTime } from '@/lib/format';

export type CommentEntityType = 'dev_task' | 'test_case' | 'bug' | 'requirement' | 'version_plan';

interface Props {
  entityType: CommentEntityType;
  entityId: string;
  entityVersionId?: string | null;
  productId?: string | null;
  projectId?: string | null;
  versionId?: string | null;
  readOnly?: boolean;
}

export function CommentPanel({ entityType, entityId, entityVersionId, productId, projectId, versionId, readOnly = false }: Props) {
  const user = useAuthStore((s) => s.user);
  const { members, fetchMembers } = useMemberStore();
  const { commentsByKey, fetchComments, createComment, deleteComment } = useCommentStore();
  const [content, setContent] = useState('');
  const [selectedIds, setSelectedIds] = useState<string[]>([]);
  const key = commentKey(entityType, entityId);
  const comments = commentsByKey[key] ?? [];

  useEffect(() => {
    void fetchComments(entityType, entityId).catch(() => {});
    void fetchMembers().catch(() => {});
  }, [entityId, entityType, fetchComments, fetchMembers]);

  const mentionNames = useMemo(() => extractMentionNames(content), [content]);
  const mentionMemberIds = useMemo(() => mergeMentionMemberIds({
    content,
    explicitMemberIds: selectedIds,
    members: members.map((member) => ({ id: member.id, name: member.name })),
  }), [content, members, selectedIds]);

  const submit = async () => {
    if (readOnly || !user?.id || !content.trim()) return;
    await createComment({
      actorId: user.id,
      entityType,
      entityId,
      entityVersionId,
      productId,
      projectId,
      versionId,
      content: content.trim(),
      mentionMemberIds,
    });
    setContent('');
    setSelectedIds([]);
  };

  const toggleMember = (id: string) => {
    setSelectedIds((current) => current.includes(id) ? current.filter((item) => item !== id) : [...current, id]);
  };

  return (
    <div className="rounded-lg border border-[var(--line)] bg-[var(--bg-card)] p-4">
      <div className="mb-3 flex items-center gap-1.5 text-[10px] uppercase tracking-wide text-[var(--ink-muted)]">
        <MessageSquare className="h-3 w-3" /> 评论
      </div>
      <div className="space-y-3">
        {comments.length === 0 ? (
          <p className="text-[12px] text-[var(--ink-muted)]">暂无评论</p>
        ) : (
          comments.map((comment) => {
            const author = members.find((member) => member.id === comment.authorId)?.name ?? comment.authorId;
            return (
              <div key={comment.id} className="rounded-md bg-[var(--bg-subtle)] px-3 py-2">
                <div className="mb-1 flex items-center gap-2">
                  <span className="text-[12px] font-medium text-[var(--ink)]">{author}</span>
                  <span className="text-[10px] tabular-nums text-[var(--ink-muted)]">{formatDateTime(comment.createdAt)}</span>
                  {!readOnly && user?.id === comment.authorId && (
                    <button onClick={() => deleteComment(entityType, entityId, comment.id, user.id).catch(() => {})} className="ml-auto rounded p-1 text-[var(--ink-muted)] hover:bg-red-50 hover:text-red-600" title="删除评论">
                      <Trash2 className="h-3 w-3" />
                    </button>
                  )}
                </div>
                <p className="whitespace-pre-wrap text-[12px] leading-5 text-[var(--ink-soft)]">{comment.content}</p>
              </div>
            );
          })
        )}
      </div>

      {!readOnly && (
        <div className="mt-3 space-y-2 border-t border-[var(--line)] pt-3">
          <textarea
            value={content}
            onChange={(event) => setContent(event.target.value)}
            rows={3}
            placeholder="写评论，输入 @成员名 可提及"
            className="w-full resize-none rounded-lg border border-[var(--line)] bg-[var(--bg)] px-3 py-2 text-[12px] leading-5 focus:border-[var(--accent)] focus:outline-none"
          />
          <div className="flex flex-wrap gap-1.5">
            {members.slice(0, 8).map((member) => (
              <button
                key={member.id}
                onClick={() => toggleMember(member.id)}
                className={`h-6 rounded-md border px-2 text-[11px] ${selectedIds.includes(member.id) ? 'border-blue-300 bg-blue-50 text-blue-700' : 'border-[var(--line)] text-[var(--ink-muted)] hover:bg-[var(--bg-subtle)]'}`}
              >
                @{member.name}
              </button>
            ))}
          </div>
          <div className="flex items-center justify-between">
            <span className="text-[10px] text-[var(--ink-muted)]">
              {mentionNames.length > 0 || selectedIds.length > 0 ? `将通知 ${mentionMemberIds.length} 人` : '未提及成员'}
            </span>
            <button onClick={submit} disabled={!content.trim() || !user?.id} className="inline-flex h-8 items-center gap-1.5 rounded-lg bg-[var(--accent)] px-3 text-[12px] font-medium text-white disabled:opacity-50">
              <Send className="h-3 w-3" /> 发送
            </button>
          </div>
        </div>
      )}
    </div>
  );
}