import ReactMarkdown from 'react-markdown'
import remarkGfm from 'remark-gfm'
import rehypeHighlight from 'rehype-highlight'
import { cn } from '@/lib/utils'

/** Markdown 渲染组件:支持 GFM(表格/列表/删除线)+ 代码高亮。

 * 用于 AI 回复的富文本展示,替代纯 whitespace-pre-wrap。
 * 流式输出时传入 streaming=true 显示光标。
 */
export function Markdown({
  content,
  streaming,
  className,
}: {
  content: string
  streaming?: boolean
  className?: string
}) {
  return (
    <div
      className={cn(
        'prose prose-sm max-w-none dark:prose-invert',
        // 继承父级文字色,不被 prose 默认色覆盖
        'prose-headings:text-foreground prose-p:text-foreground prose-li:text-foreground',
        'prose-strong:text-foreground prose-a:text-primary',
        // 紧凑间距
        'prose-headings:my-2 prose-headings:first:mt-0 prose-p:my-2',
        'prose-ul:my-2 prose-ol:my-2 prose-li:my-0.5',
        'prose-pre:my-3 prose-code:before:content-none prose-code:after:content-none',
        'prose-table:my-3 prose-th:px-2 prose-th:py-1 prose-td:px-2 prose-td:py-1',
        className,
      )}
    >
      <ReactMarkdown
        remarkPlugins={[remarkGfm]}
        rehypePlugins={[rehypeHighlight]}
        components={{
          // 代码块:圆角 + 暗色背景
          pre: ({ children, ...props }) => (
            <pre
              className="rounded-lg bg-slate-900 p-3 text-xs text-slate-100 overflow-x-auto"
              {...props}
            >
              {children}
            </pre>
          ),
          // 行内代码:浅灰背景
          code: ({ children, className, ...props }) => {
            const isInline = !className?.includes('language-')
            if (isInline) {
              return (
                <code
                  className="rounded bg-muted px-1 py-0.5 text-xs font-mono"
                  {...props}
                >
                  {children}
                </code>
              )
            }
            return (
              <code className={className} {...props}>
                {children}
              </code>
            )
          },
          // 表格:外层包裹 overflow-x-auto 防止小屏溢出
          table: ({ children, ...props }) => (
            <div className="overflow-x-auto">
              <table
                className="w-full min-w-full border-collapse border text-xs"
                {...props}
              >
                {children}
              </table>
            </div>
          ),
          th: ({ children, ...props }) => (
            <th
              className="border bg-muted/50 font-semibold text-left"
              {...props}
            >
              {children}
            </th>
          ),
          td: ({ children, ...props }) => (
            <td className="border" {...props}>
              {children}
            </td>
          ),
          // 链接:新标签打开
          a: ({ children, href, ...props }) => (
            <a
              href={href}
              target="_blank"
              rel="noopener noreferrer"
              className="text-primary underline underline-offset-2"
              {...props}
            >
              {children}
            </a>
          ),
        }}
      >
        {content + (streaming && content && !content.endsWith('\n') ? '\n' : '')}
      </ReactMarkdown>
      {streaming && (
        <span className="ml-0.5 inline-block h-4 w-0.5 animate-pulse bg-current align-text-bottom" aria-hidden />
      )}
    </div>
  )
}