/**
 * @fileoverview Link component for rendering <a> tags in Markdown.
 * Extracted from the main markdown renderer for modularity.
 * Handles special rendering for "abbr:" type links for interactive chat actions.
 */
import * as React from 'react'
import { useChatContext } from '@/app/components/base/chat/chat/context'
import { isValidUrl } from './utils'

const filePreviewPathPattern = /\/files\/[^/?#]+\/file-preview(?:[?#]|$)/
const asAttachmentParamPattern = /[?&]as_attachment=/

const withFilePreviewAttachment = (href: string) => {
  if (!filePreviewPathPattern.test(href) || asAttachmentParamPattern.test(href)) return href

  const url = new URL(href, 'http://dify.local')
  url.searchParams.set('as_attachment', 'true')

  return href.startsWith('//') ? url.href.replace(url.protocol, '') : url.href
}

const Link = ({ node, children, ...props }: any) => {
  const { onSend } = useChatContext()
  const commonClassName = 'cursor-pointer underline decoration-primary-700! decoration-dashed'
  if (node.properties?.href && node.properties.href?.toString().startsWith('abbr')) {
    const hidden_text = decodeURIComponent(node.properties.href.toString().split('abbr:')[1])

    return (
      <abbr
        className={commonClassName}
        onClick={() => onSend?.(hidden_text)}
        title={node.children[0]?.value || ''}
      >
        {node.children[0]?.value || ''}
      </abbr>
    )
  } else {
    const rawHref = props.href || node.properties?.href
    const href = rawHref?.toString()
    if (href && /^#[\w-]+$/.test(href)) {
      const handleClick = (e: React.MouseEvent<HTMLAnchorElement>) => {
        e.preventDefault()
        // scroll to target element if exists within the answer container
        const answerContainer = e.currentTarget.closest('.chat-answer-container')

        if (answerContainer) {
          const targetId = CSS.escape(href.toString().substring(1))
          const targetElement = answerContainer.querySelector(`[id="${targetId}"]`)
          if (targetElement) targetElement.scrollIntoView({ behavior: 'smooth' })
        }
      }
      return (
        <a href={href} onClick={handleClick} className={commonClassName}>
          {children || 'ScrollView'}
        </a>
      )
    }

    if (!href || !isValidUrl(href)) return <span>{children}</span>

    return (
      <a
        href={withFilePreviewAttachment(href)}
        target="_blank"
        rel="noopener noreferrer"
        className={commonClassName}
      >
        {children || 'Download'}
      </a>
    )
  }
}

export default Link