import type { InsertResult } from '@admin/utils/editor/insert-result'
import type { EditorView } from '@codemirror/view'
import { findMarkdownLinkRange } from '@admin/utils/editor/find-markdown-link-range'

export function setMarkdownLinkAtCursor(
  view: EditorView | null,
  currentValue: string,
  url: string
): InsertResult {
  const href = url.trim()
  if (!href) {
    return {
      newValue: currentValue,
      newCursorPos: currentValue.length
    }
  }

  if (!view) {
    const linkText = href
    const markdownLink = `[${linkText}](${href})`

    return {
      newValue: currentValue + markdownLink,
      newCursorPos: currentValue.length + 1 + linkText.length
    }
  }

  const markdown = view.state.doc.toString()
  const { from, to } = view.state.selection.main
  const selected = view.state.sliceDoc(from, to)
  const existingLink = findMarkdownLinkRange(markdown, from, to)
  const linkText = existingLink?.text || selected || href
  const markdownLink = `[${linkText}](${href})`
  const replaceFrom = existingLink?.start ?? from
  const replaceTo = existingLink?.end ?? to
  const nextCursorPos = replaceFrom + 1 + linkText.length

  view.dispatch({
    changes: { from: replaceFrom, to: replaceTo, insert: markdownLink },
    selection: {
      anchor: replaceFrom + 1,
      head: nextCursorPos
    }
  })

  return {
    newValue: markdown.slice(0, replaceFrom) + markdownLink + markdown.slice(replaceTo),
    newCursorPos: nextCursorPos
  }
}