import type { InsertResult } from '@admin/utils/editor/insert-result'
import type { EditorView } from '@codemirror/view'
import { findHighlightSpanRange } from '@admin/utils/editor/find-highlight-span-range'
import { HIGHLIGHT_SPAN_PATTERN } from '@admin/utils/editor/highlight-span-pattern'

export function removeHighlightSpanAtCursor(
  view: EditorView | null,
  currentValue: string
): InsertResult {
  if (!view) {
    return {
      newValue: currentValue,
      newCursorPos: currentValue.length
    }
  }

  const markdown = view.state.doc.toString()
  const { from, to } = view.state.selection.main
  const selected = markdown.slice(from, to)
  HIGHLIGHT_SPAN_PATTERN.lastIndex = 0
  const unwrappedSelected = selected.replace(HIGHLIGHT_SPAN_PATTERN, '$1')

  if (selected && selected !== unwrappedSelected) {
    view.dispatch({
      changes: { from, to, insert: unwrappedSelected },
      selection: { anchor: from + unwrappedSelected.length }
    })

    return {
      newValue: markdown.slice(0, from) + unwrappedSelected + markdown.slice(to),
      newCursorPos: from + unwrappedSelected.length
    }
  }

  const highlightRange = findHighlightSpanRange(markdown, from, to)
  if (!highlightRange) {
    return {
      newValue: markdown,
      newCursorPos: to
    }
  }

  view.dispatch({
    changes: {
      from: highlightRange.start,
      to: highlightRange.end,
      insert: highlightRange.text
    },
    selection: { anchor: highlightRange.start + highlightRange.text.length }
  })

  return {
    newValue:
      markdown.slice(0, highlightRange.start) +
      highlightRange.text +
      markdown.slice(highlightRange.end),
    newCursorPos: highlightRange.start + highlightRange.text.length
  }
}