import { Tree, TreeCursor } from '@lezer/common'
import { assertNever } from '#utils/utils'
import { type Value, fromValue } from 'reefvm'

export const treeToString = (tree: Tree, input: string): string => {
  const lines: string[] = []

  const addNode = (cursor: TreeCursor, depth: number) => {
    if (!cursor.name) return

    const indent = '  '.repeat(depth)
    const text = input.slice(cursor.from, cursor.to)
    const nodeName = cursor.name // Save the node name before moving cursor

    if (cursor.firstChild()) {
      lines.push(`${indent}${nodeName}`)
      do {
        addNode(cursor, depth + 1)
      } while (cursor.nextSibling())
      cursor.parent()
    } else {
      const cleanText = nodeName === 'String' ? text.slice(1, -1) : text
      lines.push(`${indent}${nodeName} ${cleanText}`)
    }
  }

  const cursor = tree.cursor()
  if (cursor.firstChild()) {
    do {
      addNode(cursor, 0)
    } while (cursor.nextSibling())
  }

  return lines.join('\n')
}

export const VMResultToValue = (result: Value): unknown => {
  if (result.type === 'function') return Function
  else return fromValue(result)
}