import { createLineData, useDocument } from '@terrace/core'
import { createStringReader } from '@terrace/core/readers/js-string'

export const SYMBOLS = {
  TAIL: Symbol('TAIL'),
  UNMATCHED: Symbol('UNMATCHED')
}

export const BASE_MACROS = {
  // string ({ line }) {
  //   return tail(line).toString()
  // },
  // number ({ line }) {
  //   const num = +tail(line)
  //   if (isNaN(num) || line === '') return
  //   return num
  // },
  // primitive (args) {
  //   const num = macros.number(args)
  //   return num !== undefined ? num : macros.string(args)
  // },
  // any (args) {
  //   const macro = args.macros[args.head]
  //   if (macro) return macro(args)
  //   const numResult = args.macros.number(args)
  //   if (numResult !== undefined) return numResult
  //   args.tail = args.line
  //   return args.macros.string(args)
  // },
  // scope ({ addScope, head, tail, line }, definition) {
  //   return addScope({ definition, head, tail, line })
  // }
}

export function getTail(key, macro) {
  return args => {
    const scope = args.scope
    const result = macro(args)
    if (result === undefined) return
    if (!scope[key]) scope[key] = []
    scope[key].push(result)
  }
}

export function getText(key, macro) {
  return (args) => {
    const scope = args.scope
    const result = macro({...args, tail: args.line })
    if (result === undefined) return
    if (!scope[key]) scope[key] = []
    scope[key].push(result)
  }
}

export function getUnmatched(macro) {
  return (args) => {
    const key = args.head
    const scope = args.scope
    const result = macro(args)
    if (result === undefined) return
    if (!scope[key]) scope[key] = []
    scope[key].push(result)
  }
}

export function isMacro (macro) {
  return (args) => args.macros[macro](args)
}

export function isCollection (macro) {
  return (args) => ({ [args.head]: macro(args) })
}

export function isScope (definition) {
  return (args) => args.macros.scope(args, definition)
}

export async function parse(lines, schema) {
  const doc = useDocument(createStringReader(lines))

  const macros = schema.macros
  const scopes = [[]]

  function addScope() {
    const scope = []
    scopes[scopes.length] = scope
    return scope
  }

  let ended = false
  let lastLevel = 0
  while (!ended) {
    ended = await doc.next()
    if (ended) break;
    const level = doc.level()
    const scope = scopes[level] || []
    scopes.length = level + 1

    let entry = [doc.line()]

    Object.keys(schema.root).forEach(key => {
      if (entry[0] === key || entry[0].startsWith(`${key} `)) {
        entry = schema.root[key]({ entry, macros })
      }
    })

    if (!scopes[level]) {
      scopes[level] = scope
      scopes[level - 1].at(-1)[1] = scopes[level]
    }
    scope.push(entry)

    if (lastLevel == level) {
      console.log('DECREASE: ', doc.line(), scope)
    }

    lastLevel = level
  }

  return scopes[0]
}