'use strict'

var assert = require('assert')
var codes = require('../character/codes.js')
var markdownLineEnding = require('../character/markdown-line-ending.js')
var markdownSpace = require('../character/markdown-space.js')
var constants = require('../constant/constants.js')
var types = require('../constant/types.js')
var factorySpace = require('./factory-space.js')

function _interopDefaultLegacy(e) {
  return e && typeof e === 'object' && 'default' in e ? e : {default: e}
}

var assert__default = /*#__PURE__*/ _interopDefaultLegacy(assert)

var thematicBreak = {
  name: 'thematicBreak',
  tokenize: tokenizeThematicBreak
}

function tokenizeThematicBreak(effects, ok, nok) {
  var size = 0
  var marker

  return start

  function start(code) {
    assert__default['default'](
      code === codes.asterisk ||
        code === codes.dash ||
        code === codes.underscore,
      'expected `*`, `-`, or `_`'
    )

    effects.enter(types.thematicBreak)
    marker = code
    return atBreak(code)
  }

  function atBreak(code) {
    if (code === marker) {
      effects.enter(types.thematicBreakSequence)
      return sequence(code)
    }

    if (markdownSpace(code)) {
      return factorySpace(effects, atBreak, types.whitespace)(code)
    }

    if (
      size < constants.thematicBreakMarkerCountMin ||
      (code !== codes.eof && !markdownLineEnding(code))
    ) {
      return nok(code)
    }

    effects.exit(types.thematicBreak)
    return ok(code)
  }

  function sequence(code) {
    if (code === marker) {
      effects.consume(code)
      size++
      return sequence
    }

    effects.exit(types.thematicBreakSequence)
    return atBreak(code)
  }
}

module.exports = thematicBreak