'use strict'

var alphabetical = require('is-alphabetical')
var locate = require('../locate/tag')
var tag = require('../util/html').tag

module.exports = inlineHTML
inlineHTML.locator = locate

var lessThan = '<'
var questionMark = '?'
var exclamationMark = '!'
var slash = '/'

var htmlLinkOpenExpression = /^<a /i
var htmlLinkCloseExpression = /^<\/a>/i

function inlineHTML(eat, value, silent) {
  var self = this
  var length = value.length
  var character
  var subvalue

  if (value.charAt(0) !== lessThan || length < 3) {
    return
  }

  character = value.charAt(1)

  if (
    !alphabetical(character) &&
    character !== questionMark &&
    character !== exclamationMark &&
    character !== slash
  ) {
    return
  }

  subvalue = value.match(tag)

  if (!subvalue) {
    return
  }

  /* istanbul ignore if - not used yet. */
  if (silent) {
    return true
  }

  subvalue = subvalue[0]

  if (!self.inLink && htmlLinkOpenExpression.test(subvalue)) {
    self.inLink = true
  } else if (self.inLink && htmlLinkCloseExpression.test(subvalue)) {
    self.inLink = false
  }

  return eat(subvalue)({type: 'html', value: subvalue})
}