'use strict'

var xtend = require('xtend')
var entities = require('stringify-entities')

module.exports = serializeComment

// See: <https://html.spec.whatwg.org/multipage/syntax.html#comments>
var breakout = /^>|^->|<!--|-->|--!>|<!-$/g
var subset = ['<', '>']
var bogusSubset = ['>']

function serializeComment(ctx, node) {
  var value = node.value

  if (ctx.bogusComments) {
    return (
      '<?' + entities(value, xtend(ctx.entities, {subset: bogusSubset})) + '>'
    )
  }

  return '<!--' + value.replace(breakout, encode) + '-->'

  function encode($0) {
    return entities($0, xtend(ctx.entities, {subset: subset}))
  }
}