const nest = require('depnest')
const getAvatar = require('ssb-avatar')
const ref = require('ssb-ref')

exports.needs = nest({
  'sbot.async.get': 'first',
  'sbot.pull.links': 'first',
  'keys.sync.id': 'first'
})
exports.gives = nest('message.async.name')

// needs an async version

exports.create = function (api) {
  return nest('message.async.name', function (id, cb) {
    if (!ref.isLink(id)) throw new Error('an id must be specified')
    var fallbackName = id.substring(0, 10) + '...'
    api.sbot.async.get(id, function (err, value) {
      if (err && err.name === 'NotFoundError') {
        return cb(null, fallbackName + '...(missing)')
      } else if (value.content.type === 'post' && typeof value.content.text === 'string') {
        if (value.content.text.trim()) {
          return cb(null, titleFromMarkdown(value.content.text, 40) || fallbackName)
        }
      } else if (typeof value.content.text === 'string') {
        return cb(null, value.content.type + ': ' + titleFromMarkdown(value.content.text, 30))
      } else {
        getAboutName(id, cb)
      }

      return cb(null, fallbackName)
    })
  })

  function getAboutName (id, cb) {
    getAvatar({
      links: api.sbot.pull.links,
      get: api.sbot.async.get
    }, api.keys.sync.id(), id, function (_, avatar) {
      cb(null, avatar && avatar.name || id.substring(0, 10) + '...')
    })
  }
}

function titleFromMarkdown (text, max) {
  text = text.trim().split('\n', 3).join('\n')
  text = text.replace(/_|`|\*|\#|^\[@.*?\]|\[|\]|\(\S*?\)/g, '').trim()
  text = text.replace(/\:$/, '')
  text = text.trim().split('\n', 1)[0].trim()
  if (text.length > max) {
    text = text.substring(0, max - 2) + '...'
  }
  return text
}