TO_REGEXP = /^to:\s+/i
REPLY_REGEXP = /^inreplyto:\s+/i
ATTACH_REGEXP = /^attach:\s+/i
URL_REGEXP = %r{\Ahttps?://\S+\Z}
MENTION_REGEXP = /\A@\w+@\S+\Z/
HASHTAG_REGEXP = /\A#\w+\Z/
# COMMENT_REGEXP = /^<!*--/

post '/create' do
  protected!
  request.body.rewind # in case someone already read it

  to = []
  inReplyTo = ''
  content = []
  tag = []
  attachment = []

  request.body.read.each_line do |line|
    line.chomp!
    case line
    when /^<!--$/
      next
    when /^-->$/
      next
    when TO_REGEXP
      line.sub(TO_REGEXP, '').split(/\s+/).each do |word|
        case word
        when 'public'
          to += ['https://www.w3.org/ns/activitystreams#Public', FOLLOWERS_URL]
        when MENTION_REGEXP
          to << actor(word)
        when URL_REGEXP
          to << word
        end
      end
    when REPLY_REGEXP
      inReplyTo = line.sub(REPLY_REGEXP, '')
    when ATTACH_REGEXP
      url, description = line.sub(ATTACH_REGEXP, '').split(/\s+/, 2)
      attachment << {
        'type' => 'Document',
        'mediaType' => media_type(url),
        'url' => url,
        'name' => description
      }
    else # create links
      # single quotes in html invalidate digest, reason unknown
      line.split(/\s+/).each do |word|
        word = word.gsub('<p>', '').gsub('</p>', '')
        case word
        when HASHTAG_REGEXP
          tag_url = File.join('https://social.pdp8.info', 'tags', word.sub('#', ''))
          tag << {
            'type' => 'Hashtag',
            'href' => tag_url,
            'name' => word
          }
        when MENTION_REGEXP
          actor = actor(word)
          tag << {
            'type' => 'Mention',
            'href' => actor,
            'name' => word
          }
        end
      end
      content << line
    end
  end

  # https://docs.joinmastodon.org/spec/activitypub/#Mention
  if to.size == 1 # mastodon DM
    m = {
      'type' => 'Mention',
      'href' => to[0],
      'name' => mention(to[0])
    }
    tag << m unless tag.include? m
  end

  object = {
    'to' => to,
    'type' => 'Note',
    'attributedTo' => ACTOR,
    'content' => "#{content.join(' ')}"
  }
  object['inReplyTo'] = inReplyTo unless inReplyTo.empty?
  object['attachment'] = attachment unless attachment.empty?
  object['tag'] = tag unless tag.empty?
  # p to
  # jj object

  create_activity 'Create', object, to

  200
end